Clarify module package documentation

README.md

@@ -1,10 +1,10 @@
 # weatherreporter
 
 `weatherreporter` is a Go application for preparing human-facing weather
-reports from normalized forecast data. It builds structured briefing packages,
-runs them through `scriptorium`, and keeps inspectable artifacts under a local
-workspace. It can also upload successfully generated managed Markdown reports
-to a configured `distributor` HTTP upload endpoint.
+reports from normalized forecast data. It builds JSON module snapshots, passes
+YAML prompt data packages to `scriptorium`, and keeps inspectable artifacts
+under a local workspace. It can also upload successfully generated managed
+Markdown reports to a configured `distributor` HTTP upload endpoint.
 
 ## Quickstart
 

docs/cli.md

@@ -1,7 +1,7 @@
 # Weatherreporter CLI
 
 `weatherreporter` generates Markdown weather reports, runs scheduled report
-batches, and inspects previously generated artifacts.
+batches, and inspects stored artifacts.
 
 ## Shortest Useful Command
 
@@ -28,17 +28,17 @@ weatherreporter run morning [--config PATH] [--units VALUE] [--tz NAME] [--out-d
 weatherreporter run evening [--config PATH] [--units VALUE] [--tz NAME] [--out-dir PATH]
 weatherreporter inspect reports [--config PATH] [--limit N]
 weatherreporter inspect metadata [--config PATH] RUN_ID
-weatherreporter inspect briefing [--config PATH] RUN_ID
+weatherreporter inspect modules [--config PATH] RUN_ID
 weatherreporter inspect data-package [--config PATH] RUN_ID
 weatherreporter inspect prior [--config PATH] RUN_ID
 weatherreporter inspect sources [--config PATH] RUN_ID
 ```
 
-`generate` commands write briefing, data package, preflight, report, and
-metadata artifacts under the configured workspace. `--out` writes an extra
-Markdown copy for the operator; distributor notification uses the managed
-report path, not the extra copy. `generate storm` requires explicit
-event-window bounds with `--start` and `--end`.
+`generate` commands write a JSON module snapshot, YAML data package, preflight
+artifact, managed Markdown report, and metadata under the configured workspace.
+`--out` writes an extra Markdown copy for the operator; distributor
+notification uses the managed report path, not the extra copy. `generate storm`
+requires explicit event-window bounds with `--start` and `--end`.
 
 `run morning` generates Daily Today and the 3-Day Outlook, plus Weekend Outlook
 except on Sunday. `run evening` generates the Tomorrow Planning Brief. Batch
@@ -88,14 +88,15 @@ weatherreporter run evening --out-dir ./reports
 ```sh
 weatherreporter inspect reports --limit 10
 weatherreporter inspect metadata 20260529T100000.000000000Z_daily_today
-weatherreporter inspect briefing 20260529T100000.000000000Z_daily_today
+weatherreporter inspect modules 20260529T100000.000000000Z_daily_today
 weatherreporter inspect data-package 20260529T100000.000000000Z_daily_today
 weatherreporter inspect prior 20260529T100000.000000000Z_daily_today
 weatherreporter inspect sources 20260529T100000.000000000Z_daily_today
 ```
 
 `inspect reports` lists recent generated runs with artifact paths and source
-warning counts. The other inspect commands require a RunID. `inspect prior`
+warning counts. The other inspect commands require a RunID. `inspect modules`
+returns the persisted ordered module snapshot for a run. `inspect prior`
 returns the prior comparable snapshot metadata selected from stored metadata, or
 `null` when none exists. `inspect sources` shows source provenance and source
 warnings without dumping full weather payloads.

docs/config.md

@@ -16,9 +16,9 @@ Precedence is:
 2. configuration file
 3. built-in defaults
 
-The implemented configuration overrides are `--units` and `--tz`. Output flags
-control report copies for the current command but do not change configuration
-files. Environment variables do not override configuration fields.
+The CLI configuration overrides are `--units` and `--tz`. Output flags control
+report copies for the current command but do not change configuration files.
+Environment variables do not override configuration fields.
 
 ## Minimal Config
 
@@ -53,7 +53,7 @@ Timezone values may be IANA names, configured aliases such as `Chicago` and
 
 ### `location`
 
-`location` is descriptive prompt context included in briefing metadata and
+`location` is descriptive prompt context included in module metadata and
 Scriptorium data packages. It does not select a Weather API endpoint or enable
 multiple configured forecast locations.
 
@@ -143,7 +143,7 @@ stub source slots use the missing-source policy.
 ### `workspace`
 
 - `root`: workspace root for managed artifacts. Default: `workspace`.
-- `snapshots_dir`: briefing and metadata directory under `workspace.root`. Default: `snapshots`.
+- `snapshots_dir`: module snapshot and metadata directory under `workspace.root`. Default: `snapshots`.
 - `reports_dir`: managed Markdown report directory under `workspace.root`. Default: `reports`.
 - `data_packages_dir`: prompt input package directory under `workspace.root`. Default: `data-packages`.
 - `preflight_dir`: Scriptorium render output directory under `workspace.root`. Default: `preflight`.
@@ -171,9 +171,47 @@ midday, afternoon, and evening.
 - `wind_gust_miles_per_hour`: wind gust change threshold. Default: `10`.
 - `precip_timing_shift_minutes`: precipitation timing shift threshold. Default: `120`.
 
-Recent Changes are added to prompt input when a prior comparable briefing
+Recent Changes are added to prompt input when a prior comparable module
 snapshot exists and a threshold is crossed.
 
+### `reports`
+
+`reports` optionally overrides the ordered deterministic modules declared by
+report definitions. Omit a report entry to use its default module order.
+
+Supported report keys are `daily`, `tomorrow`, `three_day`, `weekend`, and
+`storm`. Canonical report IDs such as `daily_today` and `daily_tomorrow` are
+also accepted.
+
+Each report entry supports:
+
+- `deterministic_modules`: ordered module list. Entries may be string module
+  IDs or objects with `id` and optional `options`.
+
+Example:
+
+```yaml
+reports:
+  daily:
+    deterministic_modules:
+      - metadata
+      - current_conditions
+      - id: area_forecast_discussion
+        options:
+          sections:
+            - short_term
+```
+
+Unknown reports, unknown modules, duplicate modules, incompatible report/module
+combinations, duplicate stanza names, and invalid options fail config loading.
+`area_forecast_discussion.options.sections` may contain `product`,
+`key_messages`, `short_term`, and `long_term`. Empty or omitted `sections`
+includes all available AFD sections.
+
+The module registry accepts all module IDs documented in
+[Module Contract Internals](internal/module.md). Modules without builders are
+valid in composition but do not emit YAML stanzas.
+
 ## Secrets
 
 Configuration files should not contain raw secrets. Use `secrets.directory` to
@@ -189,6 +227,6 @@ notification, this allows a file such as
 - [examples/minimal-config.yml](../examples/minimal-config.yml): smallest
   useful config for generation and fetching.
 - [examples/config.yml](../examples/config.yml): production-oriented config
-  covering implemented fields.
+  covering maintained fields.
 
 Both example files are loaded by the config test suite.

docs/integrations/scriptorium.md

@@ -30,8 +30,9 @@ scriptorium run \
 ```
 
 `weatherreporter` always passes prompt input as
-`--input data_package=<path>`. The data package is structured JSON created by
-`internal/promptinput`.
+`--input data_package=<path>`. The data package is structured YAML created by
+`internal/promptinput`; module snapshots remain separate JSON artifacts for
+inspection and Recent Changes.
 
 ## Configured Arguments
 

docs/integrations/weatherapi.md

@@ -6,7 +6,7 @@ This document describes the external Weather API contract used by
 ## Purpose
 
 `weatherreporter` uses a configured Weather API base URL to fetch normalized
-weather source data and assemble a `forecast.Bundle`. This is an integration
+weather source data and assemble a `weatherdata.Bundle`. This is an integration
 contract for the project adapter, not a complete public API reference for the
 upstream service.
 
@@ -45,8 +45,7 @@ they fail the fetch; optional malformed sources follow the missing-source policy
 
 The adapter sends these query parameters:
 
-- `format`: from `weather_api.format`; the implemented configuration requires
-  `json`
+- `format`: from `weather_api.format`; configuration validation requires `json`
 - `units`: from `weather_api.units`
 - `precision`: from `weather_api.precision` on observations, current
   conditions, hourly forecast, and narrative forecast requests

docs/internal/app-orchestration.md

@@ -1,15 +1,15 @@
 # App Orchestration Internals
 
-This document describes the implemented workflow coordinator in `internal/app`.
+This document describes the workflow coordinator in `internal/app`.
 
 ## Purpose
 
 `internal/app` coordinates the top-level use cases after CLI parsing and config
 loading are complete. It resolves report definitions, fetches weather data,
-builds briefing and prompt-input artifacts, invokes Scriptorium through the
-adapter boundary, optionally notifies distributor through an app-owned notifier
-boundary, persists managed state, runs batches, and reads existing artifacts for
-inspection.
+builds collected and derived facts, builds module snapshots and prompt-input
+artifacts, invokes Scriptorium through the adapter boundary, optionally
+notifies distributor through an app-owned notifier boundary, persists managed
+state, runs batches, and reads existing artifacts for inspection.
 
 ## Inputs And Outputs
 
@@ -18,32 +18,32 @@ Inputs:
 - `GenerateRequest` for one report command
 - `BatchRequest` for morning or evening batch commands
 - `FetchBundleRequest` for explicit bundle fetch and save workflows
-- `BriefingRequest` and `ReportRequest` for package-level orchestration tests
-  and internal composition
+- `ReportRequest` for single-report generation
 - resolved report definitions from `internal/report`
-- forecast bundles from `internal/adapters/weatherapi`
+- weather data bundles from `internal/adapters/weatherapi`
 - prior snapshots loaded from `internal/state`
 - optional renderer, notifier, and state-store fakes for tests
 
 Outputs:
 
-- generated report results with briefing, data package, preflight, report,
-  metadata, prior snapshot, Recent Changes, Scriptorium result details, and
-  notification result when attempted
+- generated report results with JSON module snapshot, YAML data package,
+  preflight, report, metadata, prior snapshot, Recent Changes, Scriptorium
+  result details, and notification result when attempted
 - batch summaries with per-report status, artifact paths, error text, and
   notification outcome when attempted
 - saved Weather API bundle JSON for fetch workflows
-- inspection JSON values for reports, metadata, briefings, data packages, prior
-  snapshots, and source provenance
+- inspection JSON values for reports, metadata, module snapshots, data
+  packages, prior snapshots, and source provenance
 
 ## Boundaries
 
 `internal/app` owns workflow order and request composition. It does not parse
-CLI flags, load YAML files directly, implement HTTP transport, derive forecast
-facts, define report periods, compare rendered Markdown, or construct
-Scriptorium argv.
+CLI flags, load YAML files directly, implement HTTP transport, own fact
+derivation algorithms, define report periods, compare rendered Markdown, or
+construct Scriptorium argv.
 
 Report selection and report identity policy come from `internal/report`.
+Collected and derived fact contracts come from `internal/facts`.
 Weather API transport stays in `internal/adapters/weatherapi`. Scriptorium
 subprocess behavior stays in `internal/adapters/scriptorium`. Distributor
 upload behavior stays in `internal/adapters/distributor`. Filesystem layout and
@@ -51,7 +51,7 @@ persisted metadata stay in `internal/state`.
 
 ## Config Fields Used
 
-- `weather_api.*` for Weather API client construction and briefing metadata
+- `weather_api.*` for Weather API client construction and module metadata
 - `scriptorium.*` for renderer construction
 - `workspace.*` for filesystem state
 - `dayparts` for daily and outlook summarization
@@ -69,10 +69,10 @@ Single-report generation follows this order:
 2. Create or use a filesystem store.
 3. Locate any prior compatible snapshot through `internal/state`.
 4. Fetch a Weather API bundle.
-5. Build a report-specific briefing package.
-6. Save the briefing snapshot.
-7. Compute Recent Changes from structured prior and current briefings.
-8. Build and save the Scriptorium `data_package`.
+5. Build collected and derived facts once.
+6. Execute configured modules and save the module snapshot.
+7. Compute Recent Changes from structured prior and current module snapshots.
+8. Build and save the YAML Scriptorium `data_package`.
 9. Run Scriptorium render preflight.
 10. Save preflight JSON when a render result is available.
 11. Save metadata for inspection.
@@ -88,7 +88,8 @@ If render preflight returns both a result and an error, preflight JSON and
 metadata are persisted before the error is returned. If Scriptorium report
 generation returns an error after writing output, the managed report and
 metadata remain inspectable. Notification is not attempted after Weather API,
-briefing, prompt input, render, Scriptorium run, or metadata-save failures.
+module snapshot, prompt input, render, Scriptorium run, or metadata-save
+failures.
 When notification is attempted, the debug artifact records request identity,
 including rendered pipeline ID, bundle paths, accepted upload fields,
 distributor status fields, raw status report JSON when available, and redacted
@@ -117,7 +118,8 @@ inspection view.
 ## Failure Behavior
 
 - Resolve errors stop the requested workflow before fetching weather data.
-- Weather API and briefing errors stop that report before Scriptorium runs.
+- Weather API and module execution errors stop that report before Scriptorium
+  runs.
 - Prompt input validation fails before render preflight.
 - Render and run errors preserve Scriptorium stderr and exit-code context.
 - Notification errors are wrapped with report ID, RunID, and managed report path
@@ -140,7 +142,7 @@ Inspect:
 - Generated reports use the same app request and result types regardless of
   report ID.
 - Render preflight precedes Scriptorium report generation.
-- Recent Changes are computed from structured briefing snapshots.
+- Recent Changes are computed from structured module snapshots.
 - Metadata links artifacts produced for a run.
 - Distributor notification maps the managed Markdown report path to configured
   bundle paths; extra output copies are not upload sources.

docs/internal/briefing.md

@@ -1,47 +1,60 @@
-# Briefing Internals
+# Module Builder Internals
 
-This document describes the implemented briefing package boundary.
+This document describes module builder behavior in `internal/briefing`.
 
 ## Purpose
 
-`internal/briefing` builds structured report-specific briefing packages from
-resolved report metadata, forecast bundles, and derived forecast summaries.
-Briefings are curated inputs for prompt data packages, not rendered report
-prose.
+`internal/briefing` turns report metadata, collected weather data, and derived
+forecast facts into prompt-facing module outputs. The package also owns the
+module registry used to validate report composition and config overrides.
+
+Module outputs are structured prompt inputs. They are not rendered report prose
+and they are not persisted by this package.
 
 ## Inputs And Outputs
 
 Inputs:
 
 - resolved report definition, generation time, timezone, and valid period
-- forecast bundle with source provenance and warnings
-- derived daily or period summaries where required
+- collected facts built from `weatherdata.Bundle`
+- derived daily, daypart, precipitation, alert, and storm-window facts where
+  required
 - configured units, timezone, and descriptive location context
+- typed module options from report defaults or config overrides
 
 Outputs:
 
-- `briefing.Package` with common metadata and one report-specific content
-  object for Daily, 3-Day, Weekend, or Storm Report
-- optional `currentConditions` prompt context from normalized
-  `/conditions/current` data when available
-- optional structured `weatherStory` context on report-specific briefing
-  objects when `/weatherstories/latest` is available
-- optional JSON file written by `briefing.Save`
+- `ModuleDefinition` values with module ID, stanza name, option type,
+  supported reports, fact requirements, missing-data behavior, and builder
+- `module.Output` values for source-oriented stanzas:
+  `metadata`, `current_conditions`, `alert_digest`,
+  `area_forecast_discussion`, and `weather_story`
+- `module.Output` values for derived stanzas:
+  `derived_daily_summary`, `derived_daypart_summaries`, `precip_timing`,
+  `outdoor_windows`, and `tomorrow_planning`
+
+The registry also contains accepted composition entries for modules that do not
+emit stanzas until a builder exists. App orchestration skips those entries when
+constructing snapshots.
 
 ## Boundaries
 
-- This package selects and shapes weather facts for prompts.
-- It does not fetch weather data, compare prior snapshots, build
-  `data_package` files, invoke Scriptorium, or write workflow metadata.
+- This package selects and shapes already-collected weather facts for prompts.
+- It validates module composition against report compatibility and option
+  types.
+- It does not fetch weather data, compare prior snapshots, write module
+  snapshots, build YAML data packages, invoke Scriptorium, or write workflow
+  metadata.
 
 ## Config Fields Used
 
-The package receives configured units and timezone from the app layer. Daypart
-configuration is consumed by `internal/forecast` before briefing builders run.
-Configured `location` values are prompt context only; Weather API
+The app layer passes effective units, timezone, and location context into the
+module context. `internal/facts` consumes daypart configuration before module
+builders run. Configured `location` values are prompt context only; Weather API
 `sourceLocationId` and `sourceLocation` remain source provenance.
-Current conditions are copied from the normalized `/conditions/current` bundle
-source only; observation station and timestamp fields remain provenance.
+
+`area_forecast_discussion` uses optional `sections` configuration to include a
+subset of discussion fields.
 
 ## External Adapters Used
 
@@ -49,39 +62,40 @@ None directly.
 
 ## State Or Manifest Behavior
 
-`briefing.Save` writes briefing JSON atomically. Managed workspace placement is
-owned by `internal/state`.
+None. `internal/app` collects module outputs into a `module.Snapshot`, and
+`internal/state` persists that snapshot.
 
 ## Skip And Resume Behavior
 
-None. Builders either return a complete briefing package or an error.
+None. Builders either emit a module output, omit optional unavailable data, or
+return an error for invalid required inputs.
 
 ## Failure Behavior
 
-- Daily briefing construction requires a Daily report definition and derived
-  daily summary.
-- 3-Day briefing construction requires a 3-Day report definition and at least
-  one derived summary.
-- Weekend briefing construction requires a Weekend report definition and at
-  least one derived summary.
-- Storm briefing construction requires a Storm Report definition and forecast
-  bundle.
-- Save failures include path and operation context.
+- Required derived modules return errors when their dependent facts are not
+  available.
+- Module registry construction rejects duplicate module IDs and duplicate
+  stanza names.
+- Composition validation rejects unknown modules, duplicate modules,
+  incompatible report/module combinations, duplicate stanza names, and invalid
+  option shapes.
+- Source-oriented module builders omit missing optional current conditions,
+  forecast discussion, and weather story stanzas.
+- Alert digest output distinguishes checked empty alert data from missing alert
+  source data.
 
 ## Tests
 
 Inspect:
 
-- `internal/briefing/daily_test.go`
-- `internal/briefing/three_day_test.go`
-- `internal/briefing/weekend_test.go`
-- `internal/briefing/storm_test.go`
+- `internal/briefing/base_modules_test.go`
+- `internal/briefing/derived_modules_test.go`
+- `internal/briefing/modules_test.go`
 - `internal/app/app_test.go`
 
 ## Invariants
 
-- Briefings contain structured weather facts and source context.
+- Module outputs contain structured weather facts and source context.
 - Common metadata includes RunID, report ID, prompt ID, valid period, source
   provenance, source hashes, source warnings, and configured prompt location.
-- LLM prompt input packaging and Scriptorium execution remain outside this
-  boundary.
+- Prompt input packaging and Scriptorium execution remain outside this package.

docs/internal/changes.md

@@ -4,15 +4,15 @@ This document describes structured Recent Changes comparison.
 
 ## Purpose
 
-`internal/changes` compares current and prior briefing packages and emits
+`internal/changes` compares current and prior module snapshots and emits
 compact change records for prompt input data packages.
 
 ## Inputs And Outputs
 
 Inputs:
 
-- prior briefing package
-- current briefing package
+- prior module snapshot
+- current module snapshot
 - comparison thresholds from configuration
 
 Outputs:
@@ -22,7 +22,7 @@ Outputs:
 
 ## Boundaries
 
-- This package compares structured briefing data only.
+- This package compares structured module snapshot data only.
 - It does not read filesystem state, find prior snapshots, render Markdown,
   invoke Scriptorium, or compare generated report text.
 
@@ -41,7 +41,7 @@ None.
 
 ## State Or Manifest Behavior
 
-None directly. The app loads prior briefing snapshots through `internal/state`
+None directly. The app loads prior module snapshots through `internal/state`
 before calling comparison functions.
 
 ## Skip And Resume Behavior
@@ -51,11 +51,12 @@ empty Recent Changes list without calling a comparison function.
 
 ## Failure Behavior
 
-- Daily comparison requires both inputs to contain Daily briefing content.
-- 3-Day comparison requires both inputs to contain 3-Day briefing content.
-- Weekend comparison requires both inputs to contain Weekend briefing content.
-- Storm Report currently has no comparison implementation, so the app leaves
-  Recent Changes empty for Storm reports.
+- Daily comparison requires `derived_daily_summary` and
+  `derived_daypart_summaries` stanzas. It also uses `alert_digest` and
+  `precip_timing` when present.
+- 3-Day comparison requires `derived_daypart_summaries`.
+- Weekend comparison requires `derived_daypart_summaries`.
+- Storm Report comparison returns no changes.
 
 ## Tests
 

docs/internal/facts.md

@@ -0,0 +1,72 @@
+# Fact Contracts Internals
+
+This document describes the fact contract boundary.
+
+## Purpose
+
+`internal/facts` separates normalized upstream facts collected for a report run
+from conservative report-scoped facts derived from them. The package gives app
+orchestration one place to build reusable facts before module execution.
+
+## Inputs And Outputs
+
+Inputs:
+
+- `weatherdata.Bundle` from the Weather API adapter
+- resolved report definition and valid period
+- report timezone
+- configured daypart definitions
+
+Outputs:
+
+- `facts.CollectedFacts` with normalized source facts plus separate source
+  provenance and warnings
+- `facts.DerivedFacts` with valid-period forecast slices, alert overlaps,
+  daily summaries, daypart summaries, and Storm Report window summary
+
+## Boundaries
+
+- This package owns fact assembly and reusable deterministic derivation for a
+  report run.
+- It does not fetch upstream data, build prompt wording, compare prior
+  snapshots, write workflow state, invoke Scriptorium, or define modules.
+
+## Config Fields Used
+
+- `dayparts[].name`
+- `dayparts[].start`
+- `dayparts[].end`
+- `weather_api.timezone`
+
+## External Adapters Used
+
+None directly. Collected facts are built from `weatherdata.Bundle`.
+
+## State Or Manifest Behavior
+
+None. Source provenance and warnings remain data fields for downstream metadata
+and inspection.
+
+## Failure Behavior
+
+- Invalid or missing report valid periods return an error.
+- Invalid timezone names return an error.
+- Missing required hourly forecast data returns the underlying forecast
+  derivation error for reports that require daily summaries.
+- Missing optional narrative, alert, discussion, daily, or weather story data
+  produces empty or nil derived fields.
+
+## Tests
+
+Inspect:
+
+- `internal/facts/facts_test.go`
+- `internal/app/app_test.go`
+
+## Invariants
+
+- Collected facts are built once from a fetched bundle.
+- Derived facts are scoped to one resolved report.
+- Source provenance and warnings stay separate from ordinary fact fields.
+- Prompt-specific wording and one-off presentation decisions stay outside this
+  package.

docs/internal/forecast-derivation.md

@@ -5,14 +5,14 @@ This document describes deterministic forecast summarization in
 
 ## Purpose
 
-`internal/forecast` converts normalized bundle data into daily and period
-summaries used by briefing builders.
+`internal/forecast` converts normalized weather data into daily and period
+summaries used by fact builders and module builders.
 
 ## Inputs And Outputs
 
 Inputs:
 
-- `forecast.Bundle`
+- `weatherdata.Bundle`
 - local date or resolved report period
 - timezone
 - configured daypart definitions
@@ -43,12 +43,12 @@ configuration.
 
 ## External Adapters Used
 
-None directly. Forecast data arrives through `forecast.Bundle`.
+None directly. Forecast data arrives through `weatherdata.Bundle`.
 
 ## State Or Manifest Behavior
 
 None. Source warnings and provenance from the bundle are carried into summaries
-for later metadata and briefing output.
+for later metadata and module output.
 
 ## Skip And Resume Behavior
 

docs/internal/module.md

@@ -0,0 +1,102 @@
+# Module Contract Internals
+
+This document describes the module contract in `internal/module`.
+
+## Purpose
+
+`internal/module` defines the shared identifiers and data envelopes used for
+prompt-facing modules. Report definitions use module IDs for composition,
+module builders produce outputs with stanza names, prompt input packages consume
+snapshots, and Recent Changes compares snapshot stanzas.
+
+## Inputs And Outputs
+
+Inputs:
+
+- ordered `module.ConfigItem` values from report definitions or config
+  overrides
+- `module.Output` values produced by module builders
+
+Outputs:
+
+- stable `module.ID` constants
+- typed option structs for registered modules
+- `module.Snapshot` with schema version `weatherreporter.modules.v1`
+- ordered snapshot outputs with module ID, stanza name, and typed value
+- typed stanza lookup through `module.StanzaValue`
+
+## Registered Module IDs
+
+The registry recognizes these IDs:
+
+- `metadata`
+- `current_conditions`
+- `derived_daily_summary`
+- `derived_daypart_summaries`
+- `hourly_table`
+- `precip_timing`
+- `alert_digest`
+- `area_forecast_discussion`
+- `weather_story`
+- `forecast_delta`
+- `outdoor_windows`
+- `tomorrow_planning`
+- `weekend_planning`
+- `storm_window_summary`
+
+Modules with builders emit stanzas into module snapshots. Registered modules
+without builders are valid composition entries but do not emit snapshot stanzas.
+That keeps report composition declarations centralized while limiting prompt
+packages to data the application builds.
+
+## Options
+
+Most modules use an empty options struct. `area_forecast_discussion` accepts:
+
+```yaml
+sections:
+  - product
+  - key_messages
+  - short_term
+  - long_term
+```
+
+An omitted or empty `sections` list includes all available discussion sections.
+Invalid option shapes fail during config normalization or composition
+validation.
+
+## Boundaries
+
+- This package owns module identifiers, config item envelopes, output
+  envelopes, snapshot validation, and typed stanza lookup.
+- It does not define report IDs, execute builders, fetch weather data, derive
+  forecast facts, write state, or invoke Scriptorium.
+
+## State Or Manifest Behavior
+
+`module.Snapshot` values are persisted by `internal/state` as JSON. Snapshot
+validation rejects missing schema version, missing module IDs, missing stanza
+names, duplicate module outputs, and duplicate stanza names while preserving
+output order.
+
+## Failure Behavior
+
+- Snapshot construction fails for duplicate module outputs or duplicate stanza
+  names.
+- Typed stanza lookup returns `found=false` for missing stanzas.
+- Typed stanza lookup wraps JSON marshal/decode failures with stanza context.
+
+## Tests
+
+Inspect:
+
+- `internal/module/module_test.go`
+- `internal/briefing/modules_test.go`
+- `internal/report/period_test.go`
+
+## Invariants
+
+- `internal/module` does not import `internal/report`.
+- Module IDs are stable strings.
+- Each emitted module output has exactly one stanza name and one typed value.
+- Snapshot output order is caller-owned and preserved.

docs/internal/prompt-input.md

@@ -1,40 +1,64 @@
 # Prompt Input Internals
 
-This document describes prompt input data package construction.
+This document describes YAML prompt data package construction in
+`internal/promptinput`.
 
 ## Purpose
 
-`internal/promptinput` converts a structured briefing package and optional
-Recent Changes into the `data_package` JSON passed to Scriptorium prompts.
+`internal/promptinput` converts report metadata, an ordered module snapshot,
+Recent Changes, and source warnings into the `data_package` file passed to
+Scriptorium.
+
+The persisted data package is YAML with schema version
+`weatherreporter.data_package.v2`. It is separate from the JSON module snapshot
+used for inspection and comparison.
 
 ## Inputs And Outputs
 
 Inputs:
 
-- `briefing.Package`
+- report metadata from app/state orchestration
+- `module.Snapshot`
 - optional `[]changes.Change`
 
 Outputs:
 
-- `promptinput.Package` containing schema version, RunID, report metadata,
-  briefing content, Recent Changes, and source warnings. Briefing content
-  includes configured location context, current conditions when available,
-  structured weather story context when available, discussion key messages, and
-  short/long-term AFD narratives when the Weather API provides them.
-- report metadata includes `currentLocalDate`, the generation date formatted as
-  `YYYY-MM-DD` in the effective report timezone.
-- optional JSON file written by `promptinput.Save`
+- `promptinput.Package` with schema version, RunID, report metadata, named
+  module stanzas, Recent Changes, and source warnings
+- YAML bytes from `promptinput.MarshalYAML`
+- YAML file written atomically by `promptinput.Save`
+
+The YAML shape includes:
+
+```yaml
+schema_version: weatherreporter.data_package.v2
+run_id: <run_id>
+report:
+  id: <report_id>
+  prompt_id: <prompt_id>
+briefing:
+  metadata: {}
+  current_conditions: {}
+recent_changes:
+  items: []
+```
+
+The `briefing` mapping contains named module stanzas. Stanza order follows the
+module snapshot output order.
 
 ## Boundaries
 
-- This package owns the prompt input schema and validation.
-- It does not fetch weather data, derive forecast summaries, find prior
-  snapshots, compare changes, or invoke Scriptorium.
+- This package owns prompt package schema, YAML marshaling, YAML loading, and
+  validation.
+- It does not fetch weather data, derive forecast summaries, execute modules,
+  find prior snapshots, compare changes, choose artifact paths, or invoke
+  Scriptorium.
 
 ## Config Fields Used
 
-None directly. Config-derived values, including timezone and prompt location
-context, are already present in briefing metadata before this package runs.
+None directly. Config-derived values such as timezone, units, and prompt
+location are already present in report metadata and module stanzas before this
+package runs.
 
 ## External Adapters Used
 
@@ -42,7 +66,7 @@ None.
 
 ## State Or Manifest Behavior
 
-`promptinput.Save` writes JSON atomically. Managed workspace paths are owned by
+`promptinput.Save` writes YAML atomically. Managed workspace paths are owned by
 `internal/state`.
 
 ## Skip And Resume Behavior
@@ -51,9 +75,10 @@ None. Recent Changes is always present as an `items` list and may be empty.
 
 ## Failure Behavior
 
-Validation fails before render preflight when required top-level or briefing
-metadata fields are missing or inconsistent, or when no report content is
-present. Save failures include filesystem operation and path context.
+Validation fails before render preflight when required top-level fields are
+missing or inconsistent, when the valid period is invalid, or when no module
+stanzas are present. Save failures include filesystem operation and path
+context.
 
 ## Tests
 
@@ -64,6 +89,7 @@ Inspect:
 
 ## Invariants
 
-- Scriptorium receives structured `data_package` JSON.
-- Briefing metadata and top-level report metadata must agree.
-- Recent Changes are not inferred from rendered report text.
+- Scriptorium receives structured YAML through `--input data_package=<path>`.
+- Module stanza order is deterministic for generated snapshots.
+- Recent Changes are provided by `internal/changes`; this package does not
+  infer changes from rendered report text.

docs/internal/report-registry.md

@@ -7,8 +7,8 @@ membership, output naming, artifact grouping, and comparison declarations in
 ## Purpose
 
 `internal/report` is the canonical source for report definitions. App, state,
-briefing, and CLI wiring consume resolved definitions instead of owning report
-identity policy themselves.
+module building, and CLI wiring consume resolved definitions instead of owning
+report identity policy themselves.
 
 ## Definition Fields
 
@@ -23,8 +23,9 @@ Each report definition declares:
 - generated-report eligibility
 - prior-report compatibility list
 - morning or evening batch membership
+- default ordered module composition
 
-## Implemented Reports
+## Reports
 
 | Report | ID | Prompt | Artifact group | Batch copy | Prior compatibility |
 | --- | --- | --- | --- | --- | --- |
@@ -34,7 +35,7 @@ Each report definition declares:
 | Weekend Outlook | `weekend` | `weather.weekend_outlook` | `weekend` | `weekend.md` | Weekend Outlook |
 | Storm Report | `storm` | `weather.storm_report` | `storm` | `storm.md` | Storm Report |
 
-All implemented report definitions are eligible for generation.
+All report definitions are eligible for generation.
 
 ## Valid Periods
 
@@ -54,8 +55,8 @@ must be after start time.
 ## Boundaries
 
 `internal/report` defines report metadata and time coverage. It does not fetch
-weather data, build briefings, compare briefing contents, write state, parse CLI
-flags, or invoke Scriptorium.
+weather data, build module values, compare snapshot contents, write state,
+parse CLI flags, or invoke Scriptorium.
 
 The CLI owns public command names. The app maps those command names to report
 IDs, then uses the registry for report policy.
@@ -70,6 +71,7 @@ output path copying uses batch output names from report definitions.
 - State paths use `ArtifactGroup`.
 - Batch output copies use `BatchOutputName`.
 - Generation checks `Generated`.
+- Module composition defaults use `Modules`.
 - Prior lookup checks `CompatiblePriorIDs` and the comparison strategy.
 - RunIDs include the resolved report ID.
 
@@ -93,5 +95,5 @@ Inspect:
 - Daily Today and Daily Tomorrow both use `weather.daily_report`.
 - Valid periods are half-open intervals independent of rendered report text.
 - Artifact grouping, batch output filenames, generated-report eligibility,
-  comparison compatibility, and comparison strategy are declared by report
-  definition.
+  default module composition, comparison compatibility, and comparison strategy
+  are declared by report definition.

docs/internal/scriptorium-adapter.md

@@ -15,7 +15,7 @@ from app and domain packages.
 Inputs:
 
 - prompt ID
-- prompt input data package path
+- YAML prompt input data package path
 - report output path for `run`
 - configured binary, config path, profile, timeout, and extra arguments
 - context for cancellation
@@ -96,5 +96,6 @@ Inspect:
 
 - No shell interpolation is used.
 - The Scriptorium input name is `data_package`.
+- The file at the data package path is YAML produced by `internal/promptinput`.
 - Render and run preserve command-specific result structs.
 - Scriptorium-specific flags stay inside adapter and config boundaries.

docs/internal/state.md

@@ -13,7 +13,7 @@ Inputs:
 
 - workspace configuration
 - resolved report definition and valid period
-- briefing package
+- module snapshot
 - prompt input data package
 - preflight artifact
 - rendered report path preparation request
@@ -21,20 +21,20 @@ Inputs:
 
 Outputs:
 
-- briefing snapshot JSON path
-- prompt input data package JSON path
+- module snapshot JSON path
+- prompt input data package YAML path
 - render preflight JSON path
 - managed Markdown report path
 - metadata JSON path
 - prior comparable snapshot metadata
-- loaded briefing or data package
+- loaded module snapshot or data package
 - recent report records for inspection
 
 ## Boundaries
 
 `internal/state` owns local filesystem layout, path validation, durable writes,
 metadata reads, prior lookup, and report listing. It does not fetch weather
-data, derive forecasts, build prompt input content, compare briefing contents,
+data, derive forecasts, build prompt input content, compare module contents,
 invoke Scriptorium, import adapter result types, or parse CLI flags.
 
 Preflight persistence uses the state-owned `PreflightArtifact` shape. The app
@@ -55,19 +55,19 @@ Workspace subdirectories must be relative paths that stay under
 ## Managed Layout
 
 Paths are derived from the resolved report definition's artifact group, the
-valid-period start date for JSON artifacts, and the RunID.
+valid-period start date for dated artifacts, and the RunID.
 
 ```text
 <workspace.root>/
-  snapshots/<artifact_group>/<YYYY-MM-DD>/<run_id>.briefing.json
+  snapshots/<artifact_group>/<YYYY-MM-DD>/<run_id>.modules.json
   snapshots/<artifact_group>/<YYYY-MM-DD>/<run_id>.metadata.json
-  data-packages/<artifact_group>/<YYYY-MM-DD>/<run_id>.data_package.json
+  data-packages/<artifact_group>/<YYYY-MM-DD>/<run_id>.data_package.yaml
   preflight/<artifact_group>/<YYYY-MM-DD>/<run_id>.render.json
   notifications/<artifact_group>/<YYYY-MM-DD>/<run_id>.distributor.json
   reports/<artifact_group>/<run_id>.md
 ```
 
-Metadata is stored beside briefing snapshots and links the briefing, data
+Metadata is stored beside module snapshots and links the module snapshot, data
 package, preflight, report paths, notification path when attempted, and
 configured prompt location. Report listing walks metadata files under the
 snapshots directory.
@@ -84,8 +84,8 @@ current report definition.
   date.
 - Weekend Outlook compares with prior Weekend snapshots for the same weekend
   window.
-- Storm Report currently has no prior lookup because explicit event-window
-  comparison is not searched by the filesystem store.
+- Storm Report has no prior lookup because explicit event-window comparison is
+  not searched by the filesystem store.
 
 ## Writes And Inspection
 
@@ -97,9 +97,9 @@ notification is attempted and include rendered distributor pipeline ID, bundle
 ID, idempotency key, bundle paths, upload status, latest run status, and
 redacted errors.
 
-Inspection helpers read existing metadata, briefing, and data package files.
-Missing metadata directories return no inspection records or no prior snapshot
-rather than creating state.
+Inspection helpers read existing metadata, module snapshot, and data package
+files. Missing metadata directories return no inspection records or no prior
+snapshot rather than creating state.
 
 ## Failure Behavior
 

docs/internal/weather-data.md

@@ -1,12 +1,12 @@
 # Weather Data Internals
 
-This document describes Weather API ingestion into `forecast.Bundle`.
+This document describes Weather API ingestion into `weatherdata.Bundle`.
 
 ## Purpose
 
 `internal/adapters/weatherapi` fetches normalized weather data from one
 configured Weather API endpoint and assembles the bundle consumed by forecast
-derivation and briefing builders. Briefing builders expose normalized current
+derivation and module builders. Module builders expose normalized current
 conditions and weather story context when those sources are available.
 
 ## Inputs And Outputs
@@ -19,7 +19,7 @@ Inputs:
 
 Outputs:
 
-- `forecast.Bundle` with observation, current conditions, hourly forecast,
+- `weatherdata.Bundle` with observation, current conditions, hourly forecast,
   narrative forecast, active alerts, discussion, latest weather story, source
   records, and source warnings
 - stub source record for the daily forecast source slot
@@ -29,7 +29,7 @@ Outputs:
 
 - The adapter owns HTTP calls, response-envelope handling, source hashing, and
   decoding into internal bundle types.
-- It does not derive dayparts, resolve report periods, build briefings, compare
+- It does not derive dayparts, resolve report periods, build module values, compare
   snapshots, write report state, or invoke Scriptorium.
 
 ## Config Fields Used

docs/operations.md

@@ -1,12 +1,12 @@
 # Weatherreporter Operations
 
 This guide covers normal operation, generated artifacts, inspection, recovery,
-and current operational caveats. For symptom-specific diagnosis, see
+and operational caveats. For symptom-specific diagnosis, see
 [Troubleshooting](troubleshooting.md).
 
 ## Normal Workflow
 
-Implemented generation commands:
+Generation commands:
 
 ```text
 weatherreporter generate daily --date 2026-05-29
@@ -17,14 +17,15 @@ weatherreporter generate storm --start 2026-05-29T18:00 --end 2026-05-30T06:00
 ```
 
 Each command resolves a report period, fetches a Weather API bundle, builds a
-briefing, builds a prompt input data package, runs `scriptorium render`, runs
-`scriptorium run`, and writes managed artifacts under the configured workspace.
+JSON module snapshot, builds a YAML prompt input data package, runs
+`scriptorium render`, runs `scriptorium run`, and writes managed artifacts under
+the configured workspace.
 When distributor notification is enabled, weatherreporter uploads the managed
 Markdown report after `scriptorium run` succeeds and final metadata is saved.
 `--out PATH` writes an extra Markdown copy for the current generated report; it
 is not used as the distributor upload source.
 
-Implemented batch commands:
+Batch commands:
 
 ```text
 weatherreporter run morning
@@ -51,33 +52,33 @@ workspace/
   snapshots/
     daily/
       YYYY-MM-DD/
-        <run_id>.briefing.json
+        <run_id>.modules.json
         <run_id>.metadata.json
     three-day/
       YYYY-MM-DD/
-        <run_id>.briefing.json
+        <run_id>.modules.json
         <run_id>.metadata.json
     weekend/
       YYYY-MM-DD/
-        <run_id>.briefing.json
+        <run_id>.modules.json
         <run_id>.metadata.json
     storm/
       YYYY-MM-DD/
-        <run_id>.briefing.json
+        <run_id>.modules.json
         <run_id>.metadata.json
   data-packages/
     daily/
       YYYY-MM-DD/
-        <run_id>.data_package.json
+        <run_id>.data_package.yaml
     three-day/
       YYYY-MM-DD/
-        <run_id>.data_package.json
+        <run_id>.data_package.yaml
     weekend/
       YYYY-MM-DD/
-        <run_id>.data_package.json
+        <run_id>.data_package.yaml
     storm/
       YYYY-MM-DD/
-        <run_id>.data_package.json
+        <run_id>.data_package.yaml
   preflight/
     daily/
       YYYY-MM-DD/
@@ -131,7 +132,7 @@ Each generated report writes metadata that links:
 - RunID, report ID, variant, and prompt ID
 - generation time, timezone, and valid period
 - source location, source hashes, and source warnings
-- briefing snapshot path
+- module snapshot path
 - prompt input data package path
 - preflight output path
 - managed Markdown report path
@@ -164,11 +165,11 @@ report generation has a distinct retry identity. The default bundle path uses
 the valid-period start date, artifact group, and RunID. Distributor owns
 destination merge, retention, and derived snapshot behavior such as `latest`.
 
-Notification happens after final metadata save. Weather API, briefing,
+Notification happens after final metadata save. Weather API, module snapshot,
 data-package, render preflight, Scriptorium run, and metadata-save failures do
-not trigger notification. A notification failure fails that report. In a batch,
-other reports continue, the failed report includes notification fields in the
-JSON summary, and the batch returns nonzero.
+not trigger notification. A notification failure fails that report.
+In a batch, other reports continue, the failed report includes notification
+fields in the JSON summary, and the batch returns nonzero.
 
 Each notification attempt writes a debug artifact under `notifications/`. The
 artifact records the rendered pipeline ID, bundle ID, idempotency key, managed
@@ -185,7 +186,7 @@ constructing a source bundle, and submitting it to the configured distributor
 HTTP endpoint. Distributor remains responsible for destination routing,
 publication, and any downstream Markdown-to-HTML transformation. Distributor
 leaves destination files alone when they are not tracked by a newly uploaded
-bundle, so previously uploaded dated report paths can remain available.
+bundle, so existing uploaded dated report paths can remain available.
 
 ## Inspection
 
@@ -195,30 +196,30 @@ They do not fetch weather data or run `scriptorium`.
 ```text
 weatherreporter inspect reports --limit 10
 weatherreporter inspect metadata RUN_ID
-weatherreporter inspect briefing RUN_ID
+weatherreporter inspect modules RUN_ID
 weatherreporter inspect data-package RUN_ID
 weatherreporter inspect prior RUN_ID
 weatherreporter inspect sources RUN_ID
 ```
 
-Use `inspect reports` to find recent RunIDs and artifact paths. Use
+Use `inspect reports` to find RunIDs and artifact paths. Use
 `inspect metadata` to see the artifact links recorded for a run. Use
-`inspect briefing` and `inspect data-package` to review the exact structured
-inputs used for rendering. Use `inspect prior` to see the prior comparable
-snapshot selected for Recent Changes, or `null` when none exists. Use
-`inspect sources` to review source provenance and warnings without dumping full
-weather payloads.
+`inspect modules` to review the persisted ordered module snapshot, and
+`inspect data-package` to review the structured prompt package used for
+rendering. Use `inspect prior` to see the prior comparable snapshot selected for
+Recent Changes, or `null` when none exists. Use `inspect sources` to review
+source provenance and warnings without dumping full weather payloads.
 
 ## Recent Changes
 
-Recent Changes are computed from structured briefing snapshots, not rendered
-Markdown text.
+Recent Changes are computed from structured module snapshots, not rendered
+Markdown or YAML text.
 
 Daily Today and Daily Tomorrow can compare with each other when they cover the
 same valid local date. 3-Day Outlook compares with prior compatible 3-Day
 snapshots for the same valid local date. Weekend Outlook compares with prior
-compatible Weekend snapshots for the same weekend window. Storm Report currently
-leaves Recent Changes empty.
+compatible Weekend snapshots for the same weekend window. Storm Report leaves
+Recent Changes empty.
 
 When no prior comparable snapshot exists, or no configured threshold is crossed,
 `recentChanges.items` is empty.
@@ -241,7 +242,7 @@ For a bad report, start with:
 ```text
 weatherreporter inspect metadata RUN_ID
 weatherreporter inspect sources RUN_ID
-weatherreporter inspect briefing RUN_ID
+weatherreporter inspect modules RUN_ID
 weatherreporter inspect data-package RUN_ID
 weatherreporter inspect prior RUN_ID
 ```

docs/policy/architecture.md

@@ -3,13 +3,13 @@
 This document defines the development principles for this Go project. It is inward-facing: developers and LLM coding agents should use it to preserve the project’s shape, boundaries, and invariants as the code evolves.
 
 ## weatherreporter
-`weatherreporter` is a deterministic weather briefing and report-preparation application. It consumes normalized weather data from the internal weatherfeeder-backed API, derives report-specific briefing packages, compares those packages against prior snapshots, and invokes an external prompt runner to produce human-facing reports.
+`weatherreporter` is a deterministic weather briefing and report-preparation application. It consumes normalized weather data from the internal weatherfeeder-backed API, derives report-specific module snapshots and prompt packages, compares module snapshots against prior runs, and invokes an external prompt runner to produce human-facing reports.
 
-The application should keep meteorological data selection, daypart grouping, threshold detection, forecast-period resolution, and recent-change comparison inside Go domain packages. LLM prompts should receive curated briefing packages rather than raw unbounded source payloads wherever practical.
+The application should keep meteorological data selection, daypart grouping, threshold detection, forecast-period resolution, and recent-change comparison inside Go domain packages. LLM prompts should receive curated module-based prompt packages rather than raw unbounded source payloads wherever practical.
 
-Report types must be defined through a registry or equivalent mechanism. Each report definition should declare its report ID, prompt ID, valid-period resolver, briefing builder, comparison strategy, and output naming behavior. Avoid scattering report-type conditionals across CLI and orchestration code.
+Report types must be defined through a registry or equivalent mechanism. Each report definition should declare its report ID, prompt ID, valid-period resolver, module composition, comparison strategy, and output naming behavior. Avoid scattering report-type conditionals across CLI and orchestration code.
 
-Generated reports must be associated with explicit metadata, including report type, location, generation time, valid period, source product timestamps or hashes, briefing snapshot path, and output path. Recent Changes must be based on structured snapshot comparison rather than comparison of rendered Markdown report text.
+Generated reports must be associated with explicit metadata, including report type, location, generation time, valid period, source product timestamps or hashes, module snapshot path, and output path. Recent Changes must be based on structured snapshot comparison rather than comparison of rendered Markdown report text.
 
 `scriptorium` is an external adapter, not domain logic. Subprocess execution must be isolated under `internal/adapters/scriptorium`, use context-aware execution, avoid shell interpolation, capture actionable stderr, and keep scriptorium-specific flags from leaking into domain packages.
 

docs/policy/development.md

@@ -16,11 +16,14 @@ Developers and LLM coding agents should use it with
 - `internal/adapters/distributor`: Distributor upload adapter.
 - `internal/adapters/weatherapi`: Weather API HTTP adapter.
 - `internal/adapters/scriptorium`: Scriptorium subprocess adapter.
-- `internal/forecast`: normalized bundle types and deterministic forecast
-  derivation.
+- `internal/weatherdata`: normalized weather source facts, source metadata, and
+  source warnings.
+- `internal/forecast`: deterministic forecast derivation.
+- `internal/facts`: collected and derived report fact contracts.
+- `internal/module`: module IDs, config items, output envelopes, and snapshots.
 - `internal/report`: report definitions, valid periods, batches, output names,
   and comparison declarations.
-- `internal/briefing`: report-specific briefing package builders.
+- `internal/briefing`: prompt-facing module value builders and module registry.
 - `internal/changes`: structured Recent Changes comparison.
 - `internal/promptinput`: Scriptorium `data_package` construction and
   validation.

docs/troubleshooting.md

@@ -195,7 +195,7 @@ Diagnostic: inspect stdout for the JSON summary and stderr for compact status
 lines.
 
 Safe fix: use the failed report's artifact paths from the summary, then inspect
-metadata, sources, briefing, and data package for that RunID.
+metadata, sources, module snapshot, and data package for that RunID.
 
 Relevant docs: [CLI reference](cli.md), [Operations guide](operations.md).
 

examples/config.yml

@@ -66,3 +66,23 @@ recent_change:
   precip_probability_points: 20
   wind_gust_miles_per_hour: 10
   precip_timing_shift_minutes: 120
+
+reports:
+  daily:
+    deterministic_modules:
+      - metadata
+      - current_conditions
+      - derived_daily_summary
+      - derived_daypart_summaries
+      - precip_timing
+      - alert_digest
+      - forecast_delta
+      - id: area_forecast_discussion
+        options:
+          sections:
+            - product
+            - key_messages
+            - short_term
+            - long_term
+      - weather_story
+      - outdoor_windows

internal/adapters/scriptorium/runner_test.go

@@ -20,7 +20,7 @@ func TestRenderConstructsCommand(t *testing.T) {
 
 	result, err := runner.Render(context.Background(), RenderRequest{
 		PromptID:        "weather.daily_report",
-		DataPackagePath: "/tmp/data_package.json",
+		DataPackagePath: "/tmp/data_package.yaml",
 	})
 	if err != nil {
 		t.Fatalf("Render() error = %v", err)
@@ -31,7 +31,7 @@ func TestRenderConstructsCommand(t *testing.T) {
 		"--config", "/etc/scriptorium.yml",
 		"--profile", "weather",
 		"--prompt", "weather.daily_report",
-		"--input", "data_package=/tmp/data_package.json",
+		"--input", "data_package=/tmp/data_package.yaml",
 		"--format", "json",
 	}
 	if commands.name != "/usr/local/bin/scriptorium" {
@@ -57,7 +57,7 @@ func TestRenderReturnsResultForNonzeroExit(t *testing.T) {
 
 	result, err := runner.Render(context.Background(), RenderRequest{
 		PromptID:        "weather.daily_report",
-		DataPackagePath: "/tmp/data_package.json",
+		DataPackagePath: "/tmp/data_package.yaml",
 	})
 	if err == nil {
 		t.Fatal("Render() error = nil, want nonzero exit error")
@@ -85,7 +85,7 @@ func TestRunConstructsCommand(t *testing.T) {
 
 	result, err := runner.Run(context.Background(), RunRequest{
 		PromptID:        "weather.daily_report",
-		DataPackagePath: "/tmp/data_package.json",
+		DataPackagePath: "/tmp/data_package.yaml",
 		OutputPath:      "/tmp/daily.md",
 	})
 	if err != nil {
@@ -97,7 +97,7 @@ func TestRunConstructsCommand(t *testing.T) {
 		"--config", "/etc/scriptorium.yml",
 		"--profile", "weather",
 		"--prompt", "weather.daily_report",
-		"--input", "data_package=/tmp/data_package.json",
+		"--input", "data_package=/tmp/data_package.yaml",
 		"--out", "/tmp/daily.md",
 	}
 	if commands.name != "/usr/local/bin/scriptorium" {
@@ -130,7 +130,7 @@ func TestRunReturnsResultForValidationExit(t *testing.T) {
 
 	result, err := runner.Run(context.Background(), RunRequest{
 		PromptID:        "weather.daily_report",
-		DataPackagePath: "/tmp/data_package.json",
+		DataPackagePath: "/tmp/data_package.yaml",
 		OutputPath:      "/tmp/daily.md",
 	})
 	if err == nil {

internal/adapters/weatherapi/client.go

@@ -1,4 +1,4 @@
-// Package weatherapi adapts the internal weather API to forecast bundles.
+// Package weatherapi adapts the internal weather API to weather data bundles.
 package weatherapi
 
 import (
@@ -18,7 +18,7 @@ import (
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/fileutil"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
 type Client struct {
@@ -83,11 +83,11 @@ func New(cfg config.Config, opts ...Option) (*Client, error) {
 	return client, nil
 }
 
-func (c *Client) FetchBundle(ctx context.Context) (*forecast.Bundle, error) {
+func (c *Client) FetchBundle(ctx context.Context) (*weatherdata.Bundle, error) {
 	fetchedAt := c.now()
 	builder := bundleBuilder{
 		client:    c,
-		bundle:    &forecast.Bundle{FetchedAt: fetchedAt},
+		bundle:    &weatherdata.Bundle{FetchedAt: fetchedAt},
 		fetchedAt: fetchedAt,
 	}
 
@@ -121,7 +121,7 @@ func (c *Client) FetchBundle(ctx context.Context) (*forecast.Bundle, error) {
 
 type bundleBuilder struct {
 	client    *Client
-	bundle    *forecast.Bundle
+	bundle    *weatherdata.Bundle
 	fetchedAt time.Time
 }
 
@@ -133,7 +133,7 @@ func (b *bundleBuilder) fetchObservation(ctx context.Context) error {
 	if raw == nil {
 		return b.handleMissing(&source, "observation data is missing", false)
 	}
-	var observation forecast.Observation
+	var observation weatherdata.Observation
 	if err := decodeSource(raw, &observation); err != nil {
 		return b.handleMalformed(&source, err, false)
 	}
@@ -151,7 +151,7 @@ func (b *bundleBuilder) fetchCurrent(ctx context.Context) error {
 	if raw == nil {
 		return b.handleMissing(&source, "current conditions data is missing", false)
 	}
-	var current forecast.Current
+	var current weatherdata.Current
 	if err := decodeSource(raw, &current); err != nil {
 		return b.handleMalformed(&source, err, false)
 	}
@@ -168,7 +168,7 @@ func (b *bundleBuilder) fetchHourly(ctx context.Context) error {
 	if raw == nil {
 		return b.handleMissing(&source, "hourly forecast data is missing", true)
 	}
-	var hourly forecast.ForecastRun
+	var hourly weatherdata.ForecastRun
 	if err := decodeSource(raw, &hourly); err != nil {
 		return fmt.Errorf("decode hourly forecast from %s: %w", source.Endpoint, err)
 	}
@@ -190,7 +190,7 @@ func (b *bundleBuilder) fetchNarrative(ctx context.Context) error {
 	if raw == nil {
 		return b.handleMissing(&source, "narrative forecast data is missing", false)
 	}
-	var narrative forecast.ForecastRun
+	var narrative weatherdata.ForecastRun
 	if err := decodeSource(raw, &narrative); err != nil {
 		return b.handleMalformed(&source, err, false)
 	}
@@ -210,11 +210,11 @@ func (b *bundleBuilder) fetchAlerts(ctx context.Context) error {
 		return b.handleMissing(&source, "active alerts data is missing", false)
 	}
 	if isJSONNull(raw) {
-		b.bundle.Alerts = &forecast.AlertRun{Raw: append(json.RawMessage(nil), raw...)}
+		b.bundle.Alerts = &weatherdata.AlertRun{Raw: append(json.RawMessage(nil), raw...)}
 		b.addSource(source)
 		return nil
 	}
-	var alerts forecast.AlertRun
+	var alerts weatherdata.AlertRun
 	if err := decodeSource(raw, &alerts); err != nil {
 		return b.handleMalformed(&source, err, false)
 	}
@@ -235,7 +235,7 @@ func (b *bundleBuilder) fetchDiscussion(ctx context.Context) error {
 	if raw == nil {
 		return b.handleMissing(&source, "forecast discussion data is missing", false)
 	}
-	var discussion forecast.Discussion
+	var discussion weatherdata.Discussion
 	if err := decodeSource(raw, &discussion); err != nil {
 		return b.handleMalformed(&source, err, false)
 	}
@@ -254,7 +254,7 @@ func (b *bundleBuilder) fetchWeatherStory(ctx context.Context) error {
 	if raw == nil {
 		return b.handleMissing(&source, "NWS weather story data is missing", false)
 	}
-	var story forecast.WeatherStory
+	var story weatherdata.WeatherStory
 	if err := decodeSource(raw, &story); err != nil {
 		return b.handleMalformed(&source, err, false)
 	}
@@ -268,7 +268,7 @@ func (b *bundleBuilder) fetchWeatherStory(ctx context.Context) error {
 }
 
 func (b *bundleBuilder) addStub(sourceName string, message string) error {
-	source := forecast.Source{
+	source := weatherdata.Source{
 		Name:      sourceName,
 		FetchedAt: b.fetchedAt,
 		Missing:   true,
@@ -276,7 +276,7 @@ func (b *bundleBuilder) addStub(sourceName string, message string) error {
 	return b.applyMissingPolicy(&source, "missing_source", message)
 }
 
-func (b *bundleBuilder) handleMissing(source *forecast.Source, message string, required bool) error {
+func (b *bundleBuilder) handleMissing(source *weatherdata.Source, message string, required bool) error {
 	source.Missing = true
 	if required {
 		return fmt.Errorf("%s from %s is required", message, source.Endpoint)
@@ -284,7 +284,7 @@ func (b *bundleBuilder) handleMissing(source *forecast.Source, message string, r
 	return b.applyMissingPolicy(source, "missing_source", message)
 }
 
-func (b *bundleBuilder) handleMalformed(source *forecast.Source, err error, required bool) error {
+func (b *bundleBuilder) handleMalformed(source *weatherdata.Source, err error, required bool) error {
 	if required {
 		return fmt.Errorf("decode %s from %s: %w", source.Name, source.Endpoint, err)
 	}
@@ -292,13 +292,13 @@ func (b *bundleBuilder) handleMalformed(source *forecast.Source, err error, requ
 	return b.applyMissingPolicy(source, "malformed_source", fmt.Sprintf("malformed %s data: %v", source.Name, err))
 }
 
-func (b *bundleBuilder) applyMissingPolicy(source *forecast.Source, code string, message string) error {
+func (b *bundleBuilder) applyMissingPolicy(source *weatherdata.Source, code string, message string) error {
 	policy := b.client.policyFor(source.Name)
 	if policy == config.MissingSourceError {
 		return fmt.Errorf("%s: %s", source.Name, message)
 	}
 	if policy == config.MissingSourceWarn {
-		warning := forecast.SourceWarning{
+		warning := weatherdata.SourceWarning{
 			Source:             source.Name,
 			Code:               code,
 			Severity:           "warning",
@@ -313,7 +313,7 @@ func (b *bundleBuilder) applyMissingPolicy(source *forecast.Source, code string,
 	return nil
 }
 
-func (b *bundleBuilder) addSource(source forecast.Source) {
+func (b *bundleBuilder) addSource(source weatherdata.Source) {
 	b.bundle.Sources = append(b.bundle.Sources, source)
 }
 
@@ -335,33 +335,33 @@ type envelope struct {
 	Data json.RawMessage `json:"data"`
 }
 
-func (c *Client) fetch(ctx context.Context, sourceName string, endpoint string, opts queryOptions) (json.RawMessage, forecast.Source, error) {
+func (c *Client) fetch(ctx context.Context, sourceName string, endpoint string, opts queryOptions) (json.RawMessage, weatherdata.Source, error) {
 	reqURL := c.endpointURL(endpoint, opts)
 	req, err := http.NewRequestWithContext(ctx, http.MethodGet, reqURL.String(), nil)
 	if err != nil {
-		return nil, forecast.Source{}, fmt.Errorf("create request for %s: %w", endpoint, err)
+		return nil, weatherdata.Source{}, fmt.Errorf("create request for %s: %w", endpoint, err)
 	}
 
 	resp, err := c.httpClient.Do(req)
 	if err != nil {
-		return nil, forecast.Source{}, fmt.Errorf("fetch %s: %w", endpoint, err)
+		return nil, weatherdata.Source{}, fmt.Errorf("fetch %s: %w", endpoint, err)
 	}
 	defer resp.Body.Close()
 
 	body, err := io.ReadAll(io.LimitReader(resp.Body, 10<<20))
 	if err != nil {
-		return nil, forecast.Source{}, fmt.Errorf("read %s response: %w", endpoint, err)
+		return nil, weatherdata.Source{}, fmt.Errorf("read %s response: %w", endpoint, err)
 	}
 	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
-		return nil, forecast.Source{}, fmt.Errorf("fetch %s: unexpected HTTP status %d: %s", endpoint, resp.StatusCode, strings.TrimSpace(string(body)))
+		return nil, weatherdata.Source{}, fmt.Errorf("fetch %s: unexpected HTTP status %d: %s", endpoint, resp.StatusCode, strings.TrimSpace(string(body)))
 	}
 
 	var env envelope
 	if err := json.Unmarshal(body, &env); err != nil {
-		return nil, forecast.Source{}, fmt.Errorf("decode %s envelope: %w", endpoint, err)
+		return nil, weatherdata.Source{}, fmt.Errorf("decode %s envelope: %w", endpoint, err)
 	}
 
-	source := forecast.Source{
+	source := weatherdata.Source{
 		Name:      sourceName,
 		Endpoint:  endpoint,
 		Query:     queryMap(reqURL.Query()),
@@ -430,7 +430,7 @@ func sourceHash(raw json.RawMessage) (string, error) {
 	return hex.EncodeToString(sum[:]), nil
 }
 
-func SaveBundle(path string, bundle *forecast.Bundle) error {
+func SaveBundle(path string, bundle *weatherdata.Bundle) error {
 	if err := fileutil.WriteJSONAtomic(path, bundle); err != nil {
 		return fmt.Errorf("save bundle: %w", err)
 	}

internal/adapters/weatherapi/client_test.go

@@ -12,7 +12,7 @@ import (
 	"time"
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
 func TestFetchBundleFromFixtures(t *testing.T) {
@@ -423,7 +423,7 @@ func containsPath(requested []string, path string) bool {
 	return false
 }
 
-func sourceByName(t *testing.T, sources []forecast.Source, name string) forecast.Source {
+func sourceByName(t *testing.T, sources []weatherdata.Source, name string) weatherdata.Source {
 	t.Helper()
 	for _, source := range sources {
 		if source.Name == name {
@@ -431,7 +431,7 @@ func sourceByName(t *testing.T, sources []forecast.Source, name string) forecast
 		}
 	}
 	t.Fatalf("source %q not found in %#v", name, sources)
-	return forecast.Source{}
+	return weatherdata.Source{}
 }
 
 func hashFixtureData(t *testing.T, fixture string) string {

internal/app/app.go

@@ -14,12 +14,15 @@ import (
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/changes"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/facts"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/fileutil"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptinput"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/state"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
 type ReportKind string
@@ -65,10 +68,14 @@ type FetchBundleRequest struct {
 	OutputPath string
 }
 
-type BriefingRequest struct {
+type ModuleSnapshotRequest struct {
 	Config   config.Config
 	Resolved report.Resolved
-	OutputPath string
+}
+
+type ReportFacts struct {
+	Collected facts.CollectedFacts
+	Derived   facts.DerivedFacts
 }
 
 type ReportRequest struct {
@@ -80,14 +87,9 @@ type ReportRequest struct {
 	Notifier   Notifier
 }
 
-type BriefingResult struct {
-	Package    briefing.Package
-	OutputPath string
-}
-
 type ReportResult struct {
-	Briefing         briefing.Package
-	BriefingPath     string
+	ModuleSnapshot     module.Snapshot
+	ModuleSnapshotPath string
 	DataPackage        promptinput.Package
 	DataPackagePath    string
 	PreflightPath      string
@@ -127,7 +129,6 @@ type BatchReportResult struct {
 	NotificationPath       string          `json:"notificationPath,omitempty"`
 	GeneratedAt            time.Time       `json:"generatedAt"`
 	ValidPeriod            timeutil.Period `json:"validPeriod"`
-	BriefingPath           string          `json:"briefingPath,omitempty"`
 	DataPackagePath        string          `json:"dataPackagePath,omitempty"`
 	PreflightPath          string          `json:"preflightPath,omitempty"`
 	ReportPath             string          `json:"reportPath,omitempty"`
@@ -260,7 +261,6 @@ func RunBatchDetailed(ctx context.Context, req BatchRequest) (*BatchResult, erro
 		for _, resolved := range resolvedReports {
 			item := batchReportResult(resolved)
 			if paths, err := store.Paths(resolved); err == nil {
-				item.BriefingPath = paths.Briefing
 				item.DataPackagePath = paths.DataPackage
 				item.PreflightPath = paths.Preflight
 				item.ReportPath = paths.RenderedReport
@@ -290,7 +290,6 @@ func RunBatchDetailed(ctx context.Context, req BatchRequest) (*BatchResult, erro
 				result.Failed++
 			} else {
 				item.Status = "succeeded"
-				item.BriefingPath = reportResult.BriefingPath
 				item.DataPackagePath = reportResult.DataPackagePath
 				item.PreflightPath = reportResult.PreflightPath
 				item.ReportPath = reportResult.ReportPath
@@ -341,7 +340,11 @@ func ResolveGenerate(req GenerateRequest, now time.Time) (report.Resolved, error
 	if err != nil {
 		return report.Resolved{}, err
 	}
-	return report.DefaultRegistry().Resolve(id, report.ResolveRequest{
+	registry, err := reportRegistry(req.Config)
+	if err != nil {
+		return report.Resolved{}, err
+	}
+	return registry.Resolve(id, report.ResolveRequest{
 		Now:        now,
 		Location:   location,
 		Date:       req.Date,
@@ -359,12 +362,24 @@ func ResolveBatch(req BatchRequest, now time.Time) ([]report.Resolved, error) {
 	if err != nil {
 		return nil, err
 	}
-	return report.DefaultRegistry().BatchReports(batch, report.ResolveRequest{
+	registry, err := reportRegistry(req.Config)
+	if err != nil {
+		return nil, err
+	}
+	return registry.BatchReports(batch, report.ResolveRequest{
 		Now:      now,
 		Location: location,
 	})
 }
 
+func reportRegistry(cfg config.Config) (report.Registry, error) {
+	registry, err := report.DefaultRegistry().WithModuleOverrides(cfg.ReportModuleOverrides())
+	if err != nil {
+		return report.Registry{}, err
+	}
+	return registry, nil
+}
+
 func reportIDForCommand(kind ReportKind) (report.ID, error) {
 	switch kind {
 	case ReportDaily:
@@ -393,7 +408,7 @@ func reportBatchForCommand(kind BatchKind) (report.Batch, error) {
 	}
 }
 
-func FetchBundle(ctx context.Context, req FetchBundleRequest) (*forecast.Bundle, error) {
+func FetchBundle(ctx context.Context, req FetchBundleRequest) (*weatherdata.Bundle, error) {
 	client, err := weatherapi.New(req.Config)
 	if err != nil {
 		return nil, err
@@ -405,7 +420,7 @@ func FetchBundle(ctx context.Context, req FetchBundleRequest) (*forecast.Bundle,
 	return bundle, nil
 }
 
-func FetchAndSaveBundle(ctx context.Context, req FetchBundleRequest) (*forecast.Bundle, error) {
+func FetchAndSaveBundle(ctx context.Context, req FetchBundleRequest) (*weatherdata.Bundle, error) {
 	if req.OutputPath == "" {
 		return nil, fmt.Errorf("output path is required")
 	}
@@ -419,33 +434,6 @@ func FetchAndSaveBundle(ctx context.Context, req FetchBundleRequest) (*forecast.
 	return bundle, nil
 }
 
-func GenerateBriefing(ctx context.Context, req BriefingRequest) (*BriefingResult, error) {
-	bundle, err := FetchBundle(ctx, FetchBundleRequest{Config: req.Config})
-	if err != nil {
-		return nil, err
-	}
-	pkg, err := BuildBriefing(req, bundle)
-	if err != nil {
-		return nil, err
-	}
-	outputPath := req.OutputPath
-	if outputPath == "" {
-		store, err := defaultStore(req.Config)
-		if err != nil {
-			return nil, err
-		}
-		paths, err := store.Paths(req.Resolved)
-		if err != nil {
-			return nil, err
-		}
-		outputPath = paths.Briefing
-	}
-	if err := briefing.Save(outputPath, pkg); err != nil {
-		return nil, err
-	}
-	return &BriefingResult{Package: pkg, OutputPath: outputPath}, nil
-}
-
 func GenerateReport(ctx context.Context, req ReportRequest) (*ReportResult, error) {
 	store := req.Store
 	if store == nil {
@@ -468,24 +456,43 @@ func GenerateReport(ctx context.Context, req ReportRequest) (*ReportResult, erro
 	if err != nil {
 		return nil, err
 	}
-	briefingPackage, err := BuildBriefing(BriefingRequest{
+	reportFacts, err := BuildReportFacts(ModuleSnapshotRequest{
 		Config:   req.Config,
 		Resolved: req.Resolved,
 	}, bundle)
 	if err != nil {
 		return nil, err
 	}
-
-	briefingPath, err := store.SaveBriefing(ctx, req.Resolved, briefingPackage)
+	moduleSnapshot, err := BuildModuleSnapshotFromFacts(ModuleSnapshotRequest{
+		Config:   req.Config,
+		Resolved: req.Resolved,
+	}, reportFacts)
 	if err != nil {
 		return nil, err
 	}
 
-	recentChanges, err := recentChanges(ctx, store, priorSnapshot, briefingPackage, req.Config.RecentChange)
+	moduleSnapshotPath, err := store.SaveModuleSnapshot(ctx, req.Resolved, moduleSnapshot)
 	if err != nil {
 		return nil, err
 	}
-	dataPackage, err := promptinput.BuildWithRecentChanges(briefingPackage, recentChanges)
+
+	recentChanges, err := recentChanges(ctx, store, priorSnapshot, req.Resolved.Definition.ID, moduleSnapshot, req.Config.RecentChange)
+	if err != nil {
+		return nil, err
+	}
+	briefingMetadata := briefing.BuildMetadata(briefingBuildContext(req.Config, req.Resolved, reportFacts.Collected))
+	metadata := state.BuildMetadataFromBriefingMetadata(req.Resolved, briefingMetadata, state.ArtifactPaths{
+		ModuleSnapshot: moduleSnapshotPath,
+		Metadata:       paths.Metadata,
+		DataPackage:    paths.DataPackage,
+		Preflight:      paths.Preflight,
+		RenderedReport: paths.RenderedReport,
+	})
+	dataPackage, err := promptinput.Build(promptinput.BuildRequest{
+		Metadata:      promptMetadata(metadata),
+		Modules:       moduleSnapshot,
+		RecentChanges: recentChanges,
+	})
 	if err != nil {
 		return nil, err
 	}
@@ -493,6 +500,7 @@ func GenerateReport(ctx context.Context, req ReportRequest) (*ReportResult, erro
 	if err != nil {
 		return nil, err
 	}
+	metadata.DataPackagePath = dataPackagePath
 
 	renderer := req.Renderer
 	if renderer == nil {
@@ -517,13 +525,7 @@ func GenerateReport(ctx context.Context, req ReportRequest) (*ReportResult, erro
 			return nil, err
 		}
 	}
-	metadata := state.BuildMetadata(req.Resolved, briefingPackage, state.ArtifactPaths{
-		Briefing:       briefingPath,
-		Metadata:       paths.Metadata,
-		DataPackage:    dataPackagePath,
-		Preflight:      preflightPath,
-		RenderedReport: paths.RenderedReport,
-	})
+	metadata.PreflightPath = preflightPath
 	metadataPath, metadataErr := store.SaveMetadata(ctx, metadata)
 	if metadataErr != nil {
 		return nil, metadataErr
@@ -572,8 +574,8 @@ func GenerateReport(ctx context.Context, req ReportRequest) (*ReportResult, erro
 	}
 
 	return &ReportResult{
-		Briefing:         briefingPackage,
-		BriefingPath:     briefingPath,
+		ModuleSnapshot:     moduleSnapshot,
+		ModuleSnapshotPath: moduleSnapshotPath,
 		DataPackage:        dataPackage,
 		DataPackagePath:    dataPackagePath,
 		PreflightPath:      preflightPath,
@@ -787,64 +789,101 @@ func distributorUploadFiles(sourcePath string, bundlePaths []string) []distribut
 	return files
 }
 
-func BuildBriefing(req BriefingRequest, bundle *forecast.Bundle) (briefing.Package, error) {
-	location, err := timeutil.LoadLocation(req.Config.WeatherAPI.Timezone)
+func BuildModuleSnapshot(req ModuleSnapshotRequest, bundle *weatherdata.Bundle) (module.Snapshot, error) {
+	reportFacts, err := BuildReportFacts(req, bundle)
 	if err != nil {
-		return briefing.Package{}, err
+		return module.Snapshot{}, err
 	}
-	dayparts := make([]forecast.DaypartDefinition, 0, len(req.Config.Dayparts))
-	for _, daypart := range req.Config.Dayparts {
+	return BuildModuleSnapshotFromFacts(req, reportFacts)
+}
+
+func BuildReportFacts(req ModuleSnapshotRequest, bundle *weatherdata.Bundle) (ReportFacts, error) {
+	collected := facts.BuildCollected(bundle)
+	derived, err := buildDerivedFacts(req.Config, req.Resolved, collected)
+	if err != nil {
+		return ReportFacts{}, err
+	}
+	return ReportFacts{
+		Collected: collected,
+		Derived:   derived,
+	}, nil
+}
+
+func BuildModuleSnapshotFromFacts(req ModuleSnapshotRequest, reportFacts ReportFacts) (module.Snapshot, error) {
+	if !req.Resolved.ValidPeriod.IsValid() {
+		return module.Snapshot{}, fmt.Errorf("resolved valid period is required")
+	}
+	registry, err := briefing.DefaultModuleRegistry()
+	if err != nil {
+		return module.Snapshot{}, err
+	}
+	moduleContext := briefing.ModuleContext{
+		Resolved:  req.Resolved,
+		Collected: reportFacts.Collected,
+		Derived:   reportFacts.Derived,
+		Units:     req.Config.WeatherAPI.Units,
+		Timezone:  req.Config.WeatherAPI.Timezone,
+		Location:  briefingLocation(req.Config),
+	}
+	var outputs []module.Output
+	for _, item := range req.Resolved.Definition.Modules {
+		definition, err := registry.Lookup(item.ID)
+		if err != nil {
+			return module.Snapshot{}, err
+		}
+		if definition.Builder == nil {
+			continue
+		}
+		output, err := registry.BuildModule(moduleContext, item)
+		if err != nil {
+			return module.Snapshot{}, err
+		}
+		if output == nil {
+			continue
+		}
+		outputs = append(outputs, *output)
+	}
+	return module.NewSnapshot(outputs)
+}
+
+func briefingBuildContext(cfg config.Config, resolved report.Resolved, collected facts.CollectedFacts) briefing.BuildContext {
+	return briefing.BuildContext{
+		Resolved: resolved,
+		Bundle:   collected.Bundle(),
+		Units:    cfg.WeatherAPI.Units,
+		Timezone: cfg.WeatherAPI.Timezone,
+		Location: briefingLocation(cfg),
+	}
+}
+
+func promptMetadata(metadata state.Metadata) promptinput.Metadata {
+	return promptinput.Metadata{
+		RunID:          metadata.RunID,
+		ReportID:       metadata.ReportID,
+		Variant:        metadata.Variant,
+		PromptID:       metadata.PromptID,
+		GeneratedAt:    metadata.GeneratedAt,
+		Timezone:       metadata.Timezone,
+		ValidPeriod:    metadata.ValidPeriod,
+		SourceWarnings: metadata.SourceWarnings,
+	}
+}
+
+func buildDerivedFacts(cfg config.Config, resolved report.Resolved, collected facts.CollectedFacts) (facts.DerivedFacts, error) {
+	dayparts := make([]forecast.DaypartDefinition, 0, len(cfg.Dayparts))
+	for _, daypart := range cfg.Dayparts {
 		dayparts = append(dayparts, forecast.DaypartDefinition{
 			Name:  daypart.Name,
 			Start: daypart.Start,
 			End:   daypart.End,
 		})
 	}
-	switch req.Resolved.Definition.ID {
-	case report.DailyToday, report.DailyTomorrow:
-		summary, err := forecast.BuildDailySummary(bundle, req.Resolved.ValidPeriod.Start, location, dayparts)
-		if err != nil {
-			return briefing.Package{}, err
-		}
-		return briefing.BuildDaily(briefing.BuildContext{
-			Resolved: req.Resolved,
-			Bundle:   bundle,
-			Units:    req.Config.WeatherAPI.Units,
-			Timezone: req.Config.WeatherAPI.Timezone,
-			Location: briefingLocation(req.Config),
-		}, summary)
-	case report.ThreeDay, report.Weekend:
-		summaries, err := forecast.BuildPeriodDailySummaries(bundle, req.Resolved.ValidPeriod, location, dayparts)
-		if err != nil {
-			return briefing.Package{}, err
-		}
-		if req.Resolved.Definition.ID == report.Weekend {
-			return briefing.BuildWeekend(briefing.BuildContext{
-				Resolved: req.Resolved,
-				Bundle:   bundle,
-				Units:    req.Config.WeatherAPI.Units,
-				Timezone: req.Config.WeatherAPI.Timezone,
-				Location: briefingLocation(req.Config),
-			}, summaries)
-		}
-		return briefing.BuildThreeDay(briefing.BuildContext{
-			Resolved: req.Resolved,
-			Bundle:   bundle,
-			Units:    req.Config.WeatherAPI.Units,
-			Timezone: req.Config.WeatherAPI.Timezone,
-			Location: briefingLocation(req.Config),
-		}, summaries)
-	case report.Storm:
-		return briefing.BuildStorm(briefing.BuildContext{
-			Resolved: req.Resolved,
-			Bundle:   bundle,
-			Units:    req.Config.WeatherAPI.Units,
-			Timezone: req.Config.WeatherAPI.Timezone,
-			Location: briefingLocation(req.Config),
+	return facts.BuildDerived(facts.BuildDerivedRequest{
+		Resolved:  resolved,
+		Timezone:  cfg.WeatherAPI.Timezone,
+		Dayparts:  dayparts,
+		Collected: collected,
 	})
-	default:
-		return briefing.Package{}, fmt.Errorf("briefing is not implemented for report %q", req.Resolved.Definition.ID)
-	}
 }
 
 func briefingLocation(cfg config.Config) *briefing.LocationContext {
@@ -864,11 +903,11 @@ func defaultStore(cfg config.Config) (*state.FilesystemStore, error) {
 	return state.NewFilesystemStore(cfg.Workspace)
 }
 
-func recentChanges(ctx context.Context, store state.Store, priorSnapshot *state.PriorSnapshot, current briefing.Package, cfg config.RecentChangeConfig) ([]changes.Change, error) {
+func recentChanges(ctx context.Context, store state.Store, priorSnapshot *state.PriorSnapshot, reportID report.ID, current module.Snapshot, cfg config.RecentChangeConfig) ([]changes.Change, error) {
 	if priorSnapshot == nil {
 		return nil, nil
 	}
-	previous, err := store.LoadBriefing(ctx, priorSnapshot.BriefingPath)
+	previous, err := store.LoadModuleSnapshot(ctx, priorSnapshot.ModuleSnapshotPath)
 	if err != nil {
 		return nil, err
 	}
@@ -878,7 +917,7 @@ func recentChanges(ctx context.Context, store state.Store, priorSnapshot *state.
 		WindGustMilesPerHour:     cfg.WindGustMilesPerHour,
 		PrecipTimingShiftMinutes: cfg.PrecipTimingShiftMinutes,
 	}
-	switch current.Metadata.ReportID {
+	switch reportID {
 	case report.DailyToday, report.DailyTomorrow:
 		return changes.CompareDaily(previous, current, thresholds)
 	case report.ThreeDay:

internal/app/app_test.go

@@ -15,9 +15,11 @@ import (
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/adapters/scriptorium"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptinput"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/state"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
 )
 
 func TestFetchAndSaveBundle(t *testing.T) {
@@ -76,67 +78,6 @@ func TestFetchAndSaveBundleRequiresOutputPath(t *testing.T) {
 	}
 }
 
-func TestGenerateBriefingWritesArtifact(t *testing.T) {
-	server := dailyBundleServer(t)
-	cfg := dailyTestConfig(t, server)
-	resolved, err := ResolveGenerate(GenerateRequest{
-		Config: cfg,
-		Report: ReportDaily,
-		Date:   mustParse("2026-05-29T12:00:00-05:00"),
-	}, mustParse("2026-05-29T05:00:00-05:00"))
-	if err != nil {
-		t.Fatalf("ResolveGenerate() error = %v", err)
-	}
-	path := filepath.Join(t.TempDir(), "daily.briefing.json")
-
-	result, err := GenerateBriefing(context.Background(), BriefingRequest{
-		Config:     cfg,
-		Resolved:   resolved,
-		OutputPath: path,
-	})
-	if err != nil {
-		t.Fatalf("GenerateBriefing() error = %v", err)
-	}
-	if result.OutputPath != path {
-		t.Fatalf("OutputPath = %q, want %q", result.OutputPath, path)
-	}
-	if result.Package.Daily == nil {
-		t.Fatal("Daily = nil")
-	}
-	data, err := os.ReadFile(path)
-	if err != nil {
-		t.Fatalf("read briefing artifact: %v", err)
-	}
-	if !strings.Contains(string(data), `"schemaVersion"`) || !strings.Contains(string(data), `"daily"`) {
-		t.Fatalf("briefing artifact missing expected fields:\n%s", string(data))
-	}
-}
-
-func TestGenerateBriefingDefaultPath(t *testing.T) {
-	server := dailyBundleServer(t)
-	cfg := dailyTestConfig(t, server)
-	cfg.Workspace.Root = t.TempDir()
-	resolved, err := ResolveGenerate(GenerateRequest{
-		Config: cfg,
-		Report: ReportDaily,
-		Date:   mustParse("2026-05-29T12:00:00-05:00"),
-	}, mustParse("2026-05-29T05:00:00-05:00"))
-	if err != nil {
-		t.Fatalf("ResolveGenerate() error = %v", err)
-	}
-
-	result, err := GenerateBriefing(context.Background(), BriefingRequest{
-		Config:   cfg,
-		Resolved: resolved,
-	})
-	if err != nil {
-		t.Fatalf("GenerateBriefing() error = %v", err)
-	}
-	if !strings.HasSuffix(result.OutputPath, filepath.Join("snapshots", "daily", "2026-05-29", "20260529T100000.000000000Z_daily_today.briefing.json")) {
-		t.Fatalf("OutputPath = %q, want deterministic daily briefing path", result.OutputPath)
-	}
-}
-
 func TestGenerateReportWritesReportAndPreflight(t *testing.T) {
 	server := dailyBundleServer(t)
 	cfg := dailyTestConfig(t, server)
@@ -164,12 +105,18 @@ func TestGenerateReportWritesReportAndPreflight(t *testing.T) {
 		runBody: "# Daily Report\n\nRain this morning.\n",
 	}
 	outputPath := filepath.Join(t.TempDir(), "daily.md")
+	filesystemStore, err := state.NewFilesystemStore(cfg.Workspace)
+	if err != nil {
+		t.Fatalf("NewFilesystemStore() error = %v", err)
+	}
+	store := &recordingStore{Store: filesystemStore}
 
 	result, err := GenerateReport(context.Background(), ReportRequest{
 		Config:     cfg,
 		Resolved:   resolved,
 		OutputPath: outputPath,
 		Renderer:   renderer,
+		Store:      store,
 	})
 	if err != nil {
 		t.Fatalf("GenerateReport() error = %v", err)
@@ -193,36 +140,47 @@ func TestGenerateReportWritesReportAndPreflight(t *testing.T) {
 	if renderer.runRequest.OutputPath != result.ReportPath {
 		t.Fatalf("run OutputPath = %q, want managed report path %q", renderer.runRequest.OutputPath, result.ReportPath)
 	}
-	assertPathsExist(t, result.BriefingPath, result.DataPackagePath, result.PreflightPath, result.ReportPath, result.MetadataPath, outputPath)
+	if got, want := strings.Join(store.calls, ","), "module_snapshot,data_package,preflight,metadata,prepare_report,metadata"; !strings.HasPrefix(got, want) {
+		t.Fatalf("store calls = %v, want prefix %s", store.calls, want)
+	}
+	assertPathsExist(t, result.ModuleSnapshotPath, result.DataPackagePath, result.PreflightPath, result.ReportPath, result.MetadataPath, outputPath)
+	snapshotData, err := os.ReadFile(result.ModuleSnapshotPath)
+	if err != nil {
+		t.Fatalf("read module snapshot: %v", err)
+	}
+	if !strings.Contains(string(snapshotData), module.SnapshotSchemaVersion) || !strings.Contains(string(snapshotData), `"metadata"`) || !strings.Contains(string(snapshotData), `"derived_daily_summary"`) {
+		t.Fatalf("module snapshot missing expected stanzas:\n%s", string(snapshotData))
+	}
 	data, err := os.ReadFile(result.DataPackagePath)
 	if err != nil {
 		t.Fatalf("read data package: %v", err)
 	}
-	if !strings.Contains(string(data), `"recentChanges"`) || !strings.Contains(string(data), `data_package.v1`) {
+	if !strings.HasSuffix(result.DataPackagePath, ".data_package.yaml") {
+		t.Fatalf("DataPackagePath = %q, want YAML data package path", result.DataPackagePath)
+	}
+	if !strings.Contains(string(data), "schema_version: weatherreporter.data_package.v2") ||
+		!strings.Contains(string(data), "recent_changes:") ||
+		!strings.Contains(string(data), "current_conditions:") ||
+		!strings.Contains(string(data), "area_forecast_discussion:") {
 		t.Fatalf("data package missing expected content:\n%s", string(data))
 	}
-	var savedDataPackage struct {
-		Report struct {
-			CurrentLocalDate string `json:"currentLocalDate"`
-		} `json:"report"`
-		Briefing briefing.Package `json:"briefing"`
-	}
-	if err := json.Unmarshal(data, &savedDataPackage); err != nil {
+	savedDataPackage, err := promptinput.LoadYAML(data)
+	if err != nil {
 		t.Fatalf("decode data package: %v", err)
 	}
 	if savedDataPackage.Report.CurrentLocalDate != "2026-05-29" {
 		t.Fatalf("data package currentLocalDate = %q, want 2026-05-29", savedDataPackage.Report.CurrentLocalDate)
 	}
-	location := savedDataPackage.Briefing.Metadata.Location
-	if location == nil || location.ID != "home" || location.Name != "Brentwood" || location.Region != "St. Louis Metro" || location.Timezone != "America/Chicago" {
-		t.Fatalf("data package location = %#v, want configured prompt location", location)
+	if _, ok := savedDataPackage.Briefing.Values["metadata"]; !ok {
+		t.Fatal("data package metadata stanza missing")
 	}
-	current := savedDataPackage.Briefing.CurrentConditions
-	if current == nil || current.ConditionText != "Clear" || current.TemperatureF == nil || *current.TemperatureF != 75 {
-		t.Fatalf("data package current conditions = %#v, want current conditions", current)
+	current, ok := savedDataPackage.Briefing.Values["current_conditions"].(map[string]any)
+	if !ok || current["condition_text"] != "Clear" {
+		t.Fatalf("data package current conditions = %#v, want current conditions", savedDataPackage.Briefing.Values["current_conditions"])
 	}
-	if savedDataPackage.Briefing.Daily == nil || savedDataPackage.Briefing.Daily.WeatherStory == nil || savedDataPackage.Briefing.Daily.WeatherStory.Title != "Several Chances for Rain Through Monday" {
-		t.Fatalf("data package weather story = %#v, want weather story title", savedDataPackage.Briefing.Daily)
+	story, ok := savedDataPackage.Briefing.Values["weather_story"].(map[string]any)
+	if !ok || story["title"] != "Several Chances for Rain Through Monday" {
+		t.Fatalf("data package weather story = %#v, want weather story title", savedDataPackage.Briefing.Values["weather_story"])
 	}
 	if !strings.Contains(string(data), "Short-term AFD narrative for generated report.") || !strings.Contains(string(data), "Long-term AFD narrative for generated report.") {
 		t.Fatalf("data package missing AFD short/long-term discussion:\n%s", string(data))
@@ -237,7 +195,7 @@ func TestGenerateReportWritesReportAndPreflight(t *testing.T) {
 	if result.Metadata.RunID != resolved.Metadata().RunID {
 		t.Fatalf("metadata RunID = %q, want %q", result.Metadata.RunID, resolved.Metadata().RunID)
 	}
-	if result.Metadata.BriefingPath != result.BriefingPath || result.Metadata.DataPackagePath != result.DataPackagePath {
+	if result.Metadata.ModuleSnapshotPath != result.ModuleSnapshotPath || result.Metadata.DataPackagePath != result.DataPackagePath {
 		t.Fatalf("metadata does not link artifact paths: %#v", result.Metadata)
 	}
 	if result.Metadata.RenderedReportPath != result.ReportPath {
@@ -635,25 +593,7 @@ func TestGenerateReportIncludesRecentChangesFromPriorSnapshot(t *testing.T) {
 	if err != nil {
 		t.Fatalf("ResolveGenerate(prior) error = %v", err)
 	}
-	priorBriefing := priorDailyBriefing(priorResolved)
-	priorBriefingPath, err := store.SaveBriefing(context.Background(), priorResolved, priorBriefing)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	priorPaths, err := store.Paths(priorResolved)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
-		Briefing:       priorBriefingPath,
-		Metadata:       priorPaths.Metadata,
-		DataPackage:    priorPaths.DataPackage,
-		Preflight:      priorPaths.Preflight,
-		RenderedReport: priorPaths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	savePriorRun(t, store, priorResolved, priorDailyModuleSnapshot(t, priorResolved))
 
 	currentResolved, err := ResolveGenerate(GenerateRequest{
 		Config: cfg,
@@ -718,14 +658,18 @@ func TestGenerateTomorrowReportUsesTomorrowBriefingDate(t *testing.T) {
 		t.Fatalf("GenerateReport() error = %v", err)
 	}
 
-	if result.Briefing.Metadata.ReportID != report.DailyTomorrow || result.Briefing.Metadata.Variant != "tomorrow" {
-		t.Fatalf("metadata report/variant = %q/%q, want tomorrow", result.Briefing.Metadata.ReportID, result.Briefing.Metadata.Variant)
+	if result.Metadata.ReportID != report.DailyTomorrow || result.Metadata.Variant != "tomorrow" {
+		t.Fatalf("metadata report/variant = %q/%q, want tomorrow", result.Metadata.ReportID, result.Metadata.Variant)
 	}
-	if result.Briefing.Daily.ForecastSummaryDate != "2026-05-30" {
-		t.Fatalf("ForecastSummaryDate = %q, want 2026-05-30", result.Briefing.Daily.ForecastSummaryDate)
+	dailySummary, ok, err := module.StanzaValue[map[string]any](result.ModuleSnapshot, "derived_daily_summary")
+	if err != nil {
+		t.Fatalf("decode daily summary: %v", err)
 	}
-	if result.Briefing.Daily.Planning == nil {
-		t.Fatal("Planning = nil, want tomorrow planning inputs")
+	if !ok || dailySummary["date"] != "2026-05-30" {
+		t.Fatalf("daily summary = %#v, want tomorrow date", dailySummary)
+	}
+	if _, ok := result.ModuleSnapshot.LookupStanza("tomorrow_planning"); !ok {
+		t.Fatal("tomorrow_planning stanza missing")
 	}
 	if !strings.Contains(filepath.Base(result.ReportPath), "daily_tomorrow") {
 		t.Fatalf("ReportPath = %q, want managed tomorrow report path", result.ReportPath)
@@ -750,25 +694,7 @@ func TestTomorrowReportCanCompareAgainstPriorDailySnapshot(t *testing.T) {
 	if err != nil {
 		t.Fatalf("ResolveGenerate(prior) error = %v", err)
 	}
-	priorBriefing := priorDailyBriefing(priorResolved)
-	priorBriefingPath, err := store.SaveBriefing(context.Background(), priorResolved, priorBriefing)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	priorPaths, err := store.Paths(priorResolved)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
-		Briefing:       priorBriefingPath,
-		Metadata:       priorPaths.Metadata,
-		DataPackage:    priorPaths.DataPackage,
-		Preflight:      priorPaths.Preflight,
-		RenderedReport: priorPaths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	savePriorRun(t, store, priorResolved, priorDailyModuleSnapshot(t, priorResolved))
 
 	currentResolved, err := ResolveGenerate(GenerateRequest{
 		Config: cfg,
@@ -817,25 +743,7 @@ func TestGenerateThreeDayReportWritesReportAndRecentChanges(t *testing.T) {
 	if err != nil {
 		t.Fatalf("ResolveGenerate(prior) error = %v", err)
 	}
-	priorBriefing := priorThreeDayBriefing(priorResolved)
-	priorBriefingPath, err := store.SaveBriefing(context.Background(), priorResolved, priorBriefing)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	priorPaths, err := store.Paths(priorResolved)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
-		Briefing:       priorBriefingPath,
-		Metadata:       priorPaths.Metadata,
-		DataPackage:    priorPaths.DataPackage,
-		Preflight:      priorPaths.Preflight,
-		RenderedReport: priorPaths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	savePriorRun(t, store, priorResolved, priorOutlookModuleSnapshot(t, "2026-05-30"))
 	currentResolved, err := ResolveGenerate(GenerateRequest{
 		Config: cfg,
 		Report: ReportThreeDay,
@@ -859,11 +767,12 @@ func TestGenerateThreeDayReportWritesReportAndRecentChanges(t *testing.T) {
 		t.Fatalf("GenerateReport() error = %v", err)
 	}
 
-	if result.Briefing.ThreeDay == nil {
-		t.Fatal("ThreeDay = nil")
+	dayparts, ok, err := module.StanzaValue[map[string]any](result.ModuleSnapshot, "derived_daypart_summaries")
+	if err != nil {
+		t.Fatalf("decode daypart summaries: %v", err)
 	}
-	if len(result.Briefing.ThreeDay.Days) != 3 {
-		t.Fatalf("ThreeDay days = %d, want 3", len(result.Briefing.ThreeDay.Days))
+	if !ok || len(dayparts) == 0 {
+		t.Fatalf("daypart summaries = %#v, want 3-day module content", dayparts)
 	}
 	if renderer.renderRequest.PromptID != "weather.three_day_outlook" {
 		t.Fatalf("render PromptID = %q, want weather.three_day_outlook", renderer.renderRequest.PromptID)
@@ -893,25 +802,7 @@ func TestGenerateWeekendReportWritesReportAndRecentChanges(t *testing.T) {
 	if err != nil {
 		t.Fatalf("ResolveGenerate(prior) error = %v", err)
 	}
-	priorBriefing := priorWeekendBriefing(priorResolved)
-	priorBriefingPath, err := store.SaveBriefing(context.Background(), priorResolved, priorBriefing)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	priorPaths, err := store.Paths(priorResolved)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), state.BuildMetadata(priorResolved, priorBriefing, state.ArtifactPaths{
-		Briefing:       priorBriefingPath,
-		Metadata:       priorPaths.Metadata,
-		DataPackage:    priorPaths.DataPackage,
-		Preflight:      priorPaths.Preflight,
-		RenderedReport: priorPaths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	savePriorRun(t, store, priorResolved, priorOutlookModuleSnapshot(t, "2026-05-30"))
 	currentResolved, err := ResolveGenerate(GenerateRequest{
 		Config: cfg,
 		Report: ReportWeekend,
@@ -935,11 +826,12 @@ func TestGenerateWeekendReportWritesReportAndRecentChanges(t *testing.T) {
 		t.Fatalf("GenerateReport() error = %v", err)
 	}
 
-	if result.Briefing.Weekend == nil {
-		t.Fatal("Weekend = nil")
+	dayparts, ok, err := module.StanzaValue[map[string]any](result.ModuleSnapshot, "derived_daypart_summaries")
+	if err != nil {
+		t.Fatalf("decode daypart summaries: %v", err)
 	}
-	if len(result.Briefing.Weekend.Days) != 3 {
-		t.Fatalf("Weekend days = %d, want 3", len(result.Briefing.Weekend.Days))
+	if !ok || len(dayparts) == 0 {
+		t.Fatalf("daypart summaries = %#v, want weekend module content", dayparts)
 	}
 	if renderer.renderRequest.PromptID != "weather.weekend_outlook" {
 		t.Fatalf("render PromptID = %q, want weather.weekend_outlook", renderer.renderRequest.PromptID)
@@ -984,14 +876,11 @@ func TestGenerateStormReportWritesReport(t *testing.T) {
 		t.Fatalf("GenerateReport() error = %v", err)
 	}
 
-	if result.Briefing.Storm == nil {
-		t.Fatal("Storm = nil")
-	}
 	if renderer.renderRequest.PromptID != "weather.storm_report" {
 		t.Fatalf("render PromptID = %q, want weather.storm_report", renderer.renderRequest.PromptID)
 	}
-	if len(result.Briefing.Storm.HourlyPeriods) == 0 || len(result.Briefing.Storm.NarrativePeriods) == 0 {
-		t.Fatalf("selected source periods hourly/narrative = %d/%d, want relevant periods", len(result.Briefing.Storm.HourlyPeriods), len(result.Briefing.Storm.NarrativePeriods))
+	if _, ok := result.ModuleSnapshot.LookupStanza("precip_timing"); !ok {
+		t.Fatal("precip_timing stanza missing")
 	}
 	if _, err := os.Stat(outputPath); err != nil {
 		t.Fatalf("expected requested report output %q: %v", outputPath, err)
@@ -1000,7 +889,7 @@ func TestGenerateStormReportWritesReport(t *testing.T) {
 	if err != nil {
 		t.Fatalf("read data package: %v", err)
 	}
-	if !strings.Contains(string(data), `"storm"`) || !strings.Contains(string(data), `"weather.storm_report"`) {
+	if !strings.Contains(string(data), "id: storm") || !strings.Contains(string(data), "prompt_id: weather.storm_report") || !strings.Contains(string(data), "precip_timing:") {
 		t.Fatalf("data package missing storm content:\n%s", string(data))
 	}
 }
@@ -1044,15 +933,15 @@ func TestInspectGeneratedReportArtifacts(t *testing.T) {
 	if err != nil {
 		t.Fatalf("InspectMetadata() error = %v", err)
 	}
-	if metadata.BriefingPath != result.BriefingPath || metadata.DataPackagePath != result.DataPackagePath {
+	if metadata.ModuleSnapshotPath != result.ModuleSnapshotPath || metadata.DataPackagePath != result.DataPackagePath {
 		t.Fatalf("metadata paths = %#v, want generated artifact paths", metadata)
 	}
-	briefingPackage, err := InspectBriefing(context.Background(), InspectRunRequest{Config: cfg, RunID: result.Metadata.RunID})
+	moduleSnapshot, err := InspectModules(context.Background(), InspectRunRequest{Config: cfg, RunID: result.Metadata.RunID})
 	if err != nil {
-		t.Fatalf("InspectBriefing() error = %v", err)
+		t.Fatalf("InspectModules() error = %v", err)
 	}
-	if briefingPackage.Metadata.RunID != result.Metadata.RunID {
-		t.Fatalf("briefing RunID = %q, want %q", briefingPackage.Metadata.RunID, result.Metadata.RunID)
+	if moduleSnapshot.SchemaVersion != module.SnapshotSchemaVersion || len(moduleSnapshot.Outputs) == 0 {
+		t.Fatalf("module snapshot = %#v, want persisted outputs", moduleSnapshot)
 	}
 	dataPackage, err := InspectDataPackage(context.Background(), InspectRunRequest{Config: cfg, RunID: result.Metadata.RunID})
 	if err != nil {
@@ -1154,6 +1043,45 @@ func TestResolveGenerateMapsCommandToReportDefinition(t *testing.T) {
 	}
 }
 
+func TestResolveGenerateUsesConfiguredReportModules(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "config.yml")
+	if err := os.WriteFile(path, []byte(`
+reports:
+  tomorrow:
+    deterministic_modules:
+      - metadata
+      - alert_digest
+      - tomorrow_planning
+`), 0o600); err != nil {
+		t.Fatalf("write config fixture: %v", err)
+	}
+	cfg, err := config.LoadFile(path)
+	if err != nil {
+		t.Fatalf("LoadFile() error = %v", err)
+	}
+	now := mustParse("2026-05-29T18:00:00-05:00")
+
+	resolved, err := ResolveGenerate(GenerateRequest{
+		Config: cfg,
+		Report: ReportTomorrow,
+	}, now)
+	if err != nil {
+		t.Fatalf("ResolveGenerate() error = %v", err)
+	}
+	want := []module.ID{module.Metadata, module.AlertDigest, module.TomorrowPlanning}
+	if got := resolved.Definition.ModuleIDs(); strings.Join(moduleIDsForTest(got), ",") != strings.Join(moduleIDsForTest(want), ",") {
+		t.Fatalf("ModuleIDs() = %#v, want %#v", got, want)
+	}
+}
+
+func moduleIDsForTest(ids []module.ID) []string {
+	out := make([]string, 0, len(ids))
+	for _, id := range ids {
+		out = append(out, string(id))
+	}
+	return out
+}
+
 func dailyBundleServer(t *testing.T) *httptest.Server {
 	t.Helper()
 	server := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
@@ -1382,13 +1310,79 @@ func assertPathsExist(t *testing.T, paths ...string) {
 	}
 }
 
-func priorDailyBriefing(resolved report.Resolved) briefing.Package {
-	low := 50.0
-	high := 58.0
-	precip := 10.0
-	return briefing.Package{
-		Metadata: briefing.Metadata{
-			SchemaVersion: briefing.SchemaVersion,
+func savePriorRun(t *testing.T, store state.Store, resolved report.Resolved, snapshot module.Snapshot) {
+	t.Helper()
+	moduleSnapshotPath, err := store.SaveModuleSnapshot(context.Background(), resolved, snapshot)
+	if err != nil {
+		t.Fatalf("SaveModuleSnapshot() error = %v", err)
+	}
+	paths, err := store.Paths(resolved)
+	if err != nil {
+		t.Fatalf("Paths() error = %v", err)
+	}
+	_, err = store.SaveMetadata(context.Background(), state.BuildMetadataFromBriefingMetadata(resolved, appBriefingMetadata(resolved), state.ArtifactPaths{
+		ModuleSnapshot: moduleSnapshotPath,
+		Metadata:       paths.Metadata,
+		DataPackage:    paths.DataPackage,
+		Preflight:      paths.Preflight,
+		RenderedReport: paths.RenderedReport,
+	}))
+	if err != nil {
+		t.Fatalf("SaveMetadata() error = %v", err)
+	}
+}
+
+func priorDailyModuleSnapshot(t *testing.T, resolved report.Resolved) module.Snapshot {
+	t.Helper()
+	low := 50
+	high := 58
+	precip := 10
+	snapshot, err := module.NewSnapshot([]module.Output{
+		{ID: module.DerivedDailySummary, StanzaName: "derived_daily_summary", Value: map[string]any{
+			"date":            resolved.ValidPeriod.Start.Format(timeutil.DateLayout),
+			"low_temp_f":      low,
+			"high_temp_f":     high,
+			"max_pop_percent": precip,
+		}},
+		{ID: module.DerivedDaypartSummaries, StanzaName: "derived_daypart_summaries", Value: map[string]any{
+			"morning": map[string]any{
+				"period":       timeutil.Period{Start: resolved.ValidPeriod.Start.Add(6 * time.Hour), End: resolved.ValidPeriod.Start.Add(10 * time.Hour)},
+				"temp_range_f": "50-58",
+			},
+		}},
+		{ID: module.PrecipTiming, StanzaName: "precip_timing", Value: map[string]any{
+			"max_pop_percent": precip,
+			"max_pop_time":    "6 AM",
+		}},
+		{ID: module.AlertDigest, StanzaName: "alert_digest", Value: map[string]any{}},
+	})
+	if err != nil {
+		t.Fatalf("NewSnapshot() error = %v", err)
+	}
+	return snapshot
+}
+
+func priorOutlookModuleSnapshot(t *testing.T, date string) module.Snapshot {
+	t.Helper()
+	precip := 10
+	snapshot, err := module.NewSnapshot([]module.Output{
+		{ID: module.DerivedDaypartSummaries, StanzaName: "derived_daypart_summaries", Value: map[string]any{
+			date + "_morning": map[string]any{
+				"period":          timeutil.Period{Start: mustParse(date + "T06:00:00Z"), End: mustParse(date + "T10:00:00Z")},
+				"temp_range_f":    "50-58",
+				"max_pop_percent": precip,
+				"max_pop_time":    "6 AM",
+			},
+		}},
+	})
+	if err != nil {
+		t.Fatalf("NewSnapshot() error = %v", err)
+	}
+	return snapshot
+}
+
+func appBriefingMetadata(resolved report.Resolved) briefing.Metadata {
+	return briefing.Metadata{
 		RunID:       resolved.Metadata().RunID,
 		ReportID:    resolved.Definition.ID,
 		Variant:     "today",
@@ -1397,77 +1391,6 @@ func priorDailyBriefing(resolved report.Resolved) briefing.Package {
 		Units:       "us",
 		Timezone:    resolved.Timezone,
 		ValidPeriod: resolved.ValidPeriod,
-		},
-		Daily: &briefing.Daily{
-			BottomLine: briefing.BottomLine{
-				Temperature: forecast.Range{Min: &low, Max: &high},
-				MaxPrecipProbability: &forecast.TimedValue{
-					Value: precip,
-					Time:  resolved.ValidPeriod.Start.Add(6 * time.Hour),
-				},
-			},
-			Dayparts: []forecast.DaypartSummary{
-				{Name: "morning"},
-			},
-		},
-	}
-}
-
-func priorThreeDayBriefing(resolved report.Resolved) briefing.Package {
-	high := 58.0
-	precip := 10.0
-	return briefing.Package{
-		Metadata: briefing.Metadata{
-			SchemaVersion: briefing.SchemaVersion,
-			RunID:         resolved.Metadata().RunID,
-			ReportID:      resolved.Definition.ID,
-			PromptID:      resolved.Definition.PromptID,
-			GeneratedAt:   resolved.GeneratedAt,
-			Units:         "us",
-			Timezone:      resolved.Timezone,
-			ValidPeriod:   resolved.ValidPeriod,
-		},
-		ThreeDay: &briefing.ThreeDay{
-			Days: []briefing.OutlookDay{
-				{
-					Date:        "2026-05-29",
-					Temperature: forecast.Range{Max: &high},
-					MaxPrecipitationProbability: &forecast.TimedValue{
-						Value: precip,
-						Time:  resolved.ValidPeriod.Start.Add(6 * time.Hour),
-					},
-				},
-			},
-		},
-	}
-}
-
-func priorWeekendBriefing(resolved report.Resolved) briefing.Package {
-	high := 58.0
-	precip := 10.0
-	return briefing.Package{
-		Metadata: briefing.Metadata{
-			SchemaVersion: briefing.SchemaVersion,
-			RunID:         resolved.Metadata().RunID,
-			ReportID:      resolved.Definition.ID,
-			PromptID:      resolved.Definition.PromptID,
-			GeneratedAt:   resolved.GeneratedAt,
-			Units:         "us",
-			Timezone:      resolved.Timezone,
-			ValidPeriod:   resolved.ValidPeriod,
-		},
-		Weekend: &briefing.Weekend{
-			Days: []briefing.OutlookDay{
-				{
-					Date:        "2026-05-30",
-					Temperature: forecast.Range{Max: &high},
-					MaxPrecipitationProbability: &forecast.TimedValue{
-						Value: precip,
-						Time:  resolved.ValidPeriod.Start.Add(12 * time.Hour),
-					},
-				},
-			},
-		},
 	}
 }
 
@@ -1483,6 +1406,36 @@ type recordingRenderer struct {
 	runBody       string
 }
 
+type recordingStore struct {
+	state.Store
+	calls []string
+}
+
+func (s *recordingStore) SaveModuleSnapshot(ctx context.Context, resolved report.Resolved, snapshot module.Snapshot) (string, error) {
+	s.calls = append(s.calls, "module_snapshot")
+	return s.Store.SaveModuleSnapshot(ctx, resolved, snapshot)
+}
+
+func (s *recordingStore) SaveDataPackage(ctx context.Context, resolved report.Resolved, pkg promptinput.Package) (string, error) {
+	s.calls = append(s.calls, "data_package")
+	return s.Store.SaveDataPackage(ctx, resolved, pkg)
+}
+
+func (s *recordingStore) SavePreflight(ctx context.Context, resolved report.Resolved, artifact state.PreflightArtifact) (string, error) {
+	s.calls = append(s.calls, "preflight")
+	return s.Store.SavePreflight(ctx, resolved, artifact)
+}
+
+func (s *recordingStore) PrepareRenderedReport(ctx context.Context, resolved report.Resolved) (string, error) {
+	s.calls = append(s.calls, "prepare_report")
+	return s.Store.PrepareRenderedReport(ctx, resolved)
+}
+
+func (s *recordingStore) SaveMetadata(ctx context.Context, metadata state.Metadata) (string, error) {
+	s.calls = append(s.calls, "metadata")
+	return s.Store.SaveMetadata(ctx, metadata)
+}
+
 func successfulRenderer(body string) *recordingRenderer {
 	return &recordingRenderer{
 		renderResult: &scriptorium.RenderResult{ExitCode: 0},

internal/app/inspect.go

@@ -6,11 +6,12 @@ import (
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptinput"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/state"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
 type InspectReportsRequest struct {
@@ -28,7 +29,7 @@ type SourceInspection struct {
 	ReportID       report.ID                   `json:"reportId"`
 	SourceLocation string                      `json:"sourceLocation,omitempty"`
 	Sources        []briefing.SourceMetadata   `json:"sources,omitempty"`
-	Warnings       []forecast.SourceWarning  `json:"warnings,omitempty"`
+	Warnings       []weatherdata.SourceWarning `json:"warnings,omitempty"`
 }
 
 func InspectReports(ctx context.Context, req InspectReportsRequest) ([]state.ReportRecord, error) {
@@ -44,12 +45,12 @@ func InspectMetadata(ctx context.Context, req InspectRunRequest) (state.Metadata
 	return inspection.metadata, err
 }
 
-func InspectBriefing(ctx context.Context, req InspectRunRequest) (briefing.Package, error) {
+func InspectModules(ctx context.Context, req InspectRunRequest) (module.Snapshot, error) {
 	inspection, err := inspectRun(ctx, req)
 	if err != nil {
-		return briefing.Package{}, err
+		return module.Snapshot{}, err
 	}
-	return inspection.store.LoadBriefing(ctx, inspection.metadata.BriefingPath)
+	return inspection.store.LoadModuleSnapshot(ctx, inspection.metadata.ModuleSnapshotPath)
 }
 
 func InspectDataPackage(ctx context.Context, req InspectRunRequest) (promptinput.Package, error) {

internal/briefing/base_modules.go

@@ -0,0 +1,269 @@
+package briefing
+
+import (
+	"fmt"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/facts"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+)
+
+type MetadataModule struct {
+	RunID          string                 `json:"run_id"`
+	ReportID       report.ID              `json:"report_id"`
+	Variant        string                 `json:"variant,omitempty"`
+	PromptID       string                 `json:"prompt_id"`
+	GeneratedAt    time.Time              `json:"generated_at"`
+	Units          string                 `json:"units"`
+	Timezone       string                 `json:"timezone"`
+	ValidPeriod    timeutil.Period        `json:"valid_period"`
+	Location       *LocationContext       `json:"location,omitempty"`
+	SourceWarnings []SourceWarningSummary `json:"source_warnings,omitempty"`
+	Alerts         *AlertDigestModule     `json:"alerts,omitempty"`
+}
+
+type SourceWarningSummary struct {
+	Source             string `json:"source"`
+	Code               string `json:"code"`
+	Severity           string `json:"severity"`
+	Message            string `json:"message"`
+	CompletenessImpact string `json:"completeness_impact,omitempty"`
+}
+
+type CurrentConditionsModule struct {
+	ConditionText           string   `json:"condition_text,omitempty"`
+	IsDay                   *bool    `json:"is_day,omitempty"`
+	TemperatureC            *float64 `json:"temperature_c,omitempty"`
+	TemperatureF            *float64 `json:"temperature_f,omitempty"`
+	ApparentTemperatureC    *float64 `json:"apparent_temperature_c,omitempty"`
+	ApparentTemperatureF    *float64 `json:"apparent_temperature_f,omitempty"`
+	DewpointC               *float64 `json:"dewpoint_c,omitempty"`
+	DewpointF               *float64 `json:"dewpoint_f,omitempty"`
+	RelativeHumidityPercent *float64 `json:"relative_humidity_percent,omitempty"`
+	WindSpeedKmh            *float64 `json:"wind_speed_kmh,omitempty"`
+	WindSpeedMph            *float64 `json:"wind_speed_mph,omitempty"`
+	WindDirectionDegrees    *float64 `json:"wind_direction_degrees,omitempty"`
+}
+
+type AlertDigestModule struct {
+	Checked       bool           `json:"checked"`
+	ActiveCount   int            `json:"active_count"`
+	RelevantCount int            `json:"relevant_count"`
+	Missing       bool           `json:"missing,omitempty"`
+	Relevant      []AlertSummary `json:"relevant,omitempty"`
+}
+
+type AlertSummary struct {
+	Event    string `json:"event,omitempty"`
+	Headline string `json:"headline,omitempty"`
+	Severity string `json:"severity,omitempty"`
+}
+
+type AreaForecastDiscussionModule struct {
+	Product     string   `json:"product,omitempty"`
+	KeyMessages []string `json:"key_messages,omitempty"`
+	ShortTerm   string   `json:"short_term,omitempty"`
+	LongTerm    string   `json:"long_term,omitempty"`
+}
+
+type WeatherStoryModule struct {
+	Available   bool       `json:"available"`
+	OfficeID    string     `json:"office_id,omitempty"`
+	StartTime   time.Time  `json:"start_time"`
+	EndTime     time.Time  `json:"end_time"`
+	UpdatedAt   *time.Time `json:"updated_at,omitempty"`
+	Title       string     `json:"title,omitempty"`
+	Description string     `json:"description,omitempty"`
+	AltText     string     `json:"alt_text,omitempty"`
+	Priority    bool       `json:"priority"`
+	Order       int        `json:"order"`
+	DownloadURL string     `json:"download_url,omitempty"`
+}
+
+func buildMetadataModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	metadata := ctx.Resolved.Metadata()
+	value := MetadataModule{
+		RunID:          metadata.RunID,
+		ReportID:       metadata.ReportID,
+		Variant:        variantForReport(metadata.ReportID),
+		PromptID:       metadata.PromptID,
+		GeneratedAt:    metadata.GeneratedAt,
+		Units:          ctx.Units,
+		Timezone:       ctx.Timezone,
+		ValidPeriod:    metadata.ValidPeriod,
+		Location:       copyLocation(ctx.Location),
+		SourceWarnings: sourceWarningSummaries(ctx.Collected.SourceWarnings),
+		Alerts:         alertDigest(ctx.Collected, ctx.Derived.AlertOverlaps),
+	}
+	return &module.Output{ID: module.Metadata, StanzaName: "metadata", Value: value}, nil
+}
+
+func buildCurrentConditionsModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	current := ctx.Collected.Current
+	if current == nil {
+		return nil, nil
+	}
+	value := CurrentConditionsModule{
+		ConditionText:           current.ConditionText,
+		IsDay:                   copyBool(current.IsDay),
+		TemperatureC:            copyFloat(current.TemperatureC),
+		TemperatureF:            copyFloat(current.TemperatureF),
+		ApparentTemperatureC:    copyFloat(current.ApparentTemperatureC),
+		ApparentTemperatureF:    copyFloat(current.ApparentTemperatureF),
+		DewpointC:               copyFloat(current.DewpointC),
+		DewpointF:               copyFloat(current.DewpointF),
+		RelativeHumidityPercent: copyFloat(current.RelativeHumidityPercent),
+		WindSpeedKmh:            copyFloat(current.WindSpeedKmh),
+		WindSpeedMph:            copyFloat(current.WindSpeedMph),
+		WindDirectionDegrees:    copyFloat(current.WindDirectionDegrees),
+	}
+	if value.isEmpty() {
+		return nil, nil
+	}
+	return &module.Output{ID: module.CurrentConditions, StanzaName: "current_conditions", Value: value}, nil
+}
+
+func buildAlertDigestModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	value := alertDigest(ctx.Collected, ctx.Derived.AlertOverlaps)
+	if value == nil {
+		value = &AlertDigestModule{}
+	}
+	return &module.Output{ID: module.AlertDigest, StanzaName: "alert_digest", Value: *value}, nil
+}
+
+func buildAreaForecastDiscussionModule(ctx ModuleContext, options any) (*module.Output, error) {
+	discussion := ctx.Collected.Discussion
+	if discussion == nil {
+		return nil, nil
+	}
+	opts, ok := options.(module.AreaForecastDiscussionOptions)
+	if !ok {
+		return nil, fmt.Errorf("area forecast discussion options have type %T", options)
+	}
+	sections, err := areaForecastDiscussionSections(opts)
+	if err != nil {
+		return nil, err
+	}
+	value := AreaForecastDiscussionModule{}
+	if sections["product"] {
+		value.Product = discussion.Product
+	}
+	if sections["key_messages"] {
+		value.KeyMessages = append([]string(nil), discussion.KeyMessages...)
+	}
+	if sections["short_term"] && discussion.ShortTerm != nil {
+		value.ShortTerm = discussion.ShortTerm.Text
+	}
+	if sections["long_term"] && discussion.LongTerm != nil {
+		value.LongTerm = discussion.LongTerm.Text
+	}
+	if value.Product == "" && len(value.KeyMessages) == 0 && value.ShortTerm == "" && value.LongTerm == "" {
+		return nil, nil
+	}
+	return &module.Output{ID: module.AreaForecastDiscussion, StanzaName: "area_forecast_discussion", Value: value}, nil
+}
+
+func areaForecastDiscussionSections(options module.AreaForecastDiscussionOptions) (map[string]bool, error) {
+	if len(options.Sections) == 0 {
+		return map[string]bool{
+			"product":      true,
+			"key_messages": true,
+			"short_term":   true,
+			"long_term":    true,
+		}, nil
+	}
+	sections := map[string]bool{}
+	for _, section := range options.Sections {
+		switch section {
+		case "product", "key_messages", "short_term", "long_term":
+			sections[section] = true
+		default:
+			return nil, fmt.Errorf("area forecast discussion section %q is not supported", section)
+		}
+	}
+	return sections, nil
+}
+
+func buildWeatherStoryModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	story := ctx.Collected.WeatherStory
+	if story == nil {
+		return nil, nil
+	}
+	value := WeatherStoryModule{
+		Available:   true,
+		OfficeID:    story.OfficeID,
+		StartTime:   story.StartTime,
+		EndTime:     story.EndTime,
+		UpdatedAt:   copyTime(story.UpdatedAt),
+		Title:       story.Title,
+		Description: story.Description,
+		AltText:     story.AltText,
+		Priority:    story.Priority,
+		Order:       story.Order,
+		DownloadURL: story.DownloadURL,
+	}
+	return &module.Output{ID: module.WeatherStory, StanzaName: "weather_story", Value: value}, nil
+}
+
+func sourceWarningSummaries(warnings []weatherdata.SourceWarning) []SourceWarningSummary {
+	out := make([]SourceWarningSummary, 0, len(warnings))
+	for _, warning := range warnings {
+		out = append(out, SourceWarningSummary{
+			Source:             warning.Source,
+			Code:               warning.Code,
+			Severity:           warning.Severity,
+			Message:            warning.Message,
+			CompletenessImpact: warning.CompletenessImpact,
+		})
+	}
+	return out
+}
+
+func alertDigest(collected facts.CollectedFacts, overlaps []forecast.AlertOverlap) *AlertDigestModule {
+	missing := sourceMissing(collected.SourceProvenance, "alerts")
+	if collected.Alerts == nil && !missing {
+		return nil
+	}
+	value := &AlertDigestModule{Missing: missing}
+	if collected.Alerts != nil {
+		value.Checked = true
+		value.ActiveCount = len(collected.Alerts.Alerts)
+	}
+	value.RelevantCount = len(overlaps)
+	for _, overlap := range overlaps {
+		value.Relevant = append(value.Relevant, AlertSummary{
+			Event:    overlap.Event,
+			Headline: overlap.Headline,
+			Severity: overlap.Severity,
+		})
+	}
+	return value
+}
+
+func sourceMissing(sources []weatherdata.Source, name string) bool {
+	for _, source := range sources {
+		if source.Name == name && source.Missing {
+			return true
+		}
+	}
+	return false
+}
+
+func (v CurrentConditionsModule) isEmpty() bool {
+	return v.ConditionText == "" &&
+		v.IsDay == nil &&
+		v.TemperatureC == nil &&
+		v.TemperatureF == nil &&
+		v.ApparentTemperatureC == nil &&
+		v.ApparentTemperatureF == nil &&
+		v.DewpointC == nil &&
+		v.DewpointF == nil &&
+		v.RelativeHumidityPercent == nil &&
+		v.WindSpeedKmh == nil &&
+		v.WindSpeedMph == nil &&
+		v.WindDirectionDegrees == nil
+}

internal/briefing/base_modules_test.go

@@ -0,0 +1,296 @@
+package briefing
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/facts"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+)
+
+func TestBaseModulesBuildAvailableSourceOutputs(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := testModuleContext()
+
+	tests := []struct {
+		id     module.ID
+		stanza string
+	}{
+		{id: module.Metadata, stanza: "metadata"},
+		{id: module.CurrentConditions, stanza: "current_conditions"},
+		{id: module.AlertDigest, stanza: "alert_digest"},
+		{id: module.AreaForecastDiscussion, stanza: "area_forecast_discussion"},
+		{id: module.WeatherStory, stanza: "weather_story"},
+	}
+	for _, tt := range tests {
+		t.Run(string(tt.id), func(t *testing.T) {
+			output, err := registry.BuildModule(ctx, module.ConfigItem{ID: tt.id})
+			if err != nil {
+				t.Fatalf("BuildModule() error = %v", err)
+			}
+			if output == nil {
+				t.Fatal("BuildModule() output = nil, want stanza")
+			}
+			if output.ID != tt.id || output.StanzaName != tt.stanza {
+				t.Fatalf("output = %#v, want id %q stanza %q", output, tt.id, tt.stanza)
+			}
+		})
+	}
+}
+
+func TestMetadataModuleUsesPromptSafeSourceWarningSummary(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := testModuleContext()
+
+	output, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.Metadata})
+	if err != nil {
+		t.Fatalf("BuildModule() error = %v", err)
+	}
+	value := moduleValue[MetadataModule](t, output)
+	if value.RunID == "" || value.ReportID != report.DailyToday || value.PromptID != "weather.daily_report" {
+		t.Fatalf("metadata = %#v, want report identity", value)
+	}
+	if value.Location == nil || value.Location.Name != "Brentwood" {
+		t.Fatalf("Location = %#v, want configured location", value.Location)
+	}
+	if len(value.SourceWarnings) != 1 || value.SourceWarnings[0].CompletenessImpact != "source omitted" {
+		t.Fatalf("SourceWarnings = %#v, want warning summary", value.SourceWarnings)
+	}
+	if value.Alerts == nil || !value.Alerts.Checked || value.Alerts.ActiveCount != 1 || value.Alerts.RelevantCount != 1 {
+		t.Fatalf("Alerts = %#v, want checked alert status", value.Alerts)
+	}
+	data, err := json.Marshal(output.Value)
+	if err != nil {
+		t.Fatalf("Marshal metadata: %v", err)
+	}
+	jsonText := string(data)
+	if !strings.Contains(jsonText, "source_warnings") || strings.Contains(jsonText, "endpoint") || strings.Contains(jsonText, "dataSha256") {
+		t.Fatalf("metadata json = %s, want source warning summary without transport provenance", jsonText)
+	}
+}
+
+func TestCurrentConditionsModuleUsesSnakeCaseUnitFields(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := testModuleContext()
+
+	output, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.CurrentConditions})
+	if err != nil {
+		t.Fatalf("BuildModule() error = %v", err)
+	}
+	value := moduleValue[CurrentConditionsModule](t, output)
+	if value.ConditionText != "Partly cloudy" || value.TemperatureF == nil || *value.TemperatureF != 74 {
+		t.Fatalf("CurrentConditions = %#v, want current condition facts", value)
+	}
+	data, err := json.Marshal(output.Value)
+	if err != nil {
+		t.Fatalf("Marshal current conditions: %v", err)
+	}
+	jsonText := string(data)
+	for _, field := range []string{"condition_text", "temperature_f", "apparent_temperature_f", "relative_humidity_percent", "wind_speed_mph"} {
+		if !strings.Contains(jsonText, field) {
+			t.Fatalf("current json = %s, want field %s", jsonText, field)
+		}
+	}
+}
+
+func TestAlertDigestDistinguishesCheckedEmptyAndMissing(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := testModuleContext()
+	ctx.Collected.Alerts = &weatherdata.AlertRun{}
+	ctx.Derived.AlertOverlaps = nil
+
+	output, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.AlertDigest})
+	if err != nil {
+		t.Fatalf("BuildModule(checked empty) error = %v", err)
+	}
+	checked := moduleValue[AlertDigestModule](t, output)
+	if !checked.Checked || checked.ActiveCount != 0 || checked.RelevantCount != 0 || checked.Missing {
+		t.Fatalf("checked empty alert digest = %#v, want checked/no active", checked)
+	}
+
+	ctx.Collected.Alerts = nil
+	ctx.Collected.SourceProvenance = []weatherdata.Source{{Name: "alerts", Missing: true}}
+	output, err = registry.BuildModule(ctx, module.ConfigItem{ID: module.AlertDigest})
+	if err != nil {
+		t.Fatalf("BuildModule(missing) error = %v", err)
+	}
+	missing := moduleValue[AlertDigestModule](t, output)
+	if missing.Checked || !missing.Missing {
+		t.Fatalf("missing alert digest = %#v, want missing unchecked source", missing)
+	}
+}
+
+func TestBaseModulesOmitMissingOptionalOutputs(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := testModuleContext()
+	ctx.Collected.Current = nil
+	ctx.Collected.Discussion = nil
+	ctx.Collected.WeatherStory = nil
+
+	for _, id := range []module.ID{module.CurrentConditions, module.AreaForecastDiscussion, module.WeatherStory} {
+		output, err := registry.BuildModule(ctx, module.ConfigItem{ID: id})
+		if err != nil {
+			t.Fatalf("BuildModule(%s) error = %v", id, err)
+		}
+		if output != nil {
+			t.Fatalf("BuildModule(%s) output = %#v, want omitted", id, output)
+		}
+	}
+}
+
+func TestAreaForecastDiscussionAndWeatherStoryModules(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := testModuleContext()
+
+	afdOutput, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.AreaForecastDiscussion})
+	if err != nil {
+		t.Fatalf("BuildModule(afd) error = %v", err)
+	}
+	afd := moduleValue[AreaForecastDiscussionModule](t, afdOutput)
+	if len(afd.KeyMessages) != 1 || afd.ShortTerm != "Showers increase this afternoon." || afd.LongTerm != "Periodic rain chances continue." {
+		t.Fatalf("AFD = %#v, want discussion sections", afd)
+	}
+
+	storyOutput, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.WeatherStory})
+	if err != nil {
+		t.Fatalf("BuildModule(weather story) error = %v", err)
+	}
+	story := moduleValue[WeatherStoryModule](t, storyOutput)
+	if !story.Available || story.Title != "Rain Chances" || story.Description != "Scattered showers are possible." {
+		t.Fatalf("WeatherStory = %#v, want structured story fields", story)
+	}
+	data, err := json.Marshal(storyOutput.Value)
+	if err != nil {
+		t.Fatalf("Marshal weather story: %v", err)
+	}
+	if !strings.Contains(string(data), "download_url") {
+		t.Fatalf("weather story json = %s, want snake_case download_url", string(data))
+	}
+}
+
+func TestAreaForecastDiscussionModuleCanSelectSections(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := testModuleContext()
+
+	output, err := registry.BuildModule(ctx, module.ConfigItem{
+		ID:      module.AreaForecastDiscussion,
+		Options: module.AreaForecastDiscussionOptions{Sections: []string{"short_term"}},
+	})
+	if err != nil {
+		t.Fatalf("BuildModule() error = %v", err)
+	}
+	afd := moduleValue[AreaForecastDiscussionModule](t, output)
+	if afd.ShortTerm != "Showers increase this afternoon." {
+		t.Fatalf("ShortTerm = %q, want selected short term section", afd.ShortTerm)
+	}
+	if afd.Product != "" || len(afd.KeyMessages) != 0 || afd.LongTerm != "" {
+		t.Fatalf("AFD = %#v, want only short_term section", afd)
+	}
+}
+
+func testModuleContext() ModuleContext {
+	generatedAt := mustParseModuleTime("2026-05-29T08:00:00-05:00")
+	definition := report.DefaultRegistry().MustLookup(report.DailyToday)
+	resolved := report.Resolved{
+		Definition:  definition,
+		GeneratedAt: generatedAt,
+		Timezone:    "America/Chicago",
+		ValidPeriod: timeutil.Period{
+			Start: mustParseModuleTime("2026-05-29T00:00:00-05:00"),
+			End:   mustParseModuleTime("2026-05-30T00:00:00-05:00"),
+		},
+	}
+	isDay := true
+	tempF := 74.0
+	apparentF := 76.0
+	humidity := 71.0
+	windMph := 8.0
+	windDirection := 190.0
+	updatedAt := mustParseModuleTime("2026-05-29T07:30:00-05:00")
+	return ModuleContext{
+		Resolved: resolved,
+		Collected: facts.CollectedFacts{
+			Current: &weatherdata.Current{
+				ConditionText:           "Partly cloudy",
+				IsDay:                   &isDay,
+				TemperatureF:            &tempF,
+				ApparentTemperatureF:    &apparentF,
+				RelativeHumidityPercent: &humidity,
+				WindSpeedMph:            &windMph,
+				WindDirectionDegrees:    &windDirection,
+			},
+			Alerts: &weatherdata.AlertRun{Alerts: []json.RawMessage{
+				json.RawMessage(`{"event":"Flood Watch","headline":"Flooding possible","severity":"Moderate"}`),
+			}},
+			Discussion: &weatherdata.Discussion{
+				Product:     "discussion",
+				KeyMessages: []string{"Scattered showers are possible."},
+				ShortTerm:   &weatherdata.DiscussionSection{Text: "Showers increase this afternoon."},
+				LongTerm:    &weatherdata.DiscussionSection{Text: "Periodic rain chances continue."},
+			},
+			WeatherStory: &weatherdata.WeatherStory{
+				OfficeID:    "LSX",
+				StartTime:   mustParseModuleTime("2026-05-29T06:00:00-05:00"),
+				EndTime:     mustParseModuleTime("2026-05-29T18:00:00-05:00"),
+				UpdatedAt:   &updatedAt,
+				Title:       "Rain Chances",
+				Description: "Scattered showers are possible.",
+				AltText:     "Weather story graphic with rain chances.",
+				Priority:    true,
+				Order:       1,
+				DownloadURL: "https://example.invalid/story.png",
+			},
+			SourceProvenance: []weatherdata.Source{{Name: "alerts", FetchedAt: generatedAt}},
+			SourceWarnings: []weatherdata.SourceWarning{{
+				Source:             "daily",
+				Code:               "missing_source",
+				Severity:           "warning",
+				Message:            "daily source is missing",
+				Endpoint:           "/forecast/daily",
+				CompletenessImpact: "source omitted",
+			}},
+		},
+		Derived: facts.DerivedFacts{
+			AlertOverlaps: []forecast.AlertOverlap{{
+				Event:    "Flood Watch",
+				Headline: "Flooding possible",
+				Severity: "Moderate",
+			}},
+		},
+		Units:    "us",
+		Timezone: "America/Chicago",
+		Location: &LocationContext{
+			ID:       "home",
+			Name:     "Brentwood",
+			Region:   "St. Louis Metro",
+			Timezone: "America/Chicago",
+		},
+	}
+}
+
+func moduleValue[T any](t *testing.T, output *module.Output) T {
+	t.Helper()
+	var value T
+	data, err := json.Marshal(output.Value)
+	if err != nil {
+		t.Fatalf("marshal module value: %v", err)
+	}
+	if err := json.Unmarshal(data, &value); err != nil {
+		t.Fatalf("decode module value: %v", err)
+	}
+	return value
+}
+
+func mustParseModuleTime(value string) time.Time {
+	parsed, err := time.Parse(time.RFC3339, value)
+	if err != nil {
+		panic(err)
+	}
+	return parsed
+}

internal/briefing/daily_test.go

@@ -1,327 +0,0 @@
-package briefing
-
-import (
-	"encoding/json"
-	"os"
-	"path/filepath"
-	"strings"
-	"testing"
-	"time"
-
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
-)
-
-func TestDailyBriefingFromRepresentativeFixture(t *testing.T) {
-	bundle := loadBundleFixture(t)
-	currentIsDay := true
-	currentTemp := 75.9
-	currentFeelsLike := 76.1
-	currentHumidity := 56.0
-	currentWind := 10.7
-	bundle.Current = &forecast.Current{
-		ConditionText:           "Partly cloudy",
-		IsDay:                   &currentIsDay,
-		TemperatureF:            &currentTemp,
-		ApparentTemperatureF:    &currentFeelsLike,
-		RelativeHumidityPercent: &currentHumidity,
-		WindSpeedMph:            &currentWind,
-	}
-	bundle.Sources[0].DataSHA256 = "abc123"
-	bundle.Warnings = []forecast.SourceWarning{{Source: "daily", Code: "missing_source", Severity: "warning"}}
-	location := mustLocation(t)
-	resolved := mustResolveDaily(t, location)
-	summary, err := forecast.BuildDailySummary(bundle, resolved.ValidPeriod.Start, location, defaultDayparts())
-	if err != nil {
-		t.Fatalf("BuildDailySummary() error = %v", err)
-	}
-
-	pkg, err := BuildDaily(BuildContext{
-		Resolved: resolved,
-		Bundle:   bundle,
-		Units:    "us",
-		Timezone: "America/Chicago",
-		Location: &LocationContext{
-			ID:       "home",
-			Name:     "Brentwood",
-			Region:   "St. Louis Metro",
-			Timezone: "America/Chicago",
-		},
-	}, summary)
-	if err != nil {
-		t.Fatalf("BuildDaily() error = %v", err)
-	}
-
-	if pkg.Metadata.SchemaVersion != SchemaVersion {
-		t.Fatalf("SchemaVersion = %q, want %q", pkg.Metadata.SchemaVersion, SchemaVersion)
-	}
-	if !strings.Contains(pkg.Metadata.RunID, "daily_today") {
-		t.Fatalf("RunID = %q, want report id", pkg.Metadata.RunID)
-	}
-	if pkg.Metadata.ReportID != report.DailyToday {
-		t.Fatalf("ReportID = %q, want daily_today", pkg.Metadata.ReportID)
-	}
-	if pkg.Metadata.Units != "us" || pkg.Metadata.Timezone != "America/Chicago" {
-		t.Fatalf("metadata units/timezone = %q/%q", pkg.Metadata.Units, pkg.Metadata.Timezone)
-	}
-	if pkg.Metadata.Location == nil || pkg.Metadata.Location.ID != "home" || pkg.Metadata.Location.Name != "Brentwood" || pkg.Metadata.Location.Region != "St. Louis Metro" || pkg.Metadata.Location.Timezone != "America/Chicago" {
-		t.Fatalf("metadata location = %#v, want configured prompt location", pkg.Metadata.Location)
-	}
-	if pkg.CurrentConditions == nil || pkg.CurrentConditions.ConditionText != "Partly cloudy" || pkg.CurrentConditions.TemperatureF == nil || *pkg.CurrentConditions.TemperatureF != currentTemp || pkg.CurrentConditions.RelativeHumidityPercent == nil || *pkg.CurrentConditions.RelativeHumidityPercent != currentHumidity {
-		t.Fatalf("CurrentConditions = %#v, want current conditions from bundle", pkg.CurrentConditions)
-	}
-	if len(pkg.Metadata.Sources) != 1 || pkg.Metadata.Sources[0].DataSHA256 != "abc123" {
-		t.Fatalf("Sources = %#v, want source hash", pkg.Metadata.Sources)
-	}
-	if len(pkg.Metadata.SourceWarnings) != 1 {
-		t.Fatalf("SourceWarnings length = %d, want 1", len(pkg.Metadata.SourceWarnings))
-	}
-	if pkg.Daily == nil {
-		t.Fatal("Daily = nil")
-	}
-	if len(pkg.Daily.Dayparts) != 5 {
-		t.Fatalf("Dayparts length = %d, want 5", len(pkg.Daily.Dayparts))
-	}
-	if len(pkg.Daily.RelevantAlerts) != 1 {
-		t.Fatalf("RelevantAlerts length = %d, want 1", len(pkg.Daily.RelevantAlerts))
-	}
-	if len(pkg.Daily.NarrativePeriods) != 1 {
-		t.Fatalf("NarrativePeriods length = %d, want 1", len(pkg.Daily.NarrativePeriods))
-	}
-	if len(pkg.Daily.Discussion.KeyMessages) != 1 {
-		t.Fatalf("Discussion key messages length = %d, want 1", len(pkg.Daily.Discussion.KeyMessages))
-	}
-	if pkg.Daily.Discussion.ShortTerm != "Morning showers taper as a weak boundary shifts east." {
-		t.Fatalf("Discussion.ShortTerm = %q, want short-term AFD narrative", pkg.Daily.Discussion.ShortTerm)
-	}
-	if pkg.Daily.Discussion.LongTerm != "Warmer and more humid conditions return with periodic rain chances." {
-		t.Fatalf("Discussion.LongTerm = %q, want long-term AFD narrative", pkg.Daily.Discussion.LongTerm)
-	}
-	if pkg.Daily.OutdoorWindows.Best == nil || pkg.Daily.OutdoorWindows.Worst == nil {
-		t.Fatalf("OutdoorWindows = %#v, want best and worst", pkg.Daily.OutdoorWindows)
-	}
-	if pkg.Daily.BottomLine.Summary == "" {
-		t.Fatal("BottomLine summary is empty")
-	}
-	if _, err := json.Marshal(pkg); err != nil {
-		t.Fatalf("briefing package is not JSON inspectable: %v", err)
-	}
-}
-
-func TestDailyBriefingQuietWeather(t *testing.T) {
-	location := mustLocation(t)
-	resolved := mustResolveDaily(t, location)
-	bundle := &forecast.Bundle{
-		Hourly: &forecast.ForecastRun{Periods: []forecast.ForecastPeriod{
-			quietHour("2026-05-29T09:00:00-05:00", "2026-05-29T10:00:00-05:00", 72),
-		}},
-		Alerts: &forecast.AlertRun{},
-		Sources: []forecast.Source{
-			{Name: "hourly", FetchedAt: time.Now()},
-			{Name: "alerts", Endpoint: "/alerts/active", FetchedAt: time.Now()},
-			{Name: "current", Endpoint: "/conditions/current", FetchedAt: time.Now(), Missing: true},
-		},
-		Warnings: []forecast.SourceWarning{{Source: "current", Code: "missing_source", Severity: "warning"}},
-	}
-	summary, err := forecast.BuildDailySummary(bundle, resolved.ValidPeriod.Start, location, defaultDayparts())
-	if err != nil {
-		t.Fatalf("BuildDailySummary() error = %v", err)
-	}
-	pkg, err := BuildDaily(BuildContext{Resolved: resolved, Bundle: bundle, Units: "us", Timezone: "America/Chicago"}, summary)
-	if err != nil {
-		t.Fatalf("BuildDaily() error = %v", err)
-	}
-	if pkg.Daily.BottomLine.Summary != "Conditions: Clear." {
-		t.Fatalf("BottomLine summary = %q, want clear conditions", pkg.Daily.BottomLine.Summary)
-	}
-	if pkg.CurrentConditions != nil {
-		t.Fatalf("CurrentConditions = %#v, want nil when current conditions are missing", pkg.CurrentConditions)
-	}
-	if len(pkg.Metadata.SourceWarnings) != 1 || pkg.Metadata.SourceWarnings[0].Source != "current" {
-		t.Fatalf("SourceWarnings = %#v, want current missing-source warning", pkg.Metadata.SourceWarnings)
-	}
-	if len(pkg.Daily.RelevantAlerts) != 0 {
-		t.Fatalf("RelevantAlerts length = %d, want 0", len(pkg.Daily.RelevantAlerts))
-	}
-	if pkg.Metadata.Alerts == nil {
-		t.Fatal("Metadata.Alerts = nil, want checked no-active-alerts status")
-	}
-	if !pkg.Metadata.Alerts.Checked || pkg.Metadata.Alerts.ActiveCount != 0 || pkg.Metadata.Alerts.RelevantCount != 0 || pkg.Metadata.Alerts.Missing {
-		t.Fatalf("Metadata.Alerts = %#v, want checked no-active-alerts status", pkg.Metadata.Alerts)
-	}
-	data, err := json.Marshal(pkg.Metadata.Alerts)
-	if err != nil {
-		t.Fatalf("marshal alert metadata: %v", err)
-	}
-	if strings.Contains(string(data), `"missing"`) {
-		t.Fatalf("alert metadata includes missing for checked empty alerts:\n%s", string(data))
-	}
-}
-
-func TestDailyBriefingAlertExclusion(t *testing.T) {
-	location := mustLocation(t)
-	resolved := mustResolveDaily(t, location)
-	bundle := loadBundleFixture(t)
-	bundle.Alerts = &forecast.AlertRun{Alerts: []json.RawMessage{
-		json.RawMessage(`{"event":"Future Watch","effective":"2026-06-01T00:00:00-05:00","expires":"2026-06-01T06:00:00-05:00"}`),
-	}}
-	summary, err := forecast.BuildDailySummary(bundle, resolved.ValidPeriod.Start, location, defaultDayparts())
-	if err != nil {
-		t.Fatalf("BuildDailySummary() error = %v", err)
-	}
-	pkg, err := BuildDaily(BuildContext{Resolved: resolved, Bundle: bundle, Units: "us", Timezone: "America/Chicago"}, summary)
-	if err != nil {
-		t.Fatalf("BuildDaily() error = %v", err)
-	}
-	if len(pkg.Daily.RelevantAlerts) != 0 {
-		t.Fatalf("RelevantAlerts length = %d, want 0", len(pkg.Daily.RelevantAlerts))
-	}
-}
-
-func TestTomorrowBriefingIncludesPlanningInputs(t *testing.T) {
-	location := mustLocation(t)
-	resolved, err := report.Resolve(report.DailyTomorrow, report.ResolveRequest{
-		Now:      mustParse("2026-05-29T18:00:00-05:00"),
-		Location: location,
-	})
-	if err != nil {
-		t.Fatalf("resolve tomorrow: %v", err)
-	}
-	precip := 70.0
-	wind := 34.0
-	summary := &forecast.DailySummary{
-		Date:   "2026-05-30",
-		Period: resolved.ValidPeriod,
-		Dayparts: []forecast.DaypartSummary{
-			{
-				Name: "overnight",
-				Period: timeutil.Period{
-					Start: mustParse("2026-05-30T00:00:00-05:00"),
-					End:   mustParse("2026-05-30T06:00:00-05:00"),
-				},
-				MaxPrecipitationProbability: &forecast.TimedValue{
-					Value: 40,
-					Time:  mustParse("2026-05-30T03:00:00-05:00"),
-				},
-			},
-			{
-				Name: "morning",
-				Period: timeutil.Period{
-					Start: mustParse("2026-05-30T06:00:00-05:00"),
-					End:   mustParse("2026-05-30T12:00:00-05:00"),
-				},
-				MaxPrecipitationProbability: &forecast.TimedValue{
-					Value: precip,
-					Time:  mustParse("2026-05-30T08:00:00-05:00"),
-				},
-				PeakWindGust: &forecast.TimedValue{
-					Value: wind,
-					Time:  mustParse("2026-05-30T09:00:00-05:00"),
-				},
-				Indicators: forecast.Indicators{Snow: true},
-			},
-		},
-	}
-
-	pkg, err := BuildDaily(BuildContext{
-		Resolved: resolved,
-		Units:    "us",
-		Timezone: "America/Chicago",
-	}, summary)
-	if err != nil {
-		t.Fatalf("BuildDaily() error = %v", err)
-	}
-
-	if pkg.Metadata.ReportID != report.DailyTomorrow || pkg.Metadata.Variant != "tomorrow" {
-		t.Fatalf("metadata report/variant = %q/%q, want tomorrow", pkg.Metadata.ReportID, pkg.Metadata.Variant)
-	}
-	if pkg.Daily.ForecastSummaryDate != "2026-05-30" {
-		t.Fatalf("ForecastSummaryDate = %q, want 2026-05-30", pkg.Daily.ForecastSummaryDate)
-	}
-	if pkg.Daily.Planning == nil {
-		t.Fatal("Planning = nil, want tomorrow planning inputs")
-	}
-	if len(pkg.Daily.Planning.MorningReadiness) == 0 || len(pkg.Daily.Planning.CommuteSchoolWorkdayConcerns) == 0 || len(pkg.Daily.Planning.OvernightChangeWatch) == 0 {
-		t.Fatalf("Planning = %#v, want populated planning inputs", pkg.Daily.Planning)
-	}
-	if !strings.Contains(strings.Join(pkg.Daily.Planning.MorningReadiness, " "), "precipitation") {
-		t.Fatalf("MorningReadiness = %#v, want precipitation note", pkg.Daily.Planning.MorningReadiness)
-	}
-}
-
-func TestSaveBriefingPackage(t *testing.T) {
-	pkg := Package{Metadata: Metadata{SchemaVersion: SchemaVersion}}
-	path := filepath.Join(t.TempDir(), "nested", "briefing.json")
-	if err := Save(path, pkg); err != nil {
-		t.Fatalf("Save() error = %v", err)
-	}
-	data, err := os.ReadFile(path)
-	if err != nil {
-		t.Fatalf("read briefing: %v", err)
-	}
-	if !strings.Contains(string(data), SchemaVersion) {
-		t.Fatalf("saved briefing missing schema version:\n%s", string(data))
-	}
-}
-
-func loadBundleFixture(t *testing.T) *forecast.Bundle {
-	t.Helper()
-	data, err := os.ReadFile(filepath.Join("..", "forecast", "testdata", "daily_bundle.json"))
-	if err != nil {
-		t.Fatalf("read bundle fixture: %v", err)
-	}
-	var bundle forecast.Bundle
-	if err := json.Unmarshal(data, &bundle); err != nil {
-		t.Fatalf("decode bundle fixture: %v", err)
-	}
-	return &bundle
-}
-
-func mustResolveDaily(t *testing.T, location *time.Location) report.Resolved {
-	t.Helper()
-	resolved, err := report.Resolve(report.DailyToday, report.ResolveRequest{
-		Now:      mustParse("2026-05-29T05:00:00-05:00"),
-		Location: location,
-	})
-	if err != nil {
-		t.Fatalf("resolve daily: %v", err)
-	}
-	return resolved
-}
-
-func defaultDayparts() []forecast.DaypartDefinition {
-	return []forecast.DaypartDefinition{
-		{Name: "overnight", Start: "00:00", End: "06:00"},
-		{Name: "morning", Start: "06:00", End: "10:00"},
-		{Name: "midday", Start: "10:00", End: "15:00"},
-		{Name: "afternoon", Start: "15:00", End: "17:00"},
-		{Name: "evening", Start: "17:00", End: "24:00"},
-	}
-}
-
-func quietHour(start string, end string, temperature float64) forecast.ForecastPeriod {
-	return forecast.ForecastPeriod{
-		StartTime:       mustParse(start),
-		EndTime:         mustParse(end),
-		TextDescription: "Clear",
-		TemperatureF:    &temperature,
-	}
-}
-
-func mustLocation(t *testing.T) *time.Location {
-	t.Helper()
-	location, err := time.LoadLocation("America/Chicago")
-	if err != nil {
-		t.Fatalf("load location: %v", err)
-	}
-	return location
-}
-
-func mustParse(value string) time.Time {
-	parsed, err := time.Parse(time.RFC3339, value)
-	if err != nil {
-		panic(err)
-	}
-	return parsed
-}

internal/briefing/derived_modules.go

@@ -0,0 +1,330 @@
+package briefing
+
+import (
+	"fmt"
+	"strings"
+	"time"
+	"unicode"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+)
+
+type DerivedDailySummaryModule struct {
+	Date               string   `json:"date,omitempty"`
+	HighTempF          *int     `json:"high_temp_f,omitempty"`
+	LowTempF           *int     `json:"low_temp_f,omitempty"`
+	MaxPopPercent      *int     `json:"max_pop_percent,omitempty"`
+	MaxPopWindow       string   `json:"max_pop_window,omitempty"`
+	FirstPrecipHour    string   `json:"first_precip_hour,omitempty"`
+	LastPrecipHour     string   `json:"last_precip_hour,omitempty"`
+	ThunderMentioned   bool     `json:"thunder_mentioned"`
+	MaxWindGustMph     *int     `json:"max_wind_gust_mph,omitempty"`
+	HeatIndexMaxF      *int     `json:"heat_index_max_f,omitempty"`
+	DominantConditions []string `json:"dominant_conditions,omitempty"`
+	Hazards            []string `json:"hazards,omitempty"`
+}
+
+type DerivedDaypartSummaryModule struct {
+	Period             timeutil.Period `json:"period"`
+	TempRangeF         string          `json:"temp_range_f,omitempty"`
+	ApparentTempRangeF string          `json:"apparent_temp_range_f,omitempty"`
+	MaxPopPercent      *int            `json:"max_pop_percent,omitempty"`
+	MaxPopTime         string          `json:"max_pop_time,omitempty"`
+	MaxWindGustMph     *int            `json:"max_wind_gust_mph,omitempty"`
+	MaxWindGustTime    string          `json:"max_wind_gust_time,omitempty"`
+	DominantCondition  string          `json:"dominant_condition,omitempty"`
+	NotableConditions  []string        `json:"notable_conditions,omitempty"`
+	Snow               bool            `json:"snow,omitempty"`
+	Ice                bool            `json:"ice,omitempty"`
+	Fog                bool            `json:"fog,omitempty"`
+	Heat               bool            `json:"heat,omitempty"`
+	Cold               bool            `json:"cold,omitempty"`
+	Wind               bool            `json:"wind,omitempty"`
+	RelevantAlertCount int             `json:"relevant_alert_count,omitempty"`
+}
+
+type PrecipTimingModule struct {
+	MaxPopPercent    *int   `json:"max_pop_percent,omitempty"`
+	MaxPopTime       string `json:"max_pop_time,omitempty"`
+	FirstPrecipHour  string `json:"first_precip_hour,omitempty"`
+	LastPrecipHour   string `json:"last_precip_hour,omitempty"`
+	ThunderMentioned bool   `json:"thunder_mentioned"`
+}
+
+type OutdoorWindowsModule struct {
+	Best  *OutdoorWindowModule `json:"best,omitempty"`
+	Worst *OutdoorWindowModule `json:"worst,omitempty"`
+}
+
+type OutdoorWindowModule struct {
+	Daypart string   `json:"daypart"`
+	Start   string   `json:"start"`
+	End     string   `json:"end"`
+	Reasons []string `json:"reasons,omitempty"`
+	Score   float64  `json:"score"`
+}
+
+type TomorrowPlanningModule struct {
+	MorningReadiness             []string `json:"morning_readiness,omitempty"`
+	CommuteSchoolWorkdayConcerns []string `json:"commute_school_workday_concerns,omitempty"`
+	OvernightChangeWatch         []string `json:"overnight_change_watch,omitempty"`
+}
+
+func buildDerivedDailySummaryModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	summary := ctx.Derived.FirstDailySummary()
+	if summary == nil {
+		return nil, fmt.Errorf("daily summary facts are required")
+	}
+	value, err := derivedDailySummaryValue(*summary, ctx.Derived.PrecipTiming, ctx.Timezone)
+	if err != nil {
+		return nil, err
+	}
+	return &module.Output{ID: module.DerivedDailySummary, StanzaName: "derived_daily_summary", Value: value}, nil
+}
+
+func buildDerivedDaypartSummariesModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	if len(ctx.Derived.DaypartSummaries) == 0 {
+		return nil, fmt.Errorf("daypart summary facts are required")
+	}
+	value := map[string]DerivedDaypartSummaryModule{}
+	prefixDates := multipleSummaryDates(ctx.Derived.DailySummaries)
+	for _, daypart := range ctx.Derived.DaypartSummaries {
+		key := daypartKey(daypart, prefixDates)
+		value[key] = derivedDaypartSummaryValue(daypart, ctx.Timezone)
+	}
+	return &module.Output{ID: module.DerivedDaypartSummaries, StanzaName: "derived_daypart_summaries", Value: value}, nil
+}
+
+func buildPrecipTimingModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	value := precipTimingValue(ctx.Derived.PrecipTiming, ctx.Timezone)
+	return &module.Output{ID: module.PrecipTiming, StanzaName: "precip_timing", Value: value}, nil
+}
+
+func buildOutdoorWindowsModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	windows := buildOutdoorWindows(ctx.Derived.DaypartSummaries)
+	value := OutdoorWindowsModule{
+		Best:  outdoorWindowValue(windows.Best),
+		Worst: outdoorWindowValue(windows.Worst),
+	}
+	return &module.Output{ID: module.OutdoorWindows, StanzaName: "outdoor_windows", Value: value}, nil
+}
+
+func buildTomorrowPlanningModule(ctx ModuleContext, _ any) (*module.Output, error) {
+	summary := ctx.Derived.FirstDailySummary()
+	if summary == nil {
+		return &module.Output{ID: module.TomorrowPlanning, StanzaName: "tomorrow_planning", Value: TomorrowPlanningModule{}}, nil
+	}
+	planning := buildTomorrowPlanning(summary)
+	value := TomorrowPlanningModule{}
+	if planning != nil {
+		value.MorningReadiness = append([]string(nil), planning.MorningReadiness...)
+		value.CommuteSchoolWorkdayConcerns = append([]string(nil), planning.CommuteSchoolWorkdayConcerns...)
+		value.OvernightChangeWatch = append([]string(nil), planning.OvernightChangeWatch...)
+	}
+	return &module.Output{ID: module.TomorrowPlanning, StanzaName: "tomorrow_planning", Value: value}, nil
+}
+
+func derivedDailySummaryValue(summary forecast.DailySummary, timing forecast.PrecipTiming, timezone string) (DerivedDailySummaryModule, error) {
+	value := DerivedDailySummaryModule{
+		Date:             summary.Date,
+		ThunderMentioned: timing.ThunderMentioned,
+	}
+	conditions := map[string]struct{}{}
+	hazards := map[string]struct{}{}
+	var temperature forecast.Range
+	var apparent forecast.Range
+	var maxPop *forecast.TimedValue
+	var maxGust *forecast.TimedValue
+	var maxPopWindow timeutil.Period
+	for _, daypart := range summary.Dayparts {
+		addRange(&temperature, daypart.Temperature)
+		addRange(&apparent, daypart.ApparentTemperature)
+		if daypart.MaxPrecipitationProbability != nil {
+			if maxPop == nil || daypart.MaxPrecipitationProbability.Value > maxPop.Value {
+				copied := *daypart.MaxPrecipitationProbability
+				maxPop = &copied
+				maxPopWindow = daypart.Period
+			}
+		}
+		maxTimedValue(&maxGust, daypart.PeakWindGust)
+		if daypart.DominantCondition != "" {
+			conditions[daypart.DominantCondition] = struct{}{}
+		}
+		for _, hazard := range hazardsForIndicators(daypart.Indicators) {
+			hazards[hazard] = struct{}{}
+		}
+	}
+	for _, alert := range summary.AlertOverlaps {
+		if alert.Event != "" {
+			hazards[alert.Event] = struct{}{}
+		}
+	}
+	value.HighTempF = roundedInt(temperature.Max)
+	value.LowTempF = roundedInt(temperature.Min)
+	value.HeatIndexMaxF = roundedInt(apparent.Max)
+	if maxPop != nil {
+		value.MaxPopPercent = roundedInt(&maxPop.Value)
+		value.MaxPopWindow = periodClockLabel(maxPopWindow, timezone)
+	}
+	if maxGust != nil {
+		value.MaxWindGustMph = roundedInt(&maxGust.Value)
+	}
+	value.FirstPrecipHour = timedClockLabel(timing.FirstPrecipitation, timezone)
+	value.LastPrecipHour = timedClockLabel(timing.LastPrecipitation, timezone)
+	value.DominantConditions = sortedSet(conditions)
+	value.Hazards = sortedSet(hazards)
+	return value, nil
+}
+
+func derivedDaypartSummaryValue(daypart forecast.DaypartSummary, timezone string) DerivedDaypartSummaryModule {
+	value := DerivedDaypartSummaryModule{
+		Period:             daypart.Period,
+		TempRangeF:         rangeLabel(daypart.Temperature),
+		ApparentTempRangeF: daypartApparentRangeLabel(daypart.ApparentTemperature),
+		DominantCondition:  daypart.DominantCondition,
+		NotableConditions:  append([]string(nil), daypart.NotableConditions...),
+		Snow:               daypart.Indicators.Snow,
+		Ice:                daypart.Indicators.Ice,
+		Fog:                daypart.Indicators.Fog,
+		Heat:               daypart.Indicators.Heat,
+		Cold:               daypart.Indicators.Cold,
+		Wind:               daypart.Indicators.Wind,
+		RelevantAlertCount: len(daypart.AlertOverlaps),
+	}
+	if daypart.MaxPrecipitationProbability != nil {
+		value.MaxPopPercent = roundedInt(&daypart.MaxPrecipitationProbability.Value)
+		value.MaxPopTime = clockLabel(daypart.MaxPrecipitationProbability.Time, timezone)
+	}
+	if daypart.PeakWindGust != nil {
+		value.MaxWindGustMph = roundedInt(&daypart.PeakWindGust.Value)
+		value.MaxWindGustTime = clockLabel(daypart.PeakWindGust.Time, timezone)
+	}
+	return value
+}
+
+func precipTimingValue(timing forecast.PrecipTiming, timezone string) PrecipTimingModule {
+	value := PrecipTimingModule{ThunderMentioned: timing.ThunderMentioned}
+	if timing.MaxPrecipitationProbability != nil {
+		value.MaxPopPercent = roundedInt(&timing.MaxPrecipitationProbability.Value)
+		value.MaxPopTime = clockLabel(timing.MaxPrecipitationProbability.Time, timezone)
+	}
+	value.FirstPrecipHour = timedClockLabel(timing.FirstPrecipitation, timezone)
+	value.LastPrecipHour = timedClockLabel(timing.LastPrecipitation, timezone)
+	return value
+}
+
+func outdoorWindowValue(window *OutdoorWindow) *OutdoorWindowModule {
+	if window == nil {
+		return nil
+	}
+	return &OutdoorWindowModule{
+		Daypart: window.Daypart,
+		Start:   window.Start,
+		End:     window.End,
+		Reasons: append([]string(nil), window.Reasons...),
+		Score:   window.Score,
+	}
+}
+
+func multipleSummaryDates(summaries []forecast.DailySummary) bool {
+	seen := map[string]struct{}{}
+	for _, summary := range summaries {
+		seen[summary.Date] = struct{}{}
+	}
+	return len(seen) > 1
+}
+
+func daypartKey(daypart forecast.DaypartSummary, prefixDate bool) string {
+	key := normalizedKey(daypart.Name)
+	if key == "" {
+		key = "unnamed"
+	}
+	if !prefixDate {
+		return key
+	}
+	return daypart.Period.Start.Format(timeutil.DateLayout) + "_" + key
+}
+
+func normalizedKey(value string) string {
+	lower := strings.ToLower(strings.TrimSpace(value))
+	var out strings.Builder
+	lastUnderscore := false
+	for _, r := range lower {
+		if unicode.IsLetter(r) || unicode.IsDigit(r) {
+			out.WriteRune(r)
+			lastUnderscore = false
+			continue
+		}
+		if !lastUnderscore {
+			out.WriteByte('_')
+			lastUnderscore = true
+		}
+	}
+	return strings.Trim(out.String(), "_")
+}
+
+func rangeLabel(value forecast.Range) string {
+	if value.Min == nil && value.Max == nil {
+		return ""
+	}
+	if value.Min != nil && value.Max != nil {
+		low := roundedInt(value.Min)
+		high := roundedInt(value.Max)
+		if low != nil && high != nil && *low == *high {
+			return fmt.Sprintf("%d", *low)
+		}
+		return fmt.Sprintf("%d-%d", *low, *high)
+	}
+	if value.Min != nil {
+		low := roundedInt(value.Min)
+		return fmt.Sprintf("%d", *low)
+	}
+	high := roundedInt(value.Max)
+	return fmt.Sprintf("%d", *high)
+}
+
+func daypartApparentRangeLabel(value forecast.Range) string {
+	if value.Min == nil && value.Max == nil {
+		return ""
+	}
+	return rangeLabel(value)
+}
+
+func roundedInt(value *float64) *int {
+	if value == nil {
+		return nil
+	}
+	rounded := int(*value + 0.5)
+	if *value < 0 {
+		rounded = int(*value - 0.5)
+	}
+	return &rounded
+}
+
+func timedClockLabel(value *forecast.TimedValue, timezone string) string {
+	if value == nil {
+		return ""
+	}
+	return clockLabel(value.Time, timezone)
+}
+
+func periodClockLabel(period timeutil.Period, timezone string) string {
+	if !period.IsValid() {
+		return ""
+	}
+	return clockLabel(period.Start, timezone) + "-" + clockLabel(period.End, timezone)
+}
+
+func clockLabel(value time.Time, timezone string) string {
+	location, err := timeutil.LoadLocation(timezone)
+	if err != nil {
+		location = time.UTC
+	}
+	label := value.In(location).Format("3 PM")
+	if label == "12 AM" && value.In(location).Minute() == 0 {
+		return "12 AM"
+	}
+	return label
+}

internal/briefing/derived_modules_test.go

@@ -0,0 +1,240 @@
+package briefing
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/facts"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+)
+
+func TestDerivedDailySummaryModulePackagesOrdinaryForecast(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := derivedModuleContext(report.DailyToday)
+
+	output, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.DerivedDailySummary})
+	if err != nil {
+		t.Fatalf("BuildModule() error = %v", err)
+	}
+	value := moduleValue[DerivedDailySummaryModule](t, output)
+
+	if value.HighTempF == nil || *value.HighTempF != 96 || value.LowTempF == nil || *value.LowTempF != 31 {
+		t.Fatalf("daily temperatures = %#v/%#v, want 96/31", value.HighTempF, value.LowTempF)
+	}
+	if value.MaxPopPercent == nil || *value.MaxPopPercent != 80 || value.MaxPopWindow != "12 PM-6 PM" {
+		t.Fatalf("max precip = %#v %q, want 80 and afternoon window", value.MaxPopPercent, value.MaxPopWindow)
+	}
+	if value.FirstPrecipHour != "8 AM" || value.LastPrecipHour != "1 PM" || !value.ThunderMentioned {
+		t.Fatalf("precip timing = %#v, want morning through afternoon thunder", value)
+	}
+	if value.MaxWindGustMph == nil || *value.MaxWindGustMph != 42 {
+		t.Fatalf("MaxWindGustMph = %#v, want 42", value.MaxWindGustMph)
+	}
+	if value.HeatIndexMaxF == nil || *value.HeatIndexMaxF != 101 {
+		t.Fatalf("HeatIndexMaxF = %#v, want 101", value.HeatIndexMaxF)
+	}
+	data, err := json.Marshal(output.Value)
+	if err != nil {
+		t.Fatalf("marshal daily summary: %v", err)
+	}
+	jsonText := string(data)
+	for _, field := range []string{"high_temp_f", "low_temp_f", "max_pop_percent", "first_precip_hour", "heat_index_max_f"} {
+		if !strings.Contains(jsonText, field) {
+			t.Fatalf("daily json = %s, want field %s", jsonText, field)
+		}
+	}
+	if strings.Contains(jsonText, "qpf") {
+		t.Fatalf("daily json = %s, want no QPF fields without upstream QPF facts", jsonText)
+	}
+}
+
+func TestPrecipTimingModuleHandlesRainyAndDryForecasts(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := derivedModuleContext(report.DailyToday)
+
+	output, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.PrecipTiming})
+	if err != nil {
+		t.Fatalf("BuildModule(rainy) error = %v", err)
+	}
+	rainy := moduleValue[PrecipTimingModule](t, output)
+	if rainy.MaxPopPercent == nil || *rainy.MaxPopPercent != 80 || rainy.FirstPrecipHour != "8 AM" || rainy.LastPrecipHour != "1 PM" || !rainy.ThunderMentioned {
+		t.Fatalf("rainy precip timing = %#v, want peak, first/last, thunder", rainy)
+	}
+
+	ctx.Derived.PrecipTiming = forecast.BuildPrecipTiming([]weatherdata.ForecastPeriod{derivedHour("2026-05-29T10:00:00-05:00", "Sunny", 0, 70, nil, 5)})
+	output, err = registry.BuildModule(ctx, module.ConfigItem{ID: module.PrecipTiming})
+	if err != nil {
+		t.Fatalf("BuildModule(dry) error = %v", err)
+	}
+	dry := moduleValue[PrecipTimingModule](t, output)
+	if dry.FirstPrecipHour != "" || dry.LastPrecipHour != "" || dry.ThunderMentioned {
+		t.Fatalf("dry precip timing = %#v, want no precip hours and no thunder", dry)
+	}
+	if dry.MaxPopPercent == nil || *dry.MaxPopPercent != 0 {
+		t.Fatalf("dry MaxPopPercent = %#v, want checked zero", dry.MaxPopPercent)
+	}
+}
+
+func TestDerivedDaypartSummariesExposeConfiguredKeysAndHazards(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := derivedModuleContext(report.DailyToday)
+
+	output, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.DerivedDaypartSummaries})
+	if err != nil {
+		t.Fatalf("BuildModule() error = %v", err)
+	}
+	value := moduleValue[map[string]DerivedDaypartSummaryModule](t, output)
+
+	morning, ok := value["morning"]
+	if !ok {
+		t.Fatalf("daypart keys = %#v, want configured morning key", value)
+	}
+	if morning.TempRangeF != "58" || morning.MaxPopPercent == nil || *morning.MaxPopPercent != 60 {
+		t.Fatalf("morning = %#v, want temp range and precip peak", morning)
+	}
+	afternoon := value["afternoon"]
+	if !afternoon.Heat || !afternoon.Wind || afternoon.MaxWindGustMph == nil || *afternoon.MaxWindGustMph != 42 {
+		t.Fatalf("afternoon = %#v, want heat and wind hazard values", afternoon)
+	}
+	overnight := value["overnight"]
+	if !overnight.Cold {
+		t.Fatalf("overnight = %#v, want cold hazard", overnight)
+	}
+	data, err := json.Marshal(output.Value)
+	if err != nil {
+		t.Fatalf("marshal daypart summaries: %v", err)
+	}
+	jsonText := string(data)
+	for _, field := range []string{"temp_range_f", "max_pop_percent", "max_wind_gust_mph", "dominant_condition"} {
+		if !strings.Contains(jsonText, field) {
+			t.Fatalf("daypart json = %s, want field %s", jsonText, field)
+		}
+	}
+}
+
+func TestOutdoorWindowsAndTomorrowPlanningModulesPreserveDailyContent(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := derivedModuleContext(report.DailyTomorrow)
+
+	outdoorOutput, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.OutdoorWindows})
+	if err != nil {
+		t.Fatalf("BuildModule(outdoor windows) error = %v", err)
+	}
+	outdoor := moduleValue[OutdoorWindowsModule](t, outdoorOutput)
+	if outdoor.Best == nil || outdoor.Worst == nil {
+		t.Fatalf("outdoor windows = %#v, want best and worst", outdoor)
+	}
+	if outdoor.Best.Daypart != "overnight" || outdoor.Worst.Daypart != "afternoon" {
+		t.Fatalf("outdoor windows = %#v, want quiet overnight and stormy afternoon", outdoor)
+	}
+
+	planningOutput, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.TomorrowPlanning})
+	if err != nil {
+		t.Fatalf("BuildModule(tomorrow planning) error = %v", err)
+	}
+	planning := moduleValue[TomorrowPlanningModule](t, planningOutput)
+	if len(planning.MorningReadiness) == 0 || len(planning.CommuteSchoolWorkdayConcerns) == 0 || len(planning.OvernightChangeWatch) == 0 {
+		t.Fatalf("tomorrow planning = %#v, want daily planning notes", planning)
+	}
+	data, err := json.Marshal(planningOutput.Value)
+	if err != nil {
+		t.Fatalf("marshal tomorrow planning: %v", err)
+	}
+	if !strings.Contains(string(data), "morning_readiness") || strings.Contains(string(data), "morningReadiness") {
+		t.Fatalf("tomorrow planning json = %s, want snake_case fields", string(data))
+	}
+}
+
+func TestDerivedModulesHandleMissingData(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	ctx := derivedModuleContext(report.DailyToday)
+	ctx.Derived.DailySummaries = nil
+	ctx.Derived.DaypartSummaries = nil
+
+	if _, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.DerivedDailySummary}); err == nil {
+		t.Fatal("BuildModule(derived daily summary) error = nil, want required facts error")
+	}
+	if _, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.DerivedDaypartSummaries}); err == nil {
+		t.Fatal("BuildModule(daypart summaries) error = nil, want required facts error")
+	}
+	output, err := registry.BuildModule(ctx, module.ConfigItem{ID: module.OutdoorWindows})
+	if err != nil {
+		t.Fatalf("BuildModule(outdoor windows) error = %v", err)
+	}
+	windows := moduleValue[OutdoorWindowsModule](t, output)
+	if windows.Best != nil || windows.Worst != nil {
+		t.Fatalf("outdoor windows = %#v, want empty output with missing dayparts", windows)
+	}
+}
+
+func derivedModuleContext(id report.ID) ModuleContext {
+	generatedAt := mustParseModuleTime("2026-05-29T08:00:00-05:00")
+	definition := report.DefaultRegistry().MustLookup(id)
+	summary := forecast.DailySummary{
+		Date: "2026-05-29",
+		Period: timeutil.Period{
+			Start: mustParseModuleTime("2026-05-29T00:00:00-05:00"),
+			End:   mustParseModuleTime("2026-05-30T00:00:00-05:00"),
+		},
+		Dayparts: []forecast.DaypartSummary{
+			derivedDaypart("overnight", "2026-05-29T00:00:00-05:00", "2026-05-29T06:00:00-05:00", "Clear and cold", 31, nil, 0, 5),
+			derivedDaypart("morning", "2026-05-29T06:00:00-05:00", "2026-05-29T12:00:00-05:00", "Showers", 58, nil, 60, 15),
+			derivedDaypart("afternoon", "2026-05-29T12:00:00-05:00", "2026-05-29T18:00:00-05:00", "Thunderstorms with gusty wind", 96, floatPtr(101), 80, 42),
+		},
+	}
+	hours := []weatherdata.ForecastPeriod{
+		derivedHour("2026-05-29T00:00:00-05:00", "Clear and cold", 0, 31, nil, 5),
+		derivedHour("2026-05-29T08:00:00-05:00", "Showers", 60, 58, nil, 15),
+		derivedHour("2026-05-29T12:00:00-05:00", "Thunderstorms with gusty wind", 80, 96, floatPtr(101), 42),
+		derivedHour("2026-05-29T13:00:00-05:00", "Heavy rain", 70, 82, nil, 30),
+	}
+	summary.Dayparts[2].AlertOverlaps = []forecast.AlertOverlap{{Event: "Severe Thunderstorm Watch"}}
+	return ModuleContext{
+		Resolved: report.Resolved{
+			Definition:  definition,
+			GeneratedAt: generatedAt,
+			Timezone:    "America/Chicago",
+			ValidPeriod: summary.Period,
+		},
+		Derived: facts.DerivedFacts{
+			ValidPeriodHourlyPeriods: hours,
+			DailySummaries:           []forecast.DailySummary{summary},
+			DaypartSummaries:         append([]forecast.DaypartSummary(nil), summary.Dayparts...),
+			PrecipTiming:             forecast.BuildPrecipTiming(hours),
+		},
+		Units:    "us",
+		Timezone: "America/Chicago",
+	}
+}
+
+func derivedDaypart(name string, start string, end string, text string, temperature float64, apparent *float64, precip float64, gust float64) forecast.DaypartSummary {
+	hour := derivedHour(start, text, precip, temperature, apparent, gust)
+	return forecast.SummarizeDaypart(name, timeutil.Period{
+		Start: mustParseModuleTime(start),
+		End:   mustParseModuleTime(end),
+	}, []weatherdata.ForecastPeriod{hour})
+}
+
+func derivedHour(start string, text string, precip float64, temperature float64, apparent *float64, gust float64) weatherdata.ForecastPeriod {
+	startTime := mustParseModuleTime(start)
+	endTime := startTime.Add(time.Hour)
+	return weatherdata.ForecastPeriod{
+		StartTime:                         startTime,
+		EndTime:                           endTime,
+		TextDescription:                   text,
+		TemperatureF:                      floatPtr(temperature),
+		ApparentTemperatureF:              apparent,
+		ProbabilityOfPrecipitationPercent: floatPtr(precip),
+		WindGustMph:                       floatPtr(gust),
+	}
+}
+
+func floatPtr(value float64) *float64 {
+	return &value
+}

internal/briefing/modules.go

@@ -0,0 +1,298 @@
+package briefing
+
+import (
+	"fmt"
+	"reflect"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/facts"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+)
+
+type ModuleContext struct {
+	Resolved  report.Resolved
+	Collected facts.CollectedFacts
+	Derived   facts.DerivedFacts
+	Units     string
+	Timezone  string
+	Location  *LocationContext
+}
+
+type ModuleBuilder func(ModuleContext, any) (*module.Output, error)
+
+type ModuleDefinition struct {
+	ID                module.ID
+	StanzaName        string
+	DefaultOptions    any
+	RequiredCollected []module.FactRequirement
+	RequiredDerived   []module.FactRequirement
+	SupportedReports  []report.ID
+	MissingData       module.MissingDataBehavior
+	AllowDuplicate    bool
+	Builder           ModuleBuilder
+}
+
+type ModuleRegistry struct {
+	definitions map[module.ID]ModuleDefinition
+}
+
+func DefaultModuleRegistry() (ModuleRegistry, error) {
+	return NewModuleRegistry(defaultModuleDefinitions())
+}
+
+func MustDefaultModuleRegistry() ModuleRegistry {
+	registry, err := DefaultModuleRegistry()
+	if err != nil {
+		panic(err)
+	}
+	return registry
+}
+
+func NewModuleRegistry(definitions []ModuleDefinition) (ModuleRegistry, error) {
+	registry := ModuleRegistry{definitions: map[module.ID]ModuleDefinition{}}
+	seenStanzas := map[string]module.ID{}
+	for i, definition := range definitions {
+		if definition.ID == "" {
+			return ModuleRegistry{}, fmt.Errorf("module definition[%d].id is required", i)
+		}
+		if definition.StanzaName == "" {
+			return ModuleRegistry{}, fmt.Errorf("module %q stanza name is required", definition.ID)
+		}
+		if _, ok := registry.definitions[definition.ID]; ok {
+			return ModuleRegistry{}, fmt.Errorf("duplicate module definition %q", definition.ID)
+		}
+		if existingID, ok := seenStanzas[definition.StanzaName]; ok {
+			return ModuleRegistry{}, fmt.Errorf("duplicate stanza name %q for modules %q and %q", definition.StanzaName, existingID, definition.ID)
+		}
+		seenStanzas[definition.StanzaName] = definition.ID
+		registry.definitions[definition.ID] = definition
+	}
+	return registry, nil
+}
+
+func (r ModuleRegistry) Lookup(id module.ID) (ModuleDefinition, error) {
+	definition, ok := r.definitions[id]
+	if !ok {
+		return ModuleDefinition{}, fmt.Errorf("unknown module %q", id)
+	}
+	return definition, nil
+}
+
+func (r ModuleRegistry) BuildModule(ctx ModuleContext, item module.ConfigItem) (*module.Output, error) {
+	definition, err := r.Lookup(item.ID)
+	if err != nil {
+		return nil, err
+	}
+	if !definition.SupportsReport(ctx.Resolved.Definition.ID) {
+		return nil, fmt.Errorf("module %q is not compatible with report %q", item.ID, ctx.Resolved.Definition.ID)
+	}
+	if err := definition.ValidateOptions(item.Options); err != nil {
+		return nil, err
+	}
+	if definition.Builder == nil {
+		return nil, fmt.Errorf("module %q has no builder", item.ID)
+	}
+	options := item.Options
+	if options == nil {
+		options = definition.DefaultOptions
+	}
+	output, err := definition.Builder(ctx, options)
+	if err != nil {
+		return nil, err
+	}
+	if output == nil {
+		return nil, nil
+	}
+	if output.ID != definition.ID {
+		return nil, fmt.Errorf("module %q produced output id %q", definition.ID, output.ID)
+	}
+	if output.StanzaName != definition.StanzaName {
+		return nil, fmt.Errorf("module %q produced stanza %q, want %q", definition.ID, output.StanzaName, definition.StanzaName)
+	}
+	return output, nil
+}
+
+func (r ModuleRegistry) ValidateComposition(reportID report.ID, items []module.ConfigItem) error {
+	seenModules := map[module.ID]struct{}{}
+	seenStanzas := map[string]module.ID{}
+	for i, item := range items {
+		definition, err := r.Lookup(item.ID)
+		if err != nil {
+			return fmt.Errorf("modules[%d]: %w", i, err)
+		}
+		if _, ok := seenModules[item.ID]; ok && !definition.AllowDuplicate {
+			return fmt.Errorf("modules[%d]: duplicate module %q", i, item.ID)
+		}
+		seenModules[item.ID] = struct{}{}
+		if existingID, ok := seenStanzas[definition.StanzaName]; ok {
+			return fmt.Errorf("modules[%d]: duplicate stanza name %q for modules %q and %q", i, definition.StanzaName, existingID, item.ID)
+		}
+		seenStanzas[definition.StanzaName] = item.ID
+		if !definition.SupportsReport(reportID) {
+			return fmt.Errorf("modules[%d]: module %q is not compatible with report %q", i, item.ID, reportID)
+		}
+		if err := definition.ValidateOptions(item.Options); err != nil {
+			return fmt.Errorf("modules[%d]: %w", i, err)
+		}
+	}
+	return nil
+}
+
+func (d ModuleDefinition) SupportsReport(id report.ID) bool {
+	if len(d.SupportedReports) == 0 {
+		return true
+	}
+	for _, supported := range d.SupportedReports {
+		if supported == id {
+			return true
+		}
+	}
+	return false
+}
+
+func (d ModuleDefinition) ValidateOptions(options any) error {
+	if options == nil {
+		return nil
+	}
+	if d.DefaultOptions == nil {
+		return fmt.Errorf("module %q does not accept options", d.ID)
+	}
+	want := reflect.TypeOf(d.DefaultOptions)
+	got := reflect.TypeOf(options)
+	if got == want {
+		return nil
+	}
+	if got.Kind() == reflect.Pointer && got.Elem() == want {
+		return nil
+	}
+	return fmt.Errorf("module %q options have type %s, want %s", d.ID, got, want)
+}
+
+func defaultModuleDefinitions() []ModuleDefinition {
+	allReports := []report.ID{report.DailyToday, report.DailyTomorrow, report.ThreeDay, report.Weekend, report.Storm}
+	daypartReports := []report.ID{report.DailyToday, report.DailyTomorrow, report.ThreeDay, report.Weekend}
+	return []ModuleDefinition{
+		{
+			ID:                module.Metadata,
+			StanzaName:        "metadata",
+			DefaultOptions:    module.MetadataOptions{},
+			RequiredCollected: []module.FactRequirement{module.CollectedSourceMetadata},
+			SupportedReports:  allReports,
+			MissingData:       module.MissingDataEmpty,
+			Builder:           buildMetadataModule,
+		},
+		{
+			ID:                module.CurrentConditions,
+			StanzaName:        "current_conditions",
+			DefaultOptions:    module.CurrentConditionsOptions{},
+			RequiredCollected: []module.FactRequirement{module.CollectedCurrentConditions},
+			SupportedReports:  allReports,
+			MissingData:       module.MissingDataOmit,
+			Builder:           buildCurrentConditionsModule,
+		},
+		{
+			ID:               module.DerivedDailySummary,
+			StanzaName:       "derived_daily_summary",
+			DefaultOptions:   module.DerivedDailySummaryOptions{},
+			RequiredDerived:  []module.FactRequirement{module.RequiresDerivedDailySummaries, module.RequiresDerivedPrecipTiming},
+			SupportedReports: []report.ID{report.DailyToday, report.DailyTomorrow},
+			MissingData:      module.MissingDataError,
+			Builder:          buildDerivedDailySummaryModule,
+		},
+		{
+			ID:               module.DerivedDaypartSummaries,
+			StanzaName:       "derived_daypart_summaries",
+			DefaultOptions:   module.DerivedDaypartSummariesOptions{},
+			RequiredDerived:  []module.FactRequirement{module.RequiresDerivedDaypartSummaries},
+			SupportedReports: daypartReports,
+			MissingData:      module.MissingDataError,
+			Builder:          buildDerivedDaypartSummariesModule,
+		},
+		{
+			ID:               module.HourlyTable,
+			StanzaName:       "hourly_table",
+			DefaultOptions:   module.HourlyTableOptions{},
+			RequiredDerived:  []module.FactRequirement{module.RequiresDerivedHourlyPeriods},
+			SupportedReports: []report.ID{report.Storm},
+			MissingData:      module.MissingDataError,
+		},
+		{
+			ID:               module.PrecipTiming,
+			StanzaName:       "precip_timing",
+			DefaultOptions:   module.PrecipTimingOptions{},
+			RequiredDerived:  []module.FactRequirement{module.RequiresDerivedDaypartSummaries},
+			SupportedReports: allReports,
+			MissingData:      module.MissingDataEmpty,
+			Builder:          buildPrecipTimingModule,
+		},
+		{
+			ID:                module.AlertDigest,
+			StanzaName:        "alert_digest",
+			DefaultOptions:    module.AlertDigestOptions{},
+			RequiredCollected: []module.FactRequirement{module.CollectedAlerts},
+			RequiredDerived:   []module.FactRequirement{module.RequiresDerivedAlertOverlaps},
+			SupportedReports:  allReports,
+			MissingData:       module.MissingDataEmpty,
+			Builder:           buildAlertDigestModule,
+		},
+		{
+			ID:                module.AreaForecastDiscussion,
+			StanzaName:        "area_forecast_discussion",
+			DefaultOptions:    module.AreaForecastDiscussionOptions{},
+			RequiredCollected: []module.FactRequirement{module.CollectedDiscussion},
+			SupportedReports:  allReports,
+			MissingData:       module.MissingDataOmit,
+			Builder:           buildAreaForecastDiscussionModule,
+		},
+		{
+			ID:                module.WeatherStory,
+			StanzaName:        "weather_story",
+			DefaultOptions:    module.WeatherStoryOptions{},
+			RequiredCollected: []module.FactRequirement{module.CollectedWeatherStory},
+			SupportedReports:  allReports,
+			MissingData:       module.MissingDataOmit,
+			Builder:           buildWeatherStoryModule,
+		},
+		{
+			ID:               module.ForecastDelta,
+			StanzaName:       "forecast_delta",
+			DefaultOptions:   module.ForecastDeltaOptions{},
+			SupportedReports: []report.ID{report.DailyToday, report.DailyTomorrow, report.ThreeDay},
+			MissingData:      module.MissingDataEmpty,
+		},
+		{
+			ID:               module.OutdoorWindows,
+			StanzaName:       "outdoor_windows",
+			DefaultOptions:   module.OutdoorWindowsOptions{},
+			RequiredDerived:  []module.FactRequirement{module.RequiresDerivedDaypartSummaries},
+			SupportedReports: daypartReports,
+			MissingData:      module.MissingDataEmpty,
+			Builder:          buildOutdoorWindowsModule,
+		},
+		{
+			ID:               module.TomorrowPlanning,
+			StanzaName:       "tomorrow_planning",
+			DefaultOptions:   module.TomorrowPlanningOptions{},
+			RequiredDerived:  []module.FactRequirement{module.RequiresDerivedDailySummaries},
+			SupportedReports: []report.ID{report.DailyTomorrow},
+			MissingData:      module.MissingDataEmpty,
+			Builder:          buildTomorrowPlanningModule,
+		},
+		{
+			ID:               module.WeekendPlanning,
+			StanzaName:       "weekend_planning",
+			DefaultOptions:   module.WeekendPlanningOptions{},
+			RequiredDerived:  []module.FactRequirement{module.RequiresDerivedDailySummaries},
+			SupportedReports: []report.ID{report.Weekend},
+			MissingData:      module.MissingDataEmpty,
+		},
+		{
+			ID:               module.StormWindowSummary,
+			StanzaName:       "storm_window_summary",
+			DefaultOptions:   module.StormWindowSummaryOptions{},
+			RequiredDerived:  []module.FactRequirement{module.RequiresDerivedStormWindowSummary},
+			SupportedReports: []report.ID{report.Storm},
+			MissingData:      module.MissingDataError,
+		},
+	}
+}

internal/briefing/modules_test.go

@@ -0,0 +1,76 @@
+package briefing
+
+import (
+	"strings"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+)
+
+func TestDefaultModuleRegistryValidatesReportDefaults(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	for _, definition := range report.DefaultRegistry().All() {
+		if err := registry.ValidateComposition(definition.ID, definition.Modules); err != nil {
+			t.Fatalf("ValidateComposition(%s) error = %v", definition.ID, err)
+		}
+	}
+}
+
+func TestModuleRegistryRejectsUnknownModule(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	err := registry.ValidateComposition(report.DailyToday, []module.ConfigItem{{ID: module.ID("unknown")}})
+	if err == nil || !strings.Contains(err.Error(), `unknown module "unknown"`) {
+		t.Fatalf("error = %v, want unknown module", err)
+	}
+}
+
+func TestModuleRegistryRejectsDuplicateModuleIDs(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	err := registry.ValidateComposition(report.DailyToday, []module.ConfigItem{
+		{ID: module.Metadata},
+		{ID: module.Metadata},
+	})
+	if err == nil || !strings.Contains(err.Error(), `duplicate module "metadata"`) {
+		t.Fatalf("error = %v, want duplicate module", err)
+	}
+}
+
+func TestModuleRegistryRejectsDuplicateStanzaNames(t *testing.T) {
+	_, err := NewModuleRegistry([]ModuleDefinition{
+		{ID: module.Metadata, StanzaName: "metadata", DefaultOptions: module.MetadataOptions{}},
+		{ID: module.CurrentConditions, StanzaName: "metadata", DefaultOptions: module.CurrentConditionsOptions{}},
+	})
+	if err == nil || !strings.Contains(err.Error(), `duplicate stanza name "metadata"`) {
+		t.Fatalf("error = %v, want duplicate stanza name", err)
+	}
+}
+
+func TestModuleRegistryRejectsIncompatibleReports(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	err := registry.ValidateComposition(report.DailyToday, []module.ConfigItem{{ID: module.StormWindowSummary}})
+	if err == nil || !strings.Contains(err.Error(), `module "storm_window_summary" is not compatible with report "daily_today"`) {
+		t.Fatalf("error = %v, want incompatible report", err)
+	}
+}
+
+func TestModuleRegistryRejectsInvalidOptionShapes(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	err := registry.ValidateComposition(report.DailyToday, []module.ConfigItem{
+		{ID: module.Metadata, Options: module.CurrentConditionsOptions{}},
+	})
+	if err == nil || !strings.Contains(err.Error(), `module "metadata" options have type module.CurrentConditionsOptions, want module.MetadataOptions`) {
+		t.Fatalf("error = %v, want invalid option shape", err)
+	}
+}
+
+func TestModuleRegistryAcceptsTypedOptions(t *testing.T) {
+	registry := MustDefaultModuleRegistry()
+	err := registry.ValidateComposition(report.DailyToday, []module.ConfigItem{
+		{ID: module.Metadata, Options: module.MetadataOptions{}},
+		{ID: module.CurrentConditions, Options: &module.CurrentConditionsOptions{}},
+	})
+	if err != nil {
+		t.Fatalf("ValidateComposition() error = %v", err)
+	}
+}

internal/briefing/package.go

@@ -1,29 +1,15 @@
-// Package briefing builds report-specific structured briefing packages.
+// Package briefing builds prompt-facing module values.
 package briefing
 
 import (
-	"fmt"
 	"time"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/fileutil"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
-const SchemaVersion = "weatherreporter.briefing.v1"
-
-type Package struct {
-	Metadata          Metadata                  `json:"metadata"`
-	CurrentConditions *CurrentConditionsContext `json:"currentConditions,omitempty"`
-	Daily             *Daily                    `json:"daily,omitempty"`
-	ThreeDay          *ThreeDay                 `json:"threeDay,omitempty"`
-	Weekend           *Weekend                  `json:"weekend,omitempty"`
-	Storm             *Storm                    `json:"storm,omitempty"`
-}
-
 type Metadata struct {
-	SchemaVersion    string                   `json:"schemaVersion"`
 	RunID            string                      `json:"runId"`
 	ReportID         report.ID                   `json:"reportId"`
 	Variant          string                      `json:"variant,omitempty"`
@@ -36,7 +22,7 @@ type Metadata struct {
 	SourceLocationID string                      `json:"sourceLocationId,omitempty"`
 	SourceLocation   string                      `json:"sourceLocation,omitempty"`
 	Sources          []SourceMetadata            `json:"sources,omitempty"`
-	SourceWarnings   []forecast.SourceWarning `json:"sourceWarnings,omitempty"`
+	SourceWarnings   []weatherdata.SourceWarning `json:"sourceWarnings,omitempty"`
 	Alerts           *AlertStatus                `json:"alerts,omitempty"`
 }
 
@@ -47,21 +33,6 @@ type LocationContext struct {
 	Timezone string `json:"timezone,omitempty"`
 }
 
-type CurrentConditionsContext struct {
-	ConditionText           string   `json:"conditionText,omitempty"`
-	IsDay                   *bool    `json:"isDay,omitempty"`
-	TemperatureC            *float64 `json:"temperatureC,omitempty"`
-	TemperatureF            *float64 `json:"temperatureF,omitempty"`
-	ApparentTemperatureC    *float64 `json:"apparentTemperatureC,omitempty"`
-	ApparentTemperatureF    *float64 `json:"apparentTemperatureF,omitempty"`
-	DewpointC               *float64 `json:"dewpointC,omitempty"`
-	DewpointF               *float64 `json:"dewpointF,omitempty"`
-	RelativeHumidityPercent *float64 `json:"relativeHumidityPercent,omitempty"`
-	WindSpeedKmh            *float64 `json:"windSpeedKmh,omitempty"`
-	WindSpeedMph            *float64 `json:"windSpeedMph,omitempty"`
-	WindDirectionDegrees    *float64 `json:"windDirectionDegrees,omitempty"`
-}
-
 type SourceMetadata struct {
 	Name       string                      `json:"name"`
 	Endpoint   string                      `json:"endpoint,omitempty"`
@@ -70,7 +41,7 @@ type SourceMetadata struct {
 	UpdatedAt  *time.Time                  `json:"updatedAt,omitempty"`
 	DataSHA256 string                      `json:"dataSha256,omitempty"`
 	Missing    bool                        `json:"missing,omitempty"`
-	Warnings   []forecast.SourceWarning `json:"warnings,omitempty"`
+	Warnings   []weatherdata.SourceWarning `json:"warnings,omitempty"`
 }
 
 type AlertStatus struct {
@@ -82,7 +53,7 @@ type AlertStatus struct {
 
 type BuildContext struct {
 	Resolved report.Resolved
-	Bundle   *forecast.Bundle
+	Bundle   *weatherdata.Bundle
 	Units    string
 	Timezone string
 	Location *LocationContext
@@ -92,7 +63,6 @@ func BuildMetadata(ctx BuildContext) Metadata {
 	metadata := ctx.Resolved.Metadata()
 	sourceLocationID, sourceLocation := sourceLocation(ctx.Bundle)
 	return Metadata{
-		SchemaVersion:    SchemaVersion,
 		RunID:            metadata.RunID,
 		ReportID:         metadata.ReportID,
 		Variant:          variantForReport(metadata.ReportID),
@@ -110,13 +80,6 @@ func BuildMetadata(ctx BuildContext) Metadata {
 	}
 }
 
-func buildPackage(ctx BuildContext) Package {
-	return Package{
-		Metadata:          BuildMetadata(ctx),
-		CurrentConditions: currentConditions(ctx.Bundle),
-	}
-}
-
 func copyLocation(location *LocationContext) *LocationContext {
 	if location == nil {
 		return nil
@@ -125,42 +88,6 @@ func copyLocation(location *LocationContext) *LocationContext {
 	return &copied
 }
 
-func currentConditions(bundle *forecast.Bundle) *CurrentConditionsContext {
-	if bundle == nil || bundle.Current == nil {
-		return nil
-	}
-	current := bundle.Current
-	context := CurrentConditionsContext{
-		ConditionText:           current.ConditionText,
-		IsDay:                   copyBool(current.IsDay),
-		TemperatureC:            copyFloat(current.TemperatureC),
-		TemperatureF:            copyFloat(current.TemperatureF),
-		ApparentTemperatureC:    copyFloat(current.ApparentTemperatureC),
-		ApparentTemperatureF:    copyFloat(current.ApparentTemperatureF),
-		DewpointC:               copyFloat(current.DewpointC),
-		DewpointF:               copyFloat(current.DewpointF),
-		RelativeHumidityPercent: copyFloat(current.RelativeHumidityPercent),
-		WindSpeedKmh:            copyFloat(current.WindSpeedKmh),
-		WindSpeedMph:            copyFloat(current.WindSpeedMph),
-		WindDirectionDegrees:    copyFloat(current.WindDirectionDegrees),
-	}
-	if context.ConditionText == "" &&
-		context.IsDay == nil &&
-		context.TemperatureC == nil &&
-		context.TemperatureF == nil &&
-		context.ApparentTemperatureC == nil &&
-		context.ApparentTemperatureF == nil &&
-		context.DewpointC == nil &&
-		context.DewpointF == nil &&
-		context.RelativeHumidityPercent == nil &&
-		context.WindSpeedKmh == nil &&
-		context.WindSpeedMph == nil &&
-		context.WindDirectionDegrees == nil {
-		return nil
-	}
-	return &context
-}
-
 func copyBool(value *bool) *bool {
 	if value == nil {
 		return nil
@@ -177,18 +104,19 @@ func copyFloat(value *float64) *float64 {
 	return &copied
 }
 
-func Save(path string, pkg Package) error {
-	if err := fileutil.WriteJSONAtomic(path, pkg); err != nil {
-		return fmt.Errorf("save briefing package: %w", err)
-	}
+func copyTime(value *time.Time) *time.Time {
+	if value == nil {
 		return nil
 	}
+	copied := *value
+	return &copied
+}
 
-func sourceLocation(bundle *forecast.Bundle) (string, string) {
+func sourceLocation(bundle *weatherdata.Bundle) (string, string) {
 	if bundle == nil {
 		return "", ""
 	}
-	for _, run := range []*forecast.ForecastRun{bundle.Hourly, bundle.Narrative, bundle.Daily} {
+	for _, run := range []*weatherdata.ForecastRun{bundle.Hourly, bundle.Narrative, bundle.Daily} {
 		if run == nil {
 			continue
 		}
@@ -199,7 +127,7 @@ func sourceLocation(bundle *forecast.Bundle) (string, string) {
 	return "", ""
 }
 
-func sourceMetadata(bundle *forecast.Bundle) []SourceMetadata {
+func sourceMetadata(bundle *weatherdata.Bundle) []SourceMetadata {
 	if bundle == nil {
 		return nil
 	}
@@ -219,14 +147,14 @@ func sourceMetadata(bundle *forecast.Bundle) []SourceMetadata {
 	return out
 }
 
-func sourceWarnings(bundle *forecast.Bundle) []forecast.SourceWarning {
+func sourceWarnings(bundle *weatherdata.Bundle) []weatherdata.SourceWarning {
 	if bundle == nil {
 		return nil
 	}
 	return bundle.Warnings
 }
 
-func alertStatus(bundle *forecast.Bundle) *AlertStatus {
+func alertStatus(bundle *weatherdata.Bundle) *AlertStatus {
 	if bundle == nil {
 		return nil
 	}
@@ -247,16 +175,6 @@ func alertStatus(bundle *forecast.Bundle) *AlertStatus {
 	return status
 }
 
-func setRelevantAlertCount(metadata *Metadata, count int) {
-	if metadata.Alerts == nil {
-		if count == 0 {
-			return
-		}
-		metadata.Alerts = &AlertStatus{}
-	}
-	metadata.Alerts.RelevantCount = count
-}
-
 func variantForReport(id report.ID) string {
 	switch id {
 	case report.DailyToday:

internal/briefing/storm.go

@@ -1,201 +0,0 @@
-package briefing
-
-import (
-	"fmt"
-
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
-)
-
-type Storm struct {
-	TimingWindow        timeutil.Period           `json:"timingWindow"`
-	EventHeadlines      []string                  `json:"eventHeadlines,omitempty"`
-	Hazards             []string                  `json:"hazards,omitempty"`
-	MostLikelyScenario  []string                  `json:"mostLikelyScenario,omitempty"`
-	ReasonableWorstCase []string                  `json:"reasonableWorstCase,omitempty"`
-	ConfidenceInputs    []string                  `json:"confidenceInputs,omitempty"`
-	WhatToWatchNext     []string                  `json:"whatToWatchNext,omitempty"`
-	RelevantAlerts      []forecast.AlertOverlap   `json:"relevantAlerts,omitempty"`
-	HourlyPeriods       []forecast.ForecastPeriod `json:"hourlyPeriods,omitempty"`
-	DailyPeriods        []forecast.ForecastPeriod `json:"dailyPeriods,omitempty"`
-	NarrativePeriods    []forecast.ForecastPeriod `json:"narrativePeriods,omitempty"`
-	WindowSummary       forecast.DaypartSummary   `json:"windowSummary"`
-	Discussion          DiscussionContext         `json:"discussion,omitempty"`
-	WeatherStory        *WeatherStoryContext      `json:"weatherStory,omitempty"`
-}
-
-func BuildStorm(ctx BuildContext) (Package, error) {
-	if ctx.Resolved.Definition.ID != report.Storm {
-		return Package{}, fmt.Errorf("storm briefing requires a storm report definition")
-	}
-	if ctx.Bundle == nil {
-		return Package{}, fmt.Errorf("forecast bundle is required")
-	}
-	period := ctx.Resolved.ValidPeriod
-	hourly := forecast.SelectHourlyPeriods(ctx.Bundle.Hourly, period)
-	narrative := forecast.SelectNarrativePeriods(ctx.Bundle, period)
-	daily := forecast.SelectHourlyPeriods(ctx.Bundle.Daily, period)
-	alerts := forecast.AlertOverlaps(ctx.Bundle.Alerts, period)
-	summary := forecast.SummarizeDaypart("storm window", period, hourly)
-	summary.AlertOverlaps = alerts
-
-	storm := &Storm{
-		TimingWindow:        period,
-		EventHeadlines:      stormHeadlines(alerts),
-		Hazards:             stormHazards(alerts, summary),
-		MostLikelyScenario:  mostLikelyStormScenario(hourly, narrative, summary),
-		ReasonableWorstCase: reasonableWorstCase(alerts, summary),
-		ConfidenceInputs:    stormConfidenceInputs(ctx.Bundle),
-		WhatToWatchNext:     stormWatchItems(alerts, summary, ctx.Bundle),
-		RelevantAlerts:      alerts,
-		HourlyPeriods:       hourly,
-		DailyPeriods:        daily,
-		NarrativePeriods:    narrative,
-		WindowSummary:       summary,
-		Discussion:          buildDiscussion(ctx.Bundle.Discussion),
-		WeatherStory:        buildWeatherStory(ctx.Bundle),
-	}
-	pkg := buildPackage(ctx)
-	pkg.Storm = storm
-	setRelevantAlertCount(&pkg.Metadata, len(alerts))
-	return pkg, nil
-}
-
-func stormHeadlines(alerts []forecast.AlertOverlap) []string {
-	var headlines []string
-	for _, alert := range alerts {
-		if alert.Headline != "" {
-			headlines = appendUnique(headlines, alert.Headline)
-			continue
-		}
-		if alert.Event != "" {
-			headlines = appendUnique(headlines, alert.Event)
-		}
-	}
-	if len(headlines) == 0 {
-		return []string{"No active alert headline overlaps the selected storm window."}
-	}
-	return headlines
-}
-
-func stormHazards(alerts []forecast.AlertOverlap, summary forecast.DaypartSummary) []string {
-	hazards := map[string]struct{}{}
-	for _, alert := range alerts {
-		if alert.Event != "" {
-			hazards[alert.Event] = struct{}{}
-		}
-	}
-	for _, hazard := range hazardsForIndicators(summary.Indicators) {
-		hazards[hazard] = struct{}{}
-	}
-	if summary.MaxPrecipitationProbability != nil && summary.MaxPrecipitationProbability.Value >= 50 {
-		hazards["precipitation"] = struct{}{}
-	}
-	if summary.PeakWindGust != nil && summary.PeakWindGust.Value >= 30 {
-		hazards["wind"] = struct{}{}
-	}
-	out := sortedSet(hazards)
-	if len(out) == 0 {
-		return []string{"No storm-specific hazard signal stands out in the selected source data."}
-	}
-	return out
-}
-
-func mostLikelyStormScenario(hourly []forecast.ForecastPeriod, narrative []forecast.ForecastPeriod, summary forecast.DaypartSummary) []string {
-	var items []string
-	if summary.DominantCondition != "" {
-		items = append(items, "Dominant hourly condition: "+summary.DominantCondition+".")
-	}
-	if summary.MaxPrecipitationProbability != nil {
-		items = append(items, fmt.Sprintf("Peak precipitation chance is near %.0f%% around %s.", summary.MaxPrecipitationProbability.Value, summary.MaxPrecipitationProbability.Time.Format("15:04")))
-	}
-	if summary.PeakWindGust != nil {
-		items = append(items, fmt.Sprintf("Peak wind gust is near %.0f mph around %s.", summary.PeakWindGust.Value, summary.PeakWindGust.Time.Format("15:04")))
-	}
-	for _, period := range narrative {
-		if period.TextDescription != "" {
-			items = append(items, "Narrative guidance: "+period.TextDescription)
-			break
-		}
-	}
-	if len(items) == 0 && len(hourly) > 0 {
-		items = append(items, "Hourly forecast periods are available, but no focused storm signal is prominent.")
-	}
-	if len(items) == 0 {
-		items = append(items, "No active storm signal is evident from the selected forecast window.")
-	}
-	return items
-}
-
-func reasonableWorstCase(alerts []forecast.AlertOverlap, summary forecast.DaypartSummary) []string {
-	var items []string
-	for _, alert := range alerts {
-		label := alert.Event
-		if label == "" {
-			label = alert.Headline
-		}
-		if label != "" {
-			items = appendUnique(items, "Alert scenario to consider: "+label+".")
-		}
-	}
-	if summary.Indicators.Wind {
-		items = appendUnique(items, "Wind impacts could be higher where stronger gusts occur.")
-	}
-	if summary.Indicators.Snow || summary.Indicators.Ice {
-		items = appendUnique(items, "Wintry precipitation could create travel impacts if it overlaps the event window.")
-	}
-	if len(items) == 0 {
-		items = append(items, "No clear reasonable worst-case signal is represented in the selected data.")
-	}
-	return items
-}
-
-func stormConfidenceInputs(bundle *forecast.Bundle) []string {
-	var items []string
-	if bundle == nil {
-		return []string{"No source bundle was available for confidence context."}
-	}
-	if bundle.Discussion != nil {
-		items = appendUnique(items, bundle.Discussion.KeyMessages...)
-		if bundle.Discussion.ShortTerm != nil && bundle.Discussion.ShortTerm.Text != "" {
-			items = appendUnique(items, "Short-term discussion is available for confidence context.")
-		}
-	}
-	if bundle.WeatherStory != nil {
-		if bundle.WeatherStory.Title != "" {
-			items = appendUnique(items, "Weather story: "+bundle.WeatherStory.Title+".")
-		} else {
-			items = appendUnique(items, "Weather story source is available.")
-		}
-	}
-	for _, warning := range bundle.Warnings {
-		if warning.Code != "" {
-			items = appendUnique(items, "Source warning: "+warning.Code+".")
-		}
-	}
-	if len(items) == 0 {
-		items = append(items, "No explicit confidence or uncertainty signal was available from the selected source context.")
-	}
-	return items
-}
-
-func stormWatchItems(alerts []forecast.AlertOverlap, summary forecast.DaypartSummary, bundle *forecast.Bundle) []string {
-	var items []string
-	if len(alerts) > 0 {
-		items = append(items, "Watch for alert extensions, cancellations, or upgrades.")
-	}
-	if summary.MaxPrecipitationProbability != nil {
-		items = append(items, "Watch precipitation timing and probability trends.")
-	}
-	if summary.PeakWindGust != nil {
-		items = append(items, "Watch wind gust trends.")
-	}
-	if bundle != nil && bundle.Discussion != nil {
-		items = append(items, "Watch the next forecast discussion update for confidence changes.")
-	}
-	if len(items) == 0 {
-		items = append(items, "Watch for new alerts or stronger wording if the weather pattern changes.")
-	}
-	return appendUnique(nil, items...)
-}

internal/briefing/storm_test.go

@@ -1,169 +0,0 @@
-package briefing
-
-import (
-	"encoding/json"
-	"strings"
-	"testing"
-	"time"
-
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
-)
-
-func TestStormBriefingWithActiveAlert(t *testing.T) {
-	location := mustLocation(t)
-	resolved, err := report.Resolve(report.Storm, report.ResolveRequest{
-		Now:        mustParse("2026-05-29T05:00:00-05:00"),
-		Location:   location,
-		StormStart: mustParse("2026-05-29T06:00:00-05:00"),
-		StormEnd:   mustParse("2026-05-29T12:00:00-05:00"),
-	})
-	if err != nil {
-		t.Fatalf("resolve storm: %v", err)
-	}
-	precip := 80.0
-	gust := 42.0
-	bundle := &forecast.Bundle{
-		Hourly: &forecast.ForecastRun{Periods: []forecast.ForecastPeriod{{
-			StartTime:                         mustParse("2026-05-29T07:00:00-05:00"),
-			EndTime:                           mustParse("2026-05-29T08:00:00-05:00"),
-			TextDescription:                   "Severe thunderstorms and gusty wind",
-			ProbabilityOfPrecipitationPercent: &precip,
-			WindGustMph:                       &gust,
-		}}},
-		Daily: &forecast.ForecastRun{Periods: []forecast.ForecastPeriod{{
-			StartTime:       mustParse("2026-05-29T06:00:00-05:00"),
-			EndTime:         mustParse("2026-05-29T18:00:00-05:00"),
-			TextDescription: "Storms likely.",
-		}}},
-		Narrative: &forecast.ForecastRun{Periods: []forecast.ForecastPeriod{{
-			StartTime:       mustParse("2026-05-29T06:00:00-05:00"),
-			EndTime:         mustParse("2026-05-29T18:00:00-05:00"),
-			TextDescription: "Damaging wind possible in stronger storms.",
-		}}},
-		Alerts: &forecast.AlertRun{Alerts: []json.RawMessage{
-			json.RawMessage(`{"event":"Severe Thunderstorm Warning","headline":"Severe storms near Testville","severity":"Severe","effective":"2026-05-29T06:30:00-05:00","expires":"2026-05-29T08:30:00-05:00"}`),
-		}},
-		Discussion: &forecast.Discussion{
-			Product:     "discussion",
-			KeyMessages: []string{"Storms may intensify quickly."},
-			ShortTerm:   &forecast.DiscussionSection{Text: "Short-term storm coverage peaks this morning."},
-			LongTerm:    &forecast.DiscussionSection{Text: "Long-term pattern stays unsettled after the event."},
-		},
-		WeatherStory: &forecast.WeatherStory{
-			OfficeID:    "LSX",
-			StartTime:   mustParse("2026-05-29T06:00:00Z"),
-			EndTime:     mustParse("2026-05-29T18:00:00Z"),
-			Title:       "Storm Risk",
-			Description: "Strong storms are possible.",
-			AltText:     "Weather story graphic showing storm risk.",
-			Order:       1,
-		},
-		Sources: []forecast.Source{{Name: "hourly", FetchedAt: time.Now()}},
-	}
-
-	pkg, err := BuildStorm(BuildContext{Resolved: resolved, Bundle: bundle, Units: "us", Timezone: "America/Chicago"})
-	if err != nil {
-		t.Fatalf("BuildStorm() error = %v", err)
-	}
-
-	if pkg.Metadata.ReportID != report.Storm {
-		t.Fatalf("ReportID = %q, want storm", pkg.Metadata.ReportID)
-	}
-	if pkg.Storm == nil {
-		t.Fatal("Storm = nil")
-	}
-	if len(pkg.Storm.RelevantAlerts) != 1 || len(pkg.Storm.EventHeadlines) != 1 {
-		t.Fatalf("alerts/headlines = %#v/%#v, want alert inputs", pkg.Storm.RelevantAlerts, pkg.Storm.EventHeadlines)
-	}
-	if !pkg.Storm.TimingWindow.Start.Equal(resolved.ValidPeriod.Start) || !pkg.Storm.TimingWindow.End.Equal(resolved.ValidPeriod.End) {
-		t.Fatalf("TimingWindow = %#v, want resolved valid period %#v", pkg.Storm.TimingWindow, resolved.ValidPeriod)
-	}
-	if !strings.Contains(strings.Join(pkg.Storm.Hazards, ","), "Severe Thunderstorm Warning") {
-		t.Fatalf("Hazards = %#v, want alert event", pkg.Storm.Hazards)
-	}
-	if len(pkg.Storm.HourlyPeriods) != 1 || len(pkg.Storm.DailyPeriods) != 1 || len(pkg.Storm.NarrativePeriods) != 1 {
-		t.Fatalf("selected periods hourly/daily/narrative = %d/%d/%d, want selected source periods", len(pkg.Storm.HourlyPeriods), len(pkg.Storm.DailyPeriods), len(pkg.Storm.NarrativePeriods))
-	}
-	if pkg.Storm.WeatherStory == nil {
-		t.Fatal("WeatherStory = nil, want available story context")
-	}
-	if pkg.Storm.WeatherStory.Title != "Storm Risk" || pkg.Storm.WeatherStory.Description != "Strong storms are possible." {
-		t.Fatalf("WeatherStory = %#v, want structured story context", pkg.Storm.WeatherStory)
-	}
-	if pkg.Storm.Discussion.ShortTerm != "Short-term storm coverage peaks this morning." {
-		t.Fatalf("Discussion.ShortTerm = %q, want short-term AFD narrative", pkg.Storm.Discussion.ShortTerm)
-	}
-	if pkg.Storm.Discussion.LongTerm != "Long-term pattern stays unsettled after the event." {
-		t.Fatalf("Discussion.LongTerm = %q, want long-term AFD narrative", pkg.Storm.Discussion.LongTerm)
-	}
-	if len(pkg.Storm.WhatToWatchNext) == 0 {
-		t.Fatal("WhatToWatchNext length = 0, want watch inputs")
-	}
-}
-
-func TestStormBriefingWithDiscussionButNoAlert(t *testing.T) {
-	location := mustLocation(t)
-	resolved, err := report.Resolve(report.Storm, report.ResolveRequest{
-		Now:        mustParse("2026-05-29T05:00:00-05:00"),
-		Location:   location,
-		StormStart: mustParse("2026-05-29T06:00:00-05:00"),
-		StormEnd:   mustParse("2026-05-29T12:00:00-05:00"),
-	})
-	if err != nil {
-		t.Fatalf("resolve storm: %v", err)
-	}
-	bundle := &forecast.Bundle{
-		Hourly:     &forecast.ForecastRun{Periods: []forecast.ForecastPeriod{{StartTime: mustParse("2026-05-29T07:00:00-05:00"), EndTime: mustParse("2026-05-29T08:00:00-05:00"), TextDescription: "Showers"}}},
-		Alerts:     &forecast.AlertRun{},
-		Discussion: &forecast.Discussion{Product: "discussion", KeyMessages: []string{"Confidence is moderate."}},
-		Sources:    []forecast.Source{{Name: "hourly", FetchedAt: time.Now()}},
-	}
-
-	pkg, err := BuildStorm(BuildContext{Resolved: resolved, Bundle: bundle, Units: "us", Timezone: "America/Chicago"})
-	if err != nil {
-		t.Fatalf("BuildStorm() error = %v", err)
-	}
-
-	if len(pkg.Storm.RelevantAlerts) != 0 {
-		t.Fatalf("RelevantAlerts length = %d, want 0", len(pkg.Storm.RelevantAlerts))
-	}
-	if !strings.Contains(strings.Join(pkg.Storm.EventHeadlines, " "), "No active alert") {
-		t.Fatalf("EventHeadlines = %#v, want no-alert fallback", pkg.Storm.EventHeadlines)
-	}
-	if !strings.Contains(strings.Join(pkg.Storm.ConfidenceInputs, " "), "Confidence is moderate") {
-		t.Fatalf("ConfidenceInputs = %#v, want discussion key message", pkg.Storm.ConfidenceInputs)
-	}
-	if len(pkg.Storm.MostLikelyScenario) == 0 {
-		t.Fatal("MostLikelyScenario length = 0, want forecast scenario inputs")
-	}
-}
-
-func TestStormBriefingQuietWindow(t *testing.T) {
-	location := mustLocation(t)
-	resolved, err := report.Resolve(report.Storm, report.ResolveRequest{
-		Now:        mustParse("2026-05-29T05:00:00-05:00"),
-		Location:   location,
-		StormStart: mustParse("2026-05-29T06:00:00-05:00"),
-		StormEnd:   mustParse("2026-05-29T12:00:00-05:00"),
-	})
-	if err != nil {
-		t.Fatalf("resolve storm: %v", err)
-	}
-	bundle := &forecast.Bundle{
-		Hourly:  &forecast.ForecastRun{Periods: []forecast.ForecastPeriod{{StartTime: mustParse("2026-05-29T07:00:00-05:00"), EndTime: mustParse("2026-05-29T08:00:00-05:00"), TextDescription: "Clear"}}},
-		Sources: []forecast.Source{{Name: "hourly", FetchedAt: time.Now()}},
-	}
-
-	pkg, err := BuildStorm(BuildContext{Resolved: resolved, Bundle: bundle, Units: "us", Timezone: "America/Chicago"})
-	if err != nil {
-		t.Fatalf("BuildStorm() error = %v", err)
-	}
-
-	if len(pkg.Storm.Hazards) != 1 || !strings.Contains(pkg.Storm.Hazards[0], "No storm-specific") {
-		t.Fatalf("Hazards = %#v, want quiet hazard fallback", pkg.Storm.Hazards)
-	}
-	if !strings.Contains(strings.Join(pkg.Storm.WhatToWatchNext, " "), "new alerts") {
-		t.Fatalf("WhatToWatchNext = %#v, want watch fallback", pkg.Storm.WhatToWatchNext)
-	}
-}

internal/briefing/summary_helpers.go

@@ -5,120 +5,27 @@ import (
 	"math"
 	"sort"
 	"strings"
-	"time"
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 )
 
-type Daily struct {
-	BottomLine          BottomLine                `json:"bottomLine"`
-	Dayparts            []forecast.DaypartSummary `json:"dayparts"`
-	RelevantAlerts      []forecast.AlertOverlap   `json:"relevantAlerts,omitempty"`
-	OutdoorWindows      OutdoorWindows            `json:"outdoorWindows"`
-	Planning            *TomorrowPlanning         `json:"planning,omitempty"`
-	NarrativePeriods    []forecast.ForecastPeriod `json:"narrativePeriods,omitempty"`
-	Discussion          DiscussionContext         `json:"discussion,omitempty"`
-	WeatherStory        *WeatherStoryContext      `json:"weatherStory,omitempty"`
-	ForecastSummaryDate string                    `json:"forecastSummaryDate"`
-}
-
-type BottomLine struct {
-	Summary              string               `json:"summary"`
-	Hazards              []string             `json:"hazards,omitempty"`
-	Temperature          forecast.Range       `json:"temperature,omitempty"`
-	MaxPrecipProbability *forecast.TimedValue `json:"maxPrecipitationProbability,omitempty"`
-	PeakWindGust         *forecast.TimedValue `json:"peakWindGust,omitempty"`
-}
-
 type OutdoorWindows struct {
-	Best  *OutdoorWindow `json:"best,omitempty"`
-	Worst *OutdoorWindow `json:"worst,omitempty"`
+	Best  *OutdoorWindow
+	Worst *OutdoorWindow
 }
 
 type OutdoorWindow struct {
-	Daypart string   `json:"daypart"`
-	Start   string   `json:"start"`
-	End     string   `json:"end"`
-	Reasons []string `json:"reasons,omitempty"`
-	Score   float64  `json:"score"`
+	Daypart string
+	Start   string
+	End     string
+	Reasons []string
+	Score   float64
 }
 
 type TomorrowPlanning struct {
-	MorningReadiness             []string `json:"morningReadiness,omitempty"`
-	CommuteSchoolWorkdayConcerns []string `json:"commuteSchoolWorkdayConcerns,omitempty"`
-	OvernightChangeWatch         []string `json:"overnightChangeWatch,omitempty"`
-}
-
-type DiscussionContext struct {
-	Product     string   `json:"product,omitempty"`
-	KeyMessages []string `json:"keyMessages,omitempty"`
-	ShortTerm   string   `json:"shortTerm,omitempty"`
-	LongTerm    string   `json:"longTerm,omitempty"`
-}
-
-type WeatherStoryContext struct {
-	Available   bool       `json:"available"`
-	OfficeID    string     `json:"officeId,omitempty"`
-	StartTime   time.Time  `json:"startTime"`
-	EndTime     time.Time  `json:"endTime"`
-	UpdatedAt   *time.Time `json:"updatedAt,omitempty"`
-	Title       string     `json:"title,omitempty"`
-	Description string     `json:"description,omitempty"`
-	AltText     string     `json:"altText,omitempty"`
-	Priority    bool       `json:"priority"`
-	Order       int        `json:"order"`
-	DownloadURL string     `json:"downloadUrl,omitempty"`
-}
-
-func BuildDaily(ctx BuildContext, summary *forecast.DailySummary) (Package, error) {
-	if ctx.Resolved.Definition.ID != report.DailyToday && ctx.Resolved.Definition.ID != report.DailyTomorrow {
-		return Package{}, fmt.Errorf("daily briefing requires a daily report definition")
-	}
-	if summary == nil {
-		return Package{}, fmt.Errorf("daily forecast summary is required")
-	}
-	pkg := buildPackage(ctx)
-	pkg.Daily = &Daily{
-		BottomLine:          buildBottomLine(summary),
-		Dayparts:            summary.Dayparts,
-		RelevantAlerts:      summary.AlertOverlaps,
-		OutdoorWindows:      buildOutdoorWindows(summary.Dayparts),
-		NarrativePeriods:    summary.NarrativePeriods,
-		Discussion:          buildDiscussion(summary.Discussion),
-		WeatherStory:        buildWeatherStory(ctx.Bundle),
-		ForecastSummaryDate: summary.Date,
-	}
-	setRelevantAlertCount(&pkg.Metadata, len(summary.AlertOverlaps))
-	if ctx.Resolved.Definition.ID == report.DailyTomorrow {
-		pkg.Daily.Planning = buildTomorrowPlanning(summary)
-	}
-	return pkg, nil
-}
-
-func buildBottomLine(summary *forecast.DailySummary) BottomLine {
-	bottomLine := BottomLine{}
-	conditions := map[string]struct{}{}
-	hazards := map[string]struct{}{}
-	for _, daypart := range summary.Dayparts {
-		addRange(&bottomLine.Temperature, daypart.Temperature)
-		maxTimedValue(&bottomLine.MaxPrecipProbability, daypart.MaxPrecipitationProbability)
-		maxTimedValue(&bottomLine.PeakWindGust, daypart.PeakWindGust)
-		if daypart.DominantCondition != "" {
-			conditions[daypart.DominantCondition] = struct{}{}
-		}
-		for _, hazard := range hazardsForIndicators(daypart.Indicators) {
-			hazards[hazard] = struct{}{}
-		}
-	}
-	for _, alert := range summary.AlertOverlaps {
-		if alert.Event != "" {
-			hazards[alert.Event] = struct{}{}
-		}
-	}
-	bottomLine.Hazards = sortedSet(hazards)
-	bottomLine.Summary = bottomLineText(sortedSet(conditions), bottomLine.Hazards)
-	return bottomLine
+	MorningReadiness             []string
+	CommuteSchoolWorkdayConcerns []string
+	OvernightChangeWatch         []string
 }
 
 func buildOutdoorWindows(dayparts []forecast.DaypartSummary) OutdoorWindows {
@@ -250,51 +157,6 @@ func daypartNamed(dayparts []forecast.DaypartSummary, name string) *forecast.Day
 	return nil
 }
 
-func buildDiscussion(discussion *forecast.Discussion) DiscussionContext {
-	if discussion == nil {
-		return DiscussionContext{}
-	}
-	ctx := DiscussionContext{
-		Product:     discussion.Product,
-		KeyMessages: discussion.KeyMessages,
-	}
-	if discussion.ShortTerm != nil {
-		ctx.ShortTerm = discussion.ShortTerm.Text
-	}
-	if discussion.LongTerm != nil {
-		ctx.LongTerm = discussion.LongTerm.Text
-	}
-	return ctx
-}
-
-func buildWeatherStory(bundle *forecast.Bundle) *WeatherStoryContext {
-	if bundle == nil || bundle.WeatherStory == nil {
-		return nil
-	}
-	story := bundle.WeatherStory
-	return &WeatherStoryContext{
-		Available:   true,
-		OfficeID:    story.OfficeID,
-		StartTime:   story.StartTime,
-		EndTime:     story.EndTime,
-		UpdatedAt:   copyTime(story.UpdatedAt),
-		Title:       story.Title,
-		Description: story.Description,
-		AltText:     story.AltText,
-		Priority:    story.Priority,
-		Order:       story.Order,
-		DownloadURL: story.DownloadURL,
-	}
-}
-
-func copyTime(value *time.Time) *time.Time {
-	if value == nil {
-		return nil
-	}
-	copied := *value
-	return &copied
-}
-
 func scoreOutdoorWindow(daypart forecast.DaypartSummary) OutdoorWindow {
 	score := 0.0
 	reasons := []string{}
@@ -335,20 +197,6 @@ func scoreOutdoorWindow(daypart forecast.DaypartSummary) OutdoorWindow {
 	}
 }
 
-func bottomLineText(conditions []string, hazards []string) string {
-	if len(conditions) == 0 && len(hazards) == 0 {
-		return "Quiet weather is expected."
-	}
-	parts := []string{}
-	if len(conditions) > 0 {
-		parts = append(parts, "Conditions: "+strings.Join(conditions, "; "))
-	}
-	if len(hazards) > 0 {
-		parts = append(parts, "Watch points: "+strings.Join(hazards, "; "))
-	}
-	return strings.Join(parts, ". ") + "."
-}
-
 func hazardsForIndicators(indicators forecast.Indicators) []string {
 	var hazards []string
 	if indicators.Snow {

internal/briefing/three_day.go

@@ -1,128 +0,0 @@
-package briefing
-
-import (
-	"fmt"
-	"sort"
-	"strings"
-
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
-)
-
-type ThreeDay struct {
-	Days           []OutlookDay            `json:"days"`
-	RelevantAlerts []forecast.AlertOverlap `json:"relevantAlerts,omitempty"`
-	Discussion     DiscussionContext       `json:"discussion,omitempty"`
-	WeatherStory   *WeatherStoryContext    `json:"weatherStory,omitempty"`
-}
-
-type OutlookDay struct {
-	Date                        string                    `json:"date"`
-	Period                      timeutil.Period           `json:"period"`
-	OverallCharacter            string                    `json:"overallCharacter"`
-	Temperature                 forecast.Range            `json:"temperature,omitempty"`
-	MaxPrecipitationProbability *forecast.TimedValue      `json:"maxPrecipitationProbability,omitempty"`
-	PeakWindGust                *forecast.TimedValue      `json:"peakWindGust,omitempty"`
-	Risks                       []string                  `json:"risks,omitempty"`
-	OutdoorWindows              OutdoorWindows            `json:"outdoorWindows"`
-	RelevantAlerts              []forecast.AlertOverlap   `json:"relevantAlerts,omitempty"`
-	Dayparts                    []forecast.DaypartSummary `json:"dayparts"`
-}
-
-func BuildThreeDay(ctx BuildContext, summaries []forecast.DailySummary) (Package, error) {
-	if ctx.Resolved.Definition.ID != report.ThreeDay {
-		return Package{}, fmt.Errorf("3-day briefing requires a 3-day report definition")
-	}
-	if len(summaries) == 0 {
-		return Package{}, fmt.Errorf("3-day forecast summaries are required")
-	}
-	pkg := buildPackage(ctx)
-	pkg.ThreeDay = &ThreeDay{
-		Discussion:   buildDiscussion(summaries[0].Discussion),
-		WeatherStory: buildWeatherStory(ctx.Bundle),
-	}
-	for _, summary := range summaries {
-		day := buildOutlookDay(summary)
-		pkg.ThreeDay.Days = append(pkg.ThreeDay.Days, day)
-	}
-	pkg.ThreeDay.RelevantAlerts = collectOutlookAlerts(pkg.ThreeDay.Days)
-	setRelevantAlertCount(&pkg.Metadata, len(pkg.ThreeDay.RelevantAlerts))
-	return pkg, nil
-}
-
-func collectOutlookAlerts(days []OutlookDay) []forecast.AlertOverlap {
-	alerts := map[string]forecast.AlertOverlap{}
-	for _, day := range days {
-		for _, alert := range day.RelevantAlerts {
-			key := alert.Event
-			if key == "" {
-				key = alert.Headline
-			}
-			if key != "" {
-				alerts[key] = alert
-			}
-		}
-	}
-	keys := make([]string, 0, len(alerts))
-	for key := range alerts {
-		keys = append(keys, key)
-	}
-	sort.Strings(keys)
-	out := make([]forecast.AlertOverlap, 0, len(keys))
-	for _, key := range keys {
-		out = append(out, alerts[key])
-	}
-	return out
-}
-
-func buildOutlookDay(summary forecast.DailySummary) OutlookDay {
-	day := OutlookDay{
-		Date:           summary.Date,
-		Period:         summary.Period,
-		OutdoorWindows: buildOutdoorWindows(summary.Dayparts),
-		RelevantAlerts: summary.AlertOverlaps,
-		Dayparts:       summary.Dayparts,
-	}
-	conditions := map[string]struct{}{}
-	risks := map[string]struct{}{}
-	for _, daypart := range summary.Dayparts {
-		addRange(&day.Temperature, daypart.Temperature)
-		maxTimedValue(&day.MaxPrecipitationProbability, daypart.MaxPrecipitationProbability)
-		maxTimedValue(&day.PeakWindGust, daypart.PeakWindGust)
-		if daypart.DominantCondition != "" {
-			conditions[daypart.DominantCondition] = struct{}{}
-		}
-		for _, risk := range hazardsForIndicators(daypart.Indicators) {
-			risks[risk] = struct{}{}
-		}
-		if daypart.MaxPrecipitationProbability != nil && daypart.MaxPrecipitationProbability.Value >= 50 {
-			risks["precipitation"] = struct{}{}
-		}
-		if daypart.PeakWindGust != nil && daypart.PeakWindGust.Value >= 30 {
-			risks["wind"] = struct{}{}
-		}
-	}
-	for _, alert := range summary.AlertOverlaps {
-		if alert.Event != "" {
-			risks[alert.Event] = struct{}{}
-		}
-	}
-	day.Risks = sortedSet(risks)
-	day.OverallCharacter = outlookCharacter(sortedSet(conditions), day.Risks)
-	return day
-}
-
-func outlookCharacter(conditions []string, risks []string) string {
-	if len(conditions) == 0 && len(risks) == 0 {
-		return "Quiet weather is expected."
-	}
-	parts := []string{}
-	if len(conditions) > 0 {
-		parts = append(parts, strings.Join(conditions, "; "))
-	}
-	if len(risks) > 0 {
-		parts = append(parts, "risks: "+strings.Join(risks, "; "))
-	}
-	return strings.Join(parts, ". ") + "."
-}

internal/briefing/three_day_test.go

@@ -1,94 +0,0 @@
-package briefing
-
-import (
-	"strings"
-	"testing"
-
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
-)
-
-func TestThreeDayBriefingBuildsOutlookDays(t *testing.T) {
-	location := mustLocation(t)
-	resolved, err := report.Resolve(report.ThreeDay, report.ResolveRequest{
-		Now:      mustParse("2026-05-29T06:00:00-05:00"),
-		Location: location,
-	})
-	if err != nil {
-		t.Fatalf("resolve 3-day: %v", err)
-	}
-	precip := 70.0
-	gust := 35.0
-	summaries := []forecast.DailySummary{
-		{
-			Date: "2026-05-29",
-			Period: timeutil.Period{
-				Start: mustParse("2026-05-29T06:00:00-05:00"),
-				End:   mustParse("2026-05-30T00:00:00-05:00"),
-			},
-			Dayparts: []forecast.DaypartSummary{
-				{
-					Name:              "morning",
-					DominantCondition: "Showers and thunderstorms",
-					MaxPrecipitationProbability: &forecast.TimedValue{
-						Value: precip,
-						Time:  mustParse("2026-05-29T09:00:00-05:00"),
-					},
-					PeakWindGust: &forecast.TimedValue{
-						Value: gust,
-						Time:  mustParse("2026-05-29T10:00:00-05:00"),
-					},
-					Indicators: forecast.Indicators{Wind: true},
-				},
-			},
-			AlertOverlaps: []forecast.AlertOverlap{{Event: "Flood Watch"}},
-			Discussion: &forecast.Discussion{
-				Product:     "discussion",
-				KeyMessages: []string{"Unsettled stretch."},
-				ShortTerm:   &forecast.DiscussionSection{Text: "Short-term rain chances remain focused today."},
-				LongTerm:    &forecast.DiscussionSection{Text: "Long-term warmth builds into the weekend."},
-			},
-		},
-		{
-			Date: "2026-05-30",
-			Period: timeutil.Period{
-				Start: mustParse("2026-05-30T00:00:00-05:00"),
-				End:   mustParse("2026-05-31T00:00:00-05:00"),
-			},
-			Dayparts: []forecast.DaypartSummary{{Name: "afternoon", DominantCondition: "Clear"}},
-		},
-	}
-
-	pkg, err := BuildThreeDay(BuildContext{
-		Resolved: resolved,
-		Units:    "us",
-		Timezone: "America/Chicago",
-	}, summaries)
-	if err != nil {
-		t.Fatalf("BuildThreeDay() error = %v", err)
-	}
-
-	if pkg.Metadata.ReportID != report.ThreeDay {
-		t.Fatalf("ReportID = %q, want three_day", pkg.Metadata.ReportID)
-	}
-	if pkg.ThreeDay == nil {
-		t.Fatal("ThreeDay = nil")
-	}
-	if len(pkg.ThreeDay.Days) != 2 {
-		t.Fatalf("Days length = %d, want 2", len(pkg.ThreeDay.Days))
-	}
-	first := pkg.ThreeDay.Days[0]
-	if !strings.Contains(first.OverallCharacter, "Showers") || !strings.Contains(strings.Join(first.Risks, ","), "wind") {
-		t.Fatalf("first day = %#v, want conditions and risks", first)
-	}
-	if len(pkg.ThreeDay.RelevantAlerts) != 1 {
-		t.Fatalf("RelevantAlerts length = %d, want 1", len(pkg.ThreeDay.RelevantAlerts))
-	}
-	if pkg.ThreeDay.Discussion.ShortTerm != "Short-term rain chances remain focused today." {
-		t.Fatalf("Discussion.ShortTerm = %q, want short-term AFD narrative", pkg.ThreeDay.Discussion.ShortTerm)
-	}
-	if pkg.ThreeDay.Discussion.LongTerm != "Long-term warmth builds into the weekend." {
-		t.Fatalf("Discussion.LongTerm = %q, want long-term AFD narrative", pkg.ThreeDay.Discussion.LongTerm)
-	}
-}

internal/briefing/weekend.go

@@ -1,121 +0,0 @@
-package briefing
-
-import (
-	"fmt"
-	"strings"
-
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
-)
-
-type Weekend struct {
-	Days           []OutlookDay            `json:"days"`
-	Planning       WeekendPlanning         `json:"planning"`
-	RelevantAlerts []forecast.AlertOverlap `json:"relevantAlerts,omitempty"`
-	Discussion     DiscussionContext       `json:"discussion,omitempty"`
-	WeatherStory   *WeatherStoryContext    `json:"weatherStory,omitempty"`
-}
-
-type WeekendPlanning struct {
-	BestOutdoorWindows  []OutdoorWindow `json:"bestOutdoorWindows,omitempty"`
-	WorstWeatherWindows []OutdoorWindow `json:"worstWeatherWindows,omitempty"`
-	RainStormTiming     []string        `json:"rainStormTiming,omitempty"`
-	ComfortConcerns     []string        `json:"comfortConcerns,omitempty"`
-	UncertaintyInputs   []string        `json:"uncertaintyInputs,omitempty"`
-}
-
-func BuildWeekend(ctx BuildContext, summaries []forecast.DailySummary) (Package, error) {
-	if ctx.Resolved.Definition.ID != report.Weekend {
-		return Package{}, fmt.Errorf("weekend briefing requires a weekend report definition")
-	}
-	if len(summaries) == 0 {
-		return Package{}, fmt.Errorf("weekend forecast summaries are required")
-	}
-	pkg := buildPackage(ctx)
-	pkg.Weekend = &Weekend{
-		Discussion:   buildDiscussion(summaries[0].Discussion),
-		WeatherStory: buildWeatherStory(ctx.Bundle),
-	}
-	for _, summary := range summaries {
-		pkg.Weekend.Days = append(pkg.Weekend.Days, buildOutlookDay(summary))
-	}
-	pkg.Weekend.RelevantAlerts = collectOutlookAlerts(pkg.Weekend.Days)
-	setRelevantAlertCount(&pkg.Metadata, len(pkg.Weekend.RelevantAlerts))
-	pkg.Weekend.Planning = buildWeekendPlanning(pkg.Weekend.Days, pkg.Weekend.Discussion, ctx.Bundle)
-	return pkg, nil
-}
-
-func buildWeekendPlanning(days []OutlookDay, discussion DiscussionContext, bundle *forecast.Bundle) WeekendPlanning {
-	planning := WeekendPlanning{}
-	for _, day := range days {
-		if day.OutdoorWindows.Best != nil {
-			window := *day.OutdoorWindows.Best
-			window.Daypart = day.Date + " " + window.Daypart
-			planning.BestOutdoorWindows = append(planning.BestOutdoorWindows, window)
-		}
-		if day.OutdoorWindows.Worst != nil {
-			window := *day.OutdoorWindows.Worst
-			window.Daypart = day.Date + " " + window.Daypart
-			planning.WorstWeatherWindows = append(planning.WorstWeatherWindows, window)
-		}
-		for _, daypart := range day.Dayparts {
-			planning.RainStormTiming = appendUnique(planning.RainStormTiming, weekendRainStormNotes(day.Date, daypart)...)
-			planning.ComfortConcerns = appendUnique(planning.ComfortConcerns, weekendComfortNotes(day.Date, daypart)...)
-		}
-	}
-	planning.UncertaintyInputs = appendUnique(planning.UncertaintyInputs, discussion.KeyMessages...)
-	if discussion.ShortTerm != "" {
-		planning.UncertaintyInputs = appendUnique(planning.UncertaintyInputs, "Short-term discussion available for confidence context.")
-	}
-	if discussion.LongTerm != "" {
-		planning.UncertaintyInputs = appendUnique(planning.UncertaintyInputs, "Long-term discussion available for uncertainty context.")
-	}
-	if bundle != nil {
-		for _, warning := range bundle.Warnings {
-			if warning.Code != "" {
-				planning.UncertaintyInputs = appendUnique(planning.UncertaintyInputs, "Source warning: "+warning.Code+".")
-			}
-		}
-	}
-	if len(planning.RainStormTiming) == 0 {
-		planning.RainStormTiming = append(planning.RainStormTiming, "No focused rain or storm timing stands out in the available weekend forecast.")
-	}
-	if len(planning.ComfortConcerns) == 0 {
-		planning.ComfortConcerns = append(planning.ComfortConcerns, "No major heat, cold, or wind comfort concern stands out in the available weekend forecast.")
-	}
-	if len(planning.UncertaintyInputs) == 0 {
-		planning.UncertaintyInputs = append(planning.UncertaintyInputs, "No explicit confidence or uncertainty signal was available from the selected source context.")
-	}
-	return planning
-}
-
-func weekendRainStormNotes(date string, daypart forecast.DaypartSummary) []string {
-	notes := []string{}
-	label := weekendWindowLabel(date, daypart.Name)
-	if daypart.MaxPrecipitationProbability != nil && daypart.MaxPrecipitationProbability.Value >= 30 {
-		notes = append(notes, fmt.Sprintf("%s precipitation chance peaks near %.0f%%.", label, daypart.MaxPrecipitationProbability.Value))
-	}
-	return notes
-}
-
-func weekendComfortNotes(date string, daypart forecast.DaypartSummary) []string {
-	notes := []string{}
-	label := weekendWindowLabel(date, daypart.Name)
-	if daypart.Indicators.Heat {
-		notes = append(notes, label+" heat may affect outdoor comfort.")
-	}
-	if daypart.Indicators.Cold {
-		notes = append(notes, label+" cold may affect outdoor comfort.")
-	}
-	if daypart.PeakWindGust != nil && daypart.PeakWindGust.Value >= 25 {
-		notes = append(notes, fmt.Sprintf("%s gusts may reach %.0f mph.", label, daypart.PeakWindGust.Value))
-	}
-	return notes
-}
-
-func weekendWindowLabel(date string, daypart string) string {
-	if daypart == "" {
-		return date
-	}
-	return strings.TrimSpace(date + " " + daypart)
-}

internal/briefing/weekend_test.go

@@ -1,99 +0,0 @@
-package briefing
-
-import (
-	"strings"
-	"testing"
-
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
-)
-
-func TestWeekendBriefingBuildsPlanningInputs(t *testing.T) {
-	location := mustLocation(t)
-	resolved, err := report.Resolve(report.Weekend, report.ResolveRequest{
-		Now:      mustParse("2026-05-29T08:00:00-05:00"),
-		Location: location,
-	})
-	if err != nil {
-		t.Fatalf("resolve weekend: %v", err)
-	}
-	precip := 70.0
-	gust := 32.0
-	summaries := []forecast.DailySummary{
-		{
-			Date: "2026-05-30",
-			Period: timeutil.Period{
-				Start: mustParse("2026-05-30T00:00:00-05:00"),
-				End:   mustParse("2026-05-31T00:00:00-05:00"),
-			},
-			Dayparts: []forecast.DaypartSummary{
-				{
-					Name:              "afternoon",
-					DominantCondition: "Showers and thunderstorms",
-					Period: timeutil.Period{
-						Start: mustParse("2026-05-30T12:00:00-05:00"),
-						End:   mustParse("2026-05-30T18:00:00-05:00"),
-					},
-					MaxPrecipitationProbability: &forecast.TimedValue{
-						Value: precip,
-						Time:  mustParse("2026-05-30T15:00:00-05:00"),
-					},
-					PeakWindGust: &forecast.TimedValue{
-						Value: gust,
-						Time:  mustParse("2026-05-30T16:00:00-05:00"),
-					},
-					Indicators: forecast.Indicators{Wind: true},
-					HourlyPeriods: []forecast.ForecastPeriod{
-						{
-							StartTime:       mustParse("2026-05-30T15:00:00-05:00"),
-							EndTime:         mustParse("2026-05-30T16:00:00-05:00"),
-							TextDescription: "Showers and thunderstorms",
-						},
-					},
-				},
-			},
-			AlertOverlaps: []forecast.AlertOverlap{{Event: "Flood Watch"}},
-			Discussion: &forecast.Discussion{
-				Product:     "discussion",
-				KeyMessages: []string{"Timing may shift."},
-				ShortTerm:   &forecast.DiscussionSection{Text: "Short-term showers exit before the weekend."},
-				LongTerm:    &forecast.DiscussionSection{Text: "Long-term weekend rain timing remains uncertain."},
-			},
-		},
-	}
-
-	pkg, err := BuildWeekend(BuildContext{
-		Resolved: resolved,
-		Units:    "us",
-		Timezone: "America/Chicago",
-	}, summaries)
-	if err != nil {
-		t.Fatalf("BuildWeekend() error = %v", err)
-	}
-
-	if pkg.Metadata.ReportID != report.Weekend {
-		t.Fatalf("ReportID = %q, want weekend", pkg.Metadata.ReportID)
-	}
-	if pkg.Weekend == nil {
-		t.Fatal("Weekend = nil")
-	}
-	if len(pkg.Weekend.Days) != 1 {
-		t.Fatalf("Days length = %d, want 1", len(pkg.Weekend.Days))
-	}
-	if len(pkg.Weekend.Planning.WorstWeatherWindows) == 0 {
-		t.Fatalf("WorstWeatherWindows = %#v, want weather window", pkg.Weekend.Planning.WorstWeatherWindows)
-	}
-	if !strings.Contains(strings.Join(pkg.Weekend.Planning.RainStormTiming, " "), "precipitation") {
-		t.Fatalf("RainStormTiming = %#v, want precipitation timing", pkg.Weekend.Planning.RainStormTiming)
-	}
-	if len(pkg.Weekend.Planning.UncertaintyInputs) == 0 {
-		t.Fatal("UncertaintyInputs length = 0, want discussion context")
-	}
-	if pkg.Weekend.Discussion.ShortTerm != "Short-term showers exit before the weekend." {
-		t.Fatalf("Discussion.ShortTerm = %q, want short-term AFD narrative", pkg.Weekend.Discussion.ShortTerm)
-	}
-	if pkg.Weekend.Discussion.LongTerm != "Long-term weekend rain timing remains uncertain." {
-		t.Fatalf("Discussion.LongTerm = %q, want long-term AFD narrative", pkg.Weekend.Discussion.LongTerm)
-	}
-}

internal/changes/daily.go

@@ -1,14 +1,16 @@
-// Package changes compares structured briefing snapshots.
+// Package changes compares structured module snapshots.
 package changes
 
 import (
 	"fmt"
 	"math"
 	"sort"
+	"strconv"
+	"strings"
 	"time"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
 )
 
 type Thresholds struct {
@@ -25,83 +27,168 @@ type Change struct {
 	Current  string `json:"current,omitempty"`
 }
 
-func CompareDaily(previous briefing.Package, current briefing.Package, thresholds Thresholds) ([]Change, error) {
-	if previous.Daily == nil {
-		return nil, fmt.Errorf("previous daily briefing is required")
+func CompareDaily(previous module.Snapshot, current module.Snapshot, thresholds Thresholds) ([]Change, error) {
+	previousSummary, err := requiredStanza[dailySummaryStanza](previous, "derived_daily_summary")
+	if err != nil {
+		return nil, fmt.Errorf("previous daily summary: %w", err)
 	}
-	if current.Daily == nil {
-		return nil, fmt.Errorf("current daily briefing is required")
+	currentSummary, err := requiredStanza[dailySummaryStanza](current, "derived_daily_summary")
+	if err != nil {
+		return nil, fmt.Errorf("current daily summary: %w", err)
 	}
+	previousDayparts, err := requiredStanza[map[string]daypartSummaryStanza](previous, "derived_daypart_summaries")
+	if err != nil {
+		return nil, fmt.Errorf("previous daypart summaries: %w", err)
+	}
+	currentDayparts, err := requiredStanza[map[string]daypartSummaryStanza](current, "derived_daypart_summaries")
+	if err != nil {
+		return nil, fmt.Errorf("current daypart summaries: %w", err)
+	}
+	previousAlerts, _, err := module.StanzaValue[alertDigestStanza](previous, "alert_digest")
+	if err != nil {
+		return nil, err
+	}
+	currentAlerts, _, err := module.StanzaValue[alertDigestStanza](current, "alert_digest")
+	if err != nil {
+		return nil, err
+	}
+	previousTiming, previousHasTiming, err := module.StanzaValue[precipTimingStanza](previous, "precip_timing")
+	if err != nil {
+		return nil, err
+	}
+	currentTiming, currentHasTiming, err := module.StanzaValue[precipTimingStanza](current, "precip_timing")
+	if err != nil {
+		return nil, err
+	}
+
 	var changes []Change
-	changes = append(changes, compareTemperature(previous.Daily.BottomLine.Temperature, current.Daily.BottomLine.Temperature, thresholds.TemperatureDegrees)...)
-	changes = append(changes, comparePrecipitation(previous.Daily.BottomLine.MaxPrecipProbability, current.Daily.BottomLine.MaxPrecipProbability, thresholds)...)
-	changes = append(changes, compareWind(previous.Daily.BottomLine.PeakWindGust, current.Daily.BottomLine.PeakWindGust, float64(thresholds.WindGustMilesPerHour))...)
-	changes = append(changes, compareAlerts(previous.Daily.RelevantAlerts, current.Daily.RelevantAlerts)...)
-	changes = append(changes, compareIndicators(aggregateIndicators(previous.Daily.Dayparts), aggregateIndicators(current.Daily.Dayparts))...)
+	changes = append(changes, compareTemperatureValues("Low", previousSummary.LowTempF, currentSummary.LowTempF, thresholds.TemperatureDegrees)...)
+	changes = append(changes, compareTemperatureValues("High", previousSummary.HighTempF, currentSummary.HighTempF, thresholds.TemperatureDegrees)...)
+	changes = append(changes, comparePrecipitationValues(previousSummary.MaxPopPercent, currentSummary.MaxPopPercent, thresholds.PrecipProbabilityPoints, "")...)
+	if previousHasTiming && currentHasTiming {
+		changes = append(changes, comparePrecipTiming(previousTiming.MaxPopTime, currentTiming.MaxPopTime, thresholds.PrecipTimingShiftMinutes, "")...)
+	}
+	changes = append(changes, compareWindValues(previousSummary.MaxWindGustMph, currentSummary.MaxWindGustMph, thresholds.WindGustMilesPerHour, "")...)
+	changes = append(changes, compareAlerts(previousAlerts.Relevant, currentAlerts.Relevant)...)
+	changes = append(changes, compareIndicators(aggregateIndicators(previousDayparts), aggregateIndicators(currentDayparts), "")...)
+	sortChanges(changes)
 	return changes, nil
 }
 
-func compareTemperature(previous forecast.Range, current forecast.Range, threshold float64) []Change {
-	var changes []Change
-	if previous.Min != nil && current.Min != nil && differenceAtLeast(*previous.Min, *current.Min, threshold) {
-		changes = append(changes, Change{
-			Type:     "temperature_shift",
-			Message:  fmt.Sprintf("Low temperature changed from %.0f to %.0f.", *previous.Min, *current.Min),
-			Previous: fmt.Sprintf("%.0f", *previous.Min),
-			Current:  fmt.Sprintf("%.0f", *current.Min),
-		})
-	}
-	if previous.Max != nil && current.Max != nil && differenceAtLeast(*previous.Max, *current.Max, threshold) {
-		changes = append(changes, Change{
-			Type:     "temperature_shift",
-			Message:  fmt.Sprintf("High temperature changed from %.0f to %.0f.", *previous.Max, *current.Max),
-			Previous: fmt.Sprintf("%.0f", *previous.Max),
-			Current:  fmt.Sprintf("%.0f", *current.Max),
-		})
-	}
-	return changes
+type dailySummaryStanza struct {
+	Date           string `json:"date,omitempty"`
+	HighTempF      *int   `json:"high_temp_f,omitempty"`
+	LowTempF       *int   `json:"low_temp_f,omitempty"`
+	MaxPopPercent  *int   `json:"max_pop_percent,omitempty"`
+	MaxWindGustMph *int   `json:"max_wind_gust_mph,omitempty"`
 }
 
-func comparePrecipitation(previous *forecast.TimedValue, current *forecast.TimedValue, thresholds Thresholds) []Change {
+type daypartSummaryStanza struct {
+	Period         timeutil.Period `json:"period"`
+	TempRangeF     string          `json:"temp_range_f,omitempty"`
+	MaxPopPercent  *int            `json:"max_pop_percent,omitempty"`
+	MaxPopTime     string          `json:"max_pop_time,omitempty"`
+	MaxWindGustMph *int            `json:"max_wind_gust_mph,omitempty"`
+	Snow           bool            `json:"snow,omitempty"`
+	Ice            bool            `json:"ice,omitempty"`
+}
+
+type precipTimingStanza struct {
+	MaxPopPercent *int   `json:"max_pop_percent,omitempty"`
+	MaxPopTime    string `json:"max_pop_time,omitempty"`
+}
+
+type alertDigestStanza struct {
+	Relevant []alertSummaryStanza `json:"relevant,omitempty"`
+}
+
+type alertSummaryStanza struct {
+	Event    string `json:"event,omitempty"`
+	Headline string `json:"headline,omitempty"`
+}
+
+type indicators struct {
+	Snow bool
+	Ice  bool
+}
+
+func requiredStanza[T any](snapshot module.Snapshot, name string) (T, error) {
+	value, ok, err := module.StanzaValue[T](snapshot, name)
+	if err != nil {
+		return value, err
+	}
+	if !ok {
+		return value, fmt.Errorf("stanza %q is required", name)
+	}
+	return value, nil
+}
+
+func compareTemperatureValues(label string, previous *int, current *int, threshold float64) []Change {
 	if previous == nil || current == nil {
 		return nil
 	}
-	var changes []Change
-	previousCategory := precipitationCategory(previous.Value)
-	currentCategory := precipitationCategory(current.Value)
-	if previousCategory != currentCategory || differenceAtLeast(previous.Value, current.Value, float64(thresholds.PrecipProbabilityPoints)) {
-		changes = append(changes, Change{
-			Type:     "precip_probability_change",
-			Message:  fmt.Sprintf("Peak precipitation chance changed from %.0f%% (%s) to %.0f%% (%s).", previous.Value, previousCategory, current.Value, currentCategory),
-			Previous: fmt.Sprintf("%.0f%% %s", previous.Value, previousCategory),
-			Current:  fmt.Sprintf("%.0f%% %s", current.Value, currentCategory),
-		})
-	}
-	shiftMinutes := int(math.Abs(current.Time.Sub(previous.Time).Minutes()))
-	if thresholds.PrecipTimingShiftMinutes > 0 && shiftMinutes >= thresholds.PrecipTimingShiftMinutes {
-		changes = append(changes, Change{
-			Type:     "precip_timing_shift",
-			Message:  fmt.Sprintf("Peak precipitation timing shifted from %s to %s.", clock(previous.Time), clock(current.Time)),
-			Previous: clock(previous.Time),
-			Current:  clock(current.Time),
-		})
-	}
-	return changes
-}
-
-func compareWind(previous *forecast.TimedValue, current *forecast.TimedValue, threshold float64) []Change {
-	if previous == nil || current == nil || !differenceAtLeast(previous.Value, current.Value, threshold) {
+	if !differenceAtLeast(float64(*previous), float64(*current), threshold) {
 		return nil
 	}
 	return []Change{{
-		Type:     "wind_gust_change",
-		Message:  fmt.Sprintf("Peak wind gust changed from %.0f mph to %.0f mph.", previous.Value, current.Value),
-		Previous: fmt.Sprintf("%.0f mph", previous.Value),
-		Current:  fmt.Sprintf("%.0f mph", current.Value),
+		Type:     "temperature_shift",
+		Message:  fmt.Sprintf("%s temperature changed from %d to %d.", label, *previous, *current),
+		Previous: fmt.Sprintf("%d", *previous),
+		Current:  fmt.Sprintf("%d", *current),
 	}}
 }
 
-func compareAlerts(previous []forecast.AlertOverlap, current []forecast.AlertOverlap) []Change {
+func comparePrecipitationValues(previous *int, current *int, threshold int, prefix string) []Change {
+	if previous == nil || current == nil {
+		return nil
+	}
+	previousCategory := precipitationCategory(float64(*previous))
+	currentCategory := precipitationCategory(float64(*current))
+	if previousCategory == currentCategory && !differenceAtLeast(float64(*previous), float64(*current), float64(threshold)) {
+		return nil
+	}
+	changeType := prefix + "precip_probability_change"
+	return []Change{{
+		Type:     changeType,
+		Message:  fmt.Sprintf("Peak precipitation chance changed from %d%% (%s) to %d%% (%s).", *previous, previousCategory, *current, currentCategory),
+		Previous: fmt.Sprintf("%d%% %s", *previous, previousCategory),
+		Current:  fmt.Sprintf("%d%% %s", *current, currentCategory),
+	}}
+}
+
+func comparePrecipTiming(previous string, current string, thresholdMinutes int, prefix string) []Change {
+	if thresholdMinutes <= 0 || previous == "" || current == "" || previous == current {
+		return nil
+	}
+	previousTime, previousOK := parseClock(previous)
+	currentTime, currentOK := parseClock(current)
+	if !previousOK || !currentOK {
+		return nil
+	}
+	if int(math.Abs(currentTime.Sub(previousTime).Minutes())) < thresholdMinutes {
+		return nil
+	}
+	return []Change{{
+		Type:     prefix + "precip_timing_shift",
+		Message:  fmt.Sprintf("Peak precipitation timing shifted from %s to %s.", previous, current),
+		Previous: previous,
+		Current:  current,
+	}}
+}
+
+func compareWindValues(previous *int, current *int, threshold int, prefix string) []Change {
+	if previous == nil || current == nil || !differenceAtLeast(float64(*previous), float64(*current), float64(threshold)) {
+		return nil
+	}
+	return []Change{{
+		Type:     prefix + "wind_gust_change",
+		Message:  fmt.Sprintf("Peak wind gust changed from %d mph to %d mph.", *previous, *current),
+		Previous: fmt.Sprintf("%d mph", *previous),
+		Current:  fmt.Sprintf("%d mph", *current),
+	}}
+}
+
+func compareAlerts(previous []alertSummaryStanza, current []alertSummaryStanza) []Change {
 	previousSet := alertSet(previous)
 	currentSet := alertSet(current)
 	var changes []Change
@@ -119,7 +206,7 @@ func compareAlerts(previous []forecast.AlertOverlap, current []forecast.AlertOve
 	return changes
 }
 
-func compareIndicators(previous forecast.Indicators, current forecast.Indicators) []Change {
+func compareIndicators(previous indicators, current indicators, prefix string) []Change {
 	var changes []Change
 	for _, item := range []struct {
 		name     string
@@ -132,7 +219,7 @@ func compareIndicators(previous forecast.Indicators, current forecast.Indicators
 		if item.previous == item.current {
 			continue
 		}
-		changeType := item.name + "_risk_change"
+		changeType := prefix + item.name + "_risk_change"
 		if item.current {
 			changes = append(changes, Change{Type: changeType, Message: fmt.Sprintf("%s risk is now present.", item.name), Current: "present"})
 		} else {
@@ -142,16 +229,16 @@ func compareIndicators(previous forecast.Indicators, current forecast.Indicators
 	return changes
 }
 
-func aggregateIndicators(dayparts []forecast.DaypartSummary) forecast.Indicators {
-	out := forecast.Indicators{}
+func aggregateIndicators(dayparts map[string]daypartSummaryStanza) indicators {
+	out := indicators{}
 	for _, daypart := range dayparts {
-		out.Snow = out.Snow || daypart.Indicators.Snow
-		out.Ice = out.Ice || daypart.Indicators.Ice
+		out.Snow = out.Snow || daypart.Snow
+		out.Ice = out.Ice || daypart.Ice
 	}
 	return out
 }
 
-func alertSet(alerts []forecast.AlertOverlap) map[string]struct{} {
+func alertSet(alerts []alertSummaryStanza) map[string]struct{} {
 	out := map[string]struct{}{}
 	for _, alert := range alerts {
 		event := alert.Event
@@ -185,10 +272,6 @@ func differenceAtLeast(previous float64, current float64, threshold float64) boo
 	return math.Abs(current-previous) >= threshold
 }
 
-func clock(t time.Time) string {
-	return t.Format("15:04")
-}
-
 func sortChanges(items []Change) {
 	sort.SliceStable(items, func(i, j int) bool {
 		if items[i].Type == items[j].Type {
@@ -197,3 +280,33 @@ func sortChanges(items []Change) {
 		return items[i].Type < items[j].Type
 	})
 }
+
+func parseClock(value string) (time.Time, bool) {
+	value = strings.TrimSpace(value)
+	for _, layout := range []string{"3 PM", "3:04 PM", "15:04"} {
+		if parsed, err := time.Parse(layout, value); err == nil {
+			return parsed, true
+		}
+	}
+	return time.Time{}, false
+}
+
+func parseTempRange(value string) (*int, *int) {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return nil, nil
+	}
+	parts := strings.Split(value, "-")
+	if len(parts) == 1 {
+		if parsed, err := strconv.Atoi(strings.TrimSpace(parts[0])); err == nil {
+			return &parsed, &parsed
+		}
+		return nil, nil
+	}
+	minValue, minErr := strconv.Atoi(strings.TrimSpace(parts[0]))
+	maxValue, maxErr := strconv.Atoi(strings.TrimSpace(parts[len(parts)-1]))
+	if minErr != nil || maxErr != nil {
+		return nil, nil
+	}
+	return &minValue, &maxValue
+}

internal/changes/daily_test.go

@@ -1,16 +1,17 @@
 package changes
 
 import (
+	"strings"
 	"testing"
 	"time"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
 )
 
 func TestCompareDailyNoMeaningfulChanges(t *testing.T) {
-	previous := dailyBriefing(60, 70, 30, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
-	current := dailyBriefing(61, 71, 35, at("2026-05-29T08:30:00Z"), nil, forecast.Indicators{})
+	previous := dailySnapshot(t, 60, 70, 30, "8 AM", nil, false)
+	current := dailySnapshot(t, 61, 71, 35, "8:30 AM", nil, false)
 
 	changes, err := CompareDaily(previous, current, testThresholds())
 	if err != nil {
@@ -22,8 +23,8 @@ func TestCompareDailyNoMeaningfulChanges(t *testing.T) {
 }
 
 func TestCompareDailyTemperatureThreshold(t *testing.T) {
-	previous := dailyBriefing(50, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
-	current := dailyBriefing(58, 79, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
+	previous := dailySnapshot(t, 50, 70, 10, "8 AM", nil, false)
+	current := dailySnapshot(t, 58, 79, 10, "8 AM", nil, false)
 
 	changes, err := CompareDaily(previous, current, testThresholds())
 	if err != nil {
@@ -35,8 +36,8 @@ func TestCompareDailyTemperatureThreshold(t *testing.T) {
 }
 
 func TestCompareDailyPrecipTimingShift(t *testing.T) {
-	previous := dailyBriefing(60, 70, 60, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
-	current := dailyBriefing(60, 70, 60, at("2026-05-29T11:00:00Z"), nil, forecast.Indicators{})
+	previous := dailySnapshot(t, 60, 70, 60, "8 AM", nil, false)
+	current := dailySnapshot(t, 60, 70, 60, "11 AM", nil, false)
 
 	changes, err := CompareDaily(previous, current, testThresholds())
 	if err != nil {
@@ -48,8 +49,8 @@ func TestCompareDailyPrecipTimingShift(t *testing.T) {
 }
 
 func TestCompareDailyAlertAddedAndRemoved(t *testing.T) {
-	previous := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), []string{"Wind Advisory"}, forecast.Indicators{})
-	current := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), []string{"Flood Watch"}, forecast.Indicators{})
+	previous := dailySnapshot(t, 60, 70, 10, "8 AM", []string{"Wind Advisory"}, false)
+	current := dailySnapshot(t, 60, 70, 10, "8 AM", []string{"Flood Watch"}, false)
 
 	changes, err := CompareDaily(previous, current, testThresholds())
 	if err != nil {
@@ -61,8 +62,8 @@ func TestCompareDailyAlertAddedAndRemoved(t *testing.T) {
 }
 
 func TestCompareDailyIndicatorChange(t *testing.T) {
-	previous := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{})
-	current := dailyBriefing(60, 70, 10, at("2026-05-29T08:00:00Z"), nil, forecast.Indicators{Snow: true})
+	previous := dailySnapshot(t, 60, 70, 10, "8 AM", nil, false)
+	current := dailySnapshot(t, 60, 70, 10, "8 AM", nil, true)
 
 	changes, err := CompareDaily(previous, current, testThresholds())
 	if err != nil {
@@ -73,26 +74,48 @@ func TestCompareDailyIndicatorChange(t *testing.T) {
 	}
 }
 
-func dailyBriefing(low float64, high float64, precip float64, precipTime time.Time, alerts []string, indicators forecast.Indicators) briefing.Package {
-	alertOverlaps := make([]forecast.AlertOverlap, 0, len(alerts))
+func TestCompareDailyRequiresComparisonStanzas(t *testing.T) {
+	_, err := CompareDaily(snapshot(t), dailySnapshot(t, 60, 70, 10, "8 AM", nil, false), testThresholds())
+	if err == nil {
+		t.Fatal("CompareDaily() error = nil, want missing stanza error")
+	}
+	if !strings.Contains(err.Error(), "derived_daily_summary") {
+		t.Fatalf("error = %q, want derived_daily_summary context", err.Error())
+	}
+}
+
+func dailySnapshot(t *testing.T, low int, high int, precip int, precipTime string, alerts []string, snow bool) module.Snapshot {
+	t.Helper()
+	relevant := make([]alertSummaryStanza, 0, len(alerts))
 	for _, alert := range alerts {
-		alertOverlaps = append(alertOverlaps, forecast.AlertOverlap{Event: alert})
+		relevant = append(relevant, alertSummaryStanza{Event: alert})
 	}
-	return briefing.Package{
-		Daily: &briefing.Daily{
-			BottomLine: briefing.BottomLine{
-				Temperature: forecast.Range{Min: &low, Max: &high},
-				MaxPrecipProbability: &forecast.TimedValue{
-					Value: precip,
-					Time:  precipTime,
-				},
-			},
-			RelevantAlerts: alertOverlaps,
-			Dayparts: []forecast.DaypartSummary{
-				{Name: "morning", Indicators: indicators},
-			},
-		},
+	return snapshot(t,
+		module.Output{ID: module.DerivedDailySummary, StanzaName: "derived_daily_summary", Value: dailySummaryStanza{
+			Date:          "2026-05-29",
+			HighTempF:     &high,
+			LowTempF:      &low,
+			MaxPopPercent: &precip,
+		}},
+		module.Output{ID: module.DerivedDaypartSummaries, StanzaName: "derived_daypart_summaries", Value: map[string]daypartSummaryStanza{
+			"morning": {Period: period("2026-05-29T06:00:00Z", "2026-05-29T10:00:00Z"), TempRangeF: "60-70", Snow: snow},
+		}},
+		module.Output{ID: module.PrecipTiming, StanzaName: "precip_timing", Value: precipTimingStanza{MaxPopPercent: &precip, MaxPopTime: precipTime}},
+		module.Output{ID: module.AlertDigest, StanzaName: "alert_digest", Value: alertDigestStanza{Relevant: relevant}},
+	)
 }
+
+func snapshot(t *testing.T, outputs ...module.Output) module.Snapshot {
+	t.Helper()
+	snapshot, err := module.NewSnapshot(outputs)
+	if err != nil {
+		t.Fatalf("NewSnapshot() error = %v", err)
+	}
+	return snapshot
+}
+
+func period(start string, end string) timeutil.Period {
+	return timeutil.Period{Start: at(start), End: at(end)}
 }
 
 func testThresholds() Thresholds {

internal/changes/three_day.go

@@ -2,77 +2,147 @@ package changes
 
 import (
 	"fmt"
-	"time"
+	"sort"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
 )
 
-func CompareThreeDay(previous briefing.Package, current briefing.Package, thresholds Thresholds) ([]Change, error) {
-	if previous.ThreeDay == nil {
-		return nil, fmt.Errorf("previous 3-day briefing is required")
+func CompareThreeDay(previous module.Snapshot, current module.Snapshot, thresholds Thresholds) ([]Change, error) {
+	previousDayparts, err := requiredStanza[map[string]daypartSummaryStanza](previous, "derived_daypart_summaries")
+	if err != nil {
+		return nil, fmt.Errorf("previous daypart summaries: %w", err)
 	}
-	if current.ThreeDay == nil {
-		return nil, fmt.Errorf("current 3-day briefing is required")
+	currentDayparts, err := requiredStanza[map[string]daypartSummaryStanza](current, "derived_daypart_summaries")
+	if err != nil {
+		return nil, fmt.Errorf("current daypart summaries: %w", err)
 	}
-	previousDays := outlookDaysByDate(previous.ThreeDay.Days)
-	currentDays := outlookDaysByDate(current.ThreeDay.Days)
+	previousDays := outlookDaysFromDayparts(previousDayparts)
+	currentDays := outlookDaysFromDayparts(currentDayparts)
+	return compareOutlookDays(previousDays, currentDays, thresholds, "")
+}
+
+type outlookDay struct {
+	Date           string
+	LowTempF       *int
+	HighTempF      *int
+	MaxPopPercent  *int
+	MaxPopTime     string
+	MaxWindGustMph *int
+	Indicators     indicators
+}
+
+func compareOutlookDays(previousDays map[string]outlookDay, currentDays map[string]outlookDay, thresholds Thresholds, prefix string) ([]Change, error) {
 	var changes []Change
 	for date, currentDay := range currentDays {
 		previousDay, ok := previousDays[date]
 		if !ok {
-			changes = append(changes, Change{Type: "outlook_day_added", Message: fmt.Sprintf("Outlook day added: %s.", date), Current: date})
+			changes = append(changes, Change{Type: prefix + "outlook_day_added", Message: fmt.Sprintf("Outlook day added: %s.", date), Current: date})
 			continue
 		}
-		changes = append(changes, compareOutlookDay(date, previousDay, currentDay, thresholds)...)
+		changes = append(changes, compareOutlookDay(date, previousDay, currentDay, thresholds, prefix)...)
 	}
 	for date := range previousDays {
 		if _, ok := currentDays[date]; !ok {
-			changes = append(changes, Change{Type: "outlook_day_removed", Message: fmt.Sprintf("Outlook day removed: %s.", date), Previous: date})
+			changes = append(changes, Change{Type: prefix + "outlook_day_removed", Message: fmt.Sprintf("Outlook day removed: %s.", date), Previous: date})
 		}
 	}
 	sortChanges(changes)
 	return changes, nil
 }
 
-func compareOutlookDay(date string, previous briefing.OutlookDay, current briefing.OutlookDay, thresholds Thresholds) []Change {
+func compareOutlookDay(date string, previous outlookDay, current outlookDay, thresholds Thresholds, prefix string) []Change {
 	var changes []Change
-	for _, change := range compareTemperature(previous.Temperature, current.Temperature, thresholds.TemperatureDegrees) {
+	for _, change := range compareTemperatureValues("Low", previous.LowTempF, current.LowTempF, thresholds.TemperatureDegrees) {
+		change.Message = date + ": " + change.Message
+		change.Type = prefix + "outlook_" + change.Type
+		changes = append(changes, change)
+	}
+	for _, change := range compareTemperatureValues("High", previous.HighTempF, current.HighTempF, thresholds.TemperatureDegrees) {
+		change.Message = date + ": " + change.Message
+		change.Type = prefix + "outlook_" + change.Type
+		changes = append(changes, change)
+	}
+	for _, change := range comparePrecipitationValues(previous.MaxPopPercent, current.MaxPopPercent, thresholds.PrecipProbabilityPoints, prefix+"outlook_") {
 		change.Message = date + ": " + change.Message
 		changes = append(changes, change)
 	}
-	for _, change := range comparePrecipitation(previous.MaxPrecipitationProbability, current.MaxPrecipitationProbability, thresholds) {
+	for _, change := range comparePrecipTiming(previous.MaxPopTime, current.MaxPopTime, thresholds.PrecipTimingShiftMinutes, prefix+"outlook_") {
 		change.Message = date + ": " + change.Message
 		changes = append(changes, change)
-		changes[len(changes)-1].Type = "outlook_" + change.Type
 	}
-	for _, change := range compareWind(previous.PeakWindGust, current.PeakWindGust, float64(thresholds.WindGustMilesPerHour)) {
+	for _, change := range compareWindValues(previous.MaxWindGustMph, current.MaxWindGustMph, thresholds.WindGustMilesPerHour, prefix+"outlook_") {
 		change.Message = date + ": " + change.Message
-		change.Type = "outlook_" + change.Type
 		changes = append(changes, change)
 	}
-	for _, change := range compareAlerts(previous.RelevantAlerts, current.RelevantAlerts) {
+	for _, change := range compareIndicators(previous.Indicators, current.Indicators, prefix+"outlook_") {
 		change.Message = date + ": " + change.Message
-		change.Type = "outlook_" + change.Type
-		changes = append(changes, change)
-	}
-	for _, change := range compareIndicators(aggregateIndicators(previous.Dayparts), aggregateIndicators(current.Dayparts)) {
-		change.Message = date + ": " + change.Message
-		change.Type = "outlook_" + change.Type
 		changes = append(changes, change)
 	}
 	return changes
 }
 
-func outlookDaysByDate(days []briefing.OutlookDay) map[string]briefing.OutlookDay {
-	out := map[string]briefing.OutlookDay{}
-	for _, day := range days {
-		date := day.Date
-		if date == "" && !day.Period.Start.IsZero() {
-			date = day.Period.Start.Format(time.DateOnly)
+func outlookDaysFromDayparts(dayparts map[string]daypartSummaryStanza) map[string]outlookDay {
+	out := map[string]outlookDay{}
+	var keys []string
+	for key := range dayparts {
+		keys = append(keys, key)
 	}
-		if date != "" {
+	sort.Strings(keys)
+	for _, key := range keys {
+		daypart := dayparts[key]
+		date := daypartDate(daypart)
+		if date == "" {
+			continue
+		}
+		day := out[date]
+		day.Date = date
+		low, high := parseTempRange(daypart.TempRangeF)
+		day.LowTempF = minInt(day.LowTempF, low)
+		day.HighTempF = maxInt(day.HighTempF, high)
+		day.MaxPopPercent = maxInt(day.MaxPopPercent, daypart.MaxPopPercent)
+		if daypart.MaxPopPercent != nil && day.MaxPopPercent != nil && *daypart.MaxPopPercent == *day.MaxPopPercent {
+			day.MaxPopTime = daypart.MaxPopTime
+		}
+		day.MaxWindGustMph = maxInt(day.MaxWindGustMph, daypart.MaxWindGustMph)
+		day.Indicators.Snow = day.Indicators.Snow || daypart.Snow
+		day.Indicators.Ice = day.Indicators.Ice || daypart.Ice
 		out[date] = day
 	}
-	}
 	return out
 }
+
+func daypartDate(daypart daypartSummaryStanza) string {
+	if !daypart.Period.Start.IsZero() {
+		return daypart.Period.Start.Format(timeutil.DateLayout)
+	}
+	return ""
+}
+
+func minInt(a *int, b *int) *int {
+	if a == nil {
+		return copyInt(b)
+	}
+	if b != nil && *b < *a {
+		return copyInt(b)
+	}
+	return a
+}
+
+func maxInt(a *int, b *int) *int {
+	if a == nil {
+		return copyInt(b)
+	}
+	if b != nil && *b > *a {
+		return copyInt(b)
+	}
+	return a
+}
+
+func copyInt(value *int) *int {
+	if value == nil {
+		return nil
+	}
+	copied := *value
+	return &copied
+}

internal/changes/three_day_test.go

@@ -2,41 +2,13 @@ package changes
 
 import (
 	"testing"
-	"time"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 )
 
 func TestCompareThreeDayDetectsDayChanges(t *testing.T) {
-	previousTemp := 70.0
-	currentTemp := 78.0
-	previousPrecip := 20.0
-	currentPrecip := 70.0
-	previous := briefing.Package{
-		Metadata: briefing.Metadata{ReportID: report.ThreeDay},
-		ThreeDay: &briefing.ThreeDay{Days: []briefing.OutlookDay{{
-			Date:        "2026-05-29",
-			Temperature: forecast.Range{Max: &previousTemp},
-			MaxPrecipitationProbability: &forecast.TimedValue{
-				Value: previousPrecip,
-				Time:  time.Date(2026, 5, 29, 9, 0, 0, 0, time.UTC),
-			},
-		}}},
-	}
-	current := briefing.Package{
-		Metadata: briefing.Metadata{ReportID: report.ThreeDay},
-		ThreeDay: &briefing.ThreeDay{Days: []briefing.OutlookDay{{
-			Date:        "2026-05-29",
-			Temperature: forecast.Range{Max: &currentTemp},
-			MaxPrecipitationProbability: &forecast.TimedValue{
-				Value: currentPrecip,
-				Time:  time.Date(2026, 5, 29, 12, 0, 0, 0, time.UTC),
-			},
-			Dayparts: []forecast.DaypartSummary{{Indicators: forecast.Indicators{Snow: true}}},
-		}}},
-	}
+	previous := outlookSnapshot(t, "2026-05-29", "70", 20, "9 AM", false)
+	current := outlookSnapshot(t, "2026-05-29", "78", 70, "12 PM", true)
 
 	changes, err := CompareThreeDay(previous, current, Thresholds{
 		TemperatureDegrees:       5,
@@ -50,17 +22,20 @@ func TestCompareThreeDayDetectsDayChanges(t *testing.T) {
 	if len(changes) == 0 {
 		t.Fatal("changes length = 0, want detected 3-day changes")
 	}
-	var foundPrecip bool
-	var foundSnow bool
-	for _, change := range changes {
-		if change.Type == "outlook_precip_probability_change" {
-			foundPrecip = true
-		}
-		if change.Type == "outlook_snow_risk_change" {
-			foundSnow = true
-		}
-	}
-	if !foundPrecip || !foundSnow {
+	if countType(changes, "outlook_precip_probability_change") == 0 || countType(changes, "outlook_snow_risk_change") == 0 {
 		t.Fatalf("changes = %#v, want precipitation and snow changes", changes)
 	}
 }
+
+func outlookSnapshot(t *testing.T, date string, tempRange string, precip int, precipTime string, snow bool) module.Snapshot {
+	t.Helper()
+	return snapshot(t, module.Output{ID: module.DerivedDaypartSummaries, StanzaName: "derived_daypart_summaries", Value: map[string]daypartSummaryStanza{
+		date + "_morning": {
+			Period:        period(date+"T06:00:00Z", date+"T10:00:00Z"),
+			TempRangeF:    tempRange,
+			MaxPopPercent: &precip,
+			MaxPopTime:    precipTime,
+			Snow:          snow,
+		},
+	}})
+}

internal/changes/weekend.go

@@ -3,24 +3,17 @@ package changes
 import (
 	"fmt"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 )
 
-func CompareWeekend(previous briefing.Package, current briefing.Package, thresholds Thresholds) ([]Change, error) {
-	if previous.Weekend == nil {
-		return nil, fmt.Errorf("previous weekend briefing is required")
-	}
-	if current.Weekend == nil {
-		return nil, fmt.Errorf("current weekend briefing is required")
-	}
-	previousOutlook := briefing.Package{ThreeDay: &briefing.ThreeDay{Days: previous.Weekend.Days}}
-	currentOutlook := briefing.Package{ThreeDay: &briefing.ThreeDay{Days: current.Weekend.Days}}
-	changes, err := CompareThreeDay(previousOutlook, currentOutlook, thresholds)
+func CompareWeekend(previous module.Snapshot, current module.Snapshot, thresholds Thresholds) ([]Change, error) {
+	previousDayparts, err := requiredStanza[map[string]daypartSummaryStanza](previous, "derived_daypart_summaries")
 	if err != nil {
-		return nil, err
+		return nil, fmt.Errorf("previous weekend daypart summaries: %w", err)
 	}
-	for i := range changes {
-		changes[i].Type = "weekend_" + changes[i].Type
+	currentDayparts, err := requiredStanza[map[string]daypartSummaryStanza](current, "derived_daypart_summaries")
+	if err != nil {
+		return nil, fmt.Errorf("current weekend daypart summaries: %w", err)
 	}
-	return changes, nil
+	return compareOutlookDays(outlookDaysFromDayparts(previousDayparts), outlookDaysFromDayparts(currentDayparts), thresholds, "weekend_")
 }

internal/changes/weekend_test.go

@@ -1,31 +1,10 @@
 package changes
 
-import (
-	"testing"
-
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
-)
+import "testing"
 
 func TestCompareWeekendDetectsOutlookChanges(t *testing.T) {
-	previousTemp := 70.0
-	currentTemp := 78.0
-	previous := briefing.Package{
-		Metadata: briefing.Metadata{ReportID: report.Weekend},
-		Weekend: &briefing.Weekend{Days: []briefing.OutlookDay{{
-			Date:        "2026-05-30",
-			Temperature: forecast.Range{Max: &previousTemp},
-		}}},
-	}
-	current := briefing.Package{
-		Metadata: briefing.Metadata{ReportID: report.Weekend},
-		Weekend: &briefing.Weekend{Days: []briefing.OutlookDay{{
-			Date:        "2026-05-30",
-			Temperature: forecast.Range{Max: &currentTemp},
-			Dayparts:    []forecast.DaypartSummary{{Indicators: forecast.Indicators{Snow: true}}},
-		}}},
-	}
+	previous := outlookSnapshot(t, "2026-05-30", "70", 10, "9 AM", false)
+	current := outlookSnapshot(t, "2026-05-30", "78", 10, "9 AM", true)
 
 	changes, err := CompareWeekend(previous, current, Thresholds{TemperatureDegrees: 5})
 	if err != nil {
@@ -34,10 +13,7 @@ func TestCompareWeekendDetectsOutlookChanges(t *testing.T) {
 	if len(changes) == 0 {
 		t.Fatal("changes length = 0, want weekend changes")
 	}
-	for _, change := range changes {
-		if change.Type == "weekend_outlook_snow_risk_change" {
-			return
-		}
-	}
+	if countType(changes, "weekend_outlook_snow_risk_change") == 0 {
 		t.Fatalf("changes = %#v, want snow risk change", changes)
 	}
+}

internal/cli/root.go

@@ -26,7 +26,7 @@ Usage:
   weatherreporter run evening [--config PATH] [--units VALUE] [--tz NAME] [--out-dir PATH]
   weatherreporter inspect reports [--config PATH] [--limit N]
   weatherreporter inspect metadata [--config PATH] RUN_ID
-  weatherreporter inspect briefing [--config PATH] RUN_ID
+  weatherreporter inspect modules [--config PATH] RUN_ID
   weatherreporter inspect data-package [--config PATH] RUN_ID
   weatherreporter inspect prior [--config PATH] RUN_ID
   weatherreporter inspect sources [--config PATH] RUN_ID
@@ -118,8 +118,8 @@ var inspectRunCommands = []inspectRunCommand{
 	{Name: "metadata", Inspect: func(ctx context.Context, req app.InspectRunRequest) (any, error) {
 		return app.InspectMetadata(ctx, req)
 	}},
-	{Name: "briefing", Inspect: func(ctx context.Context, req app.InspectRunRequest) (any, error) {
-		return app.InspectBriefing(ctx, req)
+	{Name: "modules", Inspect: func(ctx context.Context, req app.InspectRunRequest) (any, error) {
+		return app.InspectModules(ctx, req)
 	}},
 	{Name: "data-package", Inspect: func(ctx context.Context, req app.InspectRunRequest) (any, error) {
 		return app.InspectDataPackage(ctx, req)

internal/cli/root_test.go

@@ -28,6 +28,10 @@ func TestRunHelpLongFlag(t *testing.T) {
 	if !strings.Contains(stdout.String(), "generate daily") {
 		t.Fatalf("help output missing generate command:\n%s", stdout.String())
 	}
+	removedInspectCommand := "inspect " + "briefing"
+	if !strings.Contains(stdout.String(), "inspect modules") || strings.Contains(stdout.String(), removedInspectCommand) {
+		t.Fatalf("help output has wrong inspect commands:\n%s", stdout.String())
+	}
 }
 
 func TestRunHelpShortFlag(t *testing.T) {
@@ -86,12 +90,12 @@ func TestRunGenerateStormWritesMarkdownReport(t *testing.T) {
 	if !strings.Contains(string(report), "# Daily Report") {
 		t.Fatalf("report output missing markdown:\n%s", string(report))
 	}
-	dataPackagePath := oneArtifact(t, workspaceRoot, "data-packages", "storm", "2026-05-29", "*.data_package.json")
+	dataPackagePath := oneArtifact(t, workspaceRoot, "data-packages", "storm", "2026-05-29", "*.data_package.yaml")
 	data, err := os.ReadFile(dataPackagePath)
 	if err != nil {
 		t.Fatalf("read managed data package: %v", err)
 	}
-	if !strings.Contains(string(data), `"storm"`) || !strings.Contains(string(data), `"weather.storm_report"`) {
+	if !strings.Contains(string(data), "id: storm") || !strings.Contains(string(data), "prompt_id: weather.storm_report") {
 		t.Fatalf("data package output missing storm content:\n%s", string(data))
 	}
 }
@@ -122,12 +126,12 @@ func TestRunGenerateTomorrowWritesMarkdownReport(t *testing.T) {
 	if !strings.Contains(string(report), "# Daily Report") {
 		t.Fatalf("report output missing markdown:\n%s", string(report))
 	}
-	dataPackagePath := oneArtifact(t, workspaceRoot, "data-packages", "daily", "2026-05-30", "*.data_package.json")
+	dataPackagePath := oneArtifact(t, workspaceRoot, "data-packages", "daily", "2026-05-30", "*.data_package.yaml")
 	data, err := os.ReadFile(dataPackagePath)
 	if err != nil {
 		t.Fatalf("read managed data package: %v", err)
 	}
-	if !strings.Contains(string(data), `"daily_tomorrow"`) || !strings.Contains(string(data), `"planning"`) {
+	if !strings.Contains(string(data), "id: daily_tomorrow") || !strings.Contains(string(data), "tomorrow_planning:") {
 		t.Fatalf("data package output missing tomorrow content:\n%s", string(data))
 	}
 	reportMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "reports", "daily", "*.md"))
@@ -160,7 +164,7 @@ func TestRunEveningGeneratesTomorrowReport(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Run() error = %v", err)
 	}
-	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-30", "*.data_package.json"))
+	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-30", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob data package: %v", err)
 	}
@@ -206,7 +210,7 @@ func TestRunGenerateThreeDayWritesMarkdownReport(t *testing.T) {
 	if !strings.Contains(string(report), "# Daily Report") {
 		t.Fatalf("report output missing markdown:\n%s", string(report))
 	}
-	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "three-day", "2026-05-29", "*.data_package.json"))
+	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "three-day", "2026-05-29", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob data package: %v", err)
 	}
@@ -217,7 +221,7 @@ func TestRunGenerateThreeDayWritesMarkdownReport(t *testing.T) {
 	if err != nil {
 		t.Fatalf("read managed data package: %v", err)
 	}
-	if !strings.Contains(string(data), `"three_day"`) || !strings.Contains(string(data), `"threeDay"`) {
+	if !strings.Contains(string(data), "id: three_day") || !strings.Contains(string(data), "derived_daypart_summaries:") {
 		t.Fatalf("data package output missing 3-day content:\n%s", string(data))
 	}
 }
@@ -252,7 +256,7 @@ func TestRunGenerateWeekendWritesMarkdownReport(t *testing.T) {
 	if !strings.Contains(string(report), "# Daily Report") {
 		t.Fatalf("report output missing markdown:\n%s", string(report))
 	}
-	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "weekend", "2026-05-29", "*.data_package.json"))
+	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "weekend", "2026-05-29", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob data package: %v", err)
 	}
@@ -263,7 +267,7 @@ func TestRunGenerateWeekendWritesMarkdownReport(t *testing.T) {
 	if err != nil {
 		t.Fatalf("read managed data package: %v", err)
 	}
-	if !strings.Contains(string(data), `"weekend"`) || !strings.Contains(string(data), `"planning"`) {
+	if !strings.Contains(string(data), "id: weekend") || !strings.Contains(string(data), "derived_daypart_summaries:") {
 		t.Fatalf("data package output missing weekend content:\n%s", string(data))
 	}
 }
@@ -289,7 +293,7 @@ func TestRunMorningIncludesWeekendExceptSunday(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Run() error = %v", err)
 	}
-	weekendPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "weekend", "2026-05-29", "*.data_package.json"))
+	weekendPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "weekend", "2026-05-29", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob weekend packages: %v", err)
 	}
@@ -333,11 +337,11 @@ func TestRunMorningReportsPartialFailureAndContinues(t *testing.T) {
 	if !strings.Contains(stderr.String(), "status=failed") || !strings.Contains(stderr.String(), "status=succeeded") {
 		t.Fatalf("stderr missing structured report logs:\n%s", stderr.String())
 	}
-	dailyPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-29", "*.data_package.json"))
+	dailyPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-29", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob daily packages: %v", err)
 	}
-	weekendPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "weekend", "2026-05-29", "*.data_package.json"))
+	weekendPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "weekend", "2026-05-29", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob weekend packages: %v", err)
 	}
@@ -589,11 +593,11 @@ func TestRunMorningGeneratesDailyAndThreeDayOnSunday(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Run() error = %v", err)
 	}
-	dailyPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-31", "*.data_package.json"))
+	dailyPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-31", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob daily packages: %v", err)
 	}
-	threeDayPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "three-day", "2026-05-31", "*.data_package.json"))
+	threeDayPackages, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "three-day", "2026-05-31", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob 3-day packages: %v", err)
 	}
@@ -634,7 +638,7 @@ func TestRunGenerateDailyWritesMarkdownReport(t *testing.T) {
 	if !strings.Contains(string(report), "# Daily Report") {
 		t.Fatalf("report output missing markdown:\n%s", string(report))
 	}
-	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-29", "*.data_package.json"))
+	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-29", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob data package: %v", err)
 	}
@@ -645,26 +649,15 @@ func TestRunGenerateDailyWritesMarkdownReport(t *testing.T) {
 	if err != nil {
 		t.Fatalf("read managed data package: %v", err)
 	}
-	if !strings.Contains(string(data), `data_package.v1`) || !strings.Contains(string(data), `"daily_today"`) {
+	if !strings.Contains(string(data), "schema_version: weatherreporter.data_package.v2") || !strings.Contains(string(data), "id: daily_today") {
 		t.Fatalf("data package output missing expected content:\n%s", string(data))
 	}
-	var decoded struct {
-		Briefing struct {
-			Metadata struct {
-				Location struct {
-					ID       string `json:"id"`
-					Name     string `json:"name"`
-					Region   string `json:"region"`
-					Timezone string `json:"timezone"`
-				} `json:"location"`
-			} `json:"metadata"`
-		} `json:"briefing"`
-	}
-	if err := json.Unmarshal(data, &decoded); err != nil {
-		t.Fatalf("decode data package: %v", err)
-	}
-	if decoded.Briefing.Metadata.Location.ID != "home" || decoded.Briefing.Metadata.Location.Name != "Brentwood" || decoded.Briefing.Metadata.Location.Region != "St. Louis Metro" || decoded.Briefing.Metadata.Location.Timezone != "UTC" {
-		t.Fatalf("location = %#v, want configured location with overridden timezone", decoded.Briefing.Metadata.Location)
+	if !strings.Contains(string(data), "location:") ||
+		!strings.Contains(string(data), "id: home") ||
+		!strings.Contains(string(data), "name: Brentwood") ||
+		!strings.Contains(string(data), "region: St. Louis Metro") ||
+		!strings.Contains(string(data), "timezone: UTC") {
+		t.Fatalf("data package missing configured location with overridden timezone:\n%s", string(data))
 	}
 	preflightMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "preflight", "daily", "2026-05-29", "*.render.json"))
 	if err != nil {
@@ -711,14 +704,14 @@ func TestRunInspectGeneratedArtifacts(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Run(generate) error = %v", err)
 	}
-	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-29", "*.data_package.json"))
+	dataPackageMatches, err := filepath.Glob(filepath.Join(workspaceRoot, "data-packages", "daily", "2026-05-29", "*.data_package.yaml"))
 	if err != nil {
 		t.Fatalf("glob data package: %v", err)
 	}
 	if len(dataPackageMatches) != 1 {
 		t.Fatalf("data package files = %#v, want one", dataPackageMatches)
 	}
-	runID := strings.TrimSuffix(filepath.Base(dataPackageMatches[0]), ".data_package.json")
+	runID := strings.TrimSuffix(filepath.Base(dataPackageMatches[0]), ".data_package.yaml")
 
 	stdout.Reset()
 	err = runner.Run(context.Background(), []string{"inspect", "reports", "--config", configPath, "--limit", "1"}, &stdout, &stderr)
@@ -729,7 +722,8 @@ func TestRunInspectGeneratedArtifacts(t *testing.T) {
 		t.Fatalf("inspect reports output missing run:\n%s", stdout.String())
 	}
 
-	for _, command := range []string{"metadata", "briefing", "data-package", "sources"} {
+	var sourcesOutput string
+	for _, command := range []string{"metadata", "modules", "data-package", "sources"} {
 		stdout.Reset()
 		err = runner.Run(context.Background(), []string{"inspect", command, "--config", configPath, runID}, &stdout, &stderr)
 		if err != nil {
@@ -738,9 +732,12 @@ func TestRunInspectGeneratedArtifacts(t *testing.T) {
 		if !strings.Contains(stdout.String(), runID) {
 			t.Fatalf("inspect %s output missing run id:\n%s", command, stdout.String())
 		}
+		if command == "sources" {
+			sourcesOutput = stdout.String()
 		}
-	if !strings.Contains(stdout.String(), `"warnings"`) {
-		t.Fatalf("inspect sources output missing warnings:\n%s", stdout.String())
+	}
+	if !strings.Contains(sourcesOutput, `"warnings"`) {
+		t.Fatalf("inspect sources output missing warnings:\n%s", sourcesOutput)
 	}
 }
 
@@ -772,7 +769,7 @@ func TestRunInspectRunCommandsParseRunIDAndConfig(t *testing.T) {
 		t.Fatalf("write config: %v", err)
 	}
 	runner := Runner{Clock: fixedClock()}
-	commands := []string{"metadata", "briefing", "data-package", "prior", "sources"}
+	commands := []string{"metadata", "modules", "data-package", "prior", "sources"}
 
 	for _, command := range commands {
 		t.Run(command+" requires run id", func(t *testing.T) {

internal/config/config.go

@@ -2,7 +2,13 @@
 // precedence, and validation.
 package config
 
-import "time"
+import (
+	"fmt"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gopkg.in/yaml.v3"
+)
 
 type MissingSourcePolicy string
 type NotifyFailurePolicy string
@@ -25,6 +31,7 @@ type Config struct {
 	Workspace     WorkspaceConfig         `yaml:"workspace"`
 	Dayparts      []DaypartConfig         `yaml:"dayparts"`
 	RecentChange  RecentChangeConfig      `yaml:"recent_change"`
+	Reports       map[string]ReportConfig `yaml:"reports"`
 }
 
 type WeatherAPIConfig struct {
@@ -96,3 +103,71 @@ type RecentChangeConfig struct {
 	WindGustMilesPerHour     int     `yaml:"wind_gust_miles_per_hour"`
 	PrecipTimingShiftMinutes int     `yaml:"precip_timing_shift_minutes"`
 }
+
+type ReportConfig struct {
+	DeterministicModules    []ModuleConfigItem `yaml:"deterministic_modules"`
+	deterministicModulesSet bool
+}
+
+type ModuleConfigItem struct {
+	ID      module.ID `yaml:"id"`
+	Options any       `yaml:"options,omitempty"`
+}
+
+func (c *ReportConfig) UnmarshalYAML(value *yaml.Node) error {
+	if value.Kind != yaml.MappingNode {
+		return fmt.Errorf("report entry must be a mapping")
+	}
+	for i := 0; i < len(value.Content); i += 2 {
+		key := value.Content[i].Value
+		node := value.Content[i+1]
+		switch key {
+		case "deterministic_modules":
+			if err := node.Decode(&c.DeterministicModules); err != nil {
+				return err
+			}
+			c.deterministicModulesSet = true
+		default:
+			return fmt.Errorf("unknown report entry field %q", key)
+		}
+	}
+	return nil
+}
+
+func (m *ModuleConfigItem) UnmarshalYAML(value *yaml.Node) error {
+	switch value.Kind {
+	case yaml.ScalarNode:
+		if value.Value == "" {
+			return fmt.Errorf("module id is required")
+		}
+		m.ID = module.ID(value.Value)
+		return nil
+	case yaml.MappingNode:
+		var sawID bool
+		for i := 0; i < len(value.Content); i += 2 {
+			key := value.Content[i].Value
+			node := value.Content[i+1]
+			switch key {
+			case "id":
+				if err := node.Decode(&m.ID); err != nil {
+					return err
+				}
+				sawID = true
+			case "options":
+				var options any
+				if err := node.Decode(&options); err != nil {
+					return err
+				}
+				m.Options = options
+			default:
+				return fmt.Errorf("unknown module entry field %q", key)
+			}
+		}
+		if !sawID || m.ID == "" {
+			return fmt.Errorf("module id is required")
+		}
+		return nil
+	default:
+		return fmt.Errorf("module entry must be a string or mapping")
+	}
+}

internal/config/config_test.go

@@ -6,6 +6,9 @@ import (
 	"strings"
 	"testing"
 	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 )
 
 func TestDefaults(t *testing.T) {
@@ -116,6 +119,138 @@ func TestLoadMinimalExampleConfig(t *testing.T) {
 	}
 }
 
+func TestLoadReportModuleOverrides(t *testing.T) {
+	path := writeConfig(t, `
+reports:
+  daily:
+    deterministic_modules:
+      - metadata
+      - current_conditions
+      - id: area_forecast_discussion
+        options:
+          sections:
+            - short_term
+`)
+
+	cfg, err := LoadFile(path)
+	if err != nil {
+		t.Fatalf("LoadFile() error = %v", err)
+	}
+	overrides := cfg.ReportModuleOverrides()
+	items := overrides[report.DailyToday]
+	if len(items) != 3 {
+		t.Fatalf("daily override length = %d, want 3", len(items))
+	}
+	if items[0].ID != module.Metadata || items[1].ID != module.CurrentConditions || items[2].ID != module.AreaForecastDiscussion {
+		t.Fatalf("daily override = %#v, want configured module order", items)
+	}
+	options, ok := items[2].Options.(module.AreaForecastDiscussionOptions)
+	if !ok {
+		t.Fatalf("AFD options type = %T, want AreaForecastDiscussionOptions", items[2].Options)
+	}
+	if strings.Join(options.Sections, ",") != "short_term" {
+		t.Fatalf("AFD sections = %#v, want short_term", options.Sections)
+	}
+}
+
+func TestReportModuleOverrideValidation(t *testing.T) {
+	tests := []struct {
+		name    string
+		yaml    string
+		wantErr string
+	}{
+		{
+			name: "UnknownReport",
+			yaml: `
+reports:
+  moon:
+    deterministic_modules:
+      - metadata
+`,
+			wantErr: "reports.moon",
+		},
+		{
+			name: "UnknownModule",
+			yaml: `
+reports:
+  daily:
+    deterministic_modules:
+      - missing_module
+`,
+			wantErr: `unknown module "missing_module"`,
+		},
+		{
+			name: "DuplicateModule",
+			yaml: `
+reports:
+  daily:
+    deterministic_modules:
+      - metadata
+      - metadata
+`,
+			wantErr: `duplicate module "metadata"`,
+		},
+		{
+			name: "IncompatibleModule",
+			yaml: `
+reports:
+  daily:
+    deterministic_modules:
+      - storm_window_summary
+`,
+			wantErr: `not compatible with report "daily_today"`,
+		},
+		{
+			name: "InvalidOptions",
+			yaml: `
+reports:
+  daily:
+    deterministic_modules:
+      - id: metadata
+        options:
+          sections:
+            - short_term
+`,
+			wantErr: "options are invalid",
+		},
+		{
+			name: "DuplicateReportAlias",
+			yaml: `
+reports:
+  daily:
+    deterministic_modules:
+      - metadata
+  daily_today:
+    deterministic_modules:
+      - current_conditions
+`,
+			wantErr: "duplicates report override",
+		},
+		{
+			name: "UnknownReportField",
+			yaml: `
+reports:
+  daily:
+    modules:
+      - metadata
+`,
+			wantErr: `unknown report entry field "modules"`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := LoadFile(writeConfig(t, tt.yaml))
+			if err == nil {
+				t.Fatal("LoadFile() error = nil, want validation error")
+			}
+			if !strings.Contains(err.Error(), tt.wantErr) {
+				t.Fatalf("error = %q, want %q", err.Error(), tt.wantErr)
+			}
+		})
+	}
+}
+
 func TestExplicitMissingConfigReturnsError(t *testing.T) {
 	_, err := LoadFile(filepath.Join(t.TempDir(), "missing.yml"))
 	if err == nil {
@@ -126,6 +261,15 @@ func TestExplicitMissingConfigReturnsError(t *testing.T) {
 	}
 }
 
+func writeConfig(t *testing.T, contents string) string {
+	t.Helper()
+	path := filepath.Join(t.TempDir(), "config.yml")
+	if err := os.WriteFile(path, []byte(contents), 0o600); err != nil {
+		t.Fatalf("write config fixture: %v", err)
+	}
+	return path
+}
+
 func TestInvalidConfigProducesActionableError(t *testing.T) {
 	dir := t.TempDir()
 	path := filepath.Join(dir, "config.yml")

internal/config/defaults.go

@@ -65,5 +65,6 @@ func Defaults() Config {
 			WindGustMilesPerHour:     10,
 			PrecipTimingShiftMinutes: 120,
 		},
+		Reports: map[string]ReportConfig{},
 	}
 }

internal/config/load.go

@@ -35,6 +35,10 @@ func Load(opts LoadOptions) (Config, error) {
 		cfg.WeatherAPI.Timezone = opts.Timezone
 	}
 
+	if err := normalizeReportModules(&cfg); err != nil {
+		return Config{}, err
+	}
+
 	if err := loadSecrets(cfg.Secrets); err != nil {
 		return Config{}, err
 	}
@@ -61,5 +65,8 @@ func mergeFile(cfg *Config, path string) error {
 	if cfg.MissingSource.Sources == nil {
 		cfg.MissingSource.Sources = map[string]MissingSourcePolicy{}
 	}
+	if cfg.Reports == nil {
+		cfg.Reports = map[string]ReportConfig{}
+	}
 	return nil
 }

internal/config/reports.go

@@ -0,0 +1,125 @@
+package config
+
+import (
+	"bytes"
+	"fmt"
+	"reflect"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+	"gopkg.in/yaml.v3"
+)
+
+func (cfg Config) ReportModuleOverrides() map[report.ID][]module.ConfigItem {
+	overrides := map[report.ID][]module.ConfigItem{}
+	for key, reportCfg := range cfg.Reports {
+		if !reportCfg.deterministicModulesSet {
+			continue
+		}
+		id, err := reportIDForConfigKey(key)
+		if err != nil {
+			continue
+		}
+		items := make([]module.ConfigItem, 0, len(reportCfg.DeterministicModules))
+		for _, item := range reportCfg.DeterministicModules {
+			items = append(items, module.ConfigItem{ID: item.ID, Options: item.Options})
+		}
+		overrides[id] = items
+	}
+	return overrides
+}
+
+func normalizeReportModules(cfg *Config) error {
+	if cfg.Reports == nil {
+		cfg.Reports = map[string]ReportConfig{}
+	}
+	moduleRegistry, err := briefing.DefaultModuleRegistry()
+	if err != nil {
+		return fmt.Errorf("initialize module registry: %w", err)
+	}
+	reportRegistry := report.DefaultRegistry()
+	seenReports := map[report.ID]string{}
+	for key, reportCfg := range cfg.Reports {
+		reportID, err := reportIDForConfigKey(key)
+		if err != nil {
+			return err
+		}
+		if previous, ok := seenReports[reportID]; ok {
+			return fmt.Errorf("reports.%s duplicates report override %q", key, previous)
+		}
+		seenReports[reportID] = key
+		if _, err := reportRegistry.Lookup(reportID); err != nil {
+			return fmt.Errorf("reports.%s: %w", key, err)
+		}
+		if !reportCfg.deterministicModulesSet {
+			continue
+		}
+		items := make([]module.ConfigItem, 0, len(reportCfg.DeterministicModules))
+		for i, rawItem := range reportCfg.DeterministicModules {
+			options, err := normalizeModuleOptions(moduleRegistry, rawItem.ID, rawItem.Options)
+			if err != nil {
+				return fmt.Errorf("reports.%s.deterministic_modules[%d]: %w", key, i, err)
+			}
+			reportCfg.DeterministicModules[i].Options = options
+			items = append(items, module.ConfigItem{ID: rawItem.ID, Options: options})
+		}
+		if err := moduleRegistry.ValidateComposition(reportID, items); err != nil {
+			return fmt.Errorf("reports.%s.deterministic_modules: %w", key, err)
+		}
+		cfg.Reports[key] = reportCfg
+	}
+	return nil
+}
+
+func normalizeModuleOptions(registry briefing.ModuleRegistry, id module.ID, raw any) (any, error) {
+	if raw == nil {
+		return nil, nil
+	}
+	definition, err := registry.Lookup(id)
+	if err != nil {
+		return nil, err
+	}
+	if definition.DefaultOptions == nil {
+		return nil, fmt.Errorf("module %q does not accept options", id)
+	}
+	optionType := reflect.TypeOf(definition.DefaultOptions)
+	normalized, err := decodeKnownOptions(raw, optionType)
+	if err != nil {
+		return nil, fmt.Errorf("module %q options are invalid: %w", id, err)
+	}
+	return normalized, nil
+}
+
+func decodeKnownOptions(raw any, optionType reflect.Type) (any, error) {
+	data, err := yaml.Marshal(raw)
+	if err != nil {
+		return nil, err
+	}
+	target := reflect.New(optionType)
+	decoder := yaml.NewDecoder(bytes.NewReader(data))
+	decoder.KnownFields(true)
+	if err := decoder.Decode(target.Interface()); err != nil {
+		return nil, err
+	}
+	return target.Elem().Interface(), nil
+}
+
+func reportIDForConfigKey(key string) (report.ID, error) {
+	normalized := strings.ReplaceAll(strings.TrimSpace(strings.ToLower(key)), "-", "_")
+	switch normalized {
+	case "daily", "daily_today":
+		return report.DailyToday, nil
+	case "tomorrow", "daily_tomorrow":
+		return report.DailyTomorrow, nil
+	case "three_day", "three_day_outlook":
+		return report.ThreeDay, nil
+	case "weekend", "weekend_outlook":
+		return report.Weekend, nil
+	case "storm", "storm_report":
+		return report.Storm, nil
+	default:
+		return "", fmt.Errorf("reports.%s is not a known report", key)
+	}
+}

internal/config/validate.go

@@ -9,6 +9,9 @@ import (
 )
 
 func Validate(cfg Config) error {
+	if err := normalizeReportModules(&cfg); err != nil {
+		return err
+	}
 	if cfg.WeatherAPI.BaseURL != "" {
 		parsed, err := url.Parse(cfg.WeatherAPI.BaseURL)
 		if err != nil || parsed.Scheme == "" || parsed.Host == "" {

internal/facts/facts.go

@@ -0,0 +1,141 @@
+// Package facts defines collected and derived report facts.
+package facts
+
+import (
+	"fmt"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+)
+
+type CollectedFacts struct {
+	FetchedAt    time.Time
+	Observation  *weatherdata.Observation
+	Current      *weatherdata.Current
+	Hourly       *weatherdata.ForecastRun
+	Narrative    *weatherdata.ForecastRun
+	Alerts       *weatherdata.AlertRun
+	Discussion   *weatherdata.Discussion
+	Daily        *weatherdata.ForecastRun
+	WeatherStory *weatherdata.WeatherStory
+
+	SourceProvenance []weatherdata.Source
+	SourceWarnings   []weatherdata.SourceWarning
+}
+
+func BuildCollected(bundle *weatherdata.Bundle) CollectedFacts {
+	if bundle == nil {
+		return CollectedFacts{}
+	}
+	return CollectedFacts{
+		FetchedAt:        bundle.FetchedAt,
+		Observation:      bundle.Observation,
+		Current:          bundle.Current,
+		Hourly:           bundle.Hourly,
+		Narrative:        bundle.Narrative,
+		Alerts:           bundle.Alerts,
+		Discussion:       bundle.Discussion,
+		Daily:            bundle.Daily,
+		WeatherStory:     bundle.WeatherStory,
+		SourceProvenance: append([]weatherdata.Source(nil), bundle.Sources...),
+		SourceWarnings:   append([]weatherdata.SourceWarning(nil), bundle.Warnings...),
+	}
+}
+
+func (f CollectedFacts) Bundle() *weatherdata.Bundle {
+	return &weatherdata.Bundle{
+		FetchedAt:    f.FetchedAt,
+		Observation:  f.Observation,
+		Current:      f.Current,
+		Hourly:       f.Hourly,
+		Narrative:    f.Narrative,
+		Alerts:       f.Alerts,
+		Discussion:   f.Discussion,
+		Daily:        f.Daily,
+		WeatherStory: f.WeatherStory,
+		Sources:      append([]weatherdata.Source(nil), f.SourceProvenance...),
+		Warnings:     append([]weatherdata.SourceWarning(nil), f.SourceWarnings...),
+	}
+}
+
+type BuildDerivedRequest struct {
+	Resolved  report.Resolved
+	Timezone  string
+	Dayparts  []forecast.DaypartDefinition
+	Collected CollectedFacts
+}
+
+type DerivedFacts struct {
+	ValidPeriodHourlyPeriods    []weatherdata.ForecastPeriod
+	ValidPeriodNarrativePeriods []weatherdata.ForecastPeriod
+	ValidPeriodDailyPeriods     []weatherdata.ForecastPeriod
+	AlertOverlaps               []forecast.AlertOverlap
+	DailySummaries              []forecast.DailySummary
+	DaypartSummaries            []forecast.DaypartSummary
+	PrecipTiming                forecast.PrecipTiming
+	StormWindowSummary          *forecast.DaypartSummary
+}
+
+func (f DerivedFacts) FirstDailySummary() *forecast.DailySummary {
+	if len(f.DailySummaries) == 0 {
+		return nil
+	}
+	return &f.DailySummaries[0]
+}
+
+func BuildDerived(req BuildDerivedRequest) (DerivedFacts, error) {
+	if !req.Resolved.ValidPeriod.IsValid() {
+		return DerivedFacts{}, fmt.Errorf("resolved valid period is required")
+	}
+	location, err := timeutil.LoadLocation(req.Timezone)
+	if err != nil {
+		return DerivedFacts{}, fmt.Errorf("load report timezone %q: %w", req.Timezone, err)
+	}
+	bundle := req.Collected.Bundle()
+	period := req.Resolved.ValidPeriod
+	derived := DerivedFacts{
+		ValidPeriodHourlyPeriods:    forecast.SelectHourlyPeriods(req.Collected.Hourly, period),
+		ValidPeriodNarrativePeriods: forecast.SelectHourlyPeriods(req.Collected.Narrative, period),
+		ValidPeriodDailyPeriods:     forecast.SelectHourlyPeriods(req.Collected.Daily, period),
+		AlertOverlaps:               forecast.AlertOverlaps(req.Collected.Alerts, period),
+	}
+	derived.PrecipTiming = forecast.BuildPrecipTiming(derived.ValidPeriodHourlyPeriods)
+
+	switch req.Resolved.Definition.ID {
+	case report.DailyToday, report.DailyTomorrow:
+		summary, err := forecast.BuildDailySummary(bundle, period.Start, location, req.Dayparts)
+		if err != nil {
+			return DerivedFacts{}, err
+		}
+		derived.DailySummaries = []forecast.DailySummary{*summary}
+	case report.ThreeDay, report.Weekend:
+		summaries, err := forecast.BuildPeriodDailySummaries(bundle, period, location, req.Dayparts)
+		if err != nil {
+			return DerivedFacts{}, err
+		}
+		derived.DailySummaries = summaries
+	case report.Storm:
+		summary := forecast.SummarizeDaypart("storm window", period, derived.ValidPeriodHourlyPeriods)
+		summary.AlertOverlaps = derived.AlertOverlaps
+		derived.StormWindowSummary = &summary
+	default:
+		return DerivedFacts{}, fmt.Errorf("derived facts are not implemented for report %q", req.Resolved.Definition.ID)
+	}
+
+	derived.DaypartSummaries = collectDaypartSummaries(derived)
+	return derived, nil
+}
+
+func collectDaypartSummaries(derived DerivedFacts) []forecast.DaypartSummary {
+	var out []forecast.DaypartSummary
+	for _, summary := range derived.DailySummaries {
+		out = append(out, summary.Dayparts...)
+	}
+	if derived.StormWindowSummary != nil {
+		out = append(out, *derived.StormWindowSummary)
+	}
+	return out
+}

internal/facts/facts_test.go

@@ -0,0 +1,247 @@
+package facts
+
+import (
+	"encoding/json"
+	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+)
+
+func TestBuildCollectedCopiesBundleFactsAndKeepsSourcesSeparate(t *testing.T) {
+	fetchedAt := mustParse("2026-05-29T10:00:00Z")
+	bundle := &weatherdata.Bundle{
+		FetchedAt: fetchedAt,
+		Current:   &weatherdata.Current{ConditionText: "Clear"},
+		Hourly:    &weatherdata.ForecastRun{Product: "hourly"},
+		Sources:   []weatherdata.Source{{Name: "hourly"}},
+		Warnings:  []weatherdata.SourceWarning{{Source: "daily", Code: "missing_source"}},
+	}
+
+	collected := BuildCollected(bundle)
+	if collected.FetchedAt != fetchedAt || collected.Current.ConditionText != "Clear" || collected.Hourly.Product != "hourly" {
+		t.Fatalf("CollectedFacts = %#v, want source facts copied from bundle", collected)
+	}
+	if len(collected.SourceProvenance) != 1 || collected.SourceProvenance[0].Name != "hourly" {
+		t.Fatalf("SourceProvenance = %#v, want hourly source", collected.SourceProvenance)
+	}
+	if len(collected.SourceWarnings) != 1 || collected.SourceWarnings[0].Source != "daily" {
+		t.Fatalf("SourceWarnings = %#v, want daily warning", collected.SourceWarnings)
+	}
+
+	bundle.Sources[0].Name = "changed"
+	bundle.Warnings[0].Source = "changed"
+	if collected.SourceProvenance[0].Name != "hourly" || collected.SourceWarnings[0].Source != "daily" {
+		t.Fatalf("collected source slices changed after bundle mutation: %#v %#v", collected.SourceProvenance, collected.SourceWarnings)
+	}
+}
+
+func TestBuildDerivedDailySlicesDaypartsAndAlerts(t *testing.T) {
+	location := testLocation()
+	resolved := resolveForTest(t, report.DailyToday, mustParse("2026-05-29T08:00:00-05:00"), location)
+	derived, err := BuildDerived(BuildDerivedRequest{
+		Resolved:  resolved,
+		Timezone:  location.String(),
+		Dayparts:  testDayparts(),
+		Collected: BuildCollected(testBundle(location)),
+	})
+	if err != nil {
+		t.Fatalf("BuildDerived() error = %v", err)
+	}
+
+	if len(derived.ValidPeriodHourlyPeriods) != 4 {
+		t.Fatalf("ValidPeriodHourlyPeriods length = %d, want 4", len(derived.ValidPeriodHourlyPeriods))
+	}
+	if len(derived.ValidPeriodNarrativePeriods) != 1 {
+		t.Fatalf("ValidPeriodNarrativePeriods length = %d, want 1", len(derived.ValidPeriodNarrativePeriods))
+	}
+	if len(derived.AlertOverlaps) != 1 || derived.AlertOverlaps[0].Event != "Flood Watch" {
+		t.Fatalf("AlertOverlaps = %#v, want Flood Watch overlap", derived.AlertOverlaps)
+	}
+	if len(derived.DailySummaries) != 1 || len(derived.DailySummaries[0].Dayparts) != 3 {
+		t.Fatalf("DailySummaries = %#v, want one summary with dayparts", derived.DailySummaries)
+	}
+	if len(derived.DaypartSummaries) != 3 {
+		t.Fatalf("DaypartSummaries length = %d, want 3", len(derived.DaypartSummaries))
+	}
+	if derived.PrecipTiming.FirstPrecipitation == nil || derived.PrecipTiming.FirstPrecipitation.Time.Format(time.RFC3339) != "2026-05-29T08:00:00-05:00" {
+		t.Fatalf("PrecipTiming.FirstPrecipitation = %#v, want valid-period rain start", derived.PrecipTiming.FirstPrecipitation)
+	}
+	if !derived.PrecipTiming.ThunderMentioned {
+		t.Fatal("PrecipTiming.ThunderMentioned = false, want true")
+	}
+	morning := derived.DailySummaries[0].Dayparts[0]
+	if len(morning.HourlyPeriods) != 1 || morning.MaxPrecipitationProbability == nil || morning.MaxPrecipitationProbability.Value != 60 {
+		t.Fatalf("morning summary = %#v, want sliced hour with precip max", morning)
+	}
+}
+
+func TestBuildDerivedOutlookBuildsPartialDaySummariesWithMissingOptionalSources(t *testing.T) {
+	location := testLocation()
+	resolved := resolveForTest(t, report.ThreeDay, mustParse("2026-05-29T08:00:00-05:00"), location)
+	bundle := testBundle(location)
+	bundle.Narrative = nil
+	bundle.Alerts = nil
+	bundle.Discussion = nil
+	bundle.WeatherStory = nil
+
+	derived, err := BuildDerived(BuildDerivedRequest{
+		Resolved:  resolved,
+		Timezone:  location.String(),
+		Dayparts:  testDayparts(),
+		Collected: BuildCollected(bundle),
+	})
+	if err != nil {
+		t.Fatalf("BuildDerived() error = %v", err)
+	}
+
+	if len(derived.DailySummaries) != 3 {
+		t.Fatalf("DailySummaries length = %d, want 3 partial-day summaries", len(derived.DailySummaries))
+	}
+	if len(derived.ValidPeriodNarrativePeriods) != 0 {
+		t.Fatalf("ValidPeriodNarrativePeriods length = %d, want 0 for missing optional source", len(derived.ValidPeriodNarrativePeriods))
+	}
+	if len(derived.AlertOverlaps) != 0 {
+		t.Fatalf("AlertOverlaps = %#v, want none for missing optional alerts", derived.AlertOverlaps)
+	}
+	if derived.DailySummaries[0].Period.Start.Format(time.RFC3339) != "2026-05-29T08:00:00-05:00" {
+		t.Fatalf("first summary start = %s, want valid-period start", derived.DailySummaries[0].Period.Start.Format(time.RFC3339))
+	}
+}
+
+func TestBuildDerivedWeekendAndTomorrow(t *testing.T) {
+	location := testLocation()
+	for _, id := range []report.ID{report.DailyTomorrow, report.Weekend} {
+		resolved := resolveForTest(t, id, mustParse("2026-05-29T08:00:00-05:00"), location)
+		derived, err := BuildDerived(BuildDerivedRequest{
+			Resolved:  resolved,
+			Timezone:  location.String(),
+			Dayparts:  testDayparts(),
+			Collected: BuildCollected(testBundle(location)),
+		})
+		if err != nil {
+			t.Fatalf("BuildDerived(%s) error = %v", id, err)
+		}
+		if len(derived.DailySummaries) == 0 {
+			t.Fatalf("BuildDerived(%s) DailySummaries length = 0, want summaries", id)
+		}
+	}
+}
+
+func TestBuildDerivedStormBuildsWindowSummary(t *testing.T) {
+	location := testLocation()
+	resolved := resolveStormForTest(t, location)
+	derived, err := BuildDerived(BuildDerivedRequest{
+		Resolved:  resolved,
+		Timezone:  location.String(),
+		Dayparts:  testDayparts(),
+		Collected: BuildCollected(testBundle(location)),
+	})
+	if err != nil {
+		t.Fatalf("BuildDerived() error = %v", err)
+	}
+
+	if len(derived.ValidPeriodHourlyPeriods) != 2 {
+		t.Fatalf("ValidPeriodHourlyPeriods length = %d, want 2 storm-window hours", len(derived.ValidPeriodHourlyPeriods))
+	}
+	if len(derived.ValidPeriodDailyPeriods) != 1 {
+		t.Fatalf("ValidPeriodDailyPeriods length = %d, want 1 daily period", len(derived.ValidPeriodDailyPeriods))
+	}
+	if derived.StormWindowSummary == nil {
+		t.Fatal("StormWindowSummary = nil, want summary")
+	}
+	if derived.StormWindowSummary.MaxPrecipitationProbability == nil || derived.StormWindowSummary.MaxPrecipitationProbability.Value != 80 {
+		t.Fatalf("StormWindowSummary = %#v, want peak precipitation", derived.StormWindowSummary)
+	}
+	if len(derived.StormWindowSummary.AlertOverlaps) != 1 {
+		t.Fatalf("StormWindowSummary.AlertOverlaps length = %d, want 1", len(derived.StormWindowSummary.AlertOverlaps))
+	}
+}
+
+func testBundle(location *time.Location) *weatherdata.Bundle {
+	return &weatherdata.Bundle{
+		FetchedAt: mustParse("2026-05-29T10:00:00Z"),
+		Current:   &weatherdata.Current{ConditionText: "Cloudy"},
+		Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
+			hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Showers", 60, 10),
+			hour(location, "2026-05-29T12:00:00-05:00", "2026-05-29T13:00:00-05:00", "Thunderstorms", 80, 35),
+			hour(location, "2026-05-29T13:00:00-05:00", "2026-05-29T14:00:00-05:00", "Heavy rain", 70, 25),
+			hour(location, "2026-05-29T14:00:00-05:00", "2026-05-29T15:00:00-05:00", "Hot", 10, 15),
+			hour(location, "2026-05-30T09:00:00-05:00", "2026-05-30T10:00:00-05:00", "Clear", 0, 5),
+		}},
+		Narrative: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
+			hour(location, "2026-05-29T06:00:00-05:00", "2026-05-29T18:00:00-05:00", "Storm chances peak midday.", 70, 20),
+		}},
+		Daily: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
+			hour(location, "2026-05-29T00:00:00-05:00", "2026-05-30T00:00:00-05:00", "Storms", 70, 20),
+		}},
+		Alerts: &weatherdata.AlertRun{Alerts: []json.RawMessage{
+			json.RawMessage(`{"event":"Flood Watch","headline":"Flooding possible","severity":"Moderate","effective":"2026-05-29T11:00:00-05:00","expires":"2026-05-29T15:00:00-05:00"}`),
+		}},
+		Discussion:   &weatherdata.Discussion{Product: "discussion", KeyMessages: []string{"Storm confidence is moderate."}},
+		WeatherStory: &weatherdata.WeatherStory{Title: "Storm Risk"},
+		Sources:      []weatherdata.Source{{Name: "hourly"}},
+		Warnings:     []weatherdata.SourceWarning{{Source: "daily", Code: "missing_source"}},
+	}
+}
+
+func hour(location *time.Location, start string, end string, text string, precip float64, gust float64) weatherdata.ForecastPeriod {
+	temperature := 70.0
+	return weatherdata.ForecastPeriod{
+		StartTime:                         mustParse(start).In(location),
+		EndTime:                           mustParse(end).In(location),
+		TextDescription:                   text,
+		TemperatureF:                      &temperature,
+		ProbabilityOfPrecipitationPercent: &precip,
+		WindGustMph:                       &gust,
+	}
+}
+
+func testDayparts() []forecast.DaypartDefinition {
+	return []forecast.DaypartDefinition{
+		{Name: "morning", Start: "06:00", End: "12:00"},
+		{Name: "afternoon", Start: "12:00", End: "18:00"},
+		{Name: "evening", Start: "18:00", End: "24:00"},
+	}
+}
+
+func resolveForTest(t *testing.T, id report.ID, now time.Time, location *time.Location) report.Resolved {
+	t.Helper()
+	resolved, err := report.Resolve(id, report.ResolveRequest{Now: now, Location: location})
+	if err != nil {
+		t.Fatalf("resolve %s: %v", id, err)
+	}
+	return resolved
+}
+
+func resolveStormForTest(t *testing.T, location *time.Location) report.Resolved {
+	t.Helper()
+	resolved, err := report.Resolve(report.Storm, report.ResolveRequest{
+		Now:        mustParse("2026-05-29T08:00:00-05:00"),
+		Location:   location,
+		StormStart: mustParse("2026-05-29T11:30:00-05:00"),
+		StormEnd:   mustParse("2026-05-29T13:30:00-05:00"),
+	})
+	if err != nil {
+		t.Fatalf("resolve storm: %v", err)
+	}
+	return resolved
+}
+
+func testLocation() *time.Location {
+	location, err := time.LoadLocation("America/Chicago")
+	if err != nil {
+		panic(err)
+	}
+	return location
+}
+
+func mustParse(value string) time.Time {
+	parsed, err := time.Parse(time.RFC3339, value)
+	if err != nil {
+		panic(err)
+	}
+	return parsed
+}

internal/forecast/dayparts.go

@@ -5,6 +5,7 @@ import (
 	"time"
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
 type DaypartDefinition struct {
@@ -48,6 +49,6 @@ func ResolveDayparts(date time.Time, location *time.Location, definitions []Dayp
 	return windows, nil
 }
 
-func PeriodForForecastPeriod(period ForecastPeriod) timeutil.Period {
+func PeriodForForecastPeriod(period weatherdata.ForecastPeriod) timeutil.Period {
 	return timeutil.Period{Start: period.StartTime, End: period.EndTime}
 }

internal/forecast/derive.go

@@ -8,23 +8,24 @@ import (
 	"time"
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
 type DailySummary struct {
 	Date             string                       `json:"date"`
 	Period           timeutil.Period              `json:"period"`
 	Dayparts         []DaypartSummary             `json:"dayparts"`
-	NarrativePeriods []ForecastPeriod `json:"narrativePeriods,omitempty"`
+	NarrativePeriods []weatherdata.ForecastPeriod `json:"narrativePeriods,omitempty"`
 	AlertOverlaps    []AlertOverlap               `json:"alertOverlaps,omitempty"`
-	Discussion       *Discussion      `json:"discussion,omitempty"`
-	SourceWarnings   []SourceWarning  `json:"sourceWarnings,omitempty"`
-	SourceProvenance []Source         `json:"sourceProvenance,omitempty"`
+	Discussion       *weatherdata.Discussion      `json:"discussion,omitempty"`
+	SourceWarnings   []weatherdata.SourceWarning  `json:"sourceWarnings,omitempty"`
+	SourceProvenance []weatherdata.Source         `json:"sourceProvenance,omitempty"`
 }
 
 type DaypartSummary struct {
 	Name                        string                       `json:"name"`
 	Period                      timeutil.Period              `json:"period"`
-	HourlyPeriods               []ForecastPeriod `json:"hourlyPeriods"`
+	HourlyPeriods               []weatherdata.ForecastPeriod `json:"hourlyPeriods"`
 	Temperature                 Range                        `json:"temperature,omitempty"`
 	ApparentTemperature         Range                        `json:"apparentTemperature,omitempty"`
 	MaxPrecipitationProbability *TimedValue                  `json:"maxPrecipitationProbability,omitempty"`
@@ -64,7 +65,39 @@ type AlertOverlap struct {
 	Description string          `json:"description,omitempty"`
 }
 
-func BuildDailySummary(bundle *Bundle, date time.Time, location *time.Location, dayparts []DaypartDefinition) (*DailySummary, error) {
+type PrecipTiming struct {
+	MaxPrecipitationProbability *TimedValue `json:"maxPrecipitationProbability,omitempty"`
+	FirstPrecipitation          *TimedValue `json:"firstPrecipitation,omitempty"`
+	LastPrecipitation           *TimedValue `json:"lastPrecipitation,omitempty"`
+	ThunderMentioned            bool        `json:"thunderMentioned,omitempty"`
+}
+
+func BuildPrecipTiming(periods []weatherdata.ForecastPeriod) PrecipTiming {
+	var timing PrecipTiming
+	for _, forecastPeriod := range periods {
+		setMaxTimedValue(&timing.MaxPrecipitationProbability, forecastPeriod.ProbabilityOfPrecipitationPercent, forecastPeriod.StartTime)
+		if forecastPeriod.ProbabilityOfPrecipitationPercent != nil && *forecastPeriod.ProbabilityOfPrecipitationPercent > 0 {
+			value := TimedValue{
+				Value: *forecastPeriod.ProbabilityOfPrecipitationPercent,
+				Time:  forecastPeriod.StartTime,
+			}
+			if timing.FirstPrecipitation == nil || value.Time.Before(timing.FirstPrecipitation.Time) {
+				copied := value
+				timing.FirstPrecipitation = &copied
+			}
+			if timing.LastPrecipitation == nil || value.Time.After(timing.LastPrecipitation.Time) {
+				copied := value
+				timing.LastPrecipitation = &copied
+			}
+		}
+		if mentionsThunder(forecastPeriod.TextDescription) {
+			timing.ThunderMentioned = true
+		}
+	}
+	return timing
+}
+
+func BuildDailySummary(bundle *weatherdata.Bundle, date time.Time, location *time.Location, dayparts []DaypartDefinition) (*DailySummary, error) {
 	if bundle == nil {
 		return nil, fmt.Errorf("forecast bundle is required")
 	}
@@ -99,7 +132,7 @@ func BuildDailySummary(bundle *Bundle, date time.Time, location *time.Location,
 	return summary, nil
 }
 
-func BuildPeriodDailySummaries(bundle *Bundle, period timeutil.Period, location *time.Location, dayparts []DaypartDefinition) ([]DailySummary, error) {
+func BuildPeriodDailySummaries(bundle *weatherdata.Bundle, period timeutil.Period, location *time.Location, dayparts []DaypartDefinition) ([]DailySummary, error) {
 	if !period.IsValid() {
 		return nil, fmt.Errorf("valid forecast period is required")
 	}
@@ -121,7 +154,7 @@ func BuildPeriodDailySummaries(bundle *Bundle, period timeutil.Period, location
 	return summaries, nil
 }
 
-func buildDailySummaryForPeriod(bundle *Bundle, period timeutil.Period, location *time.Location, dayparts []DaypartDefinition) (*DailySummary, error) {
+func buildDailySummaryForPeriod(bundle *weatherdata.Bundle, period timeutil.Period, location *time.Location, dayparts []DaypartDefinition) (*DailySummary, error) {
 	if bundle == nil {
 		return nil, fmt.Errorf("forecast bundle is required")
 	}
@@ -155,11 +188,11 @@ func buildDailySummaryForPeriod(bundle *Bundle, period timeutil.Period, location
 	return summary, nil
 }
 
-func SelectHourlyPeriods(run *ForecastRun, period timeutil.Period) []ForecastPeriod {
+func SelectHourlyPeriods(run *weatherdata.ForecastRun, period timeutil.Period) []weatherdata.ForecastPeriod {
 	if run == nil {
 		return nil
 	}
-	var selected []ForecastPeriod
+	var selected []weatherdata.ForecastPeriod
 	for _, forecastPeriod := range run.Periods {
 		if PeriodForForecastPeriod(forecastPeriod).Overlaps(period) {
 			selected = append(selected, forecastPeriod)
@@ -171,21 +204,21 @@ func SelectHourlyPeriods(run *ForecastRun, period timeutil.Period) []ForecastPer
 	return selected
 }
 
-func SelectNarrativePeriods(bundle *Bundle, period timeutil.Period) []ForecastPeriod {
+func SelectNarrativePeriods(bundle *weatherdata.Bundle, period timeutil.Period) []weatherdata.ForecastPeriod {
 	if bundle == nil || bundle.Narrative == nil {
 		return nil
 	}
 	return SelectHourlyPeriods(bundle.Narrative, period)
 }
 
-func SelectDiscussion(bundle *Bundle) *Discussion {
+func SelectDiscussion(bundle *weatherdata.Bundle) *weatherdata.Discussion {
 	if bundle == nil {
 		return nil
 	}
 	return bundle.Discussion
 }
 
-func SummarizeDaypart(name string, period timeutil.Period, periods []ForecastPeriod) DaypartSummary {
+func SummarizeDaypart(name string, period timeutil.Period, periods []weatherdata.ForecastPeriod) DaypartSummary {
 	summary := DaypartSummary{
 		Name:          name,
 		Period:        period,
@@ -215,7 +248,7 @@ func SummarizeDaypart(name string, period timeutil.Period, periods []ForecastPer
 	return summary
 }
 
-func periodTemperatureValues(period ForecastPeriod) []*float64 {
+func periodTemperatureValues(period weatherdata.ForecastPeriod) []*float64 {
 	values := []*float64{}
 	values = append(values, valueFromPointers(period.TemperatureF, period.TemperatureC)...)
 	values = append(values, valueFromPointers(period.TemperatureFMin, period.TemperatureCMin)...)
@@ -297,7 +330,11 @@ func indicatorsForText(text string) Indicators {
 	}
 }
 
-func numericIndicators(period ForecastPeriod) Indicators {
+func mentionsThunder(text string) bool {
+	return strings.Contains(strings.ToLower(text), "thunder")
+}
+
+func numericIndicators(period weatherdata.ForecastPeriod) Indicators {
 	windGust := firstValue(period.WindGustMph, period.WindGustKmh)
 	windSpeed := firstValue(period.WindSpeedMph, period.WindSpeedKmh)
 	indicators := Indicators{}
@@ -325,7 +362,7 @@ func mergeIndicators(left Indicators, right Indicators) Indicators {
 	}
 }
 
-func AlertOverlaps(alertRun *AlertRun, period timeutil.Period) []AlertOverlap {
+func AlertOverlaps(alertRun *weatherdata.AlertRun, period timeutil.Period) []AlertOverlap {
 	if alertRun == nil {
 		return nil
 	}

internal/forecast/derive_test.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
 func TestBuildDailySummaryGroupsDaypartsAndComputesMetrics(t *testing.T) {
@@ -72,7 +73,7 @@ func TestBuildDailySummaryFromFixtureBundle(t *testing.T) {
 	if err != nil {
 		t.Fatalf("read fixture bundle: %v", err)
 	}
-	var bundle Bundle
+	var bundle weatherdata.Bundle
 	if err := json.Unmarshal(data, &bundle); err != nil {
 		t.Fatalf("decode fixture bundle: %v", err)
 	}
@@ -98,7 +99,7 @@ func TestBuildDailySummaryFromFixtureBundle(t *testing.T) {
 func TestOvernightGroupingAcrossMidnight(t *testing.T) {
 	location := time.FixedZone("Test", -5*60*60)
 	date := time.Date(2026, 5, 29, 12, 0, 0, 0, location)
-	bundle := &Bundle{Hourly: &ForecastRun{Periods: []ForecastPeriod{
+	bundle := &weatherdata.Bundle{Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
 		hour(location, "2026-05-29T23:00:00-05:00", "2026-05-30T00:00:00-05:00", "Snow", 31, nil, nil, nil, nil),
 		hour(location, "2026-05-30T05:00:00-05:00", "2026-05-30T06:00:00-05:00", "Fog", 30, nil, nil, nil, nil),
 		hour(location, "2026-05-30T06:00:00-05:00", "2026-05-30T07:00:00-05:00", "Clear", 35, nil, nil, nil, nil),
@@ -122,7 +123,7 @@ func TestOvernightGroupingAcrossMidnight(t *testing.T) {
 func TestBoundaryTimestampsAtDaypartEdges(t *testing.T) {
 	location := time.FixedZone("Test", -5*60*60)
 	date := time.Date(2026, 5, 29, 12, 0, 0, 0, location)
-	bundle := &Bundle{Hourly: &ForecastRun{Periods: []ForecastPeriod{
+	bundle := &weatherdata.Bundle{Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
 		hour(location, "2026-05-29T05:00:00-05:00", "2026-05-29T06:00:00-05:00", "Before", 55, nil, nil, nil, nil),
 		hour(location, "2026-05-29T06:00:00-05:00", "2026-05-29T07:00:00-05:00", "Start", 56, nil, nil, nil, nil),
 		hour(location, "2026-05-29T12:00:00-05:00", "2026-05-29T13:00:00-05:00", "After", 70, nil, nil, nil, nil),
@@ -145,7 +146,7 @@ func TestBoundaryTimestampsAtDaypartEdges(t *testing.T) {
 
 func TestBuildDailySummaryRequiresHourlyData(t *testing.T) {
 	location := time.UTC
-	_, err := BuildDailySummary(&Bundle{}, time.Now(), location, []DaypartDefinition{
+	_, err := BuildDailySummary(&weatherdata.Bundle{}, time.Now(), location, []DaypartDefinition{
 		{Name: "morning", Start: "06:00", End: "12:00"},
 	})
 	if err == nil {
@@ -155,7 +156,7 @@ func TestBuildDailySummaryRequiresHourlyData(t *testing.T) {
 
 func TestBuildPeriodDailySummariesClipsPartialDays(t *testing.T) {
 	location := time.FixedZone("Test", -5*60*60)
-	bundle := &Bundle{Hourly: &ForecastRun{Periods: []ForecastPeriod{
+	bundle := &weatherdata.Bundle{Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
 		hour(location, "2026-05-29T05:00:00-05:00", "2026-05-29T06:00:00-05:00", "Before", 50, nil, nil, nil, nil),
 		hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Showers", 60, nil, ptr(60), nil, nil),
 		hour(location, "2026-05-30T14:00:00-05:00", "2026-05-30T15:00:00-05:00", "Hot", 95, nil, nil, nil, nil),
@@ -191,7 +192,7 @@ func TestBuildPeriodDailySummariesClipsPartialDays(t *testing.T) {
 func TestAlertOverlap(t *testing.T) {
 	location := time.FixedZone("Test", -5*60*60)
 	raw := json.RawMessage(`{"event":"Flood Watch","headline":"Flooding possible","severity":"Moderate","effective":"2026-05-29T07:00:00-05:00","expires":"2026-05-29T10:00:00-05:00"}`)
-	alertRun := &AlertRun{Alerts: []json.RawMessage{raw}}
+	alertRun := &weatherdata.AlertRun{Alerts: []json.RawMessage{raw}}
 	period := timeutil.Period{
 		Start: mustParse("2026-05-29T06:00:00-05:00").In(location),
 		End:   mustParse("2026-05-29T09:00:00-05:00").In(location),
@@ -209,6 +210,47 @@ func TestAlertOverlap(t *testing.T) {
 	}
 }
 
+func TestBuildPrecipTimingTracksRainAndThunder(t *testing.T) {
+	location := time.FixedZone("Test", -5*60*60)
+	periods := []weatherdata.ForecastPeriod{
+		hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Cloudy", 70, nil, ptr(0), nil, nil),
+		hour(location, "2026-05-29T09:00:00-05:00", "2026-05-29T10:00:00-05:00", "Showers", 70, nil, ptr(30), nil, nil),
+		hour(location, "2026-05-29T12:00:00-05:00", "2026-05-29T13:00:00-05:00", "Thunderstorms", 70, nil, ptr(80), nil, nil),
+		hour(location, "2026-05-29T18:00:00-05:00", "2026-05-29T19:00:00-05:00", "Dry", 70, nil, ptr(0), nil, nil),
+	}
+
+	timing := BuildPrecipTiming(periods)
+
+	if timing.FirstPrecipitation == nil || timing.FirstPrecipitation.Time.Format(time.RFC3339) != "2026-05-29T09:00:00-05:00" {
+		t.Fatalf("FirstPrecipitation = %#v, want 9 AM shower", timing.FirstPrecipitation)
+	}
+	if timing.LastPrecipitation == nil || timing.LastPrecipitation.Time.Format(time.RFC3339) != "2026-05-29T12:00:00-05:00" {
+		t.Fatalf("LastPrecipitation = %#v, want noon thunderstorm", timing.LastPrecipitation)
+	}
+	if timing.MaxPrecipitationProbability == nil || timing.MaxPrecipitationProbability.Value != 80 {
+		t.Fatalf("MaxPrecipitationProbability = %#v, want 80", timing.MaxPrecipitationProbability)
+	}
+	if !timing.ThunderMentioned {
+		t.Fatal("ThunderMentioned = false, want true")
+	}
+}
+
+func TestBuildPrecipTimingHandlesDryForecast(t *testing.T) {
+	location := time.FixedZone("Test", -5*60*60)
+	periods := []weatherdata.ForecastPeriod{
+		hour(location, "2026-05-29T08:00:00-05:00", "2026-05-29T09:00:00-05:00", "Sunny", 70, nil, ptr(0), nil, nil),
+	}
+
+	timing := BuildPrecipTiming(periods)
+
+	if timing.FirstPrecipitation != nil || timing.LastPrecipitation != nil || timing.ThunderMentioned {
+		t.Fatalf("dry timing = %#v, want no precip timing and no thunder", timing)
+	}
+	if timing.MaxPrecipitationProbability == nil || timing.MaxPrecipitationProbability.Value != 0 {
+		t.Fatalf("dry max precip = %#v, want checked zero chance", timing.MaxPrecipitationProbability)
+	}
+}
+
 func TestThresholdHelpers(t *testing.T) {
 	if !DifferenceAtLeast(50, 56, 5) {
 		t.Fatal("DifferenceAtLeast = false, want true")
@@ -221,31 +263,31 @@ func TestThresholdHelpers(t *testing.T) {
 	}
 }
 
-func testBundle(location *time.Location) *Bundle {
-	return &Bundle{
-		Hourly: &ForecastRun{Periods: []ForecastPeriod{
+func testBundle(location *time.Location) *weatherdata.Bundle {
+	return &weatherdata.Bundle{
+		Hourly: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
 			hour(location, "2026-05-29T05:00:00-05:00", "2026-05-29T06:00:00-05:00", "Cloudy", 55, nil, nil, nil, nil),
 			hour(location, "2026-05-29T06:00:00-05:00", "2026-05-29T07:00:00-05:00", "Thunderstorms and gusty wind", 58, ptr(57), ptr(70), ptr(22), ptr(40)),
 			hour(location, "2026-05-29T11:00:00-05:00", "2026-05-29T12:00:00-05:00", "Thunderstorms and gusty wind", 72, ptr(74), ptr(60), ptr(18), ptr(35)),
 			hour(location, "2026-05-29T14:00:00-05:00", "2026-05-29T15:00:00-05:00", "Hot and sunny", 96, ptr(100), ptr(5), ptr(10), ptr(12)),
 		}},
-		Narrative: &ForecastRun{Periods: []ForecastPeriod{
+		Narrative: &weatherdata.ForecastRun{Periods: []weatherdata.ForecastPeriod{
 			hour(location, "2026-05-29T06:00:00-05:00", "2026-05-29T18:00:00-05:00", "Storms early, hot later.", 96, nil, nil, nil, nil),
 		}},
-		Alerts: &AlertRun{Alerts: []json.RawMessage{
+		Alerts: &weatherdata.AlertRun{Alerts: []json.RawMessage{
 			json.RawMessage(`{"event":"Severe Thunderstorm Watch","headline":"Storms possible","severity":"Severe","effective":"2026-05-29T06:30:00-05:00","expires":"2026-05-29T11:30:00-05:00"}`),
 		}},
-		Discussion: &Discussion{Product: "discussion", KeyMessages: []string{"Storms possible."}},
-		Sources:    []Source{{Name: "hourly"}},
-		Warnings:   []SourceWarning{{Source: "daily", Code: "missing_source"}},
+		Discussion: &weatherdata.Discussion{Product: "discussion", KeyMessages: []string{"Storms possible."}},
+		Sources:    []weatherdata.Source{{Name: "hourly"}},
+		Warnings:   []weatherdata.SourceWarning{{Source: "daily", Code: "missing_source"}},
 	}
 }
 
-func hour(location *time.Location, start string, end string, text string, temperature float64, apparent *float64, precip *float64, wind *float64, gust *float64) ForecastPeriod {
+func hour(location *time.Location, start string, end string, text string, temperature float64, apparent *float64, precip *float64, wind *float64, gust *float64) weatherdata.ForecastPeriod {
 	startTime := mustParse(start).In(location)
 	endTime := mustParse(end).In(location)
 	temp := temperature
-	return ForecastPeriod{
+	return weatherdata.ForecastPeriod{
 		StartTime:                         startTime,
 		EndTime:                           endTime,
 		TextDescription:                   text,

internal/module/module.go

@@ -0,0 +1,148 @@
+// Package module defines stable module contracts for prompt-facing stanzas.
+package module
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+const SnapshotSchemaVersion = "weatherreporter.modules.v1"
+
+type ID string
+
+const (
+	Metadata                ID = "metadata"
+	CurrentConditions       ID = "current_conditions"
+	DerivedDailySummary     ID = "derived_daily_summary"
+	DerivedDaypartSummaries ID = "derived_daypart_summaries"
+	HourlyTable             ID = "hourly_table"
+	PrecipTiming            ID = "precip_timing"
+	AlertDigest             ID = "alert_digest"
+	AreaForecastDiscussion  ID = "area_forecast_discussion"
+	WeatherStory            ID = "weather_story"
+	ForecastDelta           ID = "forecast_delta"
+	OutdoorWindows          ID = "outdoor_windows"
+	TomorrowPlanning        ID = "tomorrow_planning"
+	WeekendPlanning         ID = "weekend_planning"
+	StormWindowSummary      ID = "storm_window_summary"
+)
+
+type ConfigItem struct {
+	ID      ID  `json:"id"`
+	Options any `json:"options,omitempty"`
+}
+
+type Output struct {
+	ID         ID     `json:"id"`
+	StanzaName string `json:"stanzaName"`
+	Value      any    `json:"value"`
+}
+
+type Snapshot struct {
+	SchemaVersion string   `json:"schemaVersion"`
+	Outputs       []Output `json:"outputs"`
+}
+
+func NewSnapshot(outputs []Output) (Snapshot, error) {
+	snapshot := Snapshot{
+		SchemaVersion: SnapshotSchemaVersion,
+		Outputs:       append([]Output(nil), outputs...),
+	}
+	if err := snapshot.Validate(); err != nil {
+		return Snapshot{}, err
+	}
+	return snapshot, nil
+}
+
+func (s Snapshot) Validate() error {
+	if s.SchemaVersion == "" {
+		return fmt.Errorf("schemaVersion is required")
+	}
+	seenModules := map[ID]struct{}{}
+	seenStanzas := map[string]struct{}{}
+	for i, output := range s.Outputs {
+		if output.ID == "" {
+			return fmt.Errorf("outputs[%d].id is required", i)
+		}
+		if output.StanzaName == "" {
+			return fmt.Errorf("outputs[%d].stanzaName is required", i)
+		}
+		if _, ok := seenModules[output.ID]; ok {
+			return fmt.Errorf("duplicate module output %q", output.ID)
+		}
+		seenModules[output.ID] = struct{}{}
+		if _, ok := seenStanzas[output.StanzaName]; ok {
+			return fmt.Errorf("duplicate stanza name %q", output.StanzaName)
+		}
+		seenStanzas[output.StanzaName] = struct{}{}
+	}
+	return nil
+}
+
+func (s Snapshot) LookupStanza(name string) (Output, bool) {
+	for _, output := range s.Outputs {
+		if output.StanzaName == name {
+			return output, true
+		}
+	}
+	return Output{}, false
+}
+
+func StanzaValue[T any](s Snapshot, name string) (T, bool, error) {
+	var zero T
+	output, ok := s.LookupStanza(name)
+	if !ok {
+		return zero, false, nil
+	}
+	data, err := json.Marshal(output.Value)
+	if err != nil {
+		return zero, true, fmt.Errorf("marshal stanza %q: %w", name, err)
+	}
+	if err := json.Unmarshal(data, &zero); err != nil {
+		return zero, true, fmt.Errorf("decode stanza %q: %w", name, err)
+	}
+	return zero, true, nil
+}
+
+type FactRequirement string
+
+const (
+	CollectedCurrentConditions        FactRequirement = "collected.current_conditions"
+	CollectedAlerts                   FactRequirement = "collected.alerts"
+	CollectedDiscussion               FactRequirement = "collected.discussion"
+	CollectedWeatherStory             FactRequirement = "collected.weather_story"
+	CollectedSourceMetadata           FactRequirement = "collected.source_metadata"
+	RequiresDerivedHourlyPeriods      FactRequirement = "derived.hourly_periods"
+	RequiresDerivedNarrativePeriods   FactRequirement = "derived.narrative_periods"
+	RequiresDerivedAlertOverlaps      FactRequirement = "derived.alert_overlaps"
+	RequiresDerivedDailySummaries     FactRequirement = "derived.daily_summaries"
+	RequiresDerivedDaypartSummaries   FactRequirement = "derived.daypart_summaries"
+	RequiresDerivedPrecipTiming       FactRequirement = "derived.precip_timing"
+	RequiresDerivedStormWindowSummary FactRequirement = "derived.storm_window_summary"
+)
+
+type MissingDataBehavior string
+
+const (
+	MissingDataOmit  MissingDataBehavior = "omit"
+	MissingDataEmpty MissingDataBehavior = "empty"
+	MissingDataError MissingDataBehavior = "error"
+	MissingDataWarn  MissingDataBehavior = "warn"
+)
+
+type MetadataOptions struct{}
+type CurrentConditionsOptions struct{}
+type DerivedDailySummaryOptions struct{}
+type DerivedDaypartSummariesOptions struct{}
+type HourlyTableOptions struct{}
+type PrecipTimingOptions struct{}
+type AlertDigestOptions struct{}
+type AreaForecastDiscussionOptions struct {
+	Sections []string `json:"sections,omitempty" yaml:"sections,omitempty"`
+}
+type WeatherStoryOptions struct{}
+type ForecastDeltaOptions struct{}
+type OutdoorWindowsOptions struct{}
+type TomorrowPlanningOptions struct{}
+type WeekendPlanningOptions struct{}
+type StormWindowSummaryOptions struct{}

internal/module/module_test.go

@@ -0,0 +1,84 @@
+package module
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+)
+
+type testStanza struct {
+	Message string `json:"message"`
+	Count   int    `json:"count"`
+}
+
+func TestSnapshotPreservesOutputOrderAndJSON(t *testing.T) {
+	snapshot, err := NewSnapshot([]Output{
+		{ID: Metadata, StanzaName: "metadata", Value: testStanza{Message: "first", Count: 1}},
+		{ID: AlertDigest, StanzaName: "alert_digest", Value: testStanza{Message: "second", Count: 2}},
+	})
+	if err != nil {
+		t.Fatalf("NewSnapshot() error = %v", err)
+	}
+	if snapshot.SchemaVersion != SnapshotSchemaVersion {
+		t.Fatalf("SchemaVersion = %q, want %q", snapshot.SchemaVersion, SnapshotSchemaVersion)
+	}
+	if snapshot.Outputs[0].ID != Metadata || snapshot.Outputs[1].ID != AlertDigest {
+		t.Fatalf("Outputs order = %#v, want input order", snapshot.Outputs)
+	}
+
+	data, err := json.Marshal(snapshot)
+	if err != nil {
+		t.Fatalf("Marshal() error = %v", err)
+	}
+	got := string(data)
+	want := `{"schemaVersion":"weatherreporter.modules.v1","outputs":[{"id":"metadata","stanzaName":"metadata","value":{"message":"first","count":1}},{"id":"alert_digest","stanzaName":"alert_digest","value":{"message":"second","count":2}}]}`
+	if got != want {
+		t.Fatalf("json = %s, want %s", got, want)
+	}
+}
+
+func TestSnapshotRejectsDuplicateOutputs(t *testing.T) {
+	_, err := NewSnapshot([]Output{
+		{ID: Metadata, StanzaName: "metadata", Value: struct{}{}},
+		{ID: Metadata, StanzaName: "other_metadata", Value: struct{}{}},
+	})
+	if err == nil || !strings.Contains(err.Error(), `duplicate module output "metadata"`) {
+		t.Fatalf("duplicate module error = %v, want duplicate module output", err)
+	}
+
+	_, err = NewSnapshot([]Output{
+		{ID: Metadata, StanzaName: "metadata", Value: struct{}{}},
+		{ID: CurrentConditions, StanzaName: "metadata", Value: struct{}{}},
+	})
+	if err == nil || !strings.Contains(err.Error(), `duplicate stanza name "metadata"`) {
+		t.Fatalf("duplicate stanza error = %v, want duplicate stanza name", err)
+	}
+}
+
+func TestStanzaValueDecodesTypedOutput(t *testing.T) {
+	snapshot, err := NewSnapshot([]Output{
+		{ID: Metadata, StanzaName: "metadata", Value: testStanza{Message: "available", Count: 3}},
+	})
+	if err != nil {
+		t.Fatalf("NewSnapshot() error = %v", err)
+	}
+
+	value, found, err := StanzaValue[testStanza](snapshot, "metadata")
+	if err != nil {
+		t.Fatalf("StanzaValue() error = %v", err)
+	}
+	if !found {
+		t.Fatal("StanzaValue() found = false, want true")
+	}
+	if value.Message != "available" || value.Count != 3 {
+		t.Fatalf("StanzaValue() = %#v, want decoded stanza", value)
+	}
+
+	_, found, err = StanzaValue[testStanza](snapshot, "missing")
+	if err != nil {
+		t.Fatalf("StanzaValue(missing) error = %v", err)
+	}
+	if found {
+		t.Fatal("StanzaValue(missing) found = true, want false")
+	}
+}

internal/promptinput/package.go

@@ -1,72 +1,93 @@
-// Package promptinput builds prompt data packages from briefing packages.
+// Package promptinput builds prompt data packages from module snapshots.
 package promptinput
 
 import (
+	"bytes"
+	"encoding/json"
 	"fmt"
 	"time"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/changes"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/fileutil"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
+	"gopkg.in/yaml.v3"
 )
 
-const SchemaVersion = "weatherreporter.data_package.v1"
+const SchemaVersion = "weatherreporter.data_package.v2"
+
+type BuildRequest struct {
+	Metadata      Metadata
+	Modules       module.Snapshot
+	RecentChanges []changes.Change
+}
+
+type Metadata struct {
+	RunID          string
+	ReportID       report.ID
+	Variant        string
+	PromptID       string
+	GeneratedAt    time.Time
+	Timezone       string
+	ValidPeriod    timeutil.Period
+	SourceWarnings []weatherdata.SourceWarning
+}
 
 type Package struct {
-	SchemaVersion  string                   `json:"schemaVersion"`
-	RunID          string                   `json:"runId"`
-	Report         Report                   `json:"report"`
-	Briefing       briefing.Package         `json:"briefing"`
-	RecentChanges  RecentChanges            `json:"recentChanges"`
-	SourceWarnings []forecast.SourceWarning `json:"sourceWarnings,omitempty"`
+	SchemaVersion  string                      `json:"schemaVersion" yaml:"schema_version"`
+	RunID          string                      `json:"runId" yaml:"run_id"`
+	Report         Report                      `json:"report" yaml:"report"`
+	Briefing       BriefingStanzas             `json:"briefing" yaml:"briefing"`
+	RecentChanges  RecentChanges               `json:"recentChanges" yaml:"recent_changes"`
+	SourceWarnings []weatherdata.SourceWarning `json:"sourceWarnings,omitempty" yaml:"source_warnings,omitempty"`
 }
 
 type Report struct {
-	ID               report.ID       `json:"id"`
-	Variant          string          `json:"variant,omitempty"`
-	PromptID         string          `json:"promptId"`
-	GeneratedAt      time.Time       `json:"generatedAt"`
-	Timezone         string          `json:"timezone"`
-	CurrentLocalDate string          `json:"currentLocalDate"`
-	ValidPeriod      timeutil.Period `json:"validPeriod"`
+	ID               report.ID       `json:"id" yaml:"id"`
+	Variant          string          `json:"variant,omitempty" yaml:"variant,omitempty"`
+	PromptID         string          `json:"promptId" yaml:"prompt_id"`
+	GeneratedAt      time.Time       `json:"generatedAt" yaml:"generated_at"`
+	Timezone         string          `json:"timezone" yaml:"timezone"`
+	CurrentLocalDate string          `json:"currentLocalDate" yaml:"current_local_date"`
+	ValidPeriod      timeutil.Period `json:"validPeriod" yaml:"valid_period"`
+}
+
+type BriefingStanzas struct {
+	Order  []string       `json:"-" yaml:"-"`
+	Values map[string]any `json:"-" yaml:"-"`
 }
 
 type RecentChanges struct {
-	Items []changes.Change `json:"items"`
+	Items []changes.Change `json:"items" yaml:"items"`
 }
 
-func Build(briefingPackage briefing.Package) (Package, error) {
-	return BuildWithRecentChanges(briefingPackage, nil)
-}
-
-func BuildWithRecentChanges(briefingPackage briefing.Package, recentChanges []changes.Change) (Package, error) {
-	localDate, err := currentLocalDate(briefingPackage.Metadata.GeneratedAt, briefingPackage.Metadata.Timezone)
+func Build(req BuildRequest) (Package, error) {
+	localDate, err := currentLocalDate(req.Metadata.GeneratedAt, req.Metadata.Timezone)
 	if err != nil {
 		return Package{}, err
 	}
-	items := make([]changes.Change, len(recentChanges))
-	copy(items, recentChanges)
+	items := make([]changes.Change, len(req.RecentChanges))
+	copy(items, req.RecentChanges)
 	if items == nil {
 		items = []changes.Change{}
 	}
 	pkg := Package{
 		SchemaVersion: SchemaVersion,
-		RunID:         briefingPackage.Metadata.RunID,
+		RunID:         req.Metadata.RunID,
 		Report: Report{
-			ID:               briefingPackage.Metadata.ReportID,
-			Variant:          briefingPackage.Metadata.Variant,
-			PromptID:         briefingPackage.Metadata.PromptID,
-			GeneratedAt:      briefingPackage.Metadata.GeneratedAt,
-			Timezone:         briefingPackage.Metadata.Timezone,
+			ID:               req.Metadata.ReportID,
+			Variant:          req.Metadata.Variant,
+			PromptID:         req.Metadata.PromptID,
+			GeneratedAt:      req.Metadata.GeneratedAt,
+			Timezone:         req.Metadata.Timezone,
 			CurrentLocalDate: localDate,
-			ValidPeriod:      briefingPackage.Metadata.ValidPeriod,
+			ValidPeriod:      req.Metadata.ValidPeriod,
 		},
-		Briefing:       briefingPackage,
+		Briefing:       stanzasFromSnapshot(req.Modules),
 		RecentChanges:  RecentChanges{Items: items},
-		SourceWarnings: briefingPackage.Metadata.SourceWarnings,
+		SourceWarnings: append([]weatherdata.SourceWarning(nil), req.Metadata.SourceWarnings...),
 	}
 	if err := Validate(pkg); err != nil {
 		return Package{}, err
@@ -74,6 +95,16 @@ func BuildWithRecentChanges(briefingPackage briefing.Package, recentChanges []ch
 	return pkg, nil
 }
 
+func stanzasFromSnapshot(snapshot module.Snapshot) BriefingStanzas {
+	values := map[string]any{}
+	order := make([]string, 0, len(snapshot.Outputs))
+	for _, output := range snapshot.Outputs {
+		order = append(order, output.StanzaName)
+		values[output.StanzaName] = output.Value
+	}
+	return BriefingStanzas{Order: order, Values: values}
+}
+
 func currentLocalDate(generatedAt time.Time, timezone string) (string, error) {
 	location, err := timeutil.LoadLocation(timezone)
 	if err != nil {
@@ -86,6 +117,9 @@ func Validate(pkg Package) error {
 	if pkg.SchemaVersion == "" {
 		return fmt.Errorf("schemaVersion is required")
 	}
+	if pkg.SchemaVersion != SchemaVersion {
+		return fmt.Errorf("schemaVersion must be %s", SchemaVersion)
+	}
 	if pkg.RunID == "" {
 		return fmt.Errorf("runId is required")
 	}
@@ -107,33 +141,134 @@ func Validate(pkg Package) error {
 	if !pkg.Report.ValidPeriod.IsValid() {
 		return fmt.Errorf("report.validPeriod must be valid")
 	}
-	if pkg.Briefing.Metadata.RunID == "" {
-		return fmt.Errorf("briefing.metadata.runId is required")
+	if len(pkg.Briefing.Order) == 0 {
+		return fmt.Errorf("briefing stanzas are required")
 	}
-	if pkg.Briefing.Metadata.RunID != pkg.RunID {
-		return fmt.Errorf("briefing.metadata.runId must match runId")
+	for _, name := range pkg.Briefing.Order {
+		if name == "" {
+			return fmt.Errorf("briefing stanza name is required")
 		}
-	if pkg.Briefing.Metadata.SchemaVersion == "" {
-		return fmt.Errorf("briefing.metadata.schemaVersion is required")
+		if _, ok := pkg.Briefing.Values[name]; !ok {
+			return fmt.Errorf("briefing stanza %q is missing", name)
 		}
-	if pkg.Briefing.Metadata.PromptID != pkg.Report.PromptID {
-		return fmt.Errorf("briefing.metadata.promptId must match report.promptId")
-	}
-	if pkg.Briefing.Metadata.ReportID != pkg.Report.ID {
-		return fmt.Errorf("briefing.metadata.reportId must match report.id")
-	}
-	if pkg.Briefing.Daily == nil && pkg.Briefing.ThreeDay == nil && pkg.Briefing.Weekend == nil && pkg.Briefing.Storm == nil {
-		return fmt.Errorf("briefing report content is required")
 	}
 	return nil
 }
 
 func Save(path string, pkg Package) error {
-	if err := Validate(pkg); err != nil {
+	data, err := MarshalYAML(pkg)
+	if err != nil {
 		return err
 	}
-	if err := fileutil.WriteJSONAtomic(path, pkg); err != nil {
+	if err := fileutil.WriteFileAtomic(path, data); err != nil {
 		return fmt.Errorf("save data package: %w", err)
 	}
 	return nil
 }
+
+func MarshalYAML(pkg Package) ([]byte, error) {
+	if err := Validate(pkg); err != nil {
+		return nil, err
+	}
+	data, err := yaml.Marshal(pkg)
+	if err != nil {
+		return nil, fmt.Errorf("marshal data package: %w", err)
+	}
+	return data, nil
+}
+
+func LoadYAML(data []byte) (Package, error) {
+	var pkg Package
+	decoder := yaml.NewDecoder(bytes.NewReader(data))
+	if err := decoder.Decode(&pkg); err != nil {
+		return Package{}, fmt.Errorf("decode data package: %w", err)
+	}
+	if err := Validate(pkg); err != nil {
+		return Package{}, err
+	}
+	return pkg, nil
+}
+
+func (b BriefingStanzas) MarshalYAML() (any, error) {
+	node := &yaml.Node{Kind: yaml.MappingNode}
+	for _, name := range b.Order {
+		value, ok := b.Values[name]
+		if !ok {
+			continue
+		}
+		keyNode := &yaml.Node{Kind: yaml.ScalarNode, Value: name}
+		valueNode, err := yamlNode(value)
+		if err != nil {
+			return nil, fmt.Errorf("marshal briefing stanza %q: %w", name, err)
+		}
+		node.Content = append(node.Content, keyNode, valueNode)
+	}
+	return node, nil
+}
+
+func (b *BriefingStanzas) UnmarshalYAML(value *yaml.Node) error {
+	if value.Kind != yaml.MappingNode {
+		return fmt.Errorf("briefing must be a mapping")
+	}
+	values := map[string]any{}
+	order := make([]string, 0, len(value.Content)/2)
+	for i := 0; i < len(value.Content); i += 2 {
+		name := value.Content[i].Value
+		var stanza any
+		if err := value.Content[i+1].Decode(&stanza); err != nil {
+			return err
+		}
+		order = append(order, name)
+		values[name] = stanza
+	}
+	b.Order = order
+	b.Values = values
+	return nil
+}
+
+func (b BriefingStanzas) MarshalJSON() ([]byte, error) {
+	out := map[string]any{}
+	for _, name := range b.Order {
+		if value, ok := b.Values[name]; ok {
+			out[name] = value
+		}
+	}
+	return json.Marshal(out)
+}
+
+func (b *BriefingStanzas) UnmarshalJSON(data []byte) error {
+	var values map[string]any
+	if err := json.Unmarshal(data, &values); err != nil {
+		return err
+	}
+	order := make([]string, 0, len(values))
+	for name := range values {
+		order = append(order, name)
+	}
+	b.Order = order
+	b.Values = values
+	return nil
+}
+
+func yamlNode(value any) (*yaml.Node, error) {
+	data, err := json.Marshal(value)
+	if err != nil {
+		return nil, err
+	}
+	var normalized any
+	if err := json.Unmarshal(data, &normalized); err != nil {
+		return nil, err
+	}
+	data, err = yaml.Marshal(normalized)
+	if err != nil {
+		return nil, err
+	}
+	var node yaml.Node
+	if err := yaml.Unmarshal(data, &node); err != nil {
+		return nil, err
+	}
+	if len(node.Content) == 0 {
+		return &yaml.Node{Kind: yaml.MappingNode}, nil
+	}
+	return node.Content[0], nil
+}

internal/promptinput/package_test.go

@@ -1,20 +1,17 @@
 package promptinput
 
 import (
-	"encoding/json"
 	"strings"
 	"testing"
 	"time"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
 )
 
 func TestBuildDailyDataPackage(t *testing.T) {
-	briefingPackage := validBriefingPackage()
-
-	pkg, err := Build(briefingPackage)
+	pkg, err := Build(validBuildRequest(t))
 	if err != nil {
 		t.Fatalf("Build() error = %v", err)
 	}
@@ -23,7 +20,7 @@ func TestBuildDailyDataPackage(t *testing.T) {
 		t.Fatalf("SchemaVersion = %q, want %q", pkg.SchemaVersion, SchemaVersion)
 	}
 	if pkg.RunID != "20260529T100000Z_daily_today" {
-		t.Fatalf("RunID = %q, want briefing run id", pkg.RunID)
+		t.Fatalf("RunID = %q, want metadata run id", pkg.RunID)
 	}
 	if pkg.Report.PromptID != "weather.daily_report" {
 		t.Fatalf("PromptID = %q, want weather.daily_report", pkg.Report.PromptID)
@@ -31,14 +28,11 @@ func TestBuildDailyDataPackage(t *testing.T) {
 	if pkg.Report.CurrentLocalDate != "2026-05-29" {
 		t.Fatalf("CurrentLocalDate = %q, want 2026-05-29", pkg.Report.CurrentLocalDate)
 	}
-	if pkg.Briefing.Daily == nil {
-		t.Fatal("Briefing.Daily = nil")
+	if pkg.Briefing.Order[0] != "metadata" || pkg.Briefing.Order[1] != "current_conditions" || pkg.Briefing.Order[2] != "derived_daily_summary" {
+		t.Fatalf("Briefing.Order = %#v, want snapshot stanza order", pkg.Briefing.Order)
 	}
-	if pkg.Briefing.Metadata.Location == nil || pkg.Briefing.Metadata.Location.Name != "Brentwood" {
-		t.Fatalf("Briefing.Metadata.Location = %#v, want configured location", pkg.Briefing.Metadata.Location)
-	}
-	if pkg.Briefing.CurrentConditions == nil || pkg.Briefing.CurrentConditions.ConditionText != "Partly cloudy" {
-		t.Fatalf("Briefing.CurrentConditions = %#v, want current conditions", pkg.Briefing.CurrentConditions)
+	if got := pkg.Briefing.Values["current_conditions"].(map[string]string)["condition_text"]; got != "Partly cloudy" {
+		t.Fatalf("current_conditions.condition_text = %q, want Partly cloudy", got)
 	}
 	if pkg.RecentChanges.Items == nil || len(pkg.RecentChanges.Items) != 0 {
 		t.Fatalf("RecentChanges.Items = %#v, want empty slice", pkg.RecentChanges.Items)
@@ -46,11 +40,11 @@ func TestBuildDailyDataPackage(t *testing.T) {
 }
 
 func TestBuildCurrentLocalDateUsesReportTimezone(t *testing.T) {
-	briefingPackage := validBriefingPackage()
-	briefingPackage.Metadata.GeneratedAt = time.Date(2026, 5, 30, 2, 30, 0, 0, time.UTC)
-	briefingPackage.Metadata.Timezone = "America/Chicago"
+	req := validBuildRequest(t)
+	req.Metadata.GeneratedAt = time.Date(2026, 5, 30, 2, 30, 0, 0, time.UTC)
+	req.Metadata.Timezone = "America/Chicago"
 
-	pkg, err := Build(briefingPackage)
+	pkg, err := Build(req)
 	if err != nil {
 		t.Fatalf("Build() error = %v", err)
 	}
@@ -61,10 +55,10 @@ func TestBuildCurrentLocalDateUsesReportTimezone(t *testing.T) {
 }
 
 func TestBuildRejectsInvalidReportTimezone(t *testing.T) {
-	briefingPackage := validBriefingPackage()
-	briefingPackage.Metadata.Timezone = "Not/AZone"
+	req := validBuildRequest(t)
+	req.Metadata.Timezone = "Not/AZone"
 
-	_, err := Build(briefingPackage)
+	_, err := Build(req)
 	if err == nil {
 		t.Fatal("Build() error = nil, want invalid timezone error")
 	}
@@ -74,7 +68,7 @@ func TestBuildRejectsInvalidReportTimezone(t *testing.T) {
 }
 
 func TestValidateRequiresFields(t *testing.T) {
-	pkg, err := Build(validBriefingPackage())
+	pkg, err := Build(validBuildRequest(t))
 	if err != nil {
 		t.Fatalf("Build() error = %v", err)
 	}
@@ -90,7 +84,7 @@ func TestValidateRequiresFields(t *testing.T) {
 }
 
 func TestValidateRequiresCurrentLocalDate(t *testing.T) {
-	pkg, err := Build(validBriefingPackage())
+	pkg, err := Build(validBuildRequest(t))
 	if err != nil {
 		t.Fatalf("Build() error = %v", err)
 	}
@@ -105,17 +99,17 @@ func TestValidateRequiresCurrentLocalDate(t *testing.T) {
 	}
 }
 
-func TestBuildThreeDayDataPackage(t *testing.T) {
-	briefingPackage := validBriefingPackage()
-	briefingPackage.Metadata.RunID = "20260529T100000Z_three_day"
-	briefingPackage.Metadata.ReportID = report.ThreeDay
-	briefingPackage.Metadata.PromptID = "weather.three_day_outlook"
-	briefingPackage.Daily = nil
-	briefingPackage.ThreeDay = &briefing.ThreeDay{
-		Days: []briefing.OutlookDay{{Date: "2026-05-29"}},
-	}
+func TestBuildUsesNamedSnapshotStanzas(t *testing.T) {
+	req := validBuildRequest(t)
+	req.Metadata.RunID = "20260529T100000Z_three_day"
+	req.Metadata.ReportID = report.ThreeDay
+	req.Metadata.PromptID = "weather.three_day_outlook"
+	req.Modules = snapshotWithOutputs(t,
+		module.Output{ID: module.Metadata, StanzaName: "metadata", Value: map[string]string{"run_id": req.Metadata.RunID}},
+		module.Output{ID: module.ForecastDelta, StanzaName: "three_day", Value: map[string]any{"days": []string{"2026-05-29"}}},
+	)
 
-	pkg, err := Build(briefingPackage)
+	pkg, err := Build(req)
 	if err != nil {
 		t.Fatalf("Build() error = %v", err)
 	}
@@ -123,107 +117,88 @@ func TestBuildThreeDayDataPackage(t *testing.T) {
 	if pkg.Report.ID != report.ThreeDay {
 		t.Fatalf("Report.ID = %q, want three_day", pkg.Report.ID)
 	}
-	if pkg.Briefing.ThreeDay == nil {
-		t.Fatal("Briefing.ThreeDay = nil")
+	if _, ok := pkg.Briefing.Values["three_day"]; !ok {
+		t.Fatal("Briefing.Values[three_day] missing")
 	}
 }
 
-func TestBuildWeekendDataPackage(t *testing.T) {
-	briefingPackage := validBriefingPackage()
-	briefingPackage.Metadata.RunID = "20260529T100000Z_weekend"
-	briefingPackage.Metadata.ReportID = report.Weekend
-	briefingPackage.Metadata.PromptID = "weather.weekend_outlook"
-	briefingPackage.Daily = nil
-	briefingPackage.Weekend = &briefing.Weekend{
-		Days: []briefing.OutlookDay{{Date: "2026-05-30"}},
-	}
-
-	pkg, err := Build(briefingPackage)
+func TestMarshalYAMLIsDeterministicAndUsesNamedStanzas(t *testing.T) {
+	pkg, err := Build(validBuildRequest(t))
 	if err != nil {
 		t.Fatalf("Build() error = %v", err)
 	}
 
-	if pkg.Report.ID != report.Weekend {
-		t.Fatalf("Report.ID = %q, want weekend", pkg.Report.ID)
-	}
-	if pkg.Briefing.Weekend == nil {
-		t.Fatal("Briefing.Weekend = nil")
-	}
-}
-
-func TestBuildStormDataPackage(t *testing.T) {
-	briefingPackage := validBriefingPackage()
-	briefingPackage.Metadata.RunID = "20260529T100000Z_storm"
-	briefingPackage.Metadata.ReportID = report.Storm
-	briefingPackage.Metadata.PromptID = "weather.storm_report"
-	briefingPackage.Daily = nil
-	briefingPackage.Storm = &briefing.Storm{
-		TimingWindow: briefingPackage.Metadata.ValidPeriod,
-		Hazards:      []string{"Thunderstorms"},
-	}
-
-	pkg, err := Build(briefingPackage)
-	if err != nil {
-		t.Fatalf("Build() error = %v", err)
-	}
-
-	if pkg.Report.ID != report.Storm {
-		t.Fatalf("Report.ID = %q, want storm", pkg.Report.ID)
-	}
-	if pkg.Report.PromptID != "weather.storm_report" {
-		t.Fatalf("PromptID = %q, want weather.storm_report", pkg.Report.PromptID)
-	}
-	if pkg.Briefing.Storm == nil {
-		t.Fatal("Briefing.Storm = nil")
-	}
-}
-
-func TestMarshalDeterministic(t *testing.T) {
-	pkg, err := Build(validBriefingPackage())
-	if err != nil {
-		t.Fatalf("Build() error = %v", err)
-	}
-
-	first, err := json.MarshalIndent(pkg, "", "  ")
+	first, err := MarshalYAML(pkg)
 	if err != nil {
 		t.Fatalf("first marshal: %v", err)
 	}
-	second, err := json.MarshalIndent(pkg, "", "  ")
+	second, err := MarshalYAML(pkg)
 	if err != nil {
 		t.Fatalf("second marshal: %v", err)
 	}
 	if string(first) != string(second) {
-		t.Fatalf("JSON output changed between marshals:\n%s\n---\n%s", string(first), string(second))
+		t.Fatalf("YAML output changed between marshals:\n%s\n---\n%s", string(first), string(second))
+	}
+	if !strings.Contains(string(first), "schema_version: weatherreporter.data_package.v2") ||
+		!strings.Contains(string(first), "briefing:\n") ||
+		!strings.Contains(string(first), "    current_conditions:\n") ||
+		!strings.Contains(string(first), "        condition_text: Partly cloudy") {
+		t.Fatalf("YAML output missing expected named stanzas:\n%s", string(first))
 	}
 }
 
-func validBriefingPackage() briefing.Package {
+func TestLoadYAMLRoundTrip(t *testing.T) {
+	pkg, err := Build(validBuildRequest(t))
+	if err != nil {
+		t.Fatalf("Build() error = %v", err)
+	}
+	data, err := MarshalYAML(pkg)
+	if err != nil {
+		t.Fatalf("MarshalYAML() error = %v", err)
+	}
+
+	loaded, err := LoadYAML(data)
+	if err != nil {
+		t.Fatalf("LoadYAML() error = %v", err)
+	}
+
+	if loaded.SchemaVersion != SchemaVersion || loaded.RunID != pkg.RunID {
+		t.Fatalf("loaded package = %#v, want schema and run id", loaded)
+	}
+	if loaded.Briefing.Order[1] != "current_conditions" {
+		t.Fatalf("loaded package order = %#v, want current_conditions second", loaded.Briefing.Order)
+	}
+}
+
+func validBuildRequest(t *testing.T) BuildRequest {
+	t.Helper()
 	generatedAt := time.Date(2026, 5, 29, 10, 0, 0, 0, time.UTC)
-	return briefing.Package{
-		Metadata: briefing.Metadata{
-			SchemaVersion: briefing.SchemaVersion,
+	return BuildRequest{
+		Metadata: Metadata{
 			RunID:       "20260529T100000Z_daily_today",
 			ReportID:    report.DailyToday,
+			Variant:     "today",
 			PromptID:    "weather.daily_report",
 			GeneratedAt: generatedAt,
-			Units:         "us",
 			Timezone:    "America/Chicago",
-			Location: &briefing.LocationContext{
-				ID:       "home",
-				Name:     "Brentwood",
-				Region:   "St. Louis Metro",
-				Timezone: "America/Chicago",
-			},
 			ValidPeriod: timeutil.Period{
 				Start: time.Date(2026, 5, 29, 5, 0, 0, 0, time.UTC),
 				End:   time.Date(2026, 5, 30, 5, 0, 0, 0, time.UTC),
 			},
 		},
-		CurrentConditions: &briefing.CurrentConditionsContext{
-			ConditionText: "Partly cloudy",
-		},
-		Daily: &briefing.Daily{
-			ForecastSummaryDate: "2026-05-29",
-		},
+		Modules: snapshotWithOutputs(t,
+			module.Output{ID: module.Metadata, StanzaName: "metadata", Value: map[string]string{"run_id": "20260529T100000Z_daily_today"}},
+			module.Output{ID: module.CurrentConditions, StanzaName: "current_conditions", Value: map[string]string{"condition_text": "Partly cloudy"}},
+			module.Output{ID: module.DerivedDailySummary, StanzaName: "derived_daily_summary", Value: map[string]string{"date": "2026-05-29"}},
+		),
 	}
 }
+
+func snapshotWithOutputs(t *testing.T, outputs ...module.Output) module.Snapshot {
+	t.Helper()
+	snapshot, err := module.NewSnapshot(outputs)
+	if err != nil {
+		t.Fatalf("NewSnapshot() error = %v", err)
+	}
+	return snapshot
+}

internal/report/definition.go

@@ -5,6 +5,7 @@ import (
 	"fmt"
 	"time"
 
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
 )
 
@@ -42,6 +43,7 @@ type Definition struct {
 	BatchOutputName    string
 	Generated          bool
 	CompatiblePriorIDs []ID
+	Modules            []module.ConfigItem
 	Morning            bool
 	Evening            bool
 	resolve            func(ResolveRequest) (timeutil.Period, error)
@@ -63,6 +65,14 @@ func (d Definition) CompatibleWithPrior(id ID) bool {
 	return false
 }
 
+func (d Definition) ModuleIDs() []module.ID {
+	ids := make([]module.ID, 0, len(d.Modules))
+	for _, item := range d.Modules {
+		ids = append(ids, item.ID)
+	}
+	return ids
+}
+
 type ResolveRequest struct {
 	Now        time.Time
 	Location   *time.Location

internal/report/period_test.go

@@ -6,6 +6,7 @@ import (
 	"testing"
 	"time"
 
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
 )
 
@@ -251,6 +252,140 @@ func TestRegistryDefinitionsDeclarePathAndCompatibilityPolicy(t *testing.T) {
 	}
 }
 
+func TestRegistryDefinitionsDeclareDefaultModules(t *testing.T) {
+	tests := []struct {
+		id   ID
+		want []module.ID
+	}{
+		{
+			id: DailyToday,
+			want: []module.ID{
+				module.Metadata,
+				module.CurrentConditions,
+				module.DerivedDailySummary,
+				module.DerivedDaypartSummaries,
+				module.PrecipTiming,
+				module.AlertDigest,
+				module.ForecastDelta,
+				module.AreaForecastDiscussion,
+				module.WeatherStory,
+				module.OutdoorWindows,
+			},
+		},
+		{
+			id: DailyTomorrow,
+			want: []module.ID{
+				module.Metadata,
+				module.CurrentConditions,
+				module.DerivedDailySummary,
+				module.DerivedDaypartSummaries,
+				module.PrecipTiming,
+				module.AlertDigest,
+				module.ForecastDelta,
+				module.AreaForecastDiscussion,
+				module.WeatherStory,
+				module.OutdoorWindows,
+				module.TomorrowPlanning,
+			},
+		},
+		{
+			id: ThreeDay,
+			want: []module.ID{
+				module.Metadata,
+				module.CurrentConditions,
+				module.DerivedDaypartSummaries,
+				module.PrecipTiming,
+				module.AlertDigest,
+				module.ForecastDelta,
+				module.AreaForecastDiscussion,
+				module.WeatherStory,
+				module.OutdoorWindows,
+			},
+		},
+		{
+			id: Weekend,
+			want: []module.ID{
+				module.Metadata,
+				module.CurrentConditions,
+				module.DerivedDaypartSummaries,
+				module.PrecipTiming,
+				module.AlertDigest,
+				module.AreaForecastDiscussion,
+				module.WeatherStory,
+				module.OutdoorWindows,
+				module.WeekendPlanning,
+			},
+		},
+		{
+			id: Storm,
+			want: []module.ID{
+				module.Metadata,
+				module.CurrentConditions,
+				module.HourlyTable,
+				module.PrecipTiming,
+				module.AlertDigest,
+				module.AreaForecastDiscussion,
+				module.WeatherStory,
+				module.StormWindowSummary,
+			},
+		},
+	}
+
+	registry := DefaultRegistry()
+	for _, tt := range tests {
+		t.Run(string(tt.id), func(t *testing.T) {
+			definition, err := registry.Lookup(tt.id)
+			if err != nil {
+				t.Fatalf("Lookup() error = %v", err)
+			}
+			if !reflect.DeepEqual(definition.ModuleIDs(), tt.want) {
+				t.Fatalf("ModuleIDs() = %#v, want %#v", definition.ModuleIDs(), tt.want)
+			}
+		})
+	}
+}
+
+func TestRegistryAppliesModuleOverridesWithoutChangingDefaults(t *testing.T) {
+	base := DefaultRegistry()
+	overridden, err := base.WithModuleOverrides(map[ID][]module.ConfigItem{
+		DailyToday: {
+			{ID: module.Metadata},
+			{ID: module.AlertDigest},
+		},
+	})
+	if err != nil {
+		t.Fatalf("WithModuleOverrides() error = %v", err)
+	}
+
+	definition, err := overridden.Lookup(DailyToday)
+	if err != nil {
+		t.Fatalf("Lookup(overridden) error = %v", err)
+	}
+	if !reflect.DeepEqual(definition.ModuleIDs(), []module.ID{module.Metadata, module.AlertDigest}) {
+		t.Fatalf("overridden ModuleIDs() = %#v, want metadata and alert digest", definition.ModuleIDs())
+	}
+
+	defaultDefinition, err := base.Lookup(DailyToday)
+	if err != nil {
+		t.Fatalf("Lookup(default) error = %v", err)
+	}
+	if len(defaultDefinition.ModuleIDs()) <= len(definition.ModuleIDs()) {
+		t.Fatalf("default ModuleIDs() = %#v, want original defaults unchanged", defaultDefinition.ModuleIDs())
+	}
+}
+
+func TestRegistryRejectsModuleOverrideForUnknownReport(t *testing.T) {
+	_, err := DefaultRegistry().WithModuleOverrides(map[ID][]module.ConfigItem{
+		ID("unknown"): {{ID: module.Metadata}},
+	})
+	if err == nil {
+		t.Fatal("WithModuleOverrides() error = nil, want unknown report")
+	}
+	if !strings.Contains(err.Error(), `unknown report "unknown"`) {
+		t.Fatalf("error = %q, want unknown report context", err.Error())
+	}
+}
+
 func TestResolvedMetadata(t *testing.T) {
 	location := mustLoadLocation(t)
 	resolved, err := Resolve(DailyToday, ResolveRequest{Now: mustParse("2026-05-29T05:00:00-05:00"), Location: location})

internal/report/registry.go

@@ -1,6 +1,10 @@
 package report
 
-import "fmt"
+import (
+	"fmt"
+
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
+)
 
 type Registry struct {
 	definitions map[ID]Definition
@@ -17,6 +21,7 @@ func DefaultRegistry() Registry {
 			BatchOutputName:    "daily.md",
 			Generated:          true,
 			CompatiblePriorIDs: []ID{DailyToday, DailyTomorrow},
+			Modules:            dailyTodayModules(),
 			Morning:            true,
 			resolve:            resolveDailyToday,
 		},
@@ -29,6 +34,7 @@ func DefaultRegistry() Registry {
 			BatchOutputName:    "tomorrow.md",
 			Generated:          true,
 			CompatiblePriorIDs: []ID{DailyToday, DailyTomorrow},
+			Modules:            dailyTomorrowModules(),
 			Evening:            true,
 			resolve:            resolveDailyTomorrow,
 		},
@@ -41,6 +47,7 @@ func DefaultRegistry() Registry {
 			BatchOutputName:    "three-day.md",
 			Generated:          true,
 			CompatiblePriorIDs: []ID{ThreeDay},
+			Modules:            threeDayModules(),
 			Morning:            true,
 			resolve:            resolveThreeDay,
 		},
@@ -53,6 +60,7 @@ func DefaultRegistry() Registry {
 			BatchOutputName:    "weekend.md",
 			Generated:          true,
 			CompatiblePriorIDs: []ID{Weekend},
+			Modules:            weekendModules(),
 			Morning:            true,
 			resolve:            resolveWeekend,
 		},
@@ -65,6 +73,7 @@ func DefaultRegistry() Registry {
 			BatchOutputName:    "storm.md",
 			Generated:          true,
 			CompatiblePriorIDs: []ID{Storm},
+			Modules:            stormModules(),
 			resolve:            resolveStorm,
 		},
 	}
@@ -75,6 +84,99 @@ func DefaultRegistry() Registry {
 	return registry
 }
 
+func (r Registry) WithModuleOverrides(overrides map[ID][]module.ConfigItem) (Registry, error) {
+	next := Registry{definitions: map[ID]Definition{}}
+	for id, definition := range r.definitions {
+		definition.Modules = append([]module.ConfigItem(nil), definition.Modules...)
+		next.definitions[id] = definition
+	}
+	for id, items := range overrides {
+		definition, ok := next.definitions[id]
+		if !ok {
+			return Registry{}, fmt.Errorf("unknown report %q", id)
+		}
+		definition.Modules = cloneModuleItems(items)
+		next.definitions[id] = definition
+	}
+	return next, nil
+}
+
+func dailyTodayModules() []module.ConfigItem {
+	return moduleItems(
+		module.Metadata,
+		module.CurrentConditions,
+		module.DerivedDailySummary,
+		module.DerivedDaypartSummaries,
+		module.PrecipTiming,
+		module.AlertDigest,
+		module.ForecastDelta,
+		module.AreaForecastDiscussion,
+		module.WeatherStory,
+		module.OutdoorWindows,
+	)
+}
+
+func dailyTomorrowModules() []module.ConfigItem {
+	items := dailyTodayModules()
+	items = append(items, module.ConfigItem{ID: module.TomorrowPlanning})
+	return items
+}
+
+func threeDayModules() []module.ConfigItem {
+	return moduleItems(
+		module.Metadata,
+		module.CurrentConditions,
+		module.DerivedDaypartSummaries,
+		module.PrecipTiming,
+		module.AlertDigest,
+		module.ForecastDelta,
+		module.AreaForecastDiscussion,
+		module.WeatherStory,
+		module.OutdoorWindows,
+	)
+}
+
+func weekendModules() []module.ConfigItem {
+	return moduleItems(
+		module.Metadata,
+		module.CurrentConditions,
+		module.DerivedDaypartSummaries,
+		module.PrecipTiming,
+		module.AlertDigest,
+		module.AreaForecastDiscussion,
+		module.WeatherStory,
+		module.OutdoorWindows,
+		module.WeekendPlanning,
+	)
+}
+
+func stormModules() []module.ConfigItem {
+	return moduleItems(
+		module.Metadata,
+		module.CurrentConditions,
+		module.HourlyTable,
+		module.PrecipTiming,
+		module.AlertDigest,
+		module.AreaForecastDiscussion,
+		module.WeatherStory,
+		module.StormWindowSummary,
+	)
+}
+
+func moduleItems(ids ...module.ID) []module.ConfigItem {
+	items := make([]module.ConfigItem, 0, len(ids))
+	for _, id := range ids {
+		items = append(items, module.ConfigItem{ID: id})
+	}
+	return items
+}
+
+func cloneModuleItems(items []module.ConfigItem) []module.ConfigItem {
+	cloned := make([]module.ConfigItem, len(items))
+	copy(cloned, items)
+	return cloned
+}
+
 func (r Registry) Lookup(id ID) (Definition, error) {
 	definition, ok := r.definitions[id]
 	if !ok {

internal/state/filesystem.go

@@ -10,9 +10,9 @@ import (
 	"strings"
 	"time"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/fileutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptinput"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 )
@@ -27,7 +27,7 @@ type FilesystemStore struct {
 }
 
 type ArtifactPaths struct {
-	Briefing       string `json:"briefing"`
+	ModuleSnapshot string `json:"moduleSnapshot"`
 	Metadata       string `json:"metadata"`
 	DataPackage    string `json:"dataPackage"`
 	Preflight      string `json:"preflight"`
@@ -44,7 +44,6 @@ type ReportRecord struct {
 	ValidStart   string    `json:"validStart"`
 	ValidEnd     string    `json:"validEnd"`
 	MetadataPath string    `json:"metadataPath"`
-	BriefingPath string    `json:"briefingPath"`
 	ReportPath   string    `json:"reportPath,omitempty"`
 	Warnings     int       `json:"warnings"`
 	metadata     Metadata
@@ -90,24 +89,27 @@ func (s *FilesystemStore) Paths(resolved report.Resolved) (ArtifactPaths, error)
 	validDate := resolved.ValidPeriod.Start.Format("2006-01-02")
 	filenameBase := metadata.RunID
 	return ArtifactPaths{
-		Briefing:       s.join(s.snapshotsDir, group, validDate, filenameBase+".briefing.json"),
+		ModuleSnapshot: s.join(s.snapshotsDir, group, validDate, filenameBase+".modules.json"),
 		Metadata:       s.join(s.snapshotsDir, group, validDate, filenameBase+".metadata.json"),
-		DataPackage:    s.join(s.dataPackagesDir, group, validDate, filenameBase+".data_package.json"),
+		DataPackage:    s.join(s.dataPackagesDir, group, validDate, filenameBase+".data_package.yaml"),
 		Preflight:      s.join(s.preflightDir, group, validDate, filenameBase+".render.json"),
 		Notification:   s.join(s.notificationsDir, group, validDate, filenameBase+".distributor.json"),
 		RenderedReport: s.join(s.reportsDir, group, filenameBase+".md"),
 	}, nil
 }
 
-func (s *FilesystemStore) SaveBriefing(_ context.Context, resolved report.Resolved, pkg briefing.Package) (string, error) {
+func (s *FilesystemStore) SaveModuleSnapshot(_ context.Context, resolved report.Resolved, snapshot module.Snapshot) (string, error) {
 	paths, err := s.Paths(resolved)
 	if err != nil {
 		return "", err
 	}
-	if err := fileutil.WriteJSONAtomic(paths.Briefing, pkg); err != nil {
+	if err := snapshot.Validate(); err != nil {
 		return "", err
 	}
-	return paths.Briefing, nil
+	if err := fileutil.WriteJSONAtomic(paths.ModuleSnapshot, snapshot); err != nil {
+		return "", err
+	}
+	return paths.ModuleSnapshot, nil
 }
 
 func (s *FilesystemStore) SaveDataPackage(_ context.Context, resolved report.Resolved, pkg promptinput.Package) (string, error) {
@@ -115,10 +117,7 @@ func (s *FilesystemStore) SaveDataPackage(_ context.Context, resolved report.Res
 	if err != nil {
 		return "", err
 	}
-	if err := promptinput.Validate(pkg); err != nil {
-		return "", err
-	}
-	if err := fileutil.WriteJSONAtomic(paths.DataPackage, pkg); err != nil {
+	if err := promptinput.Save(paths.DataPackage, pkg); err != nil {
 		return "", err
 	}
 	return paths.DataPackage, nil
@@ -164,8 +163,8 @@ func (s *FilesystemStore) SaveMetadata(_ context.Context, metadata Metadata) (st
 	if metadata.RunID == "" {
 		return "", fmt.Errorf("metadata run id is required")
 	}
-	if metadata.BriefingPath == "" {
-		return "", fmt.Errorf("metadata briefing path is required")
+	if metadata.ModuleSnapshotPath == "" {
+		return "", fmt.Errorf("metadata module snapshot path is required")
 	}
 	if metadata.DataPackagePath == "" {
 		return "", fmt.Errorf("metadata data package path is required")
@@ -236,7 +235,7 @@ func (s *FilesystemStore) FindPriorSnapshot(_ context.Context, resolved report.R
 	})
 	return &PriorSnapshot{
 		Metadata:           candidates[0],
-		BriefingPath: candidates[0].BriefingPath,
+		ModuleSnapshotPath: candidates[0].ModuleSnapshotPath,
 	}, nil
 }
 
@@ -301,13 +300,31 @@ func (s *FilesystemStore) LoadDataPackage(_ context.Context, path string) (promp
 	if path == "" {
 		return promptinput.Package{}, fmt.Errorf("data package path is required")
 	}
-	var pkg promptinput.Package
-	if err := readJSON(path, &pkg); err != nil {
+	data, err := os.ReadFile(path)
+	if err != nil {
+		return promptinput.Package{}, fmt.Errorf("read %q: %w", path, err)
+	}
+	pkg, err := promptinput.LoadYAML(data)
+	if err != nil {
 		return promptinput.Package{}, err
 	}
 	return pkg, nil
 }
 
+func (s *FilesystemStore) LoadModuleSnapshot(_ context.Context, path string) (module.Snapshot, error) {
+	if path == "" {
+		return module.Snapshot{}, fmt.Errorf("module snapshot path is required")
+	}
+	var snapshot module.Snapshot
+	if err := readJSON(path, &snapshot); err != nil {
+		return module.Snapshot{}, err
+	}
+	if err := snapshot.Validate(); err != nil {
+		return module.Snapshot{}, err
+	}
+	return snapshot, nil
+}
+
 func (s *FilesystemStore) reportRecord(path string) (ReportRecord, error) {
 	var metadata Metadata
 	if err := readJSON(path, &metadata); err != nil {
@@ -322,7 +339,6 @@ func (s *FilesystemStore) reportRecord(path string) (ReportRecord, error) {
 		ValidStart:   metadata.ValidPeriod.Start.Format(time.RFC3339Nano),
 		ValidEnd:     metadata.ValidPeriod.End.Format(time.RFC3339Nano),
 		MetadataPath: path,
-		BriefingPath: metadata.BriefingPath,
 		ReportPath:   metadata.RenderedReportPath,
 		Warnings:     len(metadata.SourceWarnings),
 		metadata:     metadata,
@@ -402,14 +418,3 @@ func comparablePeriod(metadata Metadata, resolved report.Resolved) bool {
 func sameWeekendWindow(metadata Metadata, resolved report.Resolved) bool {
 	return metadata.ValidPeriod.End.Equal(resolved.ValidPeriod.End) && !metadata.ValidPeriod.Start.After(resolved.ValidPeriod.Start)
 }
-
-func (s *FilesystemStore) LoadBriefing(_ context.Context, path string) (briefing.Package, error) {
-	if path == "" {
-		return briefing.Package{}, fmt.Errorf("briefing path is required")
-	}
-	var pkg briefing.Package
-	if err := readJSON(path, &pkg); err != nil {
-		return briefing.Package{}, err
-	}
-	return pkg, nil
-}

internal/state/filesystem_test.go

@@ -11,6 +11,7 @@ import (
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/config"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptinput"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
@@ -26,9 +27,9 @@ func TestPathsUseRunIDAndWorkspace(t *testing.T) {
 	}
 
 	for _, want := range []string{
-		filepath.Join("snapshots", "daily", "2026-05-29", "20260529T100000.000000000Z_daily_today.briefing.json"),
+		filepath.Join("snapshots", "daily", "2026-05-29", "20260529T100000.000000000Z_daily_today.modules.json"),
 		filepath.Join("snapshots", "daily", "2026-05-29", "20260529T100000.000000000Z_daily_today.metadata.json"),
-		filepath.Join("data-packages", "daily", "2026-05-29", "20260529T100000.000000000Z_daily_today.data_package.json"),
+		filepath.Join("data-packages", "daily", "2026-05-29", "20260529T100000.000000000Z_daily_today.data_package.yaml"),
 		filepath.Join("preflight", "daily", "2026-05-29", "20260529T100000.000000000Z_daily_today.render.json"),
 		filepath.Join("notifications", "daily", "2026-05-29", "20260529T100000.000000000Z_daily_today.distributor.json"),
 		filepath.Join("reports", "daily", "20260529T100000.000000000Z_daily_today.md"),
@@ -42,20 +43,35 @@ func TestPathsUseRunIDAndWorkspace(t *testing.T) {
 func TestSaveArtifactsAndMetadataRoundTrip(t *testing.T) {
 	store := newTestStore(t)
 	resolved := resolveDailyAt(t, "2026-05-29T05:00:00-05:00")
-	briefingPackage := stateBriefingPackage(resolved)
-	dataPackage, err := promptinput.Build(briefingPackage)
+	briefingMetadata := stateBriefingMetadata(resolved)
+	snapshot, err := module.NewSnapshot([]module.Output{{ID: module.Metadata, StanzaName: "metadata", Value: map[string]string{"run_id": resolved.Metadata().RunID}}})
+	if err != nil {
+		t.Fatalf("NewSnapshot() error = %v", err)
+	}
+	dataPackage, err := promptinput.Build(promptinput.BuildRequest{
+		Metadata: promptinput.Metadata{
+			RunID:       resolved.Metadata().RunID,
+			ReportID:    resolved.Definition.ID,
+			Variant:     briefingMetadata.Variant,
+			PromptID:    resolved.Definition.PromptID,
+			GeneratedAt: resolved.GeneratedAt,
+			Timezone:    resolved.Timezone,
+			ValidPeriod: resolved.ValidPeriod,
+		},
+		Modules: snapshot,
+	})
 	if err != nil {
 		t.Fatalf("Build() error = %v", err)
 	}
 
-	briefingPath, err := store.SaveBriefing(context.Background(), resolved, briefingPackage)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
 	dataPackagePath, err := store.SaveDataPackage(context.Background(), resolved, dataPackage)
 	if err != nil {
 		t.Fatalf("SaveDataPackage() error = %v", err)
 	}
+	moduleSnapshotPath, err := store.SaveModuleSnapshot(context.Background(), resolved, snapshot)
+	if err != nil {
+		t.Fatalf("SaveModuleSnapshot() error = %v", err)
+	}
 	preflightPath, err := store.SavePreflight(context.Background(), resolved, PreflightArtifact{Stdout: `{"ok":true}`})
 	if err != nil {
 		t.Fatalf("SavePreflight() error = %v", err)
@@ -110,8 +126,8 @@ func TestSaveArtifactsAndMetadataRoundTrip(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Paths() error = %v", err)
 	}
-	metadata := BuildMetadata(resolved, briefingPackage, ArtifactPaths{
-		Briefing:       briefingPath,
+	metadata := BuildMetadataFromBriefingMetadata(resolved, briefingMetadata, ArtifactPaths{
+		ModuleSnapshot: moduleSnapshotPath,
 		Metadata:       paths.Metadata,
 		DataPackage:    dataPackagePath,
 		Preflight:      preflightPath,
@@ -122,17 +138,24 @@ func TestSaveArtifactsAndMetadataRoundTrip(t *testing.T) {
 		t.Fatalf("SaveMetadata() error = %v", err)
 	}
 
-	for _, path := range []string{briefingPath, dataPackagePath, preflightPath, notificationPath, renderedReportPath, metadataPath} {
+	for _, path := range []string{moduleSnapshotPath, dataPackagePath, preflightPath, notificationPath, renderedReportPath, metadataPath} {
 		if _, err := os.Stat(path); err != nil {
 			t.Fatalf("expected artifact %q: %v", path, err)
 		}
 	}
-	loadedBriefing, err := store.LoadBriefing(context.Background(), briefingPath)
+	loadedSnapshot, err := store.LoadModuleSnapshot(context.Background(), moduleSnapshotPath)
 	if err != nil {
-		t.Fatalf("LoadBriefing() error = %v", err)
+		t.Fatalf("LoadModuleSnapshot() error = %v", err)
 	}
-	if loadedBriefing.Metadata.RunID != resolved.Metadata().RunID {
-		t.Fatalf("loaded briefing RunID = %q, want %q", loadedBriefing.Metadata.RunID, resolved.Metadata().RunID)
+	if loadedSnapshot.SchemaVersion != module.SnapshotSchemaVersion || len(loadedSnapshot.Outputs) != 1 {
+		t.Fatalf("loaded module snapshot = %#v, want one metadata output", loadedSnapshot)
+	}
+	loadedDataPackage, err := store.LoadDataPackage(context.Background(), dataPackagePath)
+	if err != nil {
+		t.Fatalf("LoadDataPackage() error = %v", err)
+	}
+	if loadedDataPackage.SchemaVersion != promptinput.SchemaVersion || loadedDataPackage.Briefing.Order[0] != "metadata" {
+		t.Fatalf("loaded data package = %#v, want YAML package with metadata stanza", loadedDataPackage)
 	}
 	var decoded Metadata
 	data, err := os.ReadFile(metadataPath)
@@ -145,7 +168,7 @@ func TestSaveArtifactsAndMetadataRoundTrip(t *testing.T) {
 	if decoded.RunID != resolved.Metadata().RunID {
 		t.Fatalf("RunID = %q, want %q", decoded.RunID, resolved.Metadata().RunID)
 	}
-	if decoded.BriefingPath != briefingPath || decoded.DataPackagePath != dataPackagePath || decoded.PreflightPath != preflightPath {
+	if decoded.ModuleSnapshotPath != moduleSnapshotPath || decoded.DataPackagePath != dataPackagePath || decoded.PreflightPath != preflightPath {
 		t.Fatalf("metadata paths = %#v, want saved artifact paths", decoded)
 	}
 	if decoded.RenderedReportPath != renderedReportPath {
@@ -162,17 +185,16 @@ func TestSaveArtifactsAndMetadataRoundTrip(t *testing.T) {
 func TestSaveMetadataUsesExplicitMetadataPath(t *testing.T) {
 	store := newTestStore(t)
 	resolved := resolveDailyAt(t, "2026-05-29T05:00:00-05:00")
-	briefingPackage := stateBriefingPackage(resolved)
+	briefingMetadata := stateBriefingMetadata(resolved)
 	paths, err := store.Paths(resolved)
 	if err != nil {
 		t.Fatalf("Paths() error = %v", err)
 	}
 	otherDir := filepath.Join(t.TempDir(), "other-artifacts")
-	otherBriefingPath := filepath.Join(otherDir, resolved.Metadata().RunID+".briefing.json")
 	derivedMetadataPath := filepath.Join(otherDir, resolved.Metadata().RunID+".metadata.json")
 
-	metadata := BuildMetadata(resolved, briefingPackage, ArtifactPaths{
-		Briefing:       otherBriefingPath,
+	metadata := BuildMetadataFromBriefingMetadata(resolved, briefingMetadata, ArtifactPaths{
+		ModuleSnapshot: paths.ModuleSnapshot,
 		Metadata:       paths.Metadata,
 		DataPackage:    paths.DataPackage,
 		Preflight:      paths.Preflight,
@@ -197,25 +219,7 @@ func TestFindPriorSnapshot(t *testing.T) {
 	store := newTestStore(t)
 	first := resolveDailyAt(t, "2026-05-29T05:00:00-05:00")
 	second := resolveDailyAt(t, "2026-05-29T08:00:00-05:00")
-	briefingPackage := stateBriefingPackage(first)
-	briefingPath, err := store.SaveBriefing(context.Background(), first, briefingPackage)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	paths, err := store.Paths(first)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), BuildMetadata(first, briefingPackage, ArtifactPaths{
-		Briefing:       briefingPath,
-		Metadata:       paths.Metadata,
-		DataPackage:    paths.DataPackage,
-		Preflight:      paths.Preflight,
-		RenderedReport: paths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	paths := savePriorMetadata(t, store, first, stateBriefingMetadata(first))
 
 	prior, err := store.FindPriorSnapshot(context.Background(), second)
 	if err != nil {
@@ -227,8 +231,8 @@ func TestFindPriorSnapshot(t *testing.T) {
 	if prior.Metadata.RunID != first.Metadata().RunID {
 		t.Fatalf("RunID = %q, want %q", prior.Metadata.RunID, first.Metadata().RunID)
 	}
-	if prior.BriefingPath != briefingPath {
-		t.Fatalf("BriefingPath = %q, want %q", prior.BriefingPath, briefingPath)
+	if prior.ModuleSnapshotPath != paths.ModuleSnapshot {
+		t.Fatalf("ModuleSnapshotPath = %q, want %q", prior.ModuleSnapshotPath, paths.ModuleSnapshot)
 	}
 }
 
@@ -236,25 +240,7 @@ func TestFindPriorSnapshotUsesValidDate(t *testing.T) {
 	store := newTestStore(t)
 	previousDate := resolveDailyAt(t, "2026-05-28T05:00:00-05:00")
 	currentDate := resolveDailyAt(t, "2026-05-29T05:00:00-05:00")
-	briefingPackage := stateBriefingPackage(previousDate)
-	briefingPath, err := store.SaveBriefing(context.Background(), previousDate, briefingPackage)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	paths, err := store.Paths(previousDate)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), BuildMetadata(previousDate, briefingPackage, ArtifactPaths{
-		Briefing:       briefingPath,
-		Metadata:       paths.Metadata,
-		DataPackage:    paths.DataPackage,
-		Preflight:      paths.Preflight,
-		RenderedReport: paths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	savePriorMetadata(t, store, previousDate, stateBriefingMetadata(previousDate))
 
 	prior, err := store.FindPriorSnapshot(context.Background(), currentDate)
 	if err != nil {
@@ -269,25 +255,7 @@ func TestFindPriorSnapshotSupportsThreeDay(t *testing.T) {
 	store := newTestStore(t)
 	first := resolveThreeDayAt(t, "2026-05-29T05:00:00-05:00")
 	second := resolveThreeDayAt(t, "2026-05-29T08:00:00-05:00")
-	briefingPackage := stateThreeDayBriefingPackage(first)
-	briefingPath, err := store.SaveBriefing(context.Background(), first, briefingPackage)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	paths, err := store.Paths(first)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), BuildMetadata(first, briefingPackage, ArtifactPaths{
-		Briefing:       briefingPath,
-		Metadata:       paths.Metadata,
-		DataPackage:    paths.DataPackage,
-		Preflight:      paths.Preflight,
-		RenderedReport: paths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	savePriorMetadata(t, store, first, stateBriefingMetadata(first))
 
 	prior, err := store.FindPriorSnapshot(context.Background(), second)
 	if err != nil {
@@ -305,25 +273,7 @@ func TestFindPriorSnapshotSupportsWeekend(t *testing.T) {
 	store := newTestStore(t)
 	first := resolveWeekendAt(t, "2026-05-29T05:00:00-05:00")
 	second := resolveWeekendAt(t, "2026-05-29T08:00:00-05:00")
-	briefingPackage := stateWeekendBriefingPackage(first)
-	briefingPath, err := store.SaveBriefing(context.Background(), first, briefingPackage)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	paths, err := store.Paths(first)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), BuildMetadata(first, briefingPackage, ArtifactPaths{
-		Briefing:       briefingPath,
-		Metadata:       paths.Metadata,
-		DataPackage:    paths.DataPackage,
-		Preflight:      paths.Preflight,
-		RenderedReport: paths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	savePriorMetadata(t, store, first, stateBriefingMetadata(first))
 
 	prior, err := store.FindPriorSnapshot(context.Background(), second)
 	if err != nil {
@@ -341,25 +291,7 @@ func TestFindPriorSnapshotSupportsNarrowedWeekendPeriod(t *testing.T) {
 	store := newTestStore(t)
 	first := resolveWeekendAt(t, "2026-05-29T19:00:00-05:00")
 	second := resolveWeekendAt(t, "2026-05-30T08:00:00-05:00")
-	briefingPackage := stateWeekendBriefingPackage(first)
-	briefingPath, err := store.SaveBriefing(context.Background(), first, briefingPackage)
-	if err != nil {
-		t.Fatalf("SaveBriefing() error = %v", err)
-	}
-	paths, err := store.Paths(first)
-	if err != nil {
-		t.Fatalf("Paths() error = %v", err)
-	}
-	_, err = store.SaveMetadata(context.Background(), BuildMetadata(first, briefingPackage, ArtifactPaths{
-		Briefing:       briefingPath,
-		Metadata:       paths.Metadata,
-		DataPackage:    paths.DataPackage,
-		Preflight:      paths.Preflight,
-		RenderedReport: paths.RenderedReport,
-	}))
-	if err != nil {
-		t.Fatalf("SaveMetadata() error = %v", err)
-	}
+	savePriorMetadata(t, store, first, stateBriefingMetadata(first))
 
 	prior, err := store.FindPriorSnapshot(context.Background(), second)
 	if err != nil {
@@ -458,10 +390,8 @@ func resolveWeekendAt(t *testing.T, value string) report.Resolved {
 	return resolved
 }
 
-func stateBriefingPackage(resolved report.Resolved) briefing.Package {
-	return briefing.Package{
-		Metadata: briefing.Metadata{
-			SchemaVersion: briefing.SchemaVersion,
+func stateBriefingMetadata(resolved report.Resolved) briefing.Metadata {
+	return briefing.Metadata{
 		RunID:       resolved.Metadata().RunID,
 		ReportID:    resolved.Definition.ID,
 		Variant:     "today",
@@ -476,51 +406,32 @@ func stateBriefingPackage(resolved report.Resolved) briefing.Package {
 			Timezone: resolved.Timezone,
 		},
 		ValidPeriod: resolved.ValidPeriod,
-		},
-		Daily: &briefing.Daily{ForecastSummaryDate: "2026-05-29"},
 	}
 }
 
-func stateThreeDayBriefingPackage(resolved report.Resolved) briefing.Package {
-	return briefing.Package{
-		Metadata: briefing.Metadata{
-			SchemaVersion: briefing.SchemaVersion,
-			RunID:         resolved.Metadata().RunID,
-			ReportID:      resolved.Definition.ID,
-			PromptID:      resolved.Definition.PromptID,
-			GeneratedAt:   resolved.GeneratedAt,
-			Units:         "us",
-			Timezone:      resolved.Timezone,
-			ValidPeriod:   resolved.ValidPeriod,
-		},
-		ThreeDay: &briefing.ThreeDay{
-			Days: []briefing.OutlookDay{{Date: "2026-05-29"}},
-		},
+func savePriorMetadata(t *testing.T, store *FilesystemStore, resolved report.Resolved, metadata briefing.Metadata) ArtifactPaths {
+	t.Helper()
+	paths, err := store.Paths(resolved)
+	if err != nil {
+		t.Fatalf("Paths() error = %v", err)
 	}
+	_, err = store.SaveMetadata(context.Background(), BuildMetadataFromBriefingMetadata(resolved, metadata, ArtifactPaths{
+		ModuleSnapshot: paths.ModuleSnapshot,
+		Metadata:       paths.Metadata,
+		DataPackage:    paths.DataPackage,
+		Preflight:      paths.Preflight,
+		RenderedReport: paths.RenderedReport,
+	}))
+	if err != nil {
+		t.Fatalf("SaveMetadata() error = %v", err)
 	}
-
-func stateWeekendBriefingPackage(resolved report.Resolved) briefing.Package {
-	return briefing.Package{
-		Metadata: briefing.Metadata{
-			SchemaVersion: briefing.SchemaVersion,
-			RunID:         resolved.Metadata().RunID,
-			ReportID:      resolved.Definition.ID,
-			PromptID:      resolved.Definition.PromptID,
-			GeneratedAt:   resolved.GeneratedAt,
-			Units:         "us",
-			Timezone:      resolved.Timezone,
-			ValidPeriod:   resolved.ValidPeriod,
-		},
-		Weekend: &briefing.Weekend{
-			Days: []briefing.OutlookDay{{Date: "2026-05-30"}},
-		},
-	}
+	return paths
 }
 
 func pathsString(paths ArtifactPaths) string {
 	return strings.Join([]string{
-		paths.Briefing,
 		paths.Metadata,
+		paths.ModuleSnapshot,
 		paths.DataPackage,
 		paths.Preflight,
 		paths.Notification,

internal/state/metadata.go

@@ -4,9 +4,9 @@ import (
 	"time"
 
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/forecast"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/timeutil"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/weatherdata"
 )
 
 const MetadataSchemaVersion = "weatherreporter.metadata.v1"
@@ -25,32 +25,32 @@ type Metadata struct {
 	SourceLocationID   string                      `json:"sourceLocationId,omitempty"`
 	SourceLocation     string                      `json:"sourceLocation,omitempty"`
 	Sources            []briefing.SourceMetadata   `json:"sources,omitempty"`
-	SourceWarnings     []forecast.SourceWarning  `json:"sourceWarnings,omitempty"`
-	BriefingPath       string                    `json:"briefingPath"`
+	SourceWarnings     []weatherdata.SourceWarning `json:"sourceWarnings,omitempty"`
+	ModuleSnapshotPath string                      `json:"moduleSnapshotPath"`
 	DataPackagePath    string                      `json:"dataPackagePath"`
 	PreflightPath      string                      `json:"preflightPath"`
 	NotificationPath   string                      `json:"notificationPath,omitempty"`
 	RenderedReportPath string                      `json:"renderedReportPath,omitempty"`
 }
 
-func BuildMetadata(resolved report.Resolved, briefingPackage briefing.Package, paths ArtifactPaths) Metadata {
+func BuildMetadataFromBriefingMetadata(resolved report.Resolved, briefingMetadata briefing.Metadata, paths ArtifactPaths) Metadata {
 	metadata := resolved.Metadata()
 	return Metadata{
 		SchemaVersion:      MetadataSchemaVersion,
 		RunID:              metadata.RunID,
 		MetadataPath:       paths.Metadata,
 		ReportID:           metadata.ReportID,
-		Variant:            briefingPackage.Metadata.Variant,
+		Variant:            briefingMetadata.Variant,
 		PromptID:           metadata.PromptID,
 		GeneratedAt:        metadata.GeneratedAt,
 		Timezone:           metadata.Timezone,
 		ValidPeriod:        metadata.ValidPeriod,
-		Location:           copyLocation(briefingPackage.Metadata.Location),
-		SourceLocationID:   briefingPackage.Metadata.SourceLocationID,
-		SourceLocation:     briefingPackage.Metadata.SourceLocation,
-		Sources:            briefingPackage.Metadata.Sources,
-		SourceWarnings:     briefingPackage.Metadata.SourceWarnings,
-		BriefingPath:       paths.Briefing,
+		Location:           copyLocation(briefingMetadata.Location),
+		SourceLocationID:   briefingMetadata.SourceLocationID,
+		SourceLocation:     briefingMetadata.SourceLocation,
+		Sources:            briefingMetadata.Sources,
+		SourceWarnings:     briefingMetadata.SourceWarnings,
+		ModuleSnapshotPath: paths.ModuleSnapshot,
 		DataPackagePath:    paths.DataPackage,
 		PreflightPath:      paths.Preflight,
 		RenderedReportPath: paths.RenderedReport,

internal/state/store.go

@@ -6,26 +6,26 @@ import (
 	"encoding/json"
 	"time"
 
-	"gitea.maximumdirect.net/eric/weatherreporter/internal/briefing"
+	"gitea.maximumdirect.net/eric/weatherreporter/internal/module"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/promptinput"
 	"gitea.maximumdirect.net/eric/weatherreporter/internal/report"
 )
 
 type Store interface {
 	Paths(report.Resolved) (ArtifactPaths, error)
-	SaveBriefing(context.Context, report.Resolved, briefing.Package) (string, error)
+	SaveModuleSnapshot(context.Context, report.Resolved, module.Snapshot) (string, error)
 	SaveDataPackage(context.Context, report.Resolved, promptinput.Package) (string, error)
 	SavePreflight(context.Context, report.Resolved, PreflightArtifact) (string, error)
 	SaveDistributorNotification(context.Context, report.Resolved, DistributorNotificationArtifact) (string, error)
 	PrepareRenderedReport(context.Context, report.Resolved) (string, error)
 	SaveMetadata(context.Context, Metadata) (string, error)
 	FindPriorSnapshot(context.Context, report.Resolved) (*PriorSnapshot, error)
-	LoadBriefing(context.Context, string) (briefing.Package, error)
+	LoadModuleSnapshot(context.Context, string) (module.Snapshot, error)
 }
 
 type PriorSnapshot struct {
 	Metadata           Metadata
-	BriefingPath string
+	ModuleSnapshotPath string
 }
 
 type PreflightArtifact struct {

internal/weatherdata/bundle.go

@@ -1,5 +1,5 @@
-// Package forecast defines normalized weather data consumed by report builders.
-package forecast
+// Package weatherdata defines normalized weather data collected from sources.
+package weatherdata
 
 import (
 	"encoding/json"
@@ -33,12 +33,12 @@ type Source struct {
 }
 
 type SourceWarning struct {
-	Source             string `json:"source"`
-	Code               string `json:"code"`
-	Severity           string `json:"severity"`
-	Message            string `json:"message"`
-	Endpoint           string `json:"endpoint,omitempty"`
-	CompletenessImpact string `json:"completenessImpact,omitempty"`
+	Source             string `json:"source" yaml:"source"`
+	Code               string `json:"code" yaml:"code"`
+	Severity           string `json:"severity" yaml:"severity"`
+	Message            string `json:"message" yaml:"message"`
+	Endpoint           string `json:"endpoint,omitempty" yaml:"endpoint,omitempty"`
+	CompletenessImpact string `json:"completenessImpact,omitempty" yaml:"completeness_impact,omitempty"`
 }
 
 type Observation struct {