Document chunk plan caching and provenance

docs/adr/0005-cache-canonical-chunk-plans-by-source.md

@@ -1,6 +1,6 @@
 # ADR-0005: Cache one canonical chunk plan per source
 
-**Status:** Proposed
+**Status:** Accepted
 **Date:** 2026-07-17
 
 ## Context
@@ -70,6 +70,9 @@ Notarius state.
 
 One mutable active plan is stored under the canonical source identity and
 retains provenance for the module and relevant runtime inputs that produced it.
+Refreshing the active plan atomically replaces that one mutable record; readers
+must observe either the previous complete plan or the replacement complete
+plan, never a partial update.
 The effective plan producer is reported separately from the chunk module
 requested by the current pipeline; reuse must not attribute cached boundaries
 or annotations to a module that did not produce them.

docs/cli.md

@@ -9,7 +9,7 @@ For the minimal end-to-end invocation, see the [README](../README.md).
 
 ```text
 notarius help
-notarius run <pipeline-id> --input path/to/source.json [--config path/to/config.yml] [--only lane-a,lane-b] [--output-dir path] [--diagnostics-dir path] [--llm-profile id] [--resume] [--session-id id] [--reference selector=path] [--without-reference selector]
+notarius run <pipeline-id> --input path/to/source.json [--config path/to/config.yml] [--only lane-a,lane-b] [--chunk_cache auto|bypass|refresh] [--output-dir path] [--diagnostics-dir path] [--llm-profile id] [--resume] [--session-id id] [--reference selector=path] [--without-reference selector]
 notarius config validate [--config path/to/config.yml] [--pipeline pipeline-id] [--only lane-a,lane-b]
 notarius pipelines list [--config path/to/config.yml] [--json]
 ```
@@ -31,6 +31,12 @@ Flags:
   comma-separated and must be non-empty.
 - `--resume`: request checkpoint reuse for this invocation. See
   [Operations](operations.md#checkpoints) for prerequisites and reuse behavior.
+- `--chunk_cache auto|bypass|refresh`: select chunk-plan reuse for this
+  invocation. `auto` reuses a valid plan by canonical source digest, `bypass`
+  performs no plan-cache I/O, and `refresh` regenerates and replaces a valid
+  plan only after chunk validation succeeds. See
+  [Configuration](config.md#workspace) for the persistent setting, precedence,
+  and cache-root selection.
 - `--output-dir path`: output root. Defaults to `./notarius-output`.
 - `--diagnostics-dir path`: diagnostics work directory override for this
   invocation. It does not change the workspace directory.
@@ -125,6 +131,24 @@ go run ./cmd/notarius run dnd-session \
   --resume
 ```
 
+Use `refresh` when intentionally replacing the cached plan for the same source:
+
+```sh
+go run ./cmd/notarius run dnd-session \
+  --config examples/dnd-spells.config.yml \
+  --input examples/seriatim-minimal-transcript.json \
+  --chunk_cache refresh
+```
+
+Use `bypass` for a one-off run that must not inspect or create plan-cache state:
+
+```sh
+go run ./cmd/notarius run dnd-session \
+  --config examples/dnd-spells.config.yml \
+  --input examples/seriatim-minimal-transcript.json \
+  --chunk_cache bypass
+```
+
 For checkpoint behavior, durable output, diagnostics, retention, and failure
 inspection, see [Operations](operations.md).
 

docs/config.md

@@ -48,6 +48,8 @@ Built-in defaults:
 - `workspace.diagnostics.enabled`: `true`
 - `workspace.resume.enabled`: `false`
 - `workspace.debug.enabled`: `false`
+- `workspace.chunk_cache.mode`: `auto`
+- `workspace.chunk_cache.directory`: unset
 
 No pipelines are built in. A run requires a configured pipeline.
 
@@ -97,6 +99,8 @@ These environment variables are applied after the config file:
 - `NOTARIUS_WORKSPACE_RESUME_ENABLED`: boolean resume checkpointing
   enablement.
 - `NOTARIUS_WORKSPACE_DEBUG_ENABLED`: boolean debug artifact enablement.
+- `NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE`: chunk-plan cache mode.
+- `NOTARIUS_WORKSPACE_CHUNK_CACHE_DIR`: chunk-plan cache root.
 - `NOTARIUS_WORK_DIR`: deprecated diagnostics work directory compatibility
   override.
 - `NOTARIUS_DIAGNOSTICS_RETENTION`: deprecated diagnostics retention
@@ -344,11 +348,35 @@ casts still must be present in the source transcript.
 - `directory`: optional workspace root for Notarius-owned local state.
 - `resume.enabled`: boolean resume checkpointing setting.
 - `debug.enabled`: boolean debug artifact setting.
+- `chunk_cache.mode`: persistent chunk-plan cache mode: `auto`, `bypass`, or
+  `refresh`. The default is `auto`.
+- `chunk_cache.directory`: optional chunk-plan cache root. This value is the
+  root itself; Notarius does not append `chunk-plans` to it.
 - `diagnostics`: optional diagnostics settings defined below.
 
-`workspace.resume.enabled` and `workspace.debug.enabled` are independent.
-Enabling one does not enable the other. For directory layout, state lifecycle,
-permissions, and sensitive content, see [Operations](operations.md).
+`workspace.resume.enabled`, `workspace.debug.enabled`, and
+`workspace.chunk_cache` are independent. `workspace.directory` does not affect
+chunk-plan placement. For directory layout, state lifecycle, permissions, and
+sensitive content, see [Operations](operations.md).
+
+`chunk_cache.mode` accepts only `auto`, `bypass`, and `refresh`. In `auto`, a
+valid source-addressed plan is reused and a missing or invalid record is
+regenerated and published after chunk validation. `bypass` neither reads nor
+writes plan-cache state. `refresh` always generates a new plan and publishes it
+only after validation succeeds.
+
+Configuration values are applied in file then environment order; an explicit
+`--chunk_cache` CLI value has highest precedence for the mode. The cache root
+is selected from environment, file, then the per-user default; there is no CLI
+root override. Every supplied value is parsed strictly even when a higher
+precedence value wins, so malformed configuration is still an error.
+
+When `chunk_cache.directory` is unset, the root is
+`<os.UserCacheDir>/notarius/chunk-plans`. On Unix this is ordinarily
+`$XDG_CACHE_HOME/notarius/chunk-plans` when `XDG_CACHE_HOME` is an absolute
+path, or `$HOME/.cache/notarius/chunk-plans` when it is unset. A relative
+`XDG_CACHE_HOME` is rejected by `os.UserCacheDir`; Notarius reports that as a
+configuration error and does not fall back to another directory.
 
 ## Diagnostics
 
@@ -390,6 +418,7 @@ Configuration validation checks:
 - supported stage-worker keys and an effective extract worker count in the
   inclusive range `1..concurrency.total_llm`;
 - supported diagnostics retention and non-empty work directory;
+- a supported chunk-cache mode and a chunk-cache directory without NUL bytes;
 - stale removed fields such as `llm_profiles`.
 
 Pipeline resolution additionally checks:

docs/integrations/json-output.md

@@ -91,6 +91,16 @@ The manifest fields are:
   identity;
 - `input_module`, `chunker`, `extractors`, `merger`, `normalizer`, and
   `output_encoder`: resolved module keys;
+- `chunk_plan`: payload-free provenance for the effective chunk plan. `mode`
+  is the effective cache mode; `action` is `reused`, `generated`,
+  `refreshed`, or `bypassed` when a plan was materialized. `requested_module`
+  is the current pipeline chunker, while `producer_input_module`,
+  `producer_module`, `producer_llm_profile`, `producer_references`,
+  `producer_metadata`, `source_digest`, `plan_digest`, `plan_schema_version`,
+  and `created_at` describe the stored or generated producer when available.
+  A cached plan can therefore identify a producer different from the requested
+  module. This object never embeds ranges, units, annotations, prompts,
+  responses, or reference content;
 - `module_metadata` and `artifact_lanes`: module and per-lane provenance,
   including prompt and response-schema provenance when provided;
 - `validator_chains`: resolved validation points and validators;
@@ -115,6 +125,10 @@ references.
 `validation_status` is `approved` when no outputs were rejected and `rejected`
 when one or more outputs were rejected.
 
+Producer warnings and the current run's chunk-validation warnings remain in
+`warnings.json`. The manifest records only provenance and decision summaries;
+empty producer-only values are omitted for compatibility with existing readers.
+
 `validator_chains` records the resolved validator chain for each validation
 point. Entries include stage, lane ID when applicable, module key, and validators
 with key and execution class. Empty chains are recorded with an empty

docs/internal/diagnostics.md

@@ -22,10 +22,18 @@ constructor.
 
 Typed methods on `RunDirectory` write invocation metadata, redacted effective
 configuration, resolved pipeline/reference data, checkpoint events, source data
-when explicitly requested, manifests, reports, warnings, and error text. The
+when explicitly requested, manifests, reports, warnings, redacted chunk-plan
+summaries, and error text. The
 current filenames and their operator-facing contents are listed in
 [Operations](../operations.md#diagnostics-directory).
 
+The chunk-plan summary records the effective mode, source and candidate
+digests, requested module, lookup decision, materialization action, validation
+decision, and publication decision. Its closed decision values make failures
+and recoverable invalid records inspectable without serializing plan ranges,
+annotations, source content, reference content, prompts, model responses, or
+raw invalid-file bytes.
+
 JSON methods indent their payload and append a newline. All artifact writes use
 a temporary file in the target directory, apply the requested permissions, and
 rename it into place. Artifact resolution accepts only a single relative base
@@ -60,7 +68,8 @@ pipeline results, and the final report. This ordering permits later failures to
 retain the context already established.
 
 Failures before construction have no `RunDirectory`. Later failures write an
-error log, preserve any available partial manifest, and apply a failed-run
+error log, preserve any available partial manifest and chunk-plan summary, and
+apply a failed-run
 retention decision. A diagnostics write failure is itself a command failure so
 the CLI does not report success after losing requested inspection data.
 

docs/internal/modules.md

@@ -67,34 +67,41 @@ rules are defined in the
 
 ## Chunkers
 
+Chunkers implement `contracts.Chunker.Plan`. A plan identifies ordered source
+unit ranges and may carry optional namespaced JSON annotations; it does not
+contain materialized chunk content. The framework canonicalizes annotations,
+validates ranges against the current source, and materializes chunk IDs,
+indexes, references, content, units, and generic metadata. Annotation
+namespaces remain optional data: generic framework code and downstream modules
+must not require D&D scene annotations or import `dnd/scenes`.
+
 ### `internal/modules/generic/chunk/units`
 
-The generic chunker validates the source document, walks units in configured
-windows, clones each selected unit, and emits deterministic ordered chunk IDs.
-Overlap changes the next window start but never reorders units. It records the
-first and last unit and unit count in chunk metadata, and derives the chunk's
-canonical source reference from those unit references.
+The generic chunker validates the source document and returns ranges over units
+in configured windows. Overlap changes the next window start but never reorders
+units. Framework materialization derives the resulting chunk identity and
+generic metadata from those ranges.
 
 The accepted options and defaults are defined in
 [Configuration](../config.md#implemented-production-modules). Generic
 framework validation canonicalizes the returned unit slices before extraction.
 The chunker decodes its options during construction and retains only the typed
-window settings used by `Chunk`.
+window settings used by `Plan`.
 
 ### `internal/modules/dnd/chunk/scenes`
 
 The scene chunker prepares a structured Scriptorium request from the full
 transcript, session, and optional D&D reference inputs. It validates the model's
 scene boundaries against source-unit IDs and converts them into deterministic
-chunks with canonical source references spanning each scene's units.
-Preparation injects the shared structured LLM client into the chunker; `Chunk`
+plan ranges with optional scene annotations. Preparation injects the shared
+structured LLM client into the chunker; `Plan`
 supplies only the run-specific profile, session, source, references, and
 metadata.
 
 Scene validation requires sequential, contiguous, non-overlapping coverage from
-the first source unit through the last. Each chunk contains JSON scene content
-and module-owned metadata for the scene description, boundaries, confidence,
-participants, and unit count. Boundary caveats become warnings. Malformed
+the first source unit through the last. Scene descriptions, boundaries,
+confidence, and participants are module-owned annotations. Boundary caveats
+become warnings. Malformed
 structured output is returned as an error; there is no fallback chunker.
 
 The package embeds its prompt and response schema and reports their non-secret

docs/internal/overview.md

@@ -35,7 +35,7 @@ normalize continuations that may overlap across lanes.
 | `internal/core/config` | Defaults, YAML parsing, environment overrides, validation, redaction, and effective pipeline resolution. |
 | `internal/core/diagnostics` | Scoped run directories, diagnostics writers, atomic writes, and retention decisions. |
 | `internal/core/source` | Generic source documents, units, chunks, canonical references, lookup, validation, and deterministic source digests. |
-| `internal/core/workspace` | Effective workspace settings, confined paths and writes, checkpoint identity, and checkpoint manifest models. |
+| `internal/core/workspace` | Effective workspace settings, confined paths and writes, and checkpoint identity and manifest models. |
 
 ## Framework Packages
 
@@ -47,6 +47,7 @@ normalize continuations that may overlap across lanes.
 | `internal/framework/llm` | Scriptorium-backed structured completions, prompt/schema registration, scheduling, profile recording, and secret redaction. |
 | `internal/framework/promptfs` | Builds module prompt filesystems from module-owned and caller-provided shared prompt assets. |
 | `internal/framework/checkpoint` | Workspace-backed checkpoint loading, recording, and payload serialization. |
+| `internal/framework/chunkplan` | Source-addressed chunk-plan filesystem storage, envelope validation, and atomic publication. |
 | `internal/framework/debug` | Workspace-backed framework and LLM debug recording. |
 
 Framework contracts provide typed artifact, provenance-wrapper, chunk-validator,
@@ -122,7 +123,8 @@ Implementation details for all production extensions are in
 | --- | --- | --- |
 | Durable output | Output module, pipeline runner, and CLI writer | Return logical consumer files and place them for a run. |
 | Diagnostics | `internal/core/diagnostics` and `internal/cli` | Record redacted invocation, resolution, result, and failure inspection data. |
-| Checkpoints | `internal/framework/checkpoint` and `internal/core/workspace` | Validate and serialize reusable stage outcomes. |
+| Checkpoints | `internal/framework/checkpoint` and `internal/core/workspace` | Validate and serialize reusable extract, merge, and normalize outcomes. |
+| Chunk-plan cache | `internal/framework/chunkplan` and `internal/cli` | Persist and select source-addressed plans before framework materialization. |
 | Debug artifacts | `internal/framework/debug` and pipeline instrumentation | Capture sensitive framework-boundary and LLM-call material. |
 
 Physical layout, retention, recovery, and sensitive-data handling are defined

docs/internal/pipeline.md

@@ -8,7 +8,8 @@ defaults, and selectable keys are defined in
 
 Resolution fixes the selected lanes and all stage bindings; preparation
 constructs every selected implementation before the runner begins source work.
-After serial input parsing and chunking, the runner dispatches extract work to
+After serial input parsing and plan selection or generation, the runner
+materializes chunks and dispatches extract work to
 one bounded run-wide worker pool in chunk-first, lane-second order. Each lane's
 merge and normalize operations remain serial and may overlap other lanes once
 all extracts for that lane are terminal.
@@ -118,7 +119,8 @@ validator context as applicable. It never invokes an operation method.
 `PreparedPipeline` keeps private constructed executors and exposes cloned
 resolved input, chunk, lane, and output identities. `pipeline.RunInput` carries
 that prepared pipeline, raw source input, run identity and timing, optional
-session and profile metadata, and checkpoint/debug collaborators. The runner
+session and profile metadata, a chunk-plan store and mode, and checkpoint/debug
+collaborators. The runner
 parses source bytes through the already constructed input adapter. Later stage
 requests receive the generic source model; extract requests receive
 chunk-scoped input material, while chunk, merge, and normalize requests retain
@@ -151,8 +153,9 @@ The runner:
 1. validates its prepared input;
 2. parses the raw input with the prepared adapter and validates the generic
    source document;
-3. obtains or executes the chunk result;
-4. validates and canonicalizes chunks;
+3. selects a stored plan or executes the configured chunker's `Plan` operation;
+4. canonicalizes and materializes the plan, then validates the resulting
+   chunks;
 5. dispatches extract jobs in source-chunk then resolved-lane order, starting a
    bounded lane continuation when all extracts for that lane are terminal;
 6. invokes the prepared output encoder and validates its logical file results;
@@ -173,6 +176,31 @@ and validators while performing these transitions:
 Module-provided warnings and payload warnings are promoted only from attempts
 whose results are accepted and used.
 
+## Chunk Plans And Reuse
+
+`Chunker.Plan` returns a `source.ChunkPlan`: the canonical source digest,
+ordered unit-ID ranges, and optional plan or range annotations. The framework
+owns plan canonicalization and materialization. It creates the generic chunks
+and therefore owns their IDs, indexes, source references, JSON content, units,
+media type, and generic metadata. Plan and range annotations are independently
+owned raw JSON and become `Chunk.PlanAnnotations` and `Chunk.Annotations`.
+
+In `auto`, the runner looks up the source digest before invoking the chunker. A
+valid hit is materialized and sent through the current run's configured chunk
+validators; it does not invoke the chunk module, consume its retry budget, or
+make a chunk-stage LLM call. A missing, invalid, or unmaterializable record
+generates a candidate. `refresh` generates without lookup; `bypass` generates
+without cache access. Generated plans are published only after the full chunk
+validator chain approves them. A validator rejection is a regular rejected
+pipeline outcome and never replaces a cached plan.
+
+The store is source-addressed, not pipeline-addressed. Changes to pipeline
+configuration, requested chunker, options, references, lanes, validators, or
+LLM profile do not prevent a source-digest hit. The manifest records both the
+currently requested chunker and the effective plan producer. Cache state and
+paths are configured and operated outside the runner; see
+[Configuration](../config.md#workspace) and [Operations](../operations.md).
+
 The extract job channel has the same capacity as the effective extract worker
 count, so dispatch applies backpressure. A fixed continuation executor prevents
 ready or checkpoint-reused lanes from creating one goroutine each. Workers and
@@ -180,19 +208,19 @@ continuations publish lane-local results; the coordinator is the only writer of
 aggregate output and merges those results in resolved lane and source-chunk
 order.
 
-## Chunk Canonicalization
+## Plan Canonicalization And Chunk Materialization
 
-Before lane execution, generic validation requires unique chunk IDs, matching
-source identity, indexes matching returned order, a valid canonical reference,
-non-empty content and media type, and at least one valid source unit per chunk.
-Units may not repeat inside a chunk and must form a contiguous range in
-source-document order. The chunk reference must exactly match the source and
-the first and last unit references.
+Plan canonicalization requires canonical JSON annotations, a matching source
+digest, at least one range, existing ordered boundaries, and increasing range
+starts. Ranges may overlap or leave gaps; a chunker may impose stricter policy.
+Materialization deterministically reconstructs each range from the current
+source document and copies annotations without interpreting their namespaces.
 
-The runner then rebuilds each chunk's unit slice from the source document by
-unit ID. It preserves the canonical reference, content, media type, and cloned
-metadata. The framework permits gaps and overlap between separate
-chunks; stricter coverage policy belongs to the chunk implementation.
+Before lane execution, generic chunk validation checks the materialized chunks'
+identities, order, source references, content, media type, units, and metadata.
+No chunk checkpoint participates in plan selection: plan storage is the only
+chunk-reuse mechanism. Extract, merge, and normalize checkpoints continue to
+use materialized chunk digests as their dependencies.
 
 ## Validation And Retries
 

docs/operations.md

@@ -57,6 +57,10 @@ Implemented diagnostics artifacts:
   binding source, without reference content.
 - `checkpoint-events.json`: checkpoint steps that were reused or executed
   during an explicit resume invocation.
+- `chunk-plan.json`: redacted plan-cache lookup, validation, and publication
+  summary. It contains identifiers and decisions, never source units, plan
+  annotations, reference content, prompts, model responses, or invalid-file
+  bytes.
 - `run-manifest.json`: the same run manifest written to durable output when it
   is available, including top-level module metadata when present.
 - `warnings.json`: warning list.
@@ -64,6 +68,54 @@ Implemented diagnostics artifacts:
 - `error.log`: failure message, written after diagnostics directory creation
   when a run fails.
 
+## Chunk-Plan Cache
+
+The chunk-plan cache is independent of the workspace and checkpoints. Its
+configuration and selection precedence are defined in
+[Configuration](config.md#workspace); the invocation override is documented in
+the [CLI reference](cli.md#run).
+
+When no root is configured, a normal Linux user uses
+`$XDG_CACHE_HOME/notarius/chunk-plans` when `XDG_CACHE_HOME` is a valid absolute
+path, or `$HOME/.cache/notarius/chunk-plans` when it is unset. A relative
+`XDG_CACHE_HOME` is a configuration error. A configured
+`workspace.chunk_cache.directory` is the root itself, not a parent to which
+Notarius adds a suffix.
+
+Each source digest has one file:
+
+```text
+<chunk-plan-root>/<source-sha256-hex>/plan.json
+```
+
+Directories are created with `0700` permissions and plan files with `0600`.
+`auto` reuses a complete valid plan or regenerates an absent or invalid one;
+`refresh` deliberately regenerates; `bypass` performs no cache I/O. A stored
+plan is still validated and materialized against the current source before use,
+and the current run's chunk validators always run. Invalid state is recoverable:
+an `auto` run regenerates and atomically replaces it only after validation
+succeeds. Delete an exact cache root or digest directory only when regeneration
+cost is acceptable.
+
+Publication uses atomic replacement. Concurrent readers observe a complete old
+or new plan, and concurrent writers leave one complete valid winner; there is
+no history, lock protocol, or rollback facility. Do not share a cache root
+between mutually untrusted users because plans can contain source-derived
+structure and annotations.
+
+For a system-wide Linux deployment under a dedicated service account, configure
+and provision a separate restrictive root such as:
+
+```yaml
+workspace:
+  chunk_cache:
+    directory: /var/cache/notarius/chunk-plans
+```
+
+`/var/cache/notarius/chunk-plans` is a recommended configured service root, not
+the unprivileged default. The operator or package installer must create it with
+restrictive service-account ownership and permissions before use.
+
 ## Checkpoints
 
 When checkpoint writing is enabled for a configured workspace, runs write
@@ -158,8 +210,12 @@ failure before a candidate exists has no candidate payload. If the envelope
 cannot be persisted, the run does not retry that module attempt and reports the
 debug failure together with any primary attempt error.
 
-Checkpoint-reused chunk, extract, merge, and normalize work retains the
-stage-level input and output artifacts but has no retry-attempt artifacts
+Chunk-plan candidates, materialized chunks, annotations, and chunk-attempt
+details appear only in these opt-in debug artifacts. They are intentionally not
+included in normal manifests or the `chunk-plan.json` diagnostics summary.
+
+Checkpoint-reused extract, merge, and normalize work retains the stage-level
+input and output artifacts but has no retry-attempt artifacts
 because no module attempt executed. Debug artifacts may contain source
 material, reference material, prompt inputs, model outputs, and other sensitive
 data. Typed artifact
@@ -218,6 +274,10 @@ rm -rf /var/lib/notarius/checkpoints/dnd-session/seriatim-abcdef123456/7890abcd1
 rm -rf /var/lib/notarius/debug/run-1234567890
 ```
 
+Chunk-plan cache entries can likewise be removed by exact digest directory or
+configured root. Removal is recoverable, but the next non-bypass run may need
+to regenerate plans and repeat any chunk-stage LLM work.
+
 Use exact run-directory paths. Avoid broad cleanup commands against parent
 directories unless they are part of your own operational policy.
 

docs/policy/architecture.md

@@ -105,6 +105,14 @@ Stage ownership is explicit:
 - normalize modules reconcile merged output;
 - output modules encode accepted results and run outcomes into logical files.
 
+Chunk modules produce source-addressed chunk plans rather than materialized
+chunks. The framework validates and materializes those plans into the generic
+chunk representation before chunk validation and lane execution. Plan reuse is
+therefore independent of the configured pipeline, module options, references,
+lanes, validators, and LLM profile: the canonical source digest selects the
+plan, while the current run still applies its configured chunk validators to
+the materialized chunks.
+
 The framework owns orchestration and handoff provenance. Modules return logical
 results and warnings; they do not own CLI reporting, workspace paths, durable
 file placement, checkpoints, or diagnostics.
@@ -191,6 +199,12 @@ surfaces with separate ownership:
 - debug artifacts are opt-in inspection data and may contain sensitive source,
   prompt, reference, and model-output content.
 
+Chunk-plan cache state is an additional independent surface. It is keyed only
+by canonical source digest, is not rooted under `workspace.directory`, and is
+not a checkpoint or a diagnostic. A cache record is atomically replaced as one
+complete plan envelope; it has no history, locking, or rollback interface.
+Invalid records are recoverable cache misses rather than pipeline state.
+
 Writes of durable state are atomic where practical. Paths for writes, moves,
 overwrites, and deletion must be narrow and explicit. Cleanup that can lose data
 is opt-in.

docs/roadmap/implementation.md

@@ -1,13 +1,12 @@
-# ADR-0005 Staged Implementation Plan
+# ADR-0005 Implementation Record
 
-This document is the executable implementation plan for the target state in
+This document records the completed implementation of the target state in
 [ADR-0005 Feature Roadmap](adr0005.md), governed by
-[ADR-0005](../adr/0005-cache-canonical-chunk-plans-by-source.md). The feature is
-not implemented.
+[ADR-0005](../adr/0005-cache-canonical-chunk-plans-by-source.md).
 
-The audience is an LLM coding agent. Implement the stages in order. Each stage
-is deliberately scoped to finish with a compiling, tested repository and may be
-assigned as one implementation prompt.
+All stages below are complete. The plan remains as historical target-state
+context; current behavior is documented in the canonical references linked from
+[Development](../development.md).
 
 ## Execution Rules
 
@@ -284,7 +283,7 @@ then fills candidate and producer fields when a plan reaches materialization.
 
 ## Stage 1: Finalize ADR and add the source-zone plan model
 
-**Status:** Not started
+**Status:** Complete
 
 ### Objective
 
@@ -351,7 +350,7 @@ tested; current modules and the runner still behave as before.
 
 ## Stage 2: Replace the chunk operation with plan generation
 
-**Status:** Not started
+**Status:** Complete
 
 ### Objective
 
@@ -432,7 +431,7 @@ is green.
 
 ## Stage 3: Add dedicated cache configuration and the plan store
 
-**Status:** Not started
+**Status:** Complete
 
 ### Objective
 
@@ -531,7 +530,7 @@ runs still use Stage 2’s generate-and-materialize behavior.
 
 ## Stage 4: Integrate cache policy and remove chunk checkpoints
 
-**Status:** Not started
+**Status:** Complete
 
 ### Objective
 
@@ -617,7 +616,7 @@ runs are not yet wired to persistent plan storage.
 
 ## Stage 5: Wire persistent policy into the CLI
 
-**Status:** Not started
+**Status:** Complete
 
 ### Objective
 
@@ -709,7 +708,7 @@ refresh have exact state semantics, and the repository is green.
 
 ## Stage 6: Expose producer provenance and safe diagnostics
 
-**Status:** Not started
+**Status:** Complete
 
 ### Objective
 
@@ -798,7 +797,7 @@ compatibility tests pass.
 
 ## Stage 7: Add cross-run, corruption, and concurrency hardening
 
-**Status:** Not started
+**Status:** Complete
 
 ### Objective
 
@@ -870,7 +869,7 @@ and race checks pass.
 
 ## Stage 8: Publish current-behavior documentation
 
-**Status:** Not started
+**Status:** Complete
 
 ### Objective
 

examples/dnd-spells-production.config.yml

@@ -12,6 +12,8 @@ workspace:
     enabled: false
   debug:
     enabled: false
+  chunk_cache:
+    directory: /var/cache/notarius/chunk-plans
 pipelines:
   dnd-session:
     input: seriatim

examples/dnd-spells.config.yml

@@ -1,4 +1,7 @@
 version: 2
+workspace:
+  chunk_cache:
+    mode: bypass
 pipelines:
   dnd-session:
     input: seriatim

internal/cli/chunk_cache_test.go

@@ -0,0 +1,480 @@
+package cli
+
+import (
+	"bytes"
+	"errors"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/diagnostics"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+)
+
+type recordingChunkPlanStore struct {
+	record   pipeline.ChunkPlanRecord
+	decision pipeline.ChunkPlanDecision
+	loadErr  error
+	saveErr  error
+	loads    int
+	saves    int
+}
+
+func (s *recordingChunkPlanStore) Load(string) (pipeline.ChunkPlanRecord, pipeline.ChunkPlanDecision, error) {
+	s.loads++
+	return s.record, s.decision, s.loadErr
+}
+
+func (s *recordingChunkPlanStore) Save(record pipeline.ChunkPlanRecord) error {
+	s.saves++
+	s.record = record
+	return s.saveErr
+}
+
+type recordingChunkPlanFactory struct {
+	roots []string
+	store *recordingChunkPlanStore
+	err   error
+}
+
+func (f *recordingChunkPlanFactory) build(root string) (pipeline.ChunkPlanStore, error) {
+	f.roots = append(f.roots, root)
+	if f.err != nil {
+		return nil, f.err
+	}
+	if f.store == nil {
+		f.store = &recordingChunkPlanStore{decision: pipeline.ChunkPlanDecision{Status: pipeline.ChunkPlanMissing}}
+	}
+	return f.store, nil
+}
+
+func TestRunChunkCachePrecedence(t *testing.T) {
+	tests := []struct {
+		name      string
+		fileMode  string
+		envMode   string
+		flagMode  string
+		wantMode  pipeline.ChunkCacheMode
+		wantBuild bool
+	}{
+		{name: "file refresh", fileMode: "refresh", wantMode: pipeline.ChunkCacheRefresh, wantBuild: true},
+		{name: "environment over file", fileMode: "bypass", envMode: "refresh", wantMode: pipeline.ChunkCacheRefresh, wantBuild: true},
+		{name: "flag over environment", fileMode: "refresh", envMode: "auto", flagMode: "bypass", wantMode: pipeline.ChunkCacheBypass},
+		{name: "explicit auto", fileMode: "bypass", envMode: "refresh", flagMode: "auto", wantMode: pipeline.ChunkCacheAuto, wantBuild: true},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			root := filepath.Join(t.TempDir(), "plans")
+			configPath := writeTestConfig(t, cacheTestConfig(tc.fileMode, root, ""))
+			inputPath := writeFile(t, "input.txt", "input")
+			values := map[string]string{}
+			if tc.envMode != "" {
+				values["NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE"] = tc.envMode
+			}
+			factory := &recordingChunkPlanFactory{}
+			args := []string{"run", "example", "--config", configPath, "--input", inputPath, "--output-dir", t.TempDir()}
+			if tc.flagMode != "" {
+				args = append(args, "--chunk_cache", tc.flagMode)
+			}
+			code, stderr := runCacheCommand(t, args, cacheTestOptions(t, values, factory))
+			if code != 0 {
+				t.Fatalf("code = %d stderr = %q", code, stderr)
+			}
+			if got := len(factory.roots) > 0; got != tc.wantBuild {
+				t.Fatalf("store built = %t roots = %#v, want %t", got, factory.roots, tc.wantBuild)
+			}
+			if !tc.wantBuild {
+				return
+			}
+			if tc.wantMode == pipeline.ChunkCacheAuto && (factory.store.loads != 1 || factory.store.saves != 1) {
+				t.Fatalf("auto calls = load %d save %d", factory.store.loads, factory.store.saves)
+			}
+			if tc.wantMode == pipeline.ChunkCacheRefresh && (factory.store.loads != 0 || factory.store.saves != 1) {
+				t.Fatalf("refresh calls = load %d save %d", factory.store.loads, factory.store.saves)
+			}
+		})
+	}
+}
+
+func TestRunChunkCacheInvalidValuesHaveEstablishedExitCodes(t *testing.T) {
+	validConfig := writeTestConfig(t, cacheTestConfig("bypass", "", ""))
+	invalidFile := writeTestConfig(t, cacheTestConfig("sometimes", "", ""))
+	inputPath := writeFile(t, "input.txt", "input")
+	tests := []struct {
+		name   string
+		config string
+		env    map[string]string
+		flag   string
+		want   int
+	}{
+		{name: "flag", config: validConfig, flag: "sometimes", want: 2},
+		{name: "environment", config: validConfig, env: map[string]string{"NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE": "sometimes"}, want: 1},
+		{name: "file", config: invalidFile, want: 1},
+		{name: "flag does not mask invalid file", config: invalidFile, flag: "bypass", want: 1},
+		{name: "flag does not mask invalid environment", config: validConfig, env: map[string]string{"NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE": "sometimes"}, flag: "bypass", want: 1},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			args := []string{"run", "example", "--config", tc.config, "--input", inputPath, "--output-dir", t.TempDir()}
+			if tc.flag != "" {
+				args = append(args, "--chunk_cache", tc.flag)
+			}
+			code, _ := runCacheCommand(t, args, cacheTestOptions(t, tc.env, &recordingChunkPlanFactory{}))
+			if code != tc.want {
+				t.Fatalf("code = %d, want %d", code, tc.want)
+			}
+		})
+	}
+}
+
+func TestRunChunkPlanRootResolution(t *testing.T) {
+	t.Run("explicit file root", func(t *testing.T) {
+		factory := &recordingChunkPlanFactory{}
+		resolverCalls := 0
+		opts := cacheTestOptions(t, nil, factory)
+		opts.UserCacheDir = func() (string, error) { resolverCalls++; return "", errors.New("must not be called") }
+		configPath := writeTestConfig(t, cacheTestConfig("auto", "/var/cache/notarius/chunk-plans", ""))
+		code, stderr := runCacheCommand(t, cacheRunArgs(t, configPath), opts)
+		if code != 0 || stderr != "" || resolverCalls != 0 || len(factory.roots) != 1 || factory.roots[0] != "/var/cache/notarius/chunk-plans" {
+			t.Fatalf("code=%d stderr=%q resolver=%d roots=%#v", code, stderr, resolverCalls, factory.roots)
+		}
+	})
+
+	t.Run("environment root", func(t *testing.T) {
+		factory := &recordingChunkPlanFactory{}
+		environmentRoot := filepath.Join(t.TempDir(), "environment-plans")
+		configPath := writeTestConfig(t, cacheTestConfig("auto", filepath.Join(t.TempDir(), "file-plans"), ""))
+		code, stderr := runCacheCommand(t, cacheRunArgs(t, configPath), cacheTestOptions(t, map[string]string{"NOTARIUS_WORKSPACE_CHUNK_CACHE_DIR": environmentRoot}, factory))
+		if code != 0 || stderr != "" || len(factory.roots) != 1 || factory.roots[0] != environmentRoot {
+			t.Fatalf("code=%d stderr=%q roots=%#v", code, stderr, factory.roots)
+		}
+	})
+
+	t.Run("per-user default", func(t *testing.T) {
+		factory := &recordingChunkPlanFactory{}
+		cacheDir := filepath.Join(t.TempDir(), "user-cache")
+		opts := cacheTestOptions(t, nil, factory)
+		opts.UserCacheDir = func() (string, error) { return cacheDir, nil }
+		configPath := writeTestConfig(t, cacheTestConfig("auto", "", ""))
+		code, stderr := runCacheCommand(t, cacheRunArgs(t, configPath), opts)
+		want := filepath.Join(cacheDir, "notarius", "chunk-plans")
+		if code != 0 || stderr != "" || len(factory.roots) != 1 || factory.roots[0] != want {
+			t.Fatalf("code=%d stderr=%q roots=%#v want=%q", code, stderr, factory.roots, want)
+		}
+	})
+}
+
+func TestRunBypassSkipsRootAndStore(t *testing.T) {
+	factory := &recordingChunkPlanFactory{err: errors.New("must not build")}
+	resolverCalls := 0
+	opts := cacheTestOptions(t, nil, factory)
+	opts.UserCacheDir = func() (string, error) { resolverCalls++; return "", errors.New("must not resolve") }
+	configPath := writeTestConfig(t, cacheTestConfig("bypass", "", ""))
+	code, stderr := runCacheCommand(t, cacheRunArgs(t, configPath), opts)
+	if code != 0 || stderr != "" || resolverCalls != 0 || len(factory.roots) != 0 {
+		t.Fatalf("code=%d stderr=%q resolver=%d roots=%#v", code, stderr, resolverCalls, factory.roots)
+	}
+}
+
+func TestRunChunkPlanSetupFailures(t *testing.T) {
+	for _, mode := range []string{"auto", "refresh"} {
+		t.Run(mode+" resolver", func(t *testing.T) {
+			factory := &recordingChunkPlanFactory{}
+			opts := cacheTestOptions(t, nil, factory)
+			opts.UserCacheDir = func() (string, error) { return "", errors.New("cache unavailable") }
+			configPath := writeTestConfig(t, cacheTestConfig(mode, "", ""))
+			code, stderr := runCacheCommand(t, cacheRunArgs(t, configPath), opts)
+			if code != 1 || !strings.Contains(stderr, "cache unavailable") || len(factory.roots) != 0 {
+				t.Fatalf("code=%d stderr=%q roots=%#v", code, stderr, factory.roots)
+			}
+		})
+	}
+
+	t.Run("store", func(t *testing.T) {
+		factory := &recordingChunkPlanFactory{err: errors.New("unwritable store")}
+		configPath := writeTestConfig(t, cacheTestConfig("auto", t.TempDir(), ""))
+		code, stderr := runCacheCommand(t, cacheRunArgs(t, configPath), cacheTestOptions(t, nil, factory))
+		if code != 1 || !strings.Contains(stderr, "unwritable store") {
+			t.Fatalf("code=%d stderr=%q", code, stderr)
+		}
+	})
+
+	t.Run("unwritable filesystem store", func(t *testing.T) {
+		root := writeFile(t, "not-a-directory", "occupied")
+		configPath := writeTestConfig(t, `version: 2
+workspace:
+  chunk_cache:
+    mode: auto
+    directory: `+root+`
+pipelines:
+  dnd-session:
+    input: seriatim
+    artifacts:
+      spells:
+        extract: dnd/spells
+`)
+		code, stderr := runCacheCommand(t, []string{"run", "dnd-session", "--config", configPath, "--input", writeSeriatimInput(t), "--output-dir", t.TempDir()}, Options{LLMClientFactory: fakeLLMFactory(newFakeRunLLMClient(false), nil), LookupEnv: mapLookup(nil)})
+		if code != 1 || (!strings.Contains(stderr, "load chunk plan") && !strings.Contains(stderr, "save chunk plan")) {
+			t.Fatalf("code=%d stderr=%q", code, stderr)
+		}
+	})
+}
+
+func TestConfigCommandsDoNotResolveOrCreateChunkPlanState(t *testing.T) {
+	configPath := writeTestConfig(t, cacheTestConfig("auto", "", ""))
+	for _, args := range [][]string{
+		{"config", "validate", "--config", configPath},
+		{"pipelines", "list", "--config", configPath},
+	} {
+		factory := &recordingChunkPlanFactory{err: errors.New("must not build")}
+		resolverCalls := 0
+		opts := cacheTestOptions(t, nil, factory)
+		opts.UserCacheDir = func() (string, error) { resolverCalls++; return "", errors.New("must not resolve") }
+		code, stderr := runCacheCommand(t, args, opts)
+		if code != 0 || stderr != "" || resolverCalls != 0 || len(factory.roots) != 0 {
+			t.Fatalf("args=%v code=%d stderr=%q resolver=%d roots=%#v", args, code, stderr, resolverCalls, factory.roots)
+		}
+	}
+}
+
+func TestRunRecordsExplicitChunkCacheOverrideAndEffectiveMode(t *testing.T) {
+	diagnosticsDir := t.TempDir()
+	configPath := writeTestConfig(t, cacheTestConfig("bypass", "", diagnosticsDir))
+	factory := &recordingChunkPlanFactory{}
+	args := append(cacheRunArgs(t, configPath), "--chunk_cache", "refresh")
+	code, stderr := runCacheCommand(t, args, cacheTestOptions(t, nil, factory))
+	if code != 0 || stderr != "" {
+		t.Fatalf("code=%d stderr=%q", code, stderr)
+	}
+	runDir := onlyChildDir(t, diagnosticsDir)
+	invocation := string(readFile(t, filepath.Join(runDir, diagnostics.ArtifactInvocationMetadata)))
+	effective := string(readFile(t, filepath.Join(runDir, diagnostics.ArtifactEffectiveConfig)))
+	if !strings.Contains(invocation, `"chunk_cache_override": "refresh"`) || !strings.Contains(effective, `"mode": "refresh"`) {
+		t.Fatalf("invocation=%s effective=%s", invocation, effective)
+	}
+}
+
+func TestDefaultAutoReusesPlanAcrossIndependentInvocations(t *testing.T) {
+	cacheBase := filepath.Join(t.TempDir(), "cache")
+	workspaceDir := filepath.Join(t.TempDir(), "workspace")
+	configPath := writeTestConfig(t, `version: 2
+workspace:
+  directory: `+workspaceDir+`
+  debug:
+    enabled: true
+pipelines:
+  dnd-session:
+    input: seriatim
+    chunk: dnd/scenes
+    artifacts:
+      spells:
+        extract: dnd/spells
+`)
+	inputPath := writeFile(t, "source.json", `{
+  "metadata": {"id": "session-alpha"},
+  "segments": [
+    {"id": 1, "start": 0, "end": 1, "speaker": "Aria", "text": "Aria casts Cure Wounds."},
+    {"id": 2, "start": 1, "end": 2, "speaker": "Borin", "text": "Borin recovers."}
+  ]
+}`)
+	client := newFakeRunLLMClient(false)
+	opts := Options{
+		LLMClientFactory: fakeLLMFactory(client, nil),
+		LookupEnv:        mapLookup(nil),
+		UserCacheDir:     func() (string, error) { return cacheBase, nil },
+	}
+	for i := 0; i < 2; i++ {
+		code, stderr := runCacheCommand(t, []string{"run", "dnd-session", "--config", configPath, "--input", inputPath, "--output-dir", t.TempDir()}, opts)
+		if code != 0 {
+			t.Fatalf("run %d code=%d stderr=%q", i+1, code, stderr)
+		}
+	}
+	if client.calls != 3 {
+		t.Fatalf("LLM calls = %d, want chunk+extract then extract-only reuse", client.calls)
+	}
+	planRoot := filepath.Join(cacheBase, "notarius", "chunk-plans")
+	entries, err := os.ReadDir(planRoot)
+	if err != nil || len(entries) != 1 {
+		t.Fatalf("plan root entries = %v error=%v", entries, err)
+	}
+	if _, err := os.Stat(filepath.Join(planRoot, entries[0].Name(), "plan.json")); err != nil {
+		t.Fatalf("plan file: %v", err)
+	}
+	debugRuns := childDirs(t, filepath.Join(workspaceDir, "debug"))
+	if len(debugRuns) != 2 {
+		t.Fatalf("debug runs = %#v", debugRuns)
+	}
+	attemptCounts := 0
+	for _, runDir := range debugRuns {
+		if _, err := os.Stat(filepath.Join(runDir, "chunk", "attempt-01.json")); err == nil {
+			attemptCounts++
+		} else if !os.IsNotExist(err) {
+			t.Fatal(err)
+		}
+	}
+	if attemptCounts != 1 {
+		t.Fatalf("chunk attempt files across runs = %d, want only generating run", attemptCounts)
+	}
+}
+
+func TestChunkPlanReuseDependsOnlyOnSourceDigest(t *testing.T) {
+	cacheRoot := filepath.Join(t.TempDir(), "plans")
+	inputPath := writeSeriatimInput(t)
+	referencePath := writeFile(t, "players.txt", "Alyx")
+	profilePath := writeScriptoriumProfileFile(t, "chunk-profile", "http://127.0.0.1:8080/v1", "test-model")
+	seedConfig := writeTestConfig(t, `version: 2
+workspace:
+  chunk_cache:
+    mode: auto
+    directory: `+cacheRoot+`
+pipelines:
+  seed:
+    input: seriatim
+    chunk:
+      module: generic
+      options:
+        max_units: 1
+        overlap_units: 0
+    artifacts:
+      spells:
+        extract: dnd/spells
+`)
+	changedConfig := writeTestConfig(t, `version: 2
+scriptorium:
+  profile_file: `+profilePath+`
+workspace:
+  chunk_cache:
+    mode: auto
+    directory: `+cacheRoot+`
+pipelines:
+  changed:
+    input: seriatim
+    chunk:
+      module: dnd/scenes
+      llm_profile: chunk-profile
+      references:
+        players: `+referencePath+`
+      validators:
+        - generic/always_accept
+    artifacts:
+      spells:
+        extract: dnd/spells
+`)
+	client := newFakeRunLLMClient(false)
+	opts := Options{LLMClientFactory: fakeLLMFactory(client, nil), LookupEnv: mapLookup(nil)}
+	for _, run := range []struct {
+		pipeline string
+		config   string
+	}{{pipeline: "seed", config: seedConfig}, {pipeline: "changed", config: changedConfig}} {
+		code, stderr := runCacheCommand(t, []string{"run", run.pipeline, "--config", run.config, "--input", inputPath, "--output-dir", t.TempDir()}, opts)
+		if code != 0 {
+			t.Fatalf("pipeline %q code=%d stderr=%q", run.pipeline, code, stderr)
+		}
+	}
+	if client.calls != 2 {
+		t.Fatalf("LLM calls = %d, want one extractor call per run and no changed chunker call", client.calls)
+	}
+}
+
+func TestResumeAndChunkCacheModesRemainIndependent(t *testing.T) {
+	for _, mode := range []pipeline.ChunkCacheMode{pipeline.ChunkCacheAuto, pipeline.ChunkCacheBypass, pipeline.ChunkCacheRefresh} {
+		t.Run(string(mode), func(t *testing.T) {
+			workspaceDir := filepath.Join(t.TempDir(), "workspace")
+			cacheRoot := filepath.Join(t.TempDir(), "plans")
+			configPath := writeTestConfig(t, cacheTestConfigWithWorkspace(string(mode), cacheRoot, workspaceDir))
+			factory := &recordingChunkPlanFactory{}
+			args := append(cacheRunArgs(t, configPath), "--resume")
+			code, stderr := runCacheCommand(t, args, cacheTestOptions(t, nil, factory))
+			if code != 0 || stderr != "" {
+				t.Fatalf("code=%d stderr=%q", code, stderr)
+			}
+			if mode == pipeline.ChunkCacheBypass {
+				if len(factory.roots) != 0 {
+					t.Fatalf("bypass roots = %#v", factory.roots)
+				}
+			} else if len(factory.roots) != 1 || factory.roots[0] != cacheRoot {
+				t.Fatalf("roots = %#v, want %q", factory.roots, cacheRoot)
+			}
+			if entries := childDirs(t, filepath.Join(workspaceDir, "checkpoints")); len(entries) != 1 {
+				t.Fatalf("checkpoint roots = %#v", entries)
+			}
+			if strings.HasPrefix(cacheRoot, workspaceDir+string(filepath.Separator)) || strings.HasPrefix(workspaceDir, cacheRoot+string(filepath.Separator)) {
+				t.Fatalf("cache root %q and workspace root %q overlap", cacheRoot, workspaceDir)
+			}
+		})
+	}
+}
+
+func TestWorkspaceDirectoryDoesNotSelectChunkPlanRoot(t *testing.T) {
+	cacheBase := filepath.Join(t.TempDir(), "user-cache")
+	factory := &recordingChunkPlanFactory{}
+	for _, workspaceDir := range []string{filepath.Join(t.TempDir(), "workspace-one"), filepath.Join(t.TempDir(), "workspace-two")} {
+		configPath := writeTestConfig(t, cacheTestConfigWithWorkspace("auto", "", workspaceDir))
+		opts := cacheTestOptions(t, nil, factory)
+		opts.UserCacheDir = func() (string, error) { return cacheBase, nil }
+		code, stderr := runCacheCommand(t, cacheRunArgs(t, configPath), opts)
+		if code != 0 || stderr != "" {
+			t.Fatalf("workspace=%q code=%d stderr=%q", workspaceDir, code, stderr)
+		}
+	}
+	want := filepath.Join(cacheBase, "notarius", "chunk-plans")
+	if len(factory.roots) != 2 || factory.roots[0] != want || factory.roots[1] != want {
+		t.Fatalf("roots = %#v, want %q twice", factory.roots, want)
+	}
+}
+
+func cacheTestOptions(t *testing.T, env map[string]string, factory *recordingChunkPlanFactory) Options {
+	t.Helper()
+	registries := fakeExecutionRegistries(t)
+	return Options{
+		Catalog:               catalogFromRegistries(registries),
+		Registries:            registries,
+		LLMClientFactory:      fakeLLMFactory(nil, nil),
+		LookupEnv:             mapLookup(env),
+		UserCacheDir:          func() (string, error) { return filepath.Join(t.TempDir(), "cache"), nil },
+		ChunkPlanStoreFactory: factory.build,
+	}
+}
+
+func cacheRunArgs(t *testing.T, configPath string) []string {
+	t.Helper()
+	return []string{"run", "example", "--config", configPath, "--input", writeFile(t, "input.txt", "input"), "--output-dir", t.TempDir()}
+}
+
+func runCacheCommand(t *testing.T, args []string, opts Options) (int, string) {
+	t.Helper()
+	var stdout bytes.Buffer
+	var stderr bytes.Buffer
+	code := RunWithOptions(args, &stdout, &stderr, opts)
+	return code, stderr.String()
+}
+
+func cacheTestConfig(mode, directory, diagnosticsDir string) string {
+	var b strings.Builder
+	b.WriteString("version: 2\n")
+	if mode != "" || directory != "" {
+		b.WriteString("workspace:\n  chunk_cache:\n")
+		if mode != "" {
+			b.WriteString("    mode: " + mode + "\n")
+		}
+		if directory != "" {
+			b.WriteString("    directory: " + directory + "\n")
+		}
+	}
+	if diagnosticsDir != "" {
+		b.WriteString("diagnostics:\n  work_dir: " + diagnosticsDir + "\n  retention: always\n")
+	}
+	b.WriteString("pipelines:\n  example:\n    input: fake/input\n    artifacts:\n      spells:\n        extract: fake/extract\n")
+	return b.String()
+}
+
+func cacheTestConfigWithWorkspace(mode, cacheRoot, workspaceDir string) string {
+	var b strings.Builder
+	b.WriteString("version: 2\nworkspace:\n  directory: " + workspaceDir + "\n  resume:\n    enabled: true\n  chunk_cache:\n    mode: " + mode + "\n")
+	if cacheRoot != "" {
+		b.WriteString("    directory: " + cacheRoot + "\n")
+	}
+	b.WriteString("pipelines:\n  example:\n    input: fake/input\n    artifacts:\n      spells:\n        extract: fake/extract\n")
+	return b.String()
+}

internal/cli/compatibility_test.go

@@ -341,7 +341,7 @@ func TestProductionLLMCallersShareScheduledClient(t *testing.T) {
 		started.Done()
 		chunker, err := scenes.New(client, scenes.Options{})
 		if err == nil {
-			_, err = chunker.Chunk(context.Background(), contracts.ChunkRequest{Source: doc})
+			_, err = chunker.Plan(context.Background(), contracts.ChunkRequest{Source: doc})
 		}
 		errs <- err
 	}()

internal/cli/run.go

@@ -20,6 +20,7 @@ import (
 	"gitea.maximumdirect.net/eric/notarius/internal/core/diagnostics"
 	"gitea.maximumdirect.net/eric/notarius/internal/core/workspace"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/checkpoint"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/chunkplan"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
 	frameworkdebug "gitea.maximumdirect.net/eric/notarius/internal/framework/debug"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
@@ -30,17 +31,19 @@ const defaultOutputRoot = "./notarius-output"
 
 const usage = `Usage:
   notarius help
-  notarius run <pipeline-id> --input path/to/source.json [--config path/to/config.yml] [--only lane-a,lane-b] [--resume] [--session-id id] [--reference selector=path] [--without-reference selector]
+  notarius run <pipeline-id> --input path/to/source.json [--config path/to/config.yml] [--only lane-a,lane-b] [--chunk_cache auto|bypass|refresh] [--resume] [--session-id id] [--reference selector=path] [--without-reference selector]
   notarius config validate --config path/to/config.yml [--pipeline pipeline-id] [--only lane-a,lane-b]
   notarius pipelines list --config path/to/config.yml [--json]
 `
 
 type Options struct {
-	Catalog          pipeline.ModuleCatalog
-	Registries       pipeline.Registries
-	LLMClientFactory LLMClientFactory
-	LookupEnv        func(string) (string, bool)
-	Now              func() time.Time
+	Catalog               pipeline.ModuleCatalog
+	Registries            pipeline.Registries
+	LLMClientFactory      LLMClientFactory
+	LookupEnv             func(string) (string, bool)
+	Now                   func() time.Time
+	UserCacheDir          func() (string, error)
+	ChunkPlanStoreFactory pipeline.ChunkPlanStoreFactory
 }
 
 type LLMClientFactory func(ctx context.Context, cfg config.Config, profileID string) (contracts.StructuredLLMClient, []artifacts.LLMProfileManifest, error)
@@ -90,6 +93,12 @@ func normalizeOptions(opts Options) (Options, error) {
 	if opts.Now == nil {
 		opts.Now = time.Now
 	}
+	if opts.UserCacheDir == nil {
+		opts.UserCacheDir = os.UserCacheDir
+	}
+	if opts.ChunkPlanStoreFactory == nil {
+		opts.ChunkPlanStoreFactory = chunkplan.NewFilesystemStore
+	}
 	if isEmptyCatalog(opts.Catalog) && isEmptyRegistries(opts.Registries) {
 		components, err := newProductionComponents()
 		if err != nil {
@@ -117,10 +126,12 @@ func runPipelineCommand(args []string, stdout, stderr io.Writer, opts Options) i
 	diagnosticsDir := fs.String("diagnostics-dir", "", "diagnostics directory")
 	llmProfile := fs.String("llm-profile", "", "LLM profile override")
 	resume := fs.Bool("resume", false, "reuse valid workspace checkpoints")
+	chunkCache := chunkCacheFlag{}
 	sessionID := sessionIDFlag{}
 	referenceFlags := stringListFlag{}
 	withoutReferenceFlags := stringListFlag{}
 	fs.Var(&sessionID, "session-id", "prompt session identifier")
+	fs.Var(&chunkCache, "chunk_cache", "chunk plan cache mode: auto, bypass, or refresh")
 	fs.Var(&referenceFlags, "reference", "reference binding, as slot=path, chunk.slot=path, merge.slot=path, lane.slot=path, lane.extract.slot=path, lane.merge.slot=path, or lane.normalize.slot=path")
 	fs.Var(&withoutReferenceFlags, "without-reference", "unbind a reference, using the same selector forms as --reference")
 	if err := validateRunFlagValues(args); err != nil {
@@ -173,6 +184,9 @@ func runPipelineCommand(args []string, stdout, stderr io.Writer, opts Options) i
 		fmt.Fprintf(stderr, "notarius: %v\n", err)
 		return 1
 	}
+	if chunkCache.set {
+		cfg.Workspace.ChunkCache.Mode = chunkCache.value
+	}
 	workspaceSettings := workspace.FromConfig(cfg)
 	if dir := strings.TrimSpace(*diagnosticsDir); dir != "" {
 		workspaceSettings.DiagnosticsRoot = dir
@@ -191,15 +205,16 @@ func runPipelineCommand(args []string, stdout, stderr io.Writer, opts Options) i
 		runID = runDir.RunID()
 	}
 	invocation := diagnostics.InvocationMetadata{
-		Operation:    "run",
-		PipelineID:   pipelineID,
-		InputPath:    strings.TrimSpace(*inputPath),
-		ConfigPath:   loadedConfigPath,
-		ConfigSource: configSource(*configPath),
-		OnlyLanes:    append([]string(nil), only...),
-		Resume:       *resume,
-		RunID:        runID,
-		StartedAt:    startedAt,
+		Operation:          "run",
+		PipelineID:         pipelineID,
+		InputPath:          strings.TrimSpace(*inputPath),
+		ConfigPath:         loadedConfigPath,
+		ConfigSource:       configSource(*configPath),
+		OnlyLanes:          append([]string(nil), only...),
+		ChunkCacheOverride: chunkCache.explicitValue(),
+		Resume:             *resume,
+		RunID:              runID,
+		StartedAt:          startedAt,
 	}
 	if err := writeDiagnostics(runDir, func() error { return runDir.WriteInvocationMetadata(invocation) }); err != nil {
 		return failPipelineCommand(stderr, runDir, cfg.Diagnostics.Retention, fmt.Errorf("write diagnostics invocation metadata: %w", err))
@@ -287,6 +302,10 @@ func runPipelineCommand(args []string, stdout, stderr io.Writer, opts Options) i
 	if err != nil {
 		return failPipelineCommand(stderr, runDir, cfg.Diagnostics.Retention, fmt.Errorf("read input %q: %w", strings.TrimSpace(*inputPath), err))
 	}
+	chunkPlans, err := chunkPlanStoreForRun(effective.Config.Workspace.ChunkCache, opts)
+	if err != nil {
+		return failPipelineCommand(stderr, runDir, cfg.Diagnostics.Retention, err)
+	}
 	checkpointRecorder, checkpointLoader, err := checkpointHandlersForRun(workspaceSettings, effective.ResolvedPipeline, rawInput, only, llmProfiles, strings.TrimSpace(*llmProfile), strings.TrimSpace(sessionID.value), *resume)
 	if err != nil {
 		return failPipelineCommand(stderr, runDir, cfg.Diagnostics.Retention, err)
@@ -302,6 +321,8 @@ func runPipelineCommand(args []string, stdout, stderr io.Writer, opts Options) i
 		LLMProfiles:    llmProfiles,
 		Metadata:       runMetadata(*outputDir, *diagnosticsDir),
 		Warnings:       referenceWarnings,
+		ChunkCacheMode: effective.Config.Workspace.ChunkCache.Mode,
+		ChunkPlans:     chunkPlans,
 		Checkpoints:    checkpointRecorder,
 		Checkpoint:     checkpointLoader,
 		Debug:          debugRecorder,
@@ -310,6 +331,9 @@ func runPipelineCommand(args []string, stdout, stderr io.Writer, opts Options) i
 	if err != nil {
 		if output.Manifest.PipelineID != "" && runDir != nil {
 			_ = runDir.WriteRunManifest(output.Manifest)
+			if output.ChunkPlan != nil {
+				_ = runDir.WriteChunkPlan(*output.ChunkPlan)
+			}
 			_ = runDir.WriteCheckpointEvents(output.CheckpointEvents)
 		}
 		return failPipelineCommand(stderr, runDir, cfg.Diagnostics.Retention, fmt.Errorf("run pipeline %q: %w", pipelineID, err))
@@ -319,6 +343,11 @@ func runPipelineCommand(args []string, stdout, stderr io.Writer, opts Options) i
 	if err := writeDiagnostics(runDir, func() error { return runDir.WriteRunManifest(output.Manifest) }); err != nil {
 		return failPipelineCommand(stderr, runDir, cfg.Diagnostics.Retention, fmt.Errorf("write diagnostics run manifest: %w", err))
 	}
+	if output.ChunkPlan != nil {
+		if err := writeDiagnostics(runDir, func() error { return runDir.WriteChunkPlan(*output.ChunkPlan) }); err != nil {
+			return failPipelineCommand(stderr, runDir, cfg.Diagnostics.Retention, fmt.Errorf("write diagnostics chunk plan: %w", err))
+		}
+	}
 	if err := writeDiagnostics(runDir, func() error { return runDir.WriteWarnings(output.Warnings) }); err != nil {
 		return failPipelineCommand(stderr, runDir, cfg.Diagnostics.Retention, fmt.Errorf("write diagnostics warnings: %w", err))
 	}
@@ -598,13 +627,64 @@ func reorderRunArgs(args []string) []string {
 
 func runFlagTakesValue(arg string) bool {
 	switch arg {
-	case "--config", "--input", "--only", "--output-dir", "--diagnostics-dir", "--llm-profile", "--session-id", "--reference", "--without-reference":
+	case "--config", "--input", "--only", "--output-dir", "--diagnostics-dir", "--llm-profile", "--session-id", "--chunk_cache", "--reference", "--without-reference":
 		return true
 	default:
 		return false
 	}
 }
 
+type chunkCacheFlag struct {
+	value pipeline.ChunkCacheMode
+	set   bool
+}
+
+func (f *chunkCacheFlag) String() string {
+	if f == nil {
+		return ""
+	}
+	return string(f.value)
+}
+
+func (f *chunkCacheFlag) Set(raw string) error {
+	mode, err := pipeline.ParseChunkCacheMode(raw)
+	if err != nil {
+		return err
+	}
+	f.value = mode
+	f.set = true
+	return nil
+}
+
+func (f chunkCacheFlag) explicitValue() string {
+	if !f.set {
+		return ""
+	}
+	return string(f.value)
+}
+
+func chunkPlanStoreForRun(cfg config.WorkspaceChunkCacheConfig, opts Options) (pipeline.ChunkPlanStore, error) {
+	if cfg.Mode == pipeline.ChunkCacheBypass {
+		return nil, nil
+	}
+	root := strings.TrimSpace(cfg.Directory)
+	if root == "" {
+		var err error
+		root, err = workspace.DefaultChunkPlanRoot(opts.UserCacheDir)
+		if err != nil {
+			return nil, fmt.Errorf("resolve chunk plan root: %w", err)
+		}
+	}
+	store, err := opts.ChunkPlanStoreFactory(root)
+	if err != nil {
+		return nil, fmt.Errorf("create chunk plan store at %q: %w", root, err)
+	}
+	if store == nil {
+		return nil, fmt.Errorf("create chunk plan store at %q: factory returned nil", root)
+	}
+	return store, nil
+}
+
 func validateRunFlagValues(args []string) error {
 	for i, arg := range args {
 		if arg != "--session-id" {

internal/cli/run_test.go

@@ -2333,8 +2333,6 @@ func TestRunPipelineWritesCheckpointsWhenWorkspaceResumeEnabled(t *testing.T) {
 	for _, name := range []string{
 		"source/manifest.json",
 		"source/source-document.json",
-		"chunk/manifest.json",
-		"chunk/chunks.json",
 		"extract/spells/manifest.json",
 		"extract/spells/outputs.json",
 		"merge/spells/manifest.json",
@@ -2346,6 +2344,7 @@ func TestRunPipelineWritesCheckpointsWhenWorkspaceResumeEnabled(t *testing.T) {
 			t.Fatalf("expected checkpoint artifact %q: %v", name, err)
 		}
 	}
+	assertPathNotExist(t, filepath.Join(checkpointDir, "chunk"))
 	assertPathNotExist(t, filepath.Join(workspaceDir, "debug"))
 }
 
@@ -3742,11 +3741,9 @@ func (fakeRunChunker) ReferenceSlots() []contracts.ReferenceSlot {
 	return nil
 }
 
-func (fakeRunChunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkResult, error) {
-	return contracts.ChunkResult{
-		Chunks: []source.Chunk{
-			{ID: "chunk-1", SourceID: req.Source.ID, Index: 0, Ref: source.SourceRef{SourceID: req.Source.ID, StartUnitID: 1, EndUnitID: 1}, Content: []byte(`{"units":[1]}`), MediaType: "application/json", Units: req.Source.Units},
-		},
+func (fakeRunChunker) Plan(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	return contracts.ChunkPlanResult{
+		Plan: source.ChunkPlan{SourceDigest: req.Source.Digest, Ranges: []source.ChunkRange{{StartUnitID: 1, EndUnitID: 1}}},
 	}, nil
 }
 

internal/cli/test_main_test.go

@@ -0,0 +1,21 @@
+package cli
+
+import (
+	"os"
+	"testing"
+)
+
+func TestMain(m *testing.M) {
+	const name = "NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE"
+	previous, existed := os.LookupEnv(name)
+	if err := os.Setenv(name, "bypass"); err != nil {
+		panic(err)
+	}
+	code := m.Run()
+	if existed {
+		_ = os.Setenv(name, previous)
+	} else {
+		_ = os.Unsetenv(name)
+	}
+	os.Exit(code)
+}

internal/core/artifacts/artifacts.go

@@ -69,12 +69,42 @@ type RejectedOutputManifest struct {
 	DiagnosticArtifactPath string `json:"diagnostic_artifact_path,omitempty"`
 }
 
+type ChunkPlanManifest struct {
+	Mode                string                `json:"mode"`
+	Action              string                `json:"action,omitempty"`
+	SourceDigest        string                `json:"source_digest,omitempty"`
+	PlanDigest          string                `json:"plan_digest,omitempty"`
+	PlanSchemaVersion   string                `json:"plan_schema_version,omitempty"`
+	RequestedModule     string                `json:"requested_module"`
+	ProducerInputModule string                `json:"producer_input_module,omitempty"`
+	ProducerModule      string                `json:"producer_module,omitempty"`
+	ProducerLLMProfile  string                `json:"producer_llm_profile,omitempty"`
+	ProducerReferences  []ReferenceProvenance `json:"producer_references,omitempty"`
+	ProducerMetadata    map[string]any        `json:"producer_metadata,omitempty"`
+	CreatedAt           *time.Time            `json:"created_at,omitempty"`
+}
+
+// ChunkPlanSummary is deliberately limited to cache and validation decisions.
+// It must never contain plan units, source content, annotations, or model I/O.
+type ChunkPlanSummary struct {
+	Mode              string `json:"mode"`
+	SourceDigest      string `json:"source_digest,omitempty"`
+	CandidateDigest   string `json:"candidate_digest,omitempty"`
+	RequestedModule   string `json:"requested_module"`
+	LookupStatus      string `json:"lookup_status"`
+	LookupReason      string `json:"lookup_reason,omitempty"`
+	Action            string `json:"action,omitempty"`
+	ValidationStatus  string `json:"validation_status"`
+	PublicationStatus string `json:"publication_status"`
+}
+
 type RunManifest struct {
 	RunID             string                     `json:"run_id,omitempty"`
 	PipelineID        string                     `json:"pipeline_id,omitempty"`
 	PipelineDigest    string                     `json:"pipeline_digest,omitempty"`
 	InputModule       string                     `json:"input_module,omitempty"`
 	Chunker           string                     `json:"chunker,omitempty"`
+	ChunkPlan         *ChunkPlanManifest         `json:"chunk_plan,omitempty"`
 	SourceDigests     []string                   `json:"source_digests,omitempty"`
 	Extractors        []string                   `json:"extractors,omitempty"`
 	Merger            string                     `json:"merger,omitempty"`

internal/core/artifacts/artifacts_test.go

@@ -2,6 +2,7 @@ package artifacts
 
 import (
 	"encoding/json"
+	"strings"
 	"testing"
 )
 
@@ -16,6 +17,37 @@ func TestRunManifestOmitsEmptyOptionalFields(t *testing.T) {
 	}
 }
 
+func TestRunManifestChunkPlanIsAdditiveAndOmitsPlanContent(t *testing.T) {
+	manifest := RunManifest{ChunkPlan: &ChunkPlanManifest{
+		Mode: "auto", Action: "reused", SourceDigest: "sha256:source", PlanDigest: "sha256:plan",
+		PlanSchemaVersion: "notarius.chunk-plan.v1", RequestedModule: "chunk/current",
+		ProducerInputModule: "input/original", ProducerModule: "chunk/original",
+	}}
+	encoded, err := json.Marshal(manifest)
+	if err != nil {
+		t.Fatal(err)
+	}
+	text := string(encoded)
+	for _, want := range []string{`"chunk_plan"`, `"action":"reused"`, `"requested_module":"chunk/current"`, `"producer_module":"chunk/original"`} {
+		if !strings.Contains(text, want) {
+			t.Fatalf("manifest JSON %s does not contain %s", text, want)
+		}
+	}
+	for _, forbidden := range []string{`"plan"`, `"units"`, `"annotations"`} {
+		if strings.Contains(text, forbidden) {
+			t.Fatalf("manifest JSON contains forbidden field %s: %s", forbidden, text)
+		}
+	}
+
+	var legacy RunManifest
+	if err := json.Unmarshal([]byte(`{"pipeline_id":"legacy"}`), &legacy); err != nil {
+		t.Fatal(err)
+	}
+	if legacy.PipelineID != "legacy" || legacy.ChunkPlan != nil {
+		t.Fatalf("legacy manifest = %#v", legacy)
+	}
+}
+
 func TestRunManifestIncludesPipelineAndArtifactLaneFields(t *testing.T) {
 	manifest := RunManifest{
 		PipelineID:     "pipeline-1",

internal/core/config/chunk_cache_test.go

@@ -0,0 +1,126 @@
+package config
+
+import (
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+)
+
+func TestChunkCacheDefaults(t *testing.T) {
+	cfg := Default()
+	if cfg.Workspace.ChunkCache.Mode != pipeline.ChunkCacheAuto || cfg.Workspace.ChunkCache.Directory != "" {
+		t.Fatalf("chunk cache defaults = %#v", cfg.Workspace.ChunkCache)
+	}
+	if err := cfg.Validate(); err != nil {
+		t.Fatalf("Validate() error = %v", err)
+	}
+}
+
+func TestChunkCacheFileConfiguration(t *testing.T) {
+	cfg := parseAndApplyConfig(t, `
+version: 2
+workspace:
+  chunk_cache:
+    mode: refresh
+    directory: " ./state/../plans "
+`)
+	if cfg.Workspace.ChunkCache.Mode != pipeline.ChunkCacheRefresh {
+		t.Fatalf("mode = %q", cfg.Workspace.ChunkCache.Mode)
+	}
+	if got, want := cfg.Workspace.ChunkCache.Directory, filepath.Clean("./state/../plans"); got != want {
+		t.Fatalf("directory = %q, want %q", got, want)
+	}
+	if err := cfg.Validate(); err != nil {
+		t.Fatalf("Validate() error = %v", err)
+	}
+}
+
+func TestChunkCacheEnvironmentOverridesFile(t *testing.T) {
+	fileCfg, err := ParseFileConfigYAML([]byte(`
+version: 2
+workspace:
+  chunk_cache:
+    mode: bypass
+    directory: /file/plans
+`))
+	if err != nil {
+		t.Fatal(err)
+	}
+	cfg := Default()
+	if err := cfg.ApplyFileConfigWithLookup(fileCfg, emptyLookup); err != nil {
+		t.Fatal(err)
+	}
+	if err := cfg.ApplyEnvOverridesWithLookup(mapLookup(map[string]string{
+		"NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE": "refresh",
+		"NOTARIUS_WORKSPACE_CHUNK_CACHE_DIR":  " /environment/../cache/plans ",
+	})); err != nil {
+		t.Fatal(err)
+	}
+	if cfg.Workspace.ChunkCache.Mode != pipeline.ChunkCacheRefresh || cfg.Workspace.ChunkCache.Directory != filepath.Clean("/environment/../cache/plans") {
+		t.Fatalf("effective chunk cache = %#v", cfg.Workspace.ChunkCache)
+	}
+}
+
+func TestChunkCacheEmptyDirectoryEnvironmentSelectsDefault(t *testing.T) {
+	cfg := Default()
+	cfg.Workspace.ChunkCache.Directory = "/file/plans"
+	if err := cfg.ApplyEnvOverridesWithLookup(mapLookup(map[string]string{"NOTARIUS_WORKSPACE_CHUNK_CACHE_DIR": " \t "})); err != nil {
+		t.Fatal(err)
+	}
+	if cfg.Workspace.ChunkCache.Directory != "" {
+		t.Fatalf("directory = %q, want unset", cfg.Workspace.ChunkCache.Directory)
+	}
+}
+
+func TestChunkCacheRejectsInvalidSuppliedModes(t *testing.T) {
+	fileCfg, err := ParseFileConfigYAML([]byte("version: 2\nworkspace:\n  chunk_cache:\n    mode: sometimes\n"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	cfg := Default()
+	if err := cfg.ApplyFileConfigWithLookup(fileCfg, emptyLookup); err == nil || !strings.Contains(err.Error(), "workspace.chunk_cache.mode") {
+		t.Fatalf("file mode error = %v", err)
+	}
+
+	cfg = Default()
+	if err := cfg.ApplyEnvOverridesWithLookup(mapLookup(map[string]string{"NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE": "sometimes"})); err == nil || !strings.Contains(err.Error(), "NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE") {
+		t.Fatalf("environment mode error = %v", err)
+	}
+
+	cfg = Default()
+	cfg.Workspace.ChunkCache.Mode = "sometimes"
+	if err := cfg.Validate(); err == nil || !strings.Contains(err.Error(), "chunk cache") {
+		t.Fatalf("Validate() error = %v", err)
+	}
+}
+
+func TestChunkCacheConfigurationClonesAndRedacts(t *testing.T) {
+	cfg := Default()
+	cfg.Workspace.ChunkCache = WorkspaceChunkCacheConfig{Mode: pipeline.ChunkCacheRefresh, Directory: "/var/cache/notarius/chunk-plans"}
+	cloned := cloneConfig(cfg)
+	redacted := cfg.Redacted()
+	if cloned.Workspace.ChunkCache != cfg.Workspace.ChunkCache || redacted.Workspace.ChunkCache != cfg.Workspace.ChunkCache {
+		t.Fatalf("cloned=%#v redacted=%#v", cloned.Workspace.ChunkCache, redacted.Workspace.ChunkCache)
+	}
+	redacted.Workspace.ChunkCache.Directory = "/changed"
+	if cfg.Workspace.ChunkCache.Directory != "/var/cache/notarius/chunk-plans" {
+		t.Fatal("redacted mutation changed original")
+	}
+	if err := cfg.Validate(); err != nil {
+		t.Fatalf("Validate() error = %v", err)
+	}
+}
+
+func TestChunkCacheDirectoryValidation(t *testing.T) {
+	cfg := Default()
+	cfg.Workspace.ChunkCache.Directory = "/var/cache/notarius/chunk-plans"
+	if err := cfg.Validate(); err != nil {
+		t.Fatalf("Validate(system root) error = %v", err)
+	}
+	cfg.Workspace.ChunkCache.Directory = "bad\x00path"
+	if err := cfg.Validate(); err == nil || !strings.Contains(err.Error(), "NUL") {
+		t.Fatalf("Validate(NUL directory) error = %v", err)
+	}
+}

internal/core/config/config.go

@@ -38,11 +38,17 @@ type DiagnosticsConfig struct {
 
 type WorkspaceConfig struct {
 	Directory   string                     `json:"directory,omitempty"`
+	ChunkCache  WorkspaceChunkCacheConfig  `json:"chunk_cache"`
 	Diagnostics WorkspaceDiagnosticsConfig `json:"diagnostics"`
 	Resume      WorkspaceResumeConfig      `json:"resume"`
 	Debug       WorkspaceDebugConfig       `json:"debug"`
 }
 
+type WorkspaceChunkCacheConfig struct {
+	Mode      pipeline.ChunkCacheMode `json:"mode"`
+	Directory string                  `json:"directory,omitempty"`
+}
+
 type WorkspaceDiagnosticsConfig struct {
 	Enabled      bool                      `json:"enabled"`
 	Retention    diagnostics.RetentionMode `json:"retention,omitempty"`
@@ -71,6 +77,7 @@ func Default() Config {
 			Retention: diagnostics.RetentionAuto,
 		},
 		Workspace: WorkspaceConfig{
+			ChunkCache: WorkspaceChunkCacheConfig{Mode: pipeline.ChunkCacheAuto},
 			Diagnostics: WorkspaceDiagnosticsConfig{
 				Enabled: true,
 			},

internal/core/config/effective_config_test.go

@@ -135,7 +135,7 @@ func TestResolveCanBindSceneChunkerFromCatalog(t *testing.T) {
 		Key:      "dnd/scenes",
 		Stage:    pipeline.StageChunk,
 		Requires: []string{"source.transcript"},
-		Provides: []string{"chunks", "chunks.scenes"},
+		Provides: []string{"chunks"},
 	})
 
 	effective, err := cfg.Resolve(ResolveInput{PipelineID: "example", Catalog: catalog})

internal/core/config/env.go

@@ -7,6 +7,7 @@ import (
 	"strings"
 
 	"gitea.maximumdirect.net/eric/notarius/internal/core/diagnostics"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
 )
 
 func LoadFromEnv() (Config, error) {
@@ -57,6 +58,16 @@ func (c *Config) applyEnvOverridesWithLookup(lookup func(string) (string, bool))
 	if raw, ok := lookup("NOTARIUS_WORKSPACE_DIR"); ok {
 		c.Workspace.Directory = strings.TrimSpace(raw)
 	}
+	if raw, ok := lookup("NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE"); ok {
+		mode, err := pipeline.ParseChunkCacheMode(raw)
+		if err != nil {
+			return fmt.Errorf("NOTARIUS_WORKSPACE_CHUNK_CACHE_MODE: %w", err)
+		}
+		c.Workspace.ChunkCache.Mode = mode
+	}
+	if raw, ok := lookup("NOTARIUS_WORKSPACE_CHUNK_CACHE_DIR"); ok {
+		c.Workspace.ChunkCache.Directory = cleanOptionalPath(raw)
+	}
 	if raw, ok := lookup("NOTARIUS_WORKSPACE_DIAGNOSTICS_ENABLED"); ok {
 		value, err := parseBoolEnv("NOTARIUS_WORKSPACE_DIAGNOSTICS_ENABLED", raw)
 		if err != nil {

internal/core/config/file_config.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"fmt"
 	"os"
+	"path/filepath"
 	"sort"
 	"strings"
 
@@ -54,11 +55,17 @@ type FileDiagnosticsConfig struct {
 
 type FileWorkspaceConfig struct {
 	Directory   *string                         `yaml:"directory,omitempty"`
+	ChunkCache  *FileWorkspaceChunkCacheConfig  `yaml:"chunk_cache,omitempty"`
 	Diagnostics *FileWorkspaceDiagnosticsConfig `yaml:"diagnostics,omitempty"`
 	Resume      *FileWorkspaceEnabledConfig     `yaml:"resume,omitempty"`
 	Debug       *FileWorkspaceEnabledConfig     `yaml:"debug,omitempty"`
 }
 
+type FileWorkspaceChunkCacheConfig struct {
+	Mode      *string `yaml:"mode,omitempty"`
+	Directory *string `yaml:"directory,omitempty"`
+}
+
 type FileWorkspaceDiagnosticsConfig struct {
 	Enabled   *bool   `yaml:"enabled,omitempty"`
 	Retention *string `yaml:"retention,omitempty"`
@@ -338,6 +345,18 @@ func (c *Config) applyFileConfigWithLookup(fileCfg FileConfig, lookup func(strin
 		if fileCfg.Workspace.Directory != nil {
 			c.Workspace.Directory = strings.TrimSpace(*fileCfg.Workspace.Directory)
 		}
+		if fileCfg.Workspace.ChunkCache != nil {
+			if fileCfg.Workspace.ChunkCache.Mode != nil {
+				mode, err := pipeline.ParseChunkCacheMode(*fileCfg.Workspace.ChunkCache.Mode)
+				if err != nil {
+					return fmt.Errorf("workspace.chunk_cache.mode: %w", err)
+				}
+				c.Workspace.ChunkCache.Mode = mode
+			}
+			if fileCfg.Workspace.ChunkCache.Directory != nil {
+				c.Workspace.ChunkCache.Directory = cleanOptionalPath(*fileCfg.Workspace.ChunkCache.Directory)
+			}
+		}
 		if fileCfg.Workspace.Diagnostics != nil {
 			if fileCfg.Workspace.Diagnostics.Enabled != nil {
 				c.Workspace.Diagnostics.Enabled = *fileCfg.Workspace.Diagnostics.Enabled
@@ -360,6 +379,14 @@ func (c *Config) applyFileConfigWithLookup(fileCfg FileConfig, lookup func(strin
 	return nil
 }
 
+func cleanOptionalPath(value string) string {
+	value = strings.TrimSpace(value)
+	if value == "" {
+		return ""
+	}
+	return filepath.Clean(value)
+}
+
 func normalizeStageWorkers(values map[string]int) (map[string]int, bool, error) {
 	workers := make(map[string]int, len(values))
 	configured := false

internal/core/config/validation.go

@@ -61,6 +61,12 @@ func validateScriptorium(cfg ScriptoriumConfig) error {
 }
 
 func validateWorkspace(cfg WorkspaceConfig) error {
+	if err := cfg.ChunkCache.Mode.Validate(); err != nil {
+		return fmt.Errorf("workspace chunk cache: %w", err)
+	}
+	if strings.ContainsRune(cfg.ChunkCache.Directory, '\x00') {
+		return fmt.Errorf("workspace chunk cache directory must not contain NUL")
+	}
 	if cfg.Diagnostics.retentionSet {
 		switch cfg.Diagnostics.Retention {
 		case "", diagnostics.RetentionAuto, diagnostics.RetentionAlways, diagnostics.RetentionNever:

internal/core/diagnostics/artifacts.go

@@ -8,6 +8,7 @@ const (
 	ArtifactCheckpointEvents   = "checkpoint-events.json"
 	ArtifactSourceDocument     = "source-document.json"
 	ArtifactRunManifest        = "run-manifest.json"
+	ArtifactChunkPlan          = "chunk-plan.json"
 	ArtifactRunReport          = "run-report.json"
 	ArtifactWarnings           = "warnings.json"
 	ArtifactErrorLog           = "error.log"

internal/core/diagnostics/artifacts_test.go

@@ -10,6 +10,7 @@ func TestArtifactNamesUseExtractionOrientedNames(t *testing.T) {
 		ArtifactResolvedReferences,
 		ArtifactSourceDocument,
 		ArtifactRunManifest,
+		ArtifactChunkPlan,
 		ArtifactRunReport,
 		ArtifactWarnings,
 		ArtifactErrorLog,

internal/core/diagnostics/run_dir.go

@@ -48,16 +48,17 @@ type RedactedEffectiveConfigPayload interface {
 
 // InvocationMetadata captures non-secret invocation details for diagnostics.
 type InvocationMetadata struct {
-	Operation      string    `json:"operation"`
-	PipelineID     string    `json:"pipeline_id,omitempty"`
-	PipelineDigest string    `json:"pipeline_digest,omitempty"`
-	Resume         bool      `json:"resume,omitempty"`
-	InputPath      string    `json:"input_path,omitempty"`
-	ConfigPath     string    `json:"config_path,omitempty"`
-	ConfigSource   string    `json:"config_source,omitempty"`
-	OnlyLanes      []string  `json:"only_lanes,omitempty"`
-	RunID          string    `json:"run_id"`
-	StartedAt      time.Time `json:"started_at"`
+	Operation          string    `json:"operation"`
+	PipelineID         string    `json:"pipeline_id,omitempty"`
+	PipelineDigest     string    `json:"pipeline_digest,omitempty"`
+	Resume             bool      `json:"resume,omitempty"`
+	InputPath          string    `json:"input_path,omitempty"`
+	ConfigPath         string    `json:"config_path,omitempty"`
+	ConfigSource       string    `json:"config_source,omitempty"`
+	OnlyLanes          []string  `json:"only_lanes,omitempty"`
+	ChunkCacheOverride string    `json:"chunk_cache_override,omitempty"`
+	RunID              string    `json:"run_id"`
+	StartedAt          time.Time `json:"started_at"`
 }
 
 func ShouldRetainRunDirectory(input RetentionDecisionInput) bool {
@@ -166,6 +167,10 @@ func (r *RunDirectory) WriteRunManifest(manifest artifacts.RunManifest) error {
 	return r.WriteJSONArtifact(ArtifactRunManifest, manifest)
 }
 
+func (r *RunDirectory) WriteChunkPlan(summary artifacts.ChunkPlanSummary) error {
+	return r.WriteJSONArtifact(ArtifactChunkPlan, summary)
+}
+
 func (r *RunDirectory) WriteRunReport(payload any) error {
 	return r.WriteJSONArtifact(ArtifactRunReport, payload)
 }

internal/core/diagnostics/run_dir_test.go

@@ -200,6 +200,9 @@ func TestWriteTypedArtifacts(t *testing.T) {
 	if err := runDir.WriteRunManifest(artifacts.RunManifest{RunID: "run-1"}); err != nil {
 		t.Fatalf("WriteRunManifest: %v", err)
 	}
+	if err := runDir.WriteChunkPlan(artifacts.ChunkPlanSummary{Mode: "auto", RequestedModule: "chunk/test", LookupStatus: "invalid", LookupReason: "stored chunk plan failed validation", ValidationStatus: "not_run", PublicationStatus: "not_published"}); err != nil {
+		t.Fatalf("WriteChunkPlan: %v", err)
+	}
 	if err := runDir.WriteRunReport(map[string]any{"ok": true}); err != nil {
 		t.Fatalf("WriteRunReport: %v", err)
 	}
@@ -213,6 +216,7 @@ func TestWriteTypedArtifacts(t *testing.T) {
 		ArtifactResolvedReferences,
 		ArtifactSourceDocument,
 		ArtifactRunManifest,
+		ArtifactChunkPlan,
 		ArtifactRunReport,
 		ArtifactWarnings,
 	} {
@@ -220,6 +224,15 @@ func TestWriteTypedArtifacts(t *testing.T) {
 			t.Fatalf("expected artifact %q: %v", name, err)
 		}
 	}
+	chunkSummary, err := os.ReadFile(filepath.Join(runDir.Path(), ArtifactChunkPlan))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, forbidden := range []string{"units", "annotations", "source content", "prompt", "response", "raw invalid"} {
+		if strings.Contains(string(chunkSummary), forbidden) {
+			t.Fatalf("chunk plan summary leaked %q: %s", forbidden, chunkSummary)
+		}
+	}
 }
 
 func TestWriteRedactedEffectiveConfigWritesPayloadReturnedByProvider(t *testing.T) {

internal/core/source/chunk_plan.go

@@ -0,0 +1,240 @@
+package source
+
+import (
+	"bytes"
+	"encoding/json"
+	"fmt"
+	"io"
+	"strings"
+)
+
+// CanonicalizeChunkAnnotations validates annotation namespaces and JSON values
+// and returns an independently owned map whose values use canonical JSON bytes.
+func CanonicalizeChunkAnnotations(annotations ChunkAnnotations) (ChunkAnnotations, error) {
+	if len(annotations) == 0 {
+		return nil, nil
+	}
+	canonical := make(ChunkAnnotations, len(annotations))
+	for namespace, raw := range annotations {
+		if strings.TrimSpace(namespace) == "" {
+			return nil, fmt.Errorf("chunk annotation namespace must not be empty")
+		}
+		if strings.TrimSpace(namespace) != namespace {
+			return nil, fmt.Errorf("chunk annotation namespace %q must not contain leading or trailing whitespace", namespace)
+		}
+		value, err := decodeAnnotation(raw)
+		if err != nil {
+			return nil, fmt.Errorf("chunk annotation %q: %w", namespace, err)
+		}
+		encoded, err := json.Marshal(value)
+		if err != nil {
+			return nil, fmt.Errorf("chunk annotation %q contains an unsupported value: %w", namespace, err)
+		}
+		canonical[namespace] = encoded
+	}
+	return canonical, nil
+}
+
+func decodeAnnotation(raw json.RawMessage) (any, error) {
+	decoder := json.NewDecoder(bytes.NewReader(raw))
+	decoder.UseNumber()
+	var value any
+	if err := decoder.Decode(&value); err != nil {
+		return nil, fmt.Errorf("must contain valid JSON: %w", err)
+	}
+	var trailing any
+	if err := decoder.Decode(&trailing); err != io.EOF {
+		if err == nil {
+			return nil, fmt.Errorf("must contain exactly one JSON value")
+		}
+		return nil, fmt.Errorf("must contain exactly one JSON value: %w", err)
+	}
+	return value, nil
+}
+
+// ValidateChunkAnnotations requires annotations to already contain canonical
+// JSON. CanonicalizeChunkAnnotations can be used at producer boundaries.
+func ValidateChunkAnnotations(annotations ChunkAnnotations) error {
+	canonical, err := CanonicalizeChunkAnnotations(annotations)
+	if err != nil {
+		return err
+	}
+	for namespace, raw := range annotations {
+		if !bytes.Equal(raw, canonical[namespace]) {
+			return fmt.Errorf("chunk annotation %q must use canonical JSON", namespace)
+		}
+	}
+	return nil
+}
+
+// CloneChunkAnnotations returns a deep clone, including every raw JSON value.
+func CloneChunkAnnotations(annotations ChunkAnnotations) ChunkAnnotations {
+	if len(annotations) == 0 {
+		return nil
+	}
+	cloned := make(ChunkAnnotations, len(annotations))
+	for namespace, raw := range annotations {
+		cloned[namespace] = append(json.RawMessage(nil), raw...)
+	}
+	return cloned
+}
+
+// CloneChunkPlan returns a deep clone of a chunk plan.
+func CloneChunkPlan(plan ChunkPlan) ChunkPlan {
+	cloned := ChunkPlan{
+		SourceDigest: plan.SourceDigest,
+		Ranges:       make([]ChunkRange, len(plan.Ranges)),
+		Annotations:  CloneChunkAnnotations(plan.Annotations),
+	}
+	for i, chunkRange := range plan.Ranges {
+		cloned.Ranges[i] = ChunkRange{
+			StartUnitID: chunkRange.StartUnitID,
+			EndUnitID:   chunkRange.EndUnitID,
+			Annotations: CloneChunkAnnotations(chunkRange.Annotations),
+		}
+	}
+	return cloned
+}
+
+// CanonicalizeChunkPlan returns a deep clone with canonical annotation bytes.
+func CanonicalizeChunkPlan(plan ChunkPlan) (ChunkPlan, error) {
+	canonical := CloneChunkPlan(plan)
+	annotations, err := CanonicalizeChunkAnnotations(plan.Annotations)
+	if err != nil {
+		return ChunkPlan{}, fmt.Errorf("chunk plan annotations: %w", err)
+	}
+	canonical.Annotations = annotations
+	for i := range plan.Ranges {
+		annotations, err := CanonicalizeChunkAnnotations(plan.Ranges[i].Annotations)
+		if err != nil {
+			return ChunkPlan{}, fmt.Errorf("chunk plan range[%d] annotations: %w", i, err)
+		}
+		canonical.Ranges[i].Annotations = annotations
+	}
+	return canonical, nil
+}
+
+// ValidateChunkPlan validates a canonical plan against the current source.
+// Ranges may contain gaps or overlap, but their start positions must increase.
+func ValidateChunkPlan(doc *SourceDocument, plan ChunkPlan) error {
+	if err := ValidateDocument(doc); err != nil {
+		return fmt.Errorf("source document: %w", err)
+	}
+	if plan.SourceDigest != doc.Digest {
+		return fmt.Errorf("chunk plan source_digest %q does not match source document digest %q", plan.SourceDigest, doc.Digest)
+	}
+	if len(plan.Ranges) == 0 {
+		return fmt.Errorf("chunk plan ranges must not be empty")
+	}
+	if err := ValidateChunkAnnotations(plan.Annotations); err != nil {
+		return fmt.Errorf("chunk plan annotations: %w", err)
+	}
+	previousStart := -1
+	for i, chunkRange := range plan.Ranges {
+		start, ok := UnitIndex(doc, chunkRange.StartUnitID)
+		if !ok {
+			return fmt.Errorf("chunk plan range[%d] start_unit_id %d was not found", i, chunkRange.StartUnitID)
+		}
+		end, ok := UnitIndex(doc, chunkRange.EndUnitID)
+		if !ok {
+			return fmt.Errorf("chunk plan range[%d] end_unit_id %d was not found", i, chunkRange.EndUnitID)
+		}
+		if start > end {
+			return fmt.Errorf("chunk plan range[%d] start_unit_id %d appears after end_unit_id %d", i, chunkRange.StartUnitID, chunkRange.EndUnitID)
+		}
+		if start <= previousStart {
+			return fmt.Errorf("chunk plan range[%d] start_unit_id %d does not appear after the previous range start", i, chunkRange.StartUnitID)
+		}
+		if err := ValidateChunkAnnotations(chunkRange.Annotations); err != nil {
+			return fmt.Errorf("chunk plan range[%d] annotations: %w", i, err)
+		}
+		previousStart = start
+	}
+	return nil
+}
+
+// MaterializeChunkPlan deterministically expands a validated plan into chunks.
+func MaterializeChunkPlan(doc *SourceDocument, plan ChunkPlan) ([]Chunk, error) {
+	if err := ValidateChunkPlan(doc, plan); err != nil {
+		return nil, err
+	}
+	chunks := make([]Chunk, 0, len(plan.Ranges))
+	for index, chunkRange := range plan.Ranges {
+		start, _ := UnitIndex(doc, chunkRange.StartUnitID)
+		end, _ := UnitIndex(doc, chunkRange.EndUnitID)
+		units := cloneSourceUnits(doc.Units[start : end+1])
+		content, err := json.Marshal(struct {
+			Units []SourceUnit `json:"units"`
+		}{Units: units})
+		if err != nil {
+			return nil, fmt.Errorf("encode chunk plan range[%d]: %w", index, err)
+		}
+		chunks = append(chunks, Chunk{
+			ID:        fmt.Sprintf("chunk-%06d", index+1),
+			SourceID:  doc.ID,
+			Index:     index,
+			Ref:       SourceRef{SourceID: doc.ID, StartUnitID: chunkRange.StartUnitID, EndUnitID: chunkRange.EndUnitID},
+			Content:   content,
+			MediaType: "application/json",
+			Units:     units,
+			Metadata: map[string]any{
+				"start_unit_id": chunkRange.StartUnitID,
+				"end_unit_id":   chunkRange.EndUnitID,
+				"unit_count":    len(units),
+			},
+			Annotations:     CloneChunkAnnotations(chunkRange.Annotations),
+			PlanAnnotations: CloneChunkAnnotations(plan.Annotations),
+		})
+	}
+	return chunks, nil
+}
+
+func cloneSourceUnits(units []SourceUnit) []SourceUnit {
+	if len(units) == 0 {
+		return nil
+	}
+	cloned := make([]SourceUnit, len(units))
+	for i, unit := range units {
+		cloned[i] = unit
+		cloned[i].Metadata = cloneJSONMap(unit.Metadata)
+	}
+	return cloned
+}
+
+func cloneJSONMap(values map[string]any) map[string]any {
+	if len(values) == 0 {
+		return nil
+	}
+	cloned := make(map[string]any, len(values))
+	for key, value := range values {
+		cloned[key] = cloneJSONValue(value)
+	}
+	return cloned
+}
+
+func cloneJSONValue(value any) any {
+	switch typed := value.(type) {
+	case map[string]any:
+		return cloneJSONMap(typed)
+	case []any:
+		cloned := make([]any, len(typed))
+		for i := range typed {
+			cloned[i] = cloneJSONValue(typed[i])
+		}
+		return cloned
+	case json.RawMessage:
+		return append(json.RawMessage(nil), typed...)
+	case []byte:
+		return append([]byte(nil), typed...)
+	case []string:
+		return append([]string(nil), typed...)
+	case map[string]string:
+		cloned := make(map[string]string, len(typed))
+		for key, item := range typed {
+			cloned[key] = item
+		}
+		return cloned
+	default:
+		return value
+	}
+}

internal/core/source/chunk_plan_test.go

@@ -0,0 +1,246 @@
+package source
+
+import (
+	"bytes"
+	"encoding/json"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestCanonicalizeChunkAnnotations(t *testing.T) {
+	original := ChunkAnnotations{
+		"domain/items": json.RawMessage(` { "z": [3, 2, 1], "a": 1.0 } `),
+	}
+	canonical, err := CanonicalizeChunkAnnotations(original)
+	if err != nil {
+		t.Fatalf("CanonicalizeChunkAnnotations() error = %v, want nil", err)
+	}
+	if got, want := string(canonical["domain/items"]), `{"a":1.0,"z":[3,2,1]}`; got != want {
+		t.Fatalf("canonical annotation = %q, want %q", got, want)
+	}
+	original["domain/items"][0] = '['
+	if got := string(canonical["domain/items"]); got != `{"a":1.0,"z":[3,2,1]}` {
+		t.Fatalf("canonical annotation changed after input mutation: %q", got)
+	}
+	canonical["domain/items"][0] = '['
+	if original["domain/items"][0] == '[' && bytes.Equal(original["domain/items"], canonical["domain/items"]) {
+		t.Fatal("input and canonical annotation share value storage")
+	}
+}
+
+func TestCanonicalizeChunkAnnotationsRejectsInvalidValues(t *testing.T) {
+	tests := []struct {
+		name        string
+		annotations ChunkAnnotations
+		want        string
+	}{
+		{name: "blank namespace", annotations: ChunkAnnotations{" \t": json.RawMessage(`true`)}, want: "namespace must not be empty"},
+		{name: "untrimmed namespace", annotations: ChunkAnnotations{" items ": json.RawMessage(`true`)}, want: "leading or trailing whitespace"},
+		{name: "invalid JSON", annotations: ChunkAnnotations{"items": json.RawMessage(`{"x":`)}, want: "valid JSON"},
+		{name: "trailing JSON", annotations: ChunkAnnotations{"items": json.RawMessage(`true false`)}, want: "exactly one JSON value"},
+		{name: "non-finite number", annotations: ChunkAnnotations{"items": json.RawMessage(`NaN`)}, want: "valid JSON"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			_, err := CanonicalizeChunkAnnotations(tt.annotations)
+			if err == nil || !strings.Contains(err.Error(), tt.want) {
+				t.Fatalf("CanonicalizeChunkAnnotations() error = %v, want containing %q", err, tt.want)
+			}
+		})
+	}
+}
+
+func TestValidateChunkAnnotationsRequiresCanonicalJSON(t *testing.T) {
+	if err := ValidateChunkAnnotations(ChunkAnnotations{"items": json.RawMessage(` {"b":2,"a":1}`)}); err == nil || !strings.Contains(err.Error(), "canonical JSON") {
+		t.Fatalf("ValidateChunkAnnotations() error = %v, want canonical JSON error", err)
+	}
+	if err := ValidateChunkAnnotations(ChunkAnnotations{"items": json.RawMessage(`{"a":1,"b":2}`)}); err != nil {
+		t.Fatalf("ValidateChunkAnnotations(canonical) error = %v, want nil", err)
+	}
+}
+
+func TestCloneChunkPlanDoesNotShareAnnotationBytes(t *testing.T) {
+	plan := validChunkPlan(planDocument())
+	cloned := CloneChunkPlan(plan)
+	cloned.Annotations["plan"][0] = '['
+	cloned.Ranges[0].Annotations["range"][0] = '['
+	if string(plan.Annotations["plan"]) != `{"value":1}` || string(plan.Ranges[0].Annotations["range"]) != `{"value":2}` {
+		t.Fatal("CloneChunkPlan() shares annotation value storage")
+	}
+}
+
+func TestValidateChunkPlanRanges(t *testing.T) {
+	doc := planDocument()
+	tests := []struct {
+		name   string
+		mutate func(*ChunkPlan)
+		want   string
+	}{
+		{name: "source mismatch", mutate: func(plan *ChunkPlan) { plan.SourceDigest = "sha256:other" }, want: "does not match"},
+		{name: "missing ranges", mutate: func(plan *ChunkPlan) { plan.Ranges = nil }, want: "ranges must not be empty"},
+		{name: "missing start", mutate: func(plan *ChunkPlan) { plan.Ranges[0].StartUnitID = 99 }, want: "start_unit_id 99 was not found"},
+		{name: "missing end", mutate: func(plan *ChunkPlan) { plan.Ranges[0].EndUnitID = 99 }, want: "end_unit_id 99 was not found"},
+		{name: "backward range", mutate: func(plan *ChunkPlan) { plan.Ranges[0] = ChunkRange{StartUnitID: 30, EndUnitID: 10} }, want: "appears after end_unit_id"},
+		{name: "duplicate start", mutate: func(plan *ChunkPlan) { plan.Ranges[1].StartUnitID = plan.Ranges[0].StartUnitID }, want: "does not appear after"},
+		{name: "backward starts", mutate: func(plan *ChunkPlan) {
+			plan.Ranges = []ChunkRange{{StartUnitID: 30, EndUnitID: 50}, {StartUnitID: 20, EndUnitID: 40}}
+		}, want: "does not appear after"},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			plan := validChunkPlan(doc)
+			tt.mutate(&plan)
+			err := ValidateChunkPlan(doc, plan)
+			if err == nil || !strings.Contains(err.Error(), tt.want) {
+				t.Fatalf("ValidateChunkPlan() error = %v, want containing %q", err, tt.want)
+			}
+		})
+	}
+
+	for name, ranges := range map[string][]ChunkRange{
+		"gap":     {{StartUnitID: 10, EndUnitID: 20}, {StartUnitID: 40, EndUnitID: 50}},
+		"overlap": {{StartUnitID: 10, EndUnitID: 30}, {StartUnitID: 20, EndUnitID: 50}},
+	} {
+		t.Run(name, func(t *testing.T) {
+			plan := validChunkPlan(doc)
+			plan.Ranges = ranges
+			if err := ValidateChunkPlan(doc, plan); err != nil {
+				t.Fatalf("ValidateChunkPlan() error = %v, want nil", err)
+			}
+		})
+	}
+}
+
+func TestDigestChunkPlanIsStableAndCoversLogicalPlan(t *testing.T) {
+	doc := planDocument()
+	plan := validChunkPlan(doc)
+	first, err := DigestChunkPlan(plan)
+	if err != nil {
+		t.Fatalf("DigestChunkPlan() error = %v, want nil", err)
+	}
+	reformatted := CloneChunkPlan(plan)
+	reformatted.Annotations["plan"] = json.RawMessage(` { "value" : 1 } `)
+	second, err := DigestChunkPlan(reformatted)
+	if err != nil {
+		t.Fatalf("DigestChunkPlan(reformatted) error = %v, want nil", err)
+	}
+	if first != second {
+		t.Fatalf("digests = %q and %q, want stable canonical annotation digest", first, second)
+	}
+
+	changes := []func(*ChunkPlan){
+		func(value *ChunkPlan) { value.Ranges[0].EndUnitID = 30 },
+		func(value *ChunkPlan) { value.Annotations["plan"] = json.RawMessage(`{"value":2}`) },
+		func(value *ChunkPlan) { value.Ranges[0].Annotations["range"] = json.RawMessage(`{"value":3}`) },
+	}
+	for i, change := range changes {
+		changed := CloneChunkPlan(plan)
+		change(&changed)
+		digest, err := DigestChunkPlan(changed)
+		if err != nil {
+			t.Fatalf("DigestChunkPlan(change %d) error = %v", i, err)
+		}
+		if digest == first {
+			t.Fatalf("DigestChunkPlan(change %d) = %q, want changed digest", i, digest)
+		}
+	}
+}
+
+func TestMaterializeChunkPlanExactOutputAndMutationSafety(t *testing.T) {
+	doc := planDocument()
+	plan := validChunkPlan(doc)
+	plan.Ranges = []ChunkRange{
+		{StartUnitID: 10, EndUnitID: 30, Annotations: ChunkAnnotations{"range": json.RawMessage(`{"value":2}`)}},
+		{StartUnitID: 20, EndUnitID: 50, Annotations: ChunkAnnotations{"range": json.RawMessage(`{"value":3}`)}},
+	}
+	chunks, err := MaterializeChunkPlan(doc, plan)
+	if err != nil {
+		t.Fatalf("MaterializeChunkPlan() error = %v, want nil", err)
+	}
+	if len(chunks) != 2 {
+		t.Fatalf("chunks = %d, want 2", len(chunks))
+	}
+	first := chunks[0]
+	if first.ID != "chunk-000001" || first.SourceID != doc.ID || first.Index != 0 || first.MediaType != "application/json" {
+		t.Fatalf("first chunk identity = %#v", first)
+	}
+	if want := (SourceRef{SourceID: doc.ID, StartUnitID: 10, EndUnitID: 30}); first.Ref != want {
+		t.Fatalf("first ref = %#v, want %#v", first.Ref, want)
+	}
+	if got, want := unitIDs(first.Units), []int{10, 20, 30}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("first unit ids = %#v, want %#v", got, want)
+	}
+	wantContent, _ := json.Marshal(struct {
+		Units []SourceUnit `json:"units"`
+	}{Units: doc.Units[:3]})
+	if !bytes.Equal(first.Content, wantContent) {
+		t.Fatalf("first content = %s, want %s", first.Content, wantContent)
+	}
+	if !reflect.DeepEqual(first.Metadata, map[string]any{"start_unit_id": 10, "end_unit_id": 30, "unit_count": 3}) {
+		t.Fatalf("first metadata = %#v", first.Metadata)
+	}
+	if string(first.Annotations["range"]) != `{"value":2}` || string(first.PlanAnnotations["plan"]) != `{"value":1}` {
+		t.Fatalf("first annotations = %#v / %#v", first.Annotations, first.PlanAnnotations)
+	}
+	if got, want := unitIDs(chunks[1].Units), []int{20, 30, 40, 50}; !reflect.DeepEqual(got, want) {
+		t.Fatalf("overlapping unit ids = %#v, want %#v", got, want)
+	}
+
+	again, err := MaterializeChunkPlan(doc, plan)
+	if err != nil {
+		t.Fatalf("MaterializeChunkPlan(repeated) error = %v", err)
+	}
+	if !reflect.DeepEqual(chunks, again) {
+		t.Fatalf("repeated materialization differs:\nfirst: %#v\nagain: %#v", chunks, again)
+	}
+	chunks[0].Units[0].Text = "mutated"
+	chunks[0].Annotations["range"][0] = '['
+	chunks[0].PlanAnnotations["plan"][0] = '['
+	if doc.Units[0].Text == "mutated" || string(plan.Ranges[0].Annotations["range"]) != `{"value":2}` || string(plan.Annotations["plan"]) != `{"value":1}` {
+		t.Fatal("materialized chunk shares owned plan or source storage")
+	}
+}
+
+func TestMaterializeChunkPlanDeepClonesUnitMetadata(t *testing.T) {
+	doc := planDocument()
+	doc.Units[0].Metadata = map[string]any{"nested": map[string]any{"values": []any{json.RawMessage(`{"ok":true}`)}}}
+	chunks, err := MaterializeChunkPlan(doc, validChunkPlan(doc))
+	if err != nil {
+		t.Fatal(err)
+	}
+	nested := chunks[0].Units[0].Metadata["nested"].(map[string]any)
+	nested["values"].([]any)[0].(json.RawMessage)[0] = '['
+	nested["changed"] = true
+	original := doc.Units[0].Metadata["nested"].(map[string]any)
+	if _, exists := original["changed"]; exists || string(original["values"].([]any)[0].(json.RawMessage)) != `{"ok":true}` {
+		t.Fatalf("source metadata changed through materialized chunk: %#v", doc.Units[0].Metadata)
+	}
+}
+
+func planDocument() *SourceDocument {
+	doc := &SourceDocument{ID: "source-plan", Kind: "test", Format: "application/test", Digest: "sha256:source-plan"}
+	for _, id := range []int{10, 20, 30, 40, 50} {
+		doc.Units = append(doc.Units, SourceUnit{ID: id, Kind: "line", Text: "unit", Ref: SourceRef{SourceID: doc.ID, StartUnitID: id, EndUnitID: id}})
+	}
+	return doc
+}
+
+func validChunkPlan(doc *SourceDocument) ChunkPlan {
+	return ChunkPlan{
+		SourceDigest: doc.Digest,
+		Ranges: []ChunkRange{
+			{StartUnitID: 10, EndUnitID: 20, Annotations: ChunkAnnotations{"range": json.RawMessage(`{"value":2}`)}},
+			{StartUnitID: 30, EndUnitID: 50},
+		},
+		Annotations: ChunkAnnotations{"plan": json.RawMessage(`{"value":1}`)},
+	}
+}
+
+func unitIDs(units []SourceUnit) []int {
+	ids := make([]int, len(units))
+	for i, unit := range units {
+		ids[i] = unit.ID
+	}
+	return ids
+}

internal/core/source/digest.go

@@ -37,24 +37,36 @@ func DigestDocument(doc *SourceDocument) (string, error) {
 // DigestChunk returns a deterministic digest of a chunk, including its source
 // provenance, content, units, and metadata.
 func DigestChunk(chunk Chunk) (string, error) {
+	annotations, err := CanonicalizeChunkAnnotations(chunk.Annotations)
+	if err != nil {
+		return "", fmt.Errorf("canonicalize source chunk annotations: %w", err)
+	}
+	planAnnotations, err := CanonicalizeChunkAnnotations(chunk.PlanAnnotations)
+	if err != nil {
+		return "", fmt.Errorf("canonicalize source chunk plan annotations: %w", err)
+	}
 	payload := struct {
-		ID        string         `json:"id"`
-		SourceID  string         `json:"source_id"`
-		Index     int            `json:"index"`
-		Ref       SourceRef      `json:"ref"`
-		Content   []byte         `json:"content"`
-		MediaType string         `json:"media_type"`
-		Units     []SourceUnit   `json:"units"`
-		Metadata  map[string]any `json:"metadata,omitempty"`
+		ID              string           `json:"id"`
+		SourceID        string           `json:"source_id"`
+		Index           int              `json:"index"`
+		Ref             SourceRef        `json:"ref"`
+		Content         []byte           `json:"content"`
+		MediaType       string           `json:"media_type"`
+		Units           []SourceUnit     `json:"units"`
+		Metadata        map[string]any   `json:"metadata,omitempty"`
+		Annotations     ChunkAnnotations `json:"annotations,omitempty"`
+		PlanAnnotations ChunkAnnotations `json:"plan_annotations,omitempty"`
 	}{
-		ID:        chunk.ID,
-		SourceID:  chunk.SourceID,
-		Index:     chunk.Index,
-		Ref:       chunk.Ref,
-		Content:   chunk.Content,
-		MediaType: chunk.MediaType,
-		Units:     chunk.Units,
-		Metadata:  chunk.Metadata,
+		ID:              chunk.ID,
+		SourceID:        chunk.SourceID,
+		Index:           chunk.Index,
+		Ref:             chunk.Ref,
+		Content:         chunk.Content,
+		MediaType:       chunk.MediaType,
+		Units:           chunk.Units,
+		Metadata:        chunk.Metadata,
+		Annotations:     annotations,
+		PlanAnnotations: planAnnotations,
 	}
 	encoded, err := json.Marshal(payload)
 	if err != nil {
@@ -63,3 +75,28 @@ func DigestChunk(chunk Chunk) (string, error) {
 	sum := sha256.Sum256(encoded)
 	return "sha256:" + hex.EncodeToString(sum[:]), nil
 }
+
+// DigestChunkPlan returns a deterministic digest of the logical plan. Storage
+// schema, producer provenance, warnings, and timestamps are intentionally not
+// part of the digest.
+func DigestChunkPlan(plan ChunkPlan) (string, error) {
+	canonical, err := CanonicalizeChunkPlan(plan)
+	if err != nil {
+		return "", err
+	}
+	if isBlank(canonical.SourceDigest) {
+		return "", fmt.Errorf("chunk plan source_digest must not be empty")
+	}
+	if hasSurroundingWhitespace(canonical.SourceDigest) {
+		return "", fmt.Errorf("chunk plan source_digest must not contain leading or trailing whitespace")
+	}
+	if len(canonical.Ranges) == 0 {
+		return "", fmt.Errorf("chunk plan ranges must not be empty")
+	}
+	encoded, err := json.Marshal(canonical)
+	if err != nil {
+		return "", fmt.Errorf("encode chunk plan for digest: %w", err)
+	}
+	sum := sha256.Sum256(encoded)
+	return "sha256:" + hex.EncodeToString(sum[:]), nil
+}

internal/core/source/source.go

@@ -1,5 +1,7 @@
 package source
 
+import "encoding/json"
+
 type SourceDocument struct {
 	ID       string         `json:"id"`
 	Kind     string         `json:"kind"`
@@ -23,13 +25,29 @@ type SourceRef struct {
 	EndUnitID   int    `json:"end_unit_id"`
 }
 
-type Chunk struct {
-	ID        string         `json:"id"`
-	SourceID  string         `json:"source_id"`
-	Index     int            `json:"index"`
-	Ref       SourceRef      `json:"ref"`
-	Content   []byte         `json:"-"`
-	MediaType string         `json:"media_type"`
-	Units     []SourceUnit   `json:"units"`
-	Metadata  map[string]any `json:"metadata,omitempty"`
+type ChunkAnnotations map[string]json.RawMessage
+
+type ChunkPlan struct {
+	SourceDigest string           `json:"source_digest"`
+	Ranges       []ChunkRange     `json:"ranges"`
+	Annotations  ChunkAnnotations `json:"annotations,omitempty"`
+}
+
+type ChunkRange struct {
+	StartUnitID int              `json:"start_unit_id"`
+	EndUnitID   int              `json:"end_unit_id"`
+	Annotations ChunkAnnotations `json:"annotations,omitempty"`
+}
+
+type Chunk struct {
+	ID              string           `json:"id"`
+	SourceID        string           `json:"source_id"`
+	Index           int              `json:"index"`
+	Ref             SourceRef        `json:"ref"`
+	Content         []byte           `json:"-"`
+	MediaType       string           `json:"media_type"`
+	Units           []SourceUnit     `json:"units"`
+	Metadata        map[string]any   `json:"metadata,omitempty"`
+	Annotations     ChunkAnnotations `json:"annotations,omitempty"`
+	PlanAnnotations ChunkAnnotations `json:"plan_annotations,omitempty"`
 }

internal/core/source/source_test.go

@@ -1,6 +1,7 @@
 package source
 
 import (
+	"encoding/json"
 	"strings"
 	"testing"
 )
@@ -258,6 +259,28 @@ func TestDigestChunkIsDeterministicAndIncludesReference(t *testing.T) {
 	}
 }
 
+func TestDigestChunkIncludesAnnotationScopes(t *testing.T) {
+	doc := validDocument()
+	chunk := Chunk{
+		ID: "chunk-1", SourceID: doc.ID, Ref: SourceRef{SourceID: doc.ID, StartUnitID: 1, EndUnitID: 2},
+		Content: []byte("content"), MediaType: "text/plain", Units: doc.Units,
+		Annotations:     ChunkAnnotations{"scope": json.RawMessage(`{"value":1}`)},
+		PlanAnnotations: ChunkAnnotations{"scope": json.RawMessage(`{"value":2}`)},
+	}
+	base, err := DigestChunk(chunk)
+	if err != nil {
+		t.Fatalf("DigestChunk() error = %v", err)
+	}
+	chunk.Annotations["scope"] = json.RawMessage(`{"value":3}`)
+	rangeChanged, _ := DigestChunk(chunk)
+	chunk.Annotations["scope"] = json.RawMessage(`{"value":1}`)
+	chunk.PlanAnnotations["scope"] = json.RawMessage(`{"value":3}`)
+	planChanged, _ := DigestChunk(chunk)
+	if base == rangeChanged || base == planChanged || rangeChanged == planChanged {
+		t.Fatalf("annotation scope digests did not change distinctly: %q %q %q", base, rangeChanged, planChanged)
+	}
+}
+
 func TestValidateRefValid(t *testing.T) {
 	doc := validDocument()
 	ref := SourceRef{

internal/core/workspace/chunk_plan.go

@@ -0,0 +1,22 @@
+package workspace
+
+import (
+	"fmt"
+	"path/filepath"
+	"strings"
+)
+
+func DefaultChunkPlanRoot(userCacheDir func() (string, error)) (string, error) {
+	if userCacheDir == nil {
+		return "", fmt.Errorf("user cache directory resolver must not be nil")
+	}
+	root, err := userCacheDir()
+	if err != nil {
+		return "", fmt.Errorf("resolve user cache directory: %w", err)
+	}
+	root = strings.TrimSpace(root)
+	if root == "" {
+		return "", fmt.Errorf("user cache directory must not be empty")
+	}
+	return filepath.Join(filepath.Clean(root), "notarius", "chunk-plans"), nil
+}

internal/core/workspace/chunk_plan_test.go

@@ -0,0 +1,57 @@
+package workspace
+
+import (
+	"errors"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/config"
+)
+
+func TestDefaultChunkPlanRoot(t *testing.T) {
+	got, err := DefaultChunkPlanRoot(func() (string, error) { return "/cache/user", nil })
+	if err != nil {
+		t.Fatalf("DefaultChunkPlanRoot() error = %v", err)
+	}
+	if want := filepath.Join("/cache/user", "notarius", "chunk-plans"); got != want {
+		t.Fatalf("root = %q, want %q", got, want)
+	}
+}
+
+func TestDefaultChunkPlanRootRejectsResolverFailures(t *testing.T) {
+	boom := errors.New("resolver failed")
+	if _, err := DefaultChunkPlanRoot(func() (string, error) { return "", boom }); !errors.Is(err, boom) {
+		t.Fatalf("resolver error = %v", err)
+	}
+	if _, err := DefaultChunkPlanRoot(func() (string, error) { return " \t ", nil }); err == nil || !strings.Contains(err.Error(), "empty") {
+		t.Fatalf("empty result error = %v", err)
+	}
+	if _, err := DefaultChunkPlanRoot(nil); err == nil {
+		t.Fatal("nil resolver error = nil")
+	}
+}
+
+func TestChunkPlanDirectoryIsIndependentFromWorkspaceSettings(t *testing.T) {
+	base := config.Default()
+	base.Workspace.Directory = "/workspace/one"
+	base.Workspace.ChunkCache.Directory = "/cache/plans"
+	first := FromConfig(base)
+
+	changedWorkspace := base
+	changedWorkspace.Workspace.Directory = "/workspace/two"
+	second := FromConfig(changedWorkspace)
+	if base.Workspace.ChunkCache.Directory != changedWorkspace.Workspace.ChunkCache.Directory {
+		t.Fatal("workspace directory changed chunk plan directory")
+	}
+	if first.RootDir == second.RootDir || first.CheckpointsRoot == second.CheckpointsRoot || first.DebugRoot == second.DebugRoot {
+		t.Fatalf("workspace settings did not follow workspace directory: %#v %#v", first, second)
+	}
+
+	changedCache := base
+	changedCache.Workspace.ChunkCache.Directory = "/cache/other"
+	third := FromConfig(changedCache)
+	if first != third {
+		t.Fatalf("chunk plan directory changed workspace settings: %#v %#v", first, third)
+	}
+}

internal/core/workspace/manifest.go

@@ -11,7 +11,6 @@ type StageName string
 
 const (
 	StageSource    StageName = "source"
-	StageChunk     StageName = "chunk"
 	StageExtract   StageName = "extract"
 	StageMerge     StageName = "merge"
 	StageNormalize StageName = "normalize"
@@ -55,11 +54,6 @@ type SourceManifest struct {
 	SourceID string `json:"source_id,omitempty"`
 }
 
-type ChunkManifest struct {
-	StageManifest
-	ChunkCount int `json:"chunk_count,omitempty"`
-}
-
 type ExtractLaneManifest struct {
 	StageManifest
 	ChunkCount  int `json:"chunk_count,omitempty"`

internal/core/workspace/manifest_test.go

@@ -42,18 +42,6 @@ func TestManifestJSONRoundTrips(t *testing.T) {
 		}
 	})
 
-	t.Run("chunk", func(t *testing.T) {
-		manifest := ChunkManifest{
-			StageManifest: populatedManifest(StageChunk, "", "generic", started, completed),
-			ChunkCount:    3,
-		}
-		var got ChunkManifest
-		roundTripManifest(t, manifest, &got)
-		if got.ChunkCount != manifest.ChunkCount || got.Stage != StageChunk {
-			t.Fatalf("round trip chunk manifest = %+v", got)
-		}
-	})
-
 	t.Run("extract", func(t *testing.T) {
 		manifest := ExtractLaneManifest{
 			StageManifest: populatedManifest(StageExtract, "spells", "dnd/spells", started, completed),

internal/framework/checkpoint/loader.go

@@ -58,36 +58,6 @@ func (l *WorkspaceLoader) Source(moduleKey string) (pipeline.SourceCheckpoint, p
 	return pipeline.SourceCheckpoint{Document: &doc}, reusedDecision()
 }
 
-func (l *WorkspaceLoader) Chunk(moduleKey string, sourceDigest string) (pipeline.ChunkCheckpoint, pipeline.CheckpointDecision) {
-	expectedDependencies := digestFingerprints("source_document", sourceDigest)
-	var manifest coreworkspace.ChunkManifest
-	if decision := l.readJSON("chunk/manifest.json", &manifest); !decision.Reused {
-		return pipeline.ChunkCheckpoint{}, decision
-	}
-	if decision := l.validateManifest(manifest.StageManifest, coreworkspace.StageChunk, "", moduleKey, coreworkspace.StatusSucceeded, expectedDependencies); !decision.Reused {
-		return pipeline.ChunkCheckpoint{}, decision
-	}
-	var payload chunksEnvelope
-	if decision := l.readJSON("chunk/chunks.json", &payload); !decision.Reused {
-		return pipeline.ChunkCheckpoint{}, decision
-	}
-	chunks, err := sourceChunksFromEnvelope(payload.Chunks)
-	if err != nil {
-		return pipeline.ChunkCheckpoint{}, invalidDecision("chunk checkpoint payload is invalid: %v", err)
-	}
-	if len(chunks) == 0 {
-		return pipeline.ChunkCheckpoint{}, invalidDecision("chunk checkpoint payload has no chunks")
-	}
-	outputDigests, err := chunkOutputDigests(chunks)
-	if err != nil {
-		return pipeline.ChunkCheckpoint{}, invalidDecision("chunk checkpoint output cannot be digested: %v", err)
-	}
-	if !fingerprintsEqual(coreworkspaceToPipelineFingerprints(manifest.OutputDigests), outputDigests) {
-		return pipeline.ChunkCheckpoint{}, invalidDecision("chunk checkpoint output digests do not match payload")
-	}
-	return pipeline.ChunkCheckpoint{Chunks: chunks, Warnings: cloneWarnings(payload.Warnings)}, reusedDecision()
-}
-
 func (l *WorkspaceLoader) Extract(laneID, moduleKey string, dependencies []pipeline.CheckpointFingerprint) (pipeline.ExtractCheckpoint, pipeline.CheckpointDecision) {
 	var manifest coreworkspace.ExtractLaneManifest
 	if d := l.readJSON(laneManifestPath("extract", laneID), &manifest); !d.Reused {
@@ -232,30 +202,6 @@ func (l *WorkspaceLoader) validateLaneManifest(manifest coreworkspace.StageManif
 	return reusedDecision()
 }
 
-func sourceChunksFromEnvelope(values []chunkEnvelope) ([]source.Chunk, error) {
-	if len(values) == 0 {
-		return nil, nil
-	}
-	out := make([]source.Chunk, 0, len(values))
-	for _, value := range values {
-		content, err := contentFromEnvelope(value.Content)
-		if err != nil {
-			return nil, err
-		}
-		out = append(out, source.Chunk{
-			ID:        value.ID,
-			SourceID:  value.SourceID,
-			Index:     value.Index,
-			Ref:       value.Ref,
-			Content:   content,
-			MediaType: value.Content.MediaType,
-			Units:     cloneSourceUnits(value.Units),
-			Metadata:  cloneMetadata(value.Metadata),
-		})
-	}
-	return out, nil
-}
-
 func contentFromEnvelope(value binaryEnvelope) ([]byte, error) {
 	content, err := base64.StdEncoding.DecodeString(value.ContentBase64)
 	if err != nil {

internal/framework/checkpoint/recorder.go

@@ -65,54 +65,6 @@ func (r *WorkspaceRecorder) SourceFailed(moduleKey string, err error) error {
 	return r.writeManifest("source/manifest.json", coreworkspace.SourceManifest{StageManifest: manifest})
 }
 
-func (r *WorkspaceRecorder) ChunkRunning(moduleKey string, sourceDigest string) error {
-	manifest := r.newStageManifest(coreworkspace.StageChunk, coreworkspace.StatusRunning)
-	manifest.ModuleKey = moduleKey
-	manifest.DependencyFingerprints = workspaceFingerprints(digestFingerprints("source_document", sourceDigest))
-	manifest.StartedAt = timePtr(r.timestamp())
-	return r.writeManifest("chunk/manifest.json", coreworkspace.ChunkManifest{StageManifest: manifest})
-}
-
-func (r *WorkspaceRecorder) ChunkSucceeded(moduleKey string, sourceDigest string, chunks []source.Chunk, warnings []contracts.Warning) error {
-	outputDigests, err := chunkOutputDigests(chunks)
-	if err != nil {
-		return fmt.Errorf("digest chunk checkpoint output: %w", err)
-	}
-	payload := chunksEnvelope{Chunks: chunkEnvelopes(chunks), Warnings: cloneWarnings(warnings)}
-	if err := r.writePayload("chunk/chunks.json", payload); err != nil {
-		return err
-	}
-	manifest := r.newStageManifest(coreworkspace.StageChunk, coreworkspace.StatusSucceeded)
-	manifest.ModuleKey = moduleKey
-	manifest.DependencyFingerprints = workspaceFingerprints(digestFingerprints("source_document", sourceDigest))
-	manifest.OutputDigests = workspaceFingerprints(outputDigests)
-	manifest.ValidationStatus = validationStatusString(warnings, nil)
-	manifest.CompletedAt = timePtr(r.timestamp())
-	return r.writeManifest("chunk/manifest.json", coreworkspace.ChunkManifest{
-		StageManifest: manifest,
-		ChunkCount:    len(chunks),
-	})
-}
-
-func (r *WorkspaceRecorder) ChunkRejected(moduleKey string, sourceDigest string, rejected contracts.RejectedOutput) error {
-	manifest := r.newStageManifest(coreworkspace.StageChunk, coreworkspace.StatusSucceededWithRejections)
-	manifest.ModuleKey = moduleKey
-	manifest.DependencyFingerprints = workspaceFingerprints(digestFingerprints("source_document", sourceDigest))
-	manifest.ValidationStatus = "rejected"
-	manifest.Rejections = rejectionSummaries([]contracts.RejectedOutput{rejected})
-	manifest.CompletedAt = timePtr(r.timestamp())
-	return r.writeManifest("chunk/manifest.json", coreworkspace.ChunkManifest{StageManifest: manifest})
-}
-
-func (r *WorkspaceRecorder) ChunkFailed(moduleKey string, sourceDigest string, err error) error {
-	manifest := r.newStageManifest(coreworkspace.StageChunk, coreworkspace.StatusFailed)
-	manifest.ModuleKey = moduleKey
-	manifest.DependencyFingerprints = workspaceFingerprints(digestFingerprints("source_document", sourceDigest))
-	manifest.CompletedAt = timePtr(r.timestamp())
-	manifest.Metadata = errorMetadata(err)
-	return r.writeManifest("chunk/manifest.json", coreworkspace.ChunkManifest{StageManifest: manifest})
-}
-
 func (r *WorkspaceRecorder) ExtractRunning(laneID string, moduleKey string, dependencies []pipeline.CheckpointFingerprint) error {
 	manifest := r.laneManifest(coreworkspace.StageExtract, coreworkspace.StatusRunning, laneID, moduleKey, dependencies)
 	manifest.StartedAt = timePtr(r.timestamp())
@@ -245,21 +197,6 @@ type sourceDocumentEnvelope struct {
 	Document source.SourceDocument `json:"document"`
 }
 
-type chunksEnvelope struct {
-	Chunks   []chunkEnvelope     `json:"chunks"`
-	Warnings []contracts.Warning `json:"warnings,omitempty"`
-}
-
-type chunkEnvelope struct {
-	ID       string              `json:"id"`
-	SourceID string              `json:"source_id"`
-	Index    int                 `json:"index"`
-	Ref      source.SourceRef    `json:"ref"`
-	Content  binaryEnvelope      `json:"content"`
-	Units    []source.SourceUnit `json:"units,omitempty"`
-	Metadata map[string]any      `json:"metadata,omitempty"`
-}
-
 type binaryEnvelope struct {
 	ContentBase64 string              `json:"content_base64,omitempty"`
 	ContentDigest string              `json:"content_digest,omitempty"`
@@ -313,25 +250,6 @@ func artifactOutputDigests(outputs []pipeline.CheckpointArtifact) []pipeline.Che
 	return normalizeFingerprints(values)
 }
 
-func chunkEnvelopes(chunks []source.Chunk) []chunkEnvelope {
-	if len(chunks) == 0 {
-		return nil
-	}
-	out := make([]chunkEnvelope, 0, len(chunks))
-	for _, chunk := range chunks {
-		out = append(out, chunkEnvelope{
-			ID:       chunk.ID,
-			SourceID: chunk.SourceID,
-			Index:    chunk.Index,
-			Ref:      chunk.Ref,
-			Content:  binaryEnvelopeFromContent(chunk.Content, chunk.MediaType, chunk.Metadata, nil),
-			Units:    cloneSourceUnits(chunk.Units),
-			Metadata: cloneMetadata(chunk.Metadata),
-		})
-	}
-	return out
-}
-
 func binaryEnvelopeFromContent(content []byte, mediaType string, metadata map[string]any, warnings []contracts.Warning) binaryEnvelope {
 	return binaryEnvelope{
 		ContentBase64: base64.StdEncoding.EncodeToString(content),
@@ -390,21 +308,6 @@ func cloneMetadata(metadata map[string]any) map[string]any {
 	return out
 }
 
-func chunkOutputDigests(chunks []source.Chunk) ([]pipeline.CheckpointFingerprint, error) {
-	values := make([]pipeline.CheckpointFingerprint, 0, len(chunks))
-	for _, chunk := range chunks {
-		digest, err := source.DigestChunk(chunk)
-		if err != nil {
-			return nil, fmt.Errorf("chunk %q: %w", chunk.ID, err)
-		}
-		values = append(values, pipeline.CheckpointFingerprint{
-			Name:  chunk.ID,
-			Value: digest,
-		})
-	}
-	return normalizeFingerprints(values), nil
-}
-
 func digestFingerprints(name string, digest string) []pipeline.CheckpointFingerprint {
 	digest = strings.TrimSpace(digest)
 	if digest == "" {

internal/framework/checkpoint/recorder_test.go

@@ -1,7 +1,6 @@
 package checkpoint
 
 import (
-	"encoding/base64"
 	"encoding/json"
 	"os"
 	"path/filepath"
@@ -24,18 +23,6 @@ func TestWorkspaceRecorderWritesSuccessfulCheckpointFiles(t *testing.T) {
 		Digest: "sha256:source",
 		Units:  []source.SourceUnit{{ID: 1, Kind: "line", Text: "hello", Ref: source.SourceRef{SourceID: "source-1", StartUnitID: 1, EndUnitID: 1}}},
 	}
-	chunks := []source.Chunk{
-		{
-			ID:        "chunk-1",
-			SourceID:  "source-1",
-			Index:     0,
-			Ref:       source.SourceRef{SourceID: "source-1", StartUnitID: 1, EndUnitID: 1},
-			Content:   []byte("chunk content"),
-			MediaType: "text/plain",
-			Units:     doc.Units,
-		},
-	}
-
 	if err := recorder.SourceRunning("seriatim"); err != nil {
 		t.Fatalf("SourceRunning: %v", err)
 	}
@@ -47,36 +34,6 @@ func TestWorkspaceRecorderWritesSuccessfulCheckpointFiles(t *testing.T) {
 	if _, err := os.Stat(filepath.Join(root, "source", "source-document.json")); err != nil {
 		t.Fatalf("expected source checkpoint payload: %v", err)
 	}
-
-	if err := recorder.ChunkRunning("generic", doc.Digest); err != nil {
-		t.Fatalf("ChunkRunning: %v", err)
-	}
-	if err := recorder.ChunkSucceeded("generic", doc.Digest, chunks, nil); err != nil {
-		t.Fatalf("ChunkSucceeded: %v", err)
-	}
-	assertManifestStatus(t, filepath.Join(root, "chunk", "manifest.json"), coreworkspace.StatusSucceeded)
-	var chunkPayload struct {
-		Chunks []struct {
-			Content struct {
-				ContentBase64 string `json:"content_base64"`
-				ContentDigest string `json:"content_digest"`
-			} `json:"content"`
-		} `json:"chunks"`
-	}
-	readJSON(t, filepath.Join(root, "chunk", "chunks.json"), &chunkPayload)
-	if len(chunkPayload.Chunks) != 1 {
-		t.Fatalf("checkpoint chunks = %#v, want one", chunkPayload.Chunks)
-	}
-	decoded, err := base64.StdEncoding.DecodeString(chunkPayload.Chunks[0].Content.ContentBase64)
-	if err != nil {
-		t.Fatalf("decode chunk content: %v", err)
-	}
-	if string(decoded) != "chunk content" {
-		t.Fatalf("chunk content = %q, want original content", decoded)
-	}
-	if got, want := chunkPayload.Chunks[0].Content.ContentDigest, contentDigest([]byte("chunk content")); got != want {
-		t.Fatalf("content digest = %q, want %q", got, want)
-	}
 }
 
 func TestWorkspaceArtifactCheckpointsRoundTripCodecIdentityAndBytes(t *testing.T) {
@@ -127,24 +84,6 @@ func TestWorkspaceLoaderInvalidatesMissingCorruptAndMismatchedCheckpoints(t *tes
 		}
 	})
 
-	t.Run("dependency mismatch", func(t *testing.T) {
-		root := t.TempDir()
-		recorder := newTestRecorder(t, root)
-		chunks := []source.Chunk{{
-			ID:        "chunk-1",
-			SourceID:  "source-1",
-			Content:   []byte("chunk content"),
-			MediaType: "text/plain",
-		}}
-		if err := recorder.ChunkSucceeded("generic", "sha256:source-a", chunks, nil); err != nil {
-			t.Fatalf("ChunkSucceeded: %v", err)
-		}
-		loader := &WorkspaceLoader{root: root}
-		if _, decision := loader.Chunk("generic", "sha256:source-b"); decision.Reused || !strings.Contains(decision.Reason, "dependency") {
-			t.Fatalf("decision = %#v, want dependency invalidation", decision)
-		}
-	})
-
 	t.Run("incompatible workspace schema remains untouched", func(t *testing.T) {
 		root := t.TempDir()
 		recorder := newTestRecorder(t, root)
@@ -176,28 +115,41 @@ func TestWorkspaceLoaderInvalidatesMissingCorruptAndMismatchedCheckpoints(t *tes
 		}
 	})
 
-	t.Run("corrupt payload", func(t *testing.T) {
-		root := t.TempDir()
-		recorder := newTestRecorder(t, root)
-		chunks := []source.Chunk{{
-			ID:        "chunk-1",
-			SourceID:  "source-1",
-			Content:   []byte("chunk content"),
-			MediaType: "text/plain",
-		}}
-		if err := recorder.ChunkSucceeded("generic", "sha256:source", chunks, nil); err != nil {
-			t.Fatalf("ChunkSucceeded: %v", err)
-		}
-		payloadPath := filepath.Join(root, "chunk", "chunks.json")
-		data := strings.ReplaceAll(string(readFile(t, payloadPath)), contentDigest([]byte("chunk content")), "sha256:bad")
-		if err := os.WriteFile(payloadPath, []byte(data), 0o644); err != nil {
-			t.Fatalf("corrupt chunk payload: %v", err)
-		}
-		loader := &WorkspaceLoader{root: root}
-		if _, decision := loader.Chunk("generic", "sha256:source"); decision.Reused || !strings.Contains(decision.Reason, "invalid") {
-			t.Fatalf("decision = %#v, want corrupt payload invalidation", decision)
-		}
-	})
+}
+
+func TestWorkspaceCheckpointsIgnoreLegacyChunkFiles(t *testing.T) {
+	root := t.TempDir()
+	legacyManifest := []byte(`{"legacy":"manifest"}`)
+	legacyPayload := []byte(`{"legacy":"chunks"}`)
+	legacyDir := filepath.Join(root, "chunk")
+	if err := os.MkdirAll(legacyDir, 0o700); err != nil {
+		t.Fatal(err)
+	}
+	manifestPath := filepath.Join(legacyDir, "manifest.json")
+	payloadPath := filepath.Join(legacyDir, "chunks.json")
+	if err := os.WriteFile(manifestPath, legacyManifest, 0o600); err != nil {
+		t.Fatal(err)
+	}
+	if err := os.WriteFile(payloadPath, legacyPayload, 0o600); err != nil {
+		t.Fatal(err)
+	}
+
+	doc := &source.SourceDocument{ID: "source-1", Kind: "document", Format: "text/plain", Units: []source.SourceUnit{{ID: 1, Kind: "line", Text: "hello", Ref: source.SourceRef{SourceID: "source-1", StartUnitID: 1, EndUnitID: 1}}}}
+	doc.Digest, _ = source.DigestDocument(doc)
+	recorder := newTestRecorder(t, root)
+	if err := recorder.SourceSucceeded("seriatim", doc); err != nil {
+		t.Fatal(err)
+	}
+	loaded, decision := (&WorkspaceLoader{root: root}).Source("seriatim")
+	if !decision.Reused || loaded.Document == nil || loaded.Document.Digest != doc.Digest {
+		t.Fatalf("source checkpoint = %#v decision = %#v", loaded, decision)
+	}
+	if got := readFile(t, manifestPath); string(got) != string(legacyManifest) {
+		t.Fatalf("legacy manifest changed: %s", got)
+	}
+	if got := readFile(t, payloadPath); string(got) != string(legacyPayload) {
+		t.Fatalf("legacy payload changed: %s", got)
+	}
 }
 
 func TestWorkspaceRecorderRecordsRejectedExtractOutputs(t *testing.T) {

internal/framework/chunkplan/import_boundaries_test.go

@@ -0,0 +1,62 @@
+package chunkplan
+
+import (
+	"go/parser"
+	"go/token"
+	"path/filepath"
+	"runtime"
+	"strconv"
+	"strings"
+	"testing"
+)
+
+const repositoryImportPrefix = "gitea.maximumdirect.net/eric/notarius/internal/"
+
+func TestPlanStoreAndSourceImportBoundaries(t *testing.T) {
+	repositoryRoot := repositoryRoot(t)
+	for _, tc := range []struct {
+		name      string
+		directory string
+		forbidden []string
+	}{
+		{name: "source is framework and module independent", directory: "internal/core/source", forbidden: []string{"framework/", "modules/"}},
+		{name: "plan store is module independent", directory: "internal/framework/chunkplan", forbidden: []string{"modules/"}},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			files, err := filepath.Glob(filepath.Join(repositoryRoot, tc.directory, "*.go"))
+			if err != nil {
+				t.Fatal(err)
+			}
+			for _, filename := range files {
+				if strings.HasSuffix(filename, "_test.go") {
+					continue
+				}
+				parsed, err := parser.ParseFile(token.NewFileSet(), filename, nil, parser.ImportsOnly)
+				if err != nil {
+					t.Fatal(err)
+				}
+				for _, item := range parsed.Imports {
+					path, err := strconv.Unquote(item.Path.Value)
+					if err != nil {
+						t.Fatal(err)
+					}
+					path = strings.TrimPrefix(path, repositoryImportPrefix)
+					for _, prefix := range tc.forbidden {
+						if strings.HasPrefix(path, prefix) {
+							t.Fatalf("%s imports %q, forbidden by %s boundary", filepath.Base(filename), path, tc.name)
+						}
+					}
+				}
+			}
+		})
+	}
+}
+
+func repositoryRoot(t *testing.T) string {
+	t.Helper()
+	_, filename, _, ok := runtime.Caller(0)
+	if !ok {
+		t.Fatal("resolve test location")
+	}
+	return filepath.Clean(filepath.Join(filepath.Dir(filename), "..", "..", ".."))
+}

internal/framework/chunkplan/store.go

@@ -0,0 +1,231 @@
+package chunkplan
+
+import (
+	"bytes"
+	"encoding/hex"
+	"encoding/json"
+	"fmt"
+	"io"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+)
+
+const SchemaVersion = pipeline.ChunkPlanSchemaVersion
+
+type filesystemStore struct {
+	root  string
+	write func(string, []byte) error
+}
+
+func NewFilesystemStore(root string) (pipeline.ChunkPlanStore, error) {
+	root = strings.TrimSpace(root)
+	if root == "" {
+		return nil, fmt.Errorf("chunk plan root must not be empty")
+	}
+	if strings.ContainsRune(root, '\x00') {
+		return nil, fmt.Errorf("chunk plan root must not contain NUL")
+	}
+	return &filesystemStore{root: filepath.Clean(root), write: writeAtomic}, nil
+}
+
+func (s *filesystemStore) Load(sourceDigest string) (pipeline.ChunkPlanRecord, pipeline.ChunkPlanDecision, error) {
+	target, err := s.planPath(sourceDigest)
+	if err != nil {
+		return pipeline.ChunkPlanRecord{}, pipeline.ChunkPlanDecision{}, err
+	}
+	data, err := os.ReadFile(target)
+	if err != nil {
+		if os.IsNotExist(err) {
+			return pipeline.ChunkPlanRecord{}, pipeline.ChunkPlanDecision{Status: pipeline.ChunkPlanMissing, Reason: "chunk plan not found"}, nil
+		}
+		return pipeline.ChunkPlanRecord{}, pipeline.ChunkPlanDecision{}, fmt.Errorf("read chunk plan: %w", err)
+	}
+
+	var record pipeline.ChunkPlanRecord
+	decoder := json.NewDecoder(bytes.NewReader(data))
+	decoder.DisallowUnknownFields()
+	decoder.UseNumber()
+	if err := decoder.Decode(&record); err != nil {
+		return invalidDecision(fmt.Sprintf("decode stored chunk plan: %v", err))
+	}
+	var trailing any
+	if err := decoder.Decode(&trailing); err != io.EOF {
+		if err == nil {
+			return invalidDecision("stored chunk plan contains trailing JSON")
+		}
+		return invalidDecision(fmt.Sprintf("decode stored chunk plan trailer: %v", err))
+	}
+	if err := validateRecord(record, sourceDigest); err != nil {
+		return invalidDecision(err.Error())
+	}
+	return record, pipeline.ChunkPlanDecision{Status: pipeline.ChunkPlanHit, Reason: "stored chunk plan is valid"}, nil
+}
+
+func (s *filesystemStore) Save(record pipeline.ChunkPlanRecord) error {
+	if err := validateRecord(record, record.SourceDigest); err != nil {
+		return fmt.Errorf("validate chunk plan record: %w", err)
+	}
+	target, err := s.planPath(record.SourceDigest)
+	if err != nil {
+		return err
+	}
+	data, err := json.Marshal(record)
+	if err != nil {
+		return fmt.Errorf("encode chunk plan record: %w", err)
+	}
+	data = append(data, '\n')
+	writer := s.write
+	if writer == nil {
+		writer = writeAtomic
+	}
+	if err := writer(target, data); err != nil {
+		return fmt.Errorf("write chunk plan: %w", err)
+	}
+	return nil
+}
+
+func (s *filesystemStore) planPath(sourceDigest string) (string, error) {
+	if s == nil || strings.TrimSpace(s.root) == "" {
+		return "", fmt.Errorf("chunk plan store must not be nil")
+	}
+	hexDigest, err := digestPathSegment(sourceDigest)
+	if err != nil {
+		return "", err
+	}
+	return filepath.Join(s.root, hexDigest, "plan.json"), nil
+}
+
+func digestPathSegment(digest string) (string, error) {
+	if !strings.HasPrefix(digest, "sha256:") {
+		return "", fmt.Errorf("source digest must use sha256:<64 lowercase hex> format")
+	}
+	hexDigest := strings.TrimPrefix(digest, "sha256:")
+	if len(hexDigest) != 64 || strings.ToLower(hexDigest) != hexDigest {
+		return "", fmt.Errorf("source digest must use sha256:<64 lowercase hex> format")
+	}
+	decoded, err := hex.DecodeString(hexDigest)
+	if err != nil || len(decoded) != 32 {
+		return "", fmt.Errorf("source digest must use sha256:<64 lowercase hex> format")
+	}
+	return hexDigest, nil
+}
+
+func validateRecord(record pipeline.ChunkPlanRecord, requestedDigest string) error {
+	if record.SchemaVersion != SchemaVersion {
+		return fmt.Errorf("schema_version %q is not supported", record.SchemaVersion)
+	}
+	if _, err := digestPathSegment(requestedDigest); err != nil {
+		return err
+	}
+	if record.SourceDigest != requestedDigest {
+		return fmt.Errorf("source_digest does not match requested source")
+	}
+	if record.Plan.SourceDigest != record.SourceDigest {
+		return fmt.Errorf("plan source_digest does not match record source_digest")
+	}
+	if len(record.Plan.Ranges) == 0 {
+		return fmt.Errorf("plan ranges must not be empty")
+	}
+	if err := source.ValidateChunkAnnotations(record.Plan.Annotations); err != nil {
+		return fmt.Errorf("plan annotations: %w", err)
+	}
+	seenStarts := make(map[int]struct{}, len(record.Plan.Ranges))
+	for i, chunkRange := range record.Plan.Ranges {
+		if chunkRange.StartUnitID <= 0 || chunkRange.EndUnitID <= 0 {
+			return fmt.Errorf("plan range[%d] boundaries must be positive", i)
+		}
+		if _, exists := seenStarts[chunkRange.StartUnitID]; exists {
+			return fmt.Errorf("plan range[%d] duplicates start_unit_id %d", i, chunkRange.StartUnitID)
+		}
+		seenStarts[chunkRange.StartUnitID] = struct{}{}
+		if err := source.ValidateChunkAnnotations(chunkRange.Annotations); err != nil {
+			return fmt.Errorf("plan range[%d] annotations: %w", i, err)
+		}
+	}
+	wantDigest, err := source.DigestChunkPlan(record.Plan)
+	if err != nil {
+		return fmt.Errorf("digest plan: %w", err)
+	}
+	if record.PlanDigest != wantDigest {
+		return fmt.Errorf("plan_digest does not match plan")
+	}
+	if strings.TrimSpace(record.Producer.InputModule) == "" {
+		return fmt.Errorf("producer input_module must not be empty")
+	}
+	if strings.TrimSpace(record.Producer.ChunkModule) == "" {
+		return fmt.Errorf("producer chunk_module must not be empty")
+	}
+	if record.CreatedAt.IsZero() {
+		return fmt.Errorf("created_at must not be zero")
+	}
+	return nil
+}
+
+func invalidDecision(reason string) (pipeline.ChunkPlanRecord, pipeline.ChunkPlanDecision, error) {
+	return pipeline.ChunkPlanRecord{}, pipeline.ChunkPlanDecision{Status: pipeline.ChunkPlanInvalid, Reason: reason}, nil
+}
+
+type atomicWriteHooks struct {
+	BeforeCreateTemp func() error
+	BeforeRename     func() error
+}
+
+func writeAtomic(target string, data []byte) error {
+	return writeAtomicWithHooks(target, data, atomicWriteHooks{})
+}
+
+func writeAtomicWithHooks(target string, data []byte, hooks atomicWriteHooks) error {
+	dir := filepath.Dir(target)
+	if err := os.MkdirAll(dir, 0o700); err != nil {
+		return err
+	}
+	if err := os.Chmod(dir, 0o700); err != nil {
+		return err
+	}
+
+	if hooks.BeforeCreateTemp != nil {
+		if err := hooks.BeforeCreateTemp(); err != nil {
+			return err
+		}
+	}
+	temp, err := os.CreateTemp(dir, ".plan.json.tmp-*")
+	if err != nil {
+		return err
+	}
+	tempPath := temp.Name()
+	removeTemp := true
+	defer func() {
+		if removeTemp {
+			_ = os.Remove(tempPath)
+		}
+	}()
+	if err := temp.Chmod(0o600); err != nil {
+		_ = temp.Close()
+		return err
+	}
+	if _, err := temp.Write(data); err != nil {
+		_ = temp.Close()
+		return err
+	}
+	if err := temp.Sync(); err != nil {
+		_ = temp.Close()
+		return err
+	}
+	if err := temp.Close(); err != nil {
+		return err
+	}
+	if hooks.BeforeRename != nil {
+		if err := hooks.BeforeRename(); err != nil {
+			return err
+		}
+	}
+	if err := os.Rename(tempPath, target); err != nil {
+		return err
+	}
+	removeTemp = false
+	return nil
+}

internal/framework/chunkplan/store_test.go

@@ -0,0 +1,360 @@
+package chunkplan
+
+import (
+	"bytes"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"reflect"
+	"strings"
+	"sync"
+	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/artifacts"
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/pipeline"
+)
+
+const testSourceDigest = "sha256:aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"
+
+func TestFilesystemStoreRoundTripAndExactPath(t *testing.T) {
+	root := filepath.Join(t.TempDir(), "plans")
+	store := newStore(t, root)
+	record := testRecord(t, 1)
+	if err := store.Save(record); err != nil {
+		t.Fatalf("Save() error = %v", err)
+	}
+
+	target := filepath.Join(root, strings.TrimPrefix(testSourceDigest, "sha256:"), "plan.json")
+	data, err := os.ReadFile(target)
+	if err != nil {
+		t.Fatalf("read exact plan path: %v", err)
+	}
+	if bytes.Contains(data, []byte("RAW REFERENCE CONTENT")) {
+		t.Fatal("stored record contains raw reference content")
+	}
+	var envelope struct {
+		Producer struct {
+			References []map[string]any `json:"references"`
+		} `json:"producer"`
+	}
+	if err := json.Unmarshal(data, &envelope); err != nil {
+		t.Fatal(err)
+	}
+	if len(envelope.Producer.References) != 1 {
+		t.Fatalf("stored references = %#v", envelope.Producer.References)
+	}
+	if _, exists := envelope.Producer.References[0]["content"]; exists {
+		t.Fatalf("stored reference contains content field: %#v", envelope.Producer.References[0])
+	}
+
+	got, decision, err := store.Load(testSourceDigest)
+	if err != nil || decision.Status != pipeline.ChunkPlanHit {
+		t.Fatalf("Load() decision=%#v error=%v", decision, err)
+	}
+	if !reflect.DeepEqual(got, record) {
+		t.Fatalf("round trip record = %#v, want %#v", got, record)
+	}
+}
+
+func TestFilesystemStorePermissions(t *testing.T) {
+	root := filepath.Join(t.TempDir(), "plans")
+	store := newStore(t, root)
+	if err := store.Save(testRecord(t, 1)); err != nil {
+		t.Fatal(err)
+	}
+	digestDir := filepath.Join(root, strings.TrimPrefix(testSourceDigest, "sha256:"))
+	for path, want := range map[string]os.FileMode{
+		root:                                  0o700,
+		digestDir:                             0o700,
+		filepath.Join(digestDir, "plan.json"): 0o600,
+	} {
+		info, err := os.Stat(path)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if got := info.Mode().Perm(); got != want {
+			t.Fatalf("%s mode = %04o, want %04o", path, got, want)
+		}
+	}
+}
+
+func TestFilesystemStoreMissingAndOperationalErrors(t *testing.T) {
+	root := t.TempDir()
+	store := newStore(t, root)
+	_, decision, err := store.Load(testSourceDigest)
+	if err != nil || decision.Status != pipeline.ChunkPlanMissing {
+		t.Fatalf("missing decision=%#v error=%v", decision, err)
+	}
+
+	target := filepath.Join(root, strings.TrimPrefix(testSourceDigest, "sha256:"), "plan.json")
+	if err := os.MkdirAll(target, 0o700); err != nil {
+		t.Fatal(err)
+	}
+	if _, _, err := store.Load(testSourceDigest); err == nil {
+		t.Fatal("Load(plan.json directory) error = nil")
+	}
+}
+
+func TestFilesystemStoreRejectsMalformedSourceDigests(t *testing.T) {
+	store := newStore(t, t.TempDir())
+	for _, digest := range []string{"", "sha1:" + strings.Repeat("a", 64), "sha256:../escape", "sha256:" + strings.Repeat("A", 64), "sha256:" + strings.Repeat("a", 63)} {
+		t.Run(digest, func(t *testing.T) {
+			if _, _, err := store.Load(digest); err == nil {
+				t.Fatal("Load() error = nil")
+			}
+			record := testRecord(t, 1)
+			record.SourceDigest = digest
+			record.Plan.SourceDigest = digest
+			record.PlanDigest, _ = source.DigestChunkPlan(record.Plan)
+			if err := store.Save(record); err == nil {
+				t.Fatal("Save() error = nil")
+			}
+		})
+	}
+}
+
+func TestFilesystemStoreReportsInvalidRecordsAsRecoverable(t *testing.T) {
+	tests := []struct {
+		name   string
+		mutate func([]byte) []byte
+		want   string
+	}{
+		{name: "unknown field", mutate: func(data []byte) []byte {
+			return bytes.Replace(data, []byte(`{"schema_version"`), []byte(`{"unknown":true,"schema_version"`), 1)
+		}, want: "unknown"},
+		{name: "truncated JSON", mutate: func(data []byte) []byte { return data[:len(data)/2] }, want: "decode"},
+		{name: "schema mismatch", mutate: replaceJSON(`notarius.chunk-plan.v1`, `notarius.chunk-plan.v2`), want: "schema_version"},
+		{name: "source mismatch", mutate: replaceJSON(testSourceDigest, "sha256:"+strings.Repeat("b", 64)), want: "source_digest"},
+		{name: "plan digest mismatch", mutate: func(data []byte) []byte {
+			prefix := []byte(`"plan_digest":"sha256:`)
+			index := bytes.Index(data, prefix)
+			if index >= 0 {
+				data[index+len(prefix)] = '0'
+			}
+			return data
+		}, want: "plan_digest"},
+		{name: "noncanonical annotation", mutate: func(data []byte) []byte {
+			return bytes.Replace(data, []byte(`{"value":1}`), []byte(`{ "value": 1 }`), 1)
+		}, want: "canonical JSON"},
+		{name: "bad boundary", mutate: func(data []byte) []byte {
+			return bytes.Replace(data, []byte(`"start_unit_id":1`), []byte(`"start_unit_id":0`), 1)
+		}, want: "boundaries must be positive"},
+		{name: "trailing JSON", mutate: func(data []byte) []byte { return append(data, []byte(` {}`)...) }, want: "trailing"},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			root := t.TempDir()
+			store := newStore(t, root)
+			record := testRecord(t, 1)
+			if err := store.Save(record); err != nil {
+				t.Fatal(err)
+			}
+			path := filepath.Join(root, strings.TrimPrefix(testSourceDigest, "sha256:"), "plan.json")
+			data, err := os.ReadFile(path)
+			if err != nil {
+				t.Fatal(err)
+			}
+			if err := os.WriteFile(path, tc.mutate(data), 0o600); err != nil {
+				t.Fatal(err)
+			}
+			got, decision, err := store.Load(testSourceDigest)
+			if err != nil || decision.Status != pipeline.ChunkPlanInvalid || !reflect.DeepEqual(got, pipeline.ChunkPlanRecord{}) || !strings.Contains(decision.Reason, tc.want) {
+				t.Fatalf("record=%#v decision=%#v error=%v", got, decision, err)
+			}
+		})
+	}
+}
+
+func TestFilesystemStoreAtomicallyReplacesAndPreservesValidRecordOnFailure(t *testing.T) {
+	root := t.TempDir()
+	store := newStore(t, root)
+	first := testRecord(t, 1)
+	second := testRecord(t, 2)
+	if err := store.Save(first); err != nil {
+		t.Fatal(err)
+	}
+	invalid := second
+	invalid.PlanDigest = "sha256:" + strings.Repeat("0", 64)
+	if err := store.Save(invalid); err == nil {
+		t.Fatal("Save(invalid) error = nil")
+	}
+	got, _, _ := store.Load(testSourceDigest)
+	if !reflect.DeepEqual(got, first) {
+		t.Fatalf("record after failed replacement = %#v", got)
+	}
+	if err := store.Save(second); err != nil {
+		t.Fatal(err)
+	}
+	got, _, _ = store.Load(testSourceDigest)
+	if !reflect.DeepEqual(got, second) {
+		t.Fatalf("record after replacement = %#v", got)
+	}
+	assertNoTemps(t, filepath.Join(root, strings.TrimPrefix(testSourceDigest, "sha256:")))
+}
+
+func TestFilesystemStoreConcurrentWritersExposeCompleteRecord(t *testing.T) {
+	store := newStore(t, t.TempDir())
+	const writers = 24
+	records := make([]pipeline.ChunkPlanRecord, writers)
+	for i := range records {
+		records[i] = testRecord(t, i+1)
+	}
+	var wg sync.WaitGroup
+	errs := make(chan error, writers)
+	for i := range records {
+		wg.Add(1)
+		go func(record pipeline.ChunkPlanRecord) {
+			defer wg.Done()
+			errs <- store.Save(record)
+		}(records[i])
+	}
+	wg.Wait()
+	close(errs)
+	for err := range errs {
+		if err != nil {
+			t.Fatalf("concurrent Save() error = %v", err)
+		}
+	}
+	got, decision, err := store.Load(testSourceDigest)
+	if err != nil || decision.Status != pipeline.ChunkPlanHit {
+		t.Fatalf("Load() decision=%#v error=%v", decision, err)
+	}
+	var annotation struct {
+		Value int `json:"value"`
+	}
+	if err := json.Unmarshal(got.Plan.Annotations["test/value"], &annotation); err != nil || annotation.Value < 1 || annotation.Value > writers {
+		t.Fatalf("final annotation=%#v error=%v", annotation, err)
+	}
+}
+
+func TestFilesystemStoreReadersObserveOnlyCompleteRecordsDuringWrites(t *testing.T) {
+	store := newStore(t, t.TempDir())
+	if err := store.Save(testRecord(t, 1)); err != nil {
+		t.Fatal(err)
+	}
+	const writers = 12
+	const readers = 12
+	errs := make(chan error, writers+readers)
+	start := make(chan struct{})
+	var writersDone sync.WaitGroup
+	for i := 0; i < writers; i++ {
+		writersDone.Add(1)
+		go func(value int) {
+			defer writersDone.Done()
+			<-start
+			errs <- store.Save(testRecord(t, value+2))
+		}(i)
+	}
+	for i := 0; i < readers; i++ {
+		go func() {
+			<-start
+			for attempt := 0; attempt < 50; attempt++ {
+				record, decision, err := store.Load(testSourceDigest)
+				if err != nil || decision.Status != pipeline.ChunkPlanHit {
+					errs <- fmt.Errorf("Load() decision=%#v error=%v", decision, err)
+					return
+				}
+				if err := validateRecord(record, testSourceDigest); err != nil {
+					errs <- fmt.Errorf("reader observed invalid record: %w", err)
+					return
+				}
+			}
+			errs <- nil
+		}()
+	}
+	close(start)
+	writersDone.Wait()
+	for i := 0; i < readers+writers; i++ {
+		if err := <-errs; err != nil {
+			t.Fatal(err)
+		}
+	}
+}
+
+func TestFilesystemStoreInterruptedWritesPreservePreviousRecord(t *testing.T) {
+	store := newStore(t, t.TempDir()).(*filesystemStore)
+	first := testRecord(t, 1)
+	if err := store.Save(first); err != nil {
+		t.Fatal(err)
+	}
+	for _, tc := range []struct {
+		name  string
+		hooks atomicWriteHooks
+	}{
+		{name: "before temporary file", hooks: atomicWriteHooks{BeforeCreateTemp: func() error { return errors.New("interrupted before temporary file") }}},
+		{name: "before rename", hooks: atomicWriteHooks{BeforeRename: func() error { return errors.New("interrupted before rename") }}},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			store.write = func(target string, data []byte) error { return writeAtomicWithHooks(target, data, tc.hooks) }
+			if err := store.Save(testRecord(t, 2)); err == nil {
+				t.Fatal("Save() error = nil")
+			}
+			store.write = writeAtomic
+			got, decision, err := store.Load(testSourceDigest)
+			if err != nil || decision.Status != pipeline.ChunkPlanHit || !reflect.DeepEqual(got, first) {
+				t.Fatalf("record after interruption=%#v decision=%#v error=%v", got, decision, err)
+			}
+		})
+	}
+}
+
+func newStore(t *testing.T, root string) pipeline.ChunkPlanStore {
+	t.Helper()
+	store, err := NewFilesystemStore(root)
+	if err != nil {
+		t.Fatalf("NewFilesystemStore() error = %v", err)
+	}
+	return store
+}
+
+func testRecord(t *testing.T, value int) pipeline.ChunkPlanRecord {
+	t.Helper()
+	annotation, err := json.Marshal(map[string]int{"value": value})
+	if err != nil {
+		t.Fatal(err)
+	}
+	plan := source.ChunkPlan{
+		SourceDigest: testSourceDigest,
+		Ranges:       []source.ChunkRange{{StartUnitID: 1, EndUnitID: 2, Annotations: source.ChunkAnnotations{"test/range": json.RawMessage(`{"range":true}`)}}},
+		Annotations:  source.ChunkAnnotations{"test/value": annotation},
+	}
+	planDigest, err := source.DigestChunkPlan(plan)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return pipeline.ChunkPlanRecord{
+		SchemaVersion: SchemaVersion,
+		SourceDigest:  testSourceDigest,
+		PlanDigest:    planDigest,
+		Plan:          plan,
+		Producer: pipeline.ChunkPlanProducer{
+			InputModule: "input/test", ChunkModule: "chunk/test", LLMProfile: "profile/test",
+			References: []artifacts.ReferenceProvenance{{Stage: "chunk", SlotName: "guide", OriginType: "file", OriginURI: "file:///guide.txt", Digest: "sha256:reference"}},
+			Metadata:   map[string]any{"prompt_id": "test/prompt", "enabled": true},
+		},
+		Warnings:  []contracts.Warning{{Scope: "chunk/test", ReasonCode: "observed", Message: "warning"}},
+		CreatedAt: time.Date(2026, 7, 18, 12, 0, 0, 0, time.UTC),
+	}
+}
+
+func replaceJSON(old, replacement string) func([]byte) []byte {
+	return func(data []byte) []byte { return bytes.Replace(data, []byte(old), []byte(replacement), 1) }
+}
+
+func assertNoTemps(t *testing.T, dir string) {
+	t.Helper()
+	entries, err := os.ReadDir(dir)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, entry := range entries {
+		if strings.Contains(entry.Name(), ".tmp-") {
+			t.Fatalf("temporary file remains: %s", entry.Name())
+		}
+	}
+}

internal/framework/contracts/contracts.go

@@ -146,15 +146,15 @@ type ChunkRequest struct {
 	Metadata    map[string]any         `json:"metadata,omitempty"`
 }
 
-type ChunkResult struct {
-	Chunks   []source.Chunk `json:"chunks"`
-	Warnings []Warning      `json:"warnings,omitempty"`
+type ChunkPlanResult struct {
+	Plan     source.ChunkPlan `json:"plan"`
+	Warnings []Warning        `json:"warnings,omitempty"`
 }
 
 type Chunker interface {
 	Key() string
 	ReferenceSlots() []ReferenceSlot
-	Chunk(ctx context.Context, req ChunkRequest) (ChunkResult, error)
+	Plan(ctx context.Context, req ChunkRequest) (ChunkPlanResult, error)
 }
 
 const (
@@ -214,6 +214,10 @@ const (
 	ExecutionClassLLMBacked     ExecutionClass = "llm_backed"
 )
 
+type ChunkExecutionClassProvider interface {
+	ExecutionClass() ExecutionClass
+}
+
 type ValidationResult struct {
 	Approved               bool      `json:"approved"`
 	ReasonCode             string    `json:"reason_code,omitempty"`

internal/framework/contracts/contracts_test.go

@@ -45,7 +45,7 @@ func TestFakeExtractorReturnsTypedOutput(t *testing.T) {
 	}
 }
 
-func TestFakeChunkerReturnsSourceChunks(t *testing.T) {
+func TestFakeChunkerReturnsSourcePlan(t *testing.T) {
 	doc := &source.SourceDocument{
 		ID:     "source-1",
 		Kind:   "document",
@@ -57,36 +57,19 @@ func TestFakeChunkerReturnsSourceChunks(t *testing.T) {
 	}
 	chunker := fakeChunker{key: "generic-chunker"}
 
-	result, err := chunker.Chunk(context.Background(), ChunkRequest{Source: doc})
+	result, err := chunker.Plan(context.Background(), ChunkRequest{Source: doc})
 	if err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
 
 	if chunker.Key() != "generic-chunker" {
 		t.Fatalf("Key() = %q, want generic-chunker", chunker.Key())
 	}
-	if len(result.Chunks) != 1 {
-		t.Fatalf("len(Chunks) = %d, want 1", len(result.Chunks))
+	if len(result.Plan.Ranges) != 1 {
+		t.Fatalf("len(Ranges) = %d, want 1", len(result.Plan.Ranges))
 	}
-
-	chunk := result.Chunks[0]
-	if chunk.ID != "source-1:chunk:0" {
-		t.Fatalf("source.Chunk.ID = %q, want source-1:chunk:0", chunk.ID)
-	}
-	if chunk.SourceID != doc.ID {
-		t.Fatalf("source.Chunk.SourceID = %q, want %q", chunk.SourceID, doc.ID)
-	}
-	if chunk.Index != 0 {
-		t.Fatalf("source.Chunk.Index = %d, want 0", chunk.Index)
-	}
-	if chunk.Ref.StartUnitID != 1 || chunk.Ref.EndUnitID != 1 {
-		t.Fatalf("source.Chunk.Ref = %#v, want source-1:1-1", chunk.Ref)
-	}
-	if chunk.MediaType != "application/json" || string(chunk.Content) != `{"units":[{"id":1,"kind":"section","text":"Source text."}]}` {
-		t.Fatalf("source.Chunk payload = %q %s, want JSON units", chunk.MediaType, chunk.Content)
-	}
-	if len(chunk.Units) != 1 {
-		t.Fatalf("len(source.Chunk.Units) = %d, want 1", len(chunk.Units))
+	if result.Plan.SourceDigest != doc.Digest || result.Plan.Ranges[0].StartUnitID != 1 || result.Plan.Ranges[0].EndUnitID != 1 {
+		t.Fatalf("Plan = %#v, want source digest and unit range", result.Plan)
 	}
 }
 
@@ -102,8 +85,8 @@ func TestFakeChunkerReceivesPerRunContext(t *testing.T) {
 	}
 	chunker := &recordingChunker{key: "llm-chunker"}
 
-	if _, err := chunker.Chunk(context.Background(), ChunkRequest{Source: doc, SessionID: "session", LLMProfile: "profile"}); err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+	if _, err := chunker.Plan(context.Background(), ChunkRequest{Source: doc, SessionID: "session", LLMProfile: "profile"}); err != nil {
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
 	if chunker.request.SessionID != "session" || chunker.request.LLMProfile != "profile" {
 		t.Fatalf("ChunkRequest = %#v, want per-run session and profile", chunker.request)
@@ -446,22 +429,14 @@ func (chunker fakeChunker) ReferenceSlots() []ReferenceSlot {
 	return nil
 }
 
-func (chunker fakeChunker) Chunk(ctx context.Context, req ChunkRequest) (ChunkResult, error) {
-	return ChunkResult{
-		Chunks: []source.Chunk{
-			{
-				ID:       req.Source.ID + ":chunk:0",
-				SourceID: req.Source.ID,
-				Index:    0,
-				Ref: source.SourceRef{
-					SourceID:    req.Source.ID,
-					StartUnitID: req.Source.Units[0].ID,
-					EndUnitID:   req.Source.Units[len(req.Source.Units)-1].ID,
-				},
-				Content:   []byte(`{"units":[{"id":1,"kind":"section","text":"Source text."}]}`),
-				MediaType: "application/json",
-				Units:     append([]source.SourceUnit(nil), req.Source.Units...),
-			},
+func (chunker fakeChunker) Plan(ctx context.Context, req ChunkRequest) (ChunkPlanResult, error) {
+	return ChunkPlanResult{
+		Plan: source.ChunkPlan{
+			SourceDigest: req.Source.Digest,
+			Ranges: []source.ChunkRange{{
+				StartUnitID: req.Source.Units[0].ID,
+				EndUnitID:   req.Source.Units[len(req.Source.Units)-1].ID,
+			}},
 		},
 	}, nil
 }
@@ -479,9 +454,9 @@ func (chunker *recordingChunker) ReferenceSlots() []ReferenceSlot {
 	return nil
 }
 
-func (chunker *recordingChunker) Chunk(ctx context.Context, req ChunkRequest) (ChunkResult, error) {
+func (chunker *recordingChunker) Plan(ctx context.Context, req ChunkRequest) (ChunkPlanResult, error) {
 	chunker.request = req
-	return fakeChunker{key: chunker.key}.Chunk(ctx, req)
+	return fakeChunker{key: chunker.key}.Plan(ctx, req)
 }
 
 type fakeExtractor struct {

internal/framework/pipeline/checkpoint.go

@@ -20,10 +20,6 @@ type CheckpointRecorder interface {
 	SourceRunning(moduleKey string) error
 	SourceSucceeded(moduleKey string, doc *source.SourceDocument) error
 	SourceFailed(moduleKey string, err error) error
-	ChunkRunning(moduleKey string, sourceDigest string) error
-	ChunkSucceeded(moduleKey string, sourceDigest string, chunks []source.Chunk, warnings []contracts.Warning) error
-	ChunkRejected(moduleKey string, sourceDigest string, rejected contracts.RejectedOutput) error
-	ChunkFailed(moduleKey string, sourceDigest string, err error) error
 	ExtractRunning(laneID string, moduleKey string, dependencies []CheckpointFingerprint) error
 	ExtractSucceeded(laneID string, moduleKey string, dependencies []CheckpointFingerprint, outputs []CheckpointArtifact, rejected []contracts.RejectedOutput, warnings []contracts.Warning) error
 	ExtractFailed(laneID string, moduleKey string, dependencies []CheckpointFingerprint, err error) error
@@ -54,11 +50,6 @@ type SourceCheckpoint struct {
 	Document *source.SourceDocument
 }
 
-type ChunkCheckpoint struct {
-	Chunks   []source.Chunk
-	Warnings []contracts.Warning
-}
-
 // CheckpointArtifact is the durable, domain-neutral value stored at a lane
 // checkpoint boundary.
 type CheckpointArtifact struct {
@@ -90,7 +81,6 @@ type NormalizeCheckpoint struct {
 type CheckpointLoader interface {
 	Enabled() bool
 	Source(moduleKey string) (SourceCheckpoint, CheckpointDecision)
-	Chunk(moduleKey string, sourceDigest string) (ChunkCheckpoint, CheckpointDecision)
 	Extract(laneID string, moduleKey string, dependencies []CheckpointFingerprint) (ExtractCheckpoint, CheckpointDecision)
 	Merge(laneID string, moduleKey string, dependencies []CheckpointFingerprint) (MergeCheckpoint, CheckpointDecision)
 	Normalize(laneID string, moduleKey string, dependencies []CheckpointFingerprint) (NormalizeCheckpoint, CheckpointDecision)
@@ -105,14 +95,6 @@ func NoopCheckpointLoader() CheckpointLoader     { return noopCheckpointLoader{}
 func (noopCheckpointRecorder) SourceRunning(string) error                           { return nil }
 func (noopCheckpointRecorder) SourceSucceeded(string, *source.SourceDocument) error { return nil }
 func (noopCheckpointRecorder) SourceFailed(string, error) error                     { return nil }
-func (noopCheckpointRecorder) ChunkRunning(string, string) error                    { return nil }
-func (noopCheckpointRecorder) ChunkSucceeded(string, string, []source.Chunk, []contracts.Warning) error {
-	return nil
-}
-func (noopCheckpointRecorder) ChunkRejected(string, string, contracts.RejectedOutput) error {
-	return nil
-}
-func (noopCheckpointRecorder) ChunkFailed(string, string, error) error { return nil }
 func (noopCheckpointRecorder) ExtractRunning(string, string, []CheckpointFingerprint) error {
 	return nil
 }
@@ -149,9 +131,6 @@ func (noopCheckpointLoader) Enabled() bool { return false }
 func (noopCheckpointLoader) Source(string) (SourceCheckpoint, CheckpointDecision) {
 	return SourceCheckpoint{}, CheckpointDecision{Reason: "checkpoint loading disabled"}
 }
-func (noopCheckpointLoader) Chunk(string, string) (ChunkCheckpoint, CheckpointDecision) {
-	return ChunkCheckpoint{}, CheckpointDecision{Reason: "checkpoint loading disabled"}
-}
 func (noopCheckpointLoader) Extract(string, string, []CheckpointFingerprint) (ExtractCheckpoint, CheckpointDecision) {
 	return ExtractCheckpoint{}, CheckpointDecision{Reason: "checkpoint loading disabled"}
 }

internal/framework/pipeline/chunk_annotations_test.go

@@ -0,0 +1,72 @@
+package pipeline
+
+import (
+	"encoding/json"
+	"strings"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+)
+
+func TestChunkCanonicalizationAndClonePreserveAnnotationScopes(t *testing.T) {
+	doc := validSourceDocument()
+	plan := source.ChunkPlan{
+		SourceDigest: doc.Digest,
+		Ranges: []source.ChunkRange{{
+			StartUnitID: doc.Units[0].ID, EndUnitID: doc.Units[0].ID,
+			Annotations: source.ChunkAnnotations{"shared": json.RawMessage(` {"range": true} `)},
+		}},
+		Annotations: source.ChunkAnnotations{"shared": json.RawMessage(` {"plan": true} `)},
+	}
+	canonical, chunks, err := validateAndMaterializeChunkPlan(doc, plan)
+	if err != nil {
+		t.Fatalf("validateAndMaterializeChunkPlan() error = %v", err)
+	}
+	if got := string(canonical.Ranges[0].Annotations["shared"]); got != `{"range":true}` {
+		t.Fatalf("range annotation = %q", got)
+	}
+	if got := string(canonical.Annotations["shared"]); got != `{"plan":true}` {
+		t.Fatalf("plan annotation = %q", got)
+	}
+
+	cloned := cloneSourceChunk(chunks[0])
+	cloned.Annotations["shared"][0] = '['
+	cloned.PlanAnnotations["shared"][0] = '['
+	if string(chunks[0].Annotations["shared"]) != `{"range":true}` || string(chunks[0].PlanAnnotations["shared"]) != `{"plan":true}` {
+		t.Fatal("cloneSourceChunk() shares annotation bytes")
+	}
+}
+
+func TestSerializedChunkValidationRepresentationIncludesAnnotationScopes(t *testing.T) {
+	doc := validSourceDocument()
+	chunks := []source.Chunk{{
+		ID: "chunk-1", SourceID: doc.ID, Ref: doc.Units[0].Ref, MediaType: "application/json", Units: doc.Units[:1],
+		Annotations:     source.ChunkAnnotations{"same": json.RawMessage(`{"range":1}`)},
+		PlanAnnotations: source.ChunkAnnotations{"same": json.RawMessage(`{"plan":2}`)},
+	}}
+	encoded, err := json.Marshal(chunks)
+	if err != nil {
+		t.Fatalf("json.Marshal(chunks) error = %v", err)
+	}
+	got := string(encoded)
+	if !strings.Contains(got, `"annotations":{"same":{"range":1}}`) || !strings.Contains(got, `"plan_annotations":{"same":{"plan":2}}`) {
+		t.Fatalf("serialized chunks = %s, want both annotation scopes", got)
+	}
+}
+
+func TestDebugChunkEnvelopeClonesAnnotationScopes(t *testing.T) {
+	chunk := source.Chunk{
+		ID: "chunk-1", SourceID: "source-1",
+		Annotations:     source.ChunkAnnotations{"same": json.RawMessage(`{"range":1}`)},
+		PlanAnnotations: source.ChunkAnnotations{"same": json.RawMessage(`{"plan":2}`)},
+	}
+	envelope := debugSourceChunkEnvelope(chunk)
+	if string(envelope.Annotations["same"]) != `{"range":1}` || string(envelope.PlanAnnotations["same"]) != `{"plan":2}` {
+		t.Fatalf("debug annotations = %#v / %#v", envelope.Annotations, envelope.PlanAnnotations)
+	}
+	envelope.Annotations["same"][0] = '['
+	envelope.PlanAnnotations["same"][0] = '['
+	if string(chunk.Annotations["same"]) != `{"range":1}` || string(chunk.PlanAnnotations["same"]) != `{"plan":2}` {
+		t.Fatal("debugSourceChunkEnvelope() shares annotation bytes")
+	}
+}

internal/framework/pipeline/chunk_cache.go

@@ -0,0 +1,29 @@
+package pipeline
+
+import (
+	"fmt"
+	"strings"
+)
+
+type ChunkCacheMode string
+
+const (
+	ChunkCacheAuto    ChunkCacheMode = "auto"
+	ChunkCacheBypass  ChunkCacheMode = "bypass"
+	ChunkCacheRefresh ChunkCacheMode = "refresh"
+)
+
+func ParseChunkCacheMode(raw string) (ChunkCacheMode, error) {
+	mode := ChunkCacheMode(strings.TrimSpace(raw))
+	switch mode {
+	case ChunkCacheAuto, ChunkCacheBypass, ChunkCacheRefresh:
+		return mode, nil
+	default:
+		return "", fmt.Errorf("chunk cache mode %q is not supported", strings.TrimSpace(raw))
+	}
+}
+
+func (m ChunkCacheMode) Validate() error {
+	_, err := ParseChunkCacheMode(string(m))
+	return err
+}

internal/framework/pipeline/chunk_cache_test.go

@@ -0,0 +1,20 @@
+package pipeline
+
+import "testing"
+
+func TestParseChunkCacheMode(t *testing.T) {
+	for _, value := range []ChunkCacheMode{ChunkCacheAuto, ChunkCacheBypass, ChunkCacheRefresh} {
+		got, err := ParseChunkCacheMode(string(value))
+		if err != nil || got != value {
+			t.Fatalf("ParseChunkCacheMode(%q) = %q, %v", value, got, err)
+		}
+		if err := value.Validate(); err != nil {
+			t.Fatalf("%q.Validate() error = %v", value, err)
+		}
+	}
+	for _, value := range []string{"", "enabled", "AUTO", "auto,refresh"} {
+		if _, err := ParseChunkCacheMode(value); err == nil {
+			t.Fatalf("ParseChunkCacheMode(%q) error = nil, want error", value)
+		}
+	}
+}

internal/framework/pipeline/chunk_plan_store.go

@@ -0,0 +1,49 @@
+package pipeline
+
+import (
+	"time"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/artifacts"
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+)
+
+const ChunkPlanSchemaVersion = "notarius.chunk-plan.v1"
+
+type ChunkPlanProducer struct {
+	InputModule string                          `json:"input_module"`
+	ChunkModule string                          `json:"chunk_module"`
+	LLMProfile  string                          `json:"llm_profile,omitempty"`
+	References  []artifacts.ReferenceProvenance `json:"references,omitempty"`
+	Metadata    map[string]any                  `json:"metadata,omitempty"`
+}
+
+type ChunkPlanRecord struct {
+	SchemaVersion string              `json:"schema_version"`
+	SourceDigest  string              `json:"source_digest"`
+	PlanDigest    string              `json:"plan_digest"`
+	Plan          source.ChunkPlan    `json:"plan"`
+	Producer      ChunkPlanProducer   `json:"producer"`
+	Warnings      []contracts.Warning `json:"warnings,omitempty"`
+	CreatedAt     time.Time           `json:"created_at"`
+}
+
+type ChunkPlanStore interface {
+	Load(sourceDigest string) (ChunkPlanRecord, ChunkPlanDecision, error)
+	Save(ChunkPlanRecord) error
+}
+
+type ChunkPlanStoreFactory func(root string) (ChunkPlanStore, error)
+
+type ChunkPlanDecision struct {
+	Status ChunkPlanStatus `json:"status"`
+	Reason string          `json:"reason,omitempty"`
+}
+
+type ChunkPlanStatus string
+
+const (
+	ChunkPlanHit     ChunkPlanStatus = "hit"
+	ChunkPlanMissing ChunkPlanStatus = "missing"
+	ChunkPlanInvalid ChunkPlanStatus = "invalid"
+)

internal/framework/pipeline/chunk_validation.go

@@ -2,100 +2,23 @@ package pipeline
 
 import (
 	"fmt"
-	"strings"
 
 	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
 )
 
-func validateAndCanonicalizeChunkResult(doc *source.SourceDocument, chunks []source.Chunk) ([]source.Chunk, error) {
-	if len(chunks) == 0 {
-		return nil, fmt.Errorf("chunks must not be empty")
+func validateAndMaterializeChunkPlan(doc *source.SourceDocument, plan source.ChunkPlan) (source.ChunkPlan, []source.Chunk, error) {
+	canonical, err := source.CanonicalizeChunkPlan(plan)
+	if err != nil {
+		return source.ChunkPlan{}, nil, fmt.Errorf("canonicalize chunk plan: %w", err)
 	}
-
-	sourceUnitIndexes := make(map[int]int, len(doc.Units))
-	sourceUnits := make(map[int]source.SourceUnit, len(doc.Units))
-	for index, unit := range doc.Units {
-		sourceUnitIndexes[unit.ID] = index
-		sourceUnits[unit.ID] = unit
+	if err := source.ValidateChunkPlan(doc, canonical); err != nil {
+		return source.ChunkPlan{}, nil, err
 	}
-
-	canonicalChunks := make([]source.Chunk, 0, len(chunks))
-	seenChunkIDs := make(map[string]struct{}, len(chunks))
-	for chunkIndex, chunk := range chunks {
-		if strings.TrimSpace(chunk.ID) == "" {
-			return nil, fmt.Errorf("chunk[%d].id must not be empty", chunkIndex)
-		}
-		if _, ok := seenChunkIDs[chunk.ID]; ok {
-			return nil, fmt.Errorf("chunk id %q is duplicated", chunk.ID)
-		}
-		seenChunkIDs[chunk.ID] = struct{}{}
-
-		if chunk.SourceID != doc.ID {
-			return nil, fmt.Errorf("chunk %q source_id %q does not match source document id %q", chunk.ID, chunk.SourceID, doc.ID)
-		}
-		if chunk.Index != chunkIndex {
-			return nil, fmt.Errorf("chunk %q index %d does not match returned order %d", chunk.ID, chunk.Index, chunkIndex)
-		}
-		if len(chunk.Units) == 0 {
-			return nil, fmt.Errorf("chunk %q units must not be empty", chunk.ID)
-		}
-		if len(chunk.Content) == 0 {
-			return nil, fmt.Errorf("chunk %q content must not be empty", chunk.ID)
-		}
-		if strings.TrimSpace(chunk.MediaType) == "" {
-			return nil, fmt.Errorf("chunk %q media_type must not be empty", chunk.ID)
-		}
-		if err := source.ValidateRef(doc, chunk.Ref); err != nil {
-			return nil, fmt.Errorf("chunk %q ref: %w", chunk.ID, err)
-		}
-
-		seenUnitIDs := make(map[int]struct{}, len(chunk.Units))
-		previousSourceIndex := -1
-		canonicalUnits := make([]source.SourceUnit, 0, len(chunk.Units))
-		for unitIndex, unit := range chunk.Units {
-			if unit.ID <= 0 {
-				return nil, fmt.Errorf("chunk %q unit[%d].id must be positive", chunk.ID, unitIndex)
-			}
-			if _, ok := seenUnitIDs[unit.ID]; ok {
-				return nil, fmt.Errorf("chunk %q repeats source unit %d", chunk.ID, unit.ID)
-			}
-			seenUnitIDs[unit.ID] = struct{}{}
-
-			sourceIndex, ok := sourceUnitIndexes[unit.ID]
-			if !ok {
-				return nil, fmt.Errorf("chunk %q source unit %d was not found in source document %q", chunk.ID, unit.ID, doc.ID)
-			}
-			if previousSourceIndex >= 0 && sourceIndex != previousSourceIndex+1 {
-				return nil, fmt.Errorf("chunk %q source units must form a contiguous range in source document order", chunk.ID)
-			}
-			if unit.Ref != sourceUnits[unit.ID].Ref {
-				return nil, fmt.Errorf("chunk %q source unit %d ref does not match source document", chunk.ID, unit.ID)
-			}
-			previousSourceIndex = sourceIndex
-			canonicalUnits = append(canonicalUnits, cloneSourceUnit(sourceUnits[unit.ID]))
-		}
-		expectedRef := source.SourceRef{
-			SourceID:    doc.ID,
-			StartUnitID: canonicalUnits[0].Ref.StartUnitID,
-			EndUnitID:   canonicalUnits[len(canonicalUnits)-1].Ref.EndUnitID,
-		}
-		if chunk.Ref != expectedRef {
-			return nil, fmt.Errorf("chunk %q ref %#v does not match unit span %#v", chunk.ID, chunk.Ref, expectedRef)
-		}
-
-		canonicalChunks = append(canonicalChunks, source.Chunk{
-			ID:        chunk.ID,
-			SourceID:  chunk.SourceID,
-			Index:     chunk.Index,
-			Ref:       expectedRef,
-			Content:   append([]byte(nil), chunk.Content...),
-			MediaType: chunk.MediaType,
-			Units:     canonicalUnits,
-			Metadata:  cloneMetadata(chunk.Metadata),
-		})
+	chunks, err := source.MaterializeChunkPlan(doc, canonical)
+	if err != nil {
+		return source.ChunkPlan{}, nil, err
 	}
-
-	return canonicalChunks, nil
+	return canonical, chunks, nil
 }
 
 func cloneSourceUnit(unit source.SourceUnit) source.SourceUnit {

internal/framework/pipeline/chunker_registry_test.go

@@ -334,8 +334,8 @@ func (chunker registryChunker) ReferenceSlots() []contracts.ReferenceSlot {
 	return nil
 }
 
-func (chunker registryChunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkResult, error) {
-	return contracts.ChunkResult{}, nil
+func (chunker registryChunker) Plan(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	return contracts.ChunkPlanResult{}, nil
 }
 
 type registryOutputEncoder struct {

internal/framework/pipeline/debug.go

@@ -100,13 +100,27 @@ type debugSourceDocument struct {
 }
 
 type debugSourceChunk struct {
-	ID       string              `json:"id"`
-	SourceID string              `json:"source_id"`
-	Index    int                 `json:"index"`
-	Ref      source.SourceRef    `json:"ref"`
-	Content  debugBinaryEnvelope `json:"content"`
-	Units    []source.SourceUnit `json:"units,omitempty"`
-	Metadata map[string]any      `json:"metadata,omitempty"`
+	ID              string                  `json:"id"`
+	SourceID        string                  `json:"source_id"`
+	Index           int                     `json:"index"`
+	Ref             source.SourceRef        `json:"ref"`
+	Content         debugBinaryEnvelope     `json:"content"`
+	Units           []source.SourceUnit     `json:"units,omitempty"`
+	Metadata        map[string]any          `json:"metadata,omitempty"`
+	Annotations     source.ChunkAnnotations `json:"annotations,omitempty"`
+	PlanAnnotations source.ChunkAnnotations `json:"plan_annotations,omitempty"`
+}
+
+type debugChunkPlan struct {
+	SourceDigest string            `json:"source_digest,omitempty"`
+	Ranges       []debugChunkRange `json:"ranges,omitempty"`
+	Annotations  map[string]any    `json:"annotations,omitempty"`
+}
+
+type debugChunkRange struct {
+	StartUnitID int            `json:"start_unit_id"`
+	EndUnitID   int            `json:"end_unit_id"`
+	Annotations map[string]any `json:"annotations,omitempty"`
 }
 
 type debugSerializedOutput struct {
@@ -464,13 +478,15 @@ func debugSourceDocumentEnvelope(doc *source.SourceDocument) *debugSourceDocumen
 
 func debugSourceChunkEnvelope(chunk source.Chunk) debugSourceChunk {
 	return debugSourceChunk{
-		ID:       chunk.ID,
-		SourceID: chunk.SourceID,
-		Index:    chunk.Index,
-		Ref:      chunk.Ref,
-		Content:  debugContentEnvelope(chunk.Content, chunk.MediaType, chunk.Metadata, nil),
-		Units:    cloneSourceUnits(chunk.Units),
-		Metadata: redactSensitiveMap(chunk.Metadata),
+		ID:              chunk.ID,
+		SourceID:        chunk.SourceID,
+		Index:           chunk.Index,
+		Ref:             chunk.Ref,
+		Content:         debugContentEnvelope(chunk.Content, chunk.MediaType, chunk.Metadata, nil),
+		Units:           cloneSourceUnits(chunk.Units),
+		Metadata:        redactSensitiveMap(chunk.Metadata),
+		Annotations:     source.CloneChunkAnnotations(chunk.Annotations),
+		PlanAnnotations: source.CloneChunkAnnotations(chunk.PlanAnnotations),
 	}
 }
 
@@ -485,6 +501,37 @@ func debugSourceChunkEnvelopes(chunks []source.Chunk) []debugSourceChunk {
 	return out
 }
 
+func debugChunkPlanEnvelope(plan source.ChunkPlan) debugChunkPlan {
+	envelope := debugChunkPlan{
+		SourceDigest: plan.SourceDigest,
+		Ranges:       make([]debugChunkRange, len(plan.Ranges)),
+		Annotations:  debugChunkAnnotations(plan.Annotations),
+	}
+	for i, chunkRange := range plan.Ranges {
+		envelope.Ranges[i] = debugChunkRange{
+			StartUnitID: chunkRange.StartUnitID,
+			EndUnitID:   chunkRange.EndUnitID,
+			Annotations: debugChunkAnnotations(chunkRange.Annotations),
+		}
+	}
+	return envelope
+}
+
+func debugChunkAnnotations(annotations source.ChunkAnnotations) map[string]any {
+	if len(annotations) == 0 {
+		return nil
+	}
+	out := make(map[string]any, len(annotations))
+	for namespace, raw := range annotations {
+		if json.Valid(raw) {
+			out[namespace] = append(json.RawMessage(nil), raw...)
+		} else {
+			out[namespace] = string(raw)
+		}
+	}
+	return out
+}
+
 func debugSerializedOutputEnvelope(output contracts.SerializedOutput) debugSerializedOutput {
 	schema := contracts.CloneArtifactSchema(output.Artifact.Schema)
 	digest := contracts.DigestArtifactSchema(schema)

internal/framework/pipeline/runner.go

@@ -38,19 +38,21 @@ func New() *Runner {
 }
 
 type RunInput struct {
-	Prepared    *PreparedPipeline
-	SourceID    string
-	Path        string
-	RawInput    []byte
-	SessionID   string
-	RunID       string
-	StartedAt   time.Time
-	LLMProfiles []artifacts.LLMProfileManifest
-	Metadata    map[string]any
-	Warnings    []contracts.Warning
-	Checkpoints CheckpointRecorder
-	Checkpoint  CheckpointLoader
-	Debug       DebugRecorder
+	Prepared       *PreparedPipeline
+	SourceID       string
+	Path           string
+	RawInput       []byte
+	SessionID      string
+	RunID          string
+	StartedAt      time.Time
+	LLMProfiles    []artifacts.LLMProfileManifest
+	Metadata       map[string]any
+	Warnings       []contracts.Warning
+	ChunkCacheMode ChunkCacheMode
+	ChunkPlans     ChunkPlanStore
+	Checkpoints    CheckpointRecorder
+	Checkpoint     CheckpointLoader
+	Debug          DebugRecorder
 	// ExtractWorkers bounds run-wide extract jobs. Values less than one use a
 	// single worker so direct framework callers retain deterministic behavior.
 	ExtractWorkers int
@@ -61,6 +63,7 @@ type RunInput struct {
 
 type RunOutput struct {
 	Manifest         artifacts.RunManifest        `json:"manifest"`
+	ChunkPlan        *artifacts.ChunkPlanSummary  `json:"chunk_plan,omitempty"`
 	NormalizeOutputs []contracts.SerializedOutput `json:"normalize_outputs,omitempty"`
 	Rejected         []contracts.RejectedOutput   `json:"rejected,omitempty"`
 	Warnings         []contracts.Warning          `json:"warnings,omitempty"`
@@ -79,6 +82,11 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 	input.llmClient = input.Prepared.dependencies.LLM
 
 	output.Manifest = manifestFromPipeline(input)
+	output.ChunkPlan = &artifacts.ChunkPlanSummary{
+		Mode: string(effectiveChunkCacheMode(input.ChunkCacheMode)), RequestedModule: input.pipeline.Chunk.Module,
+		LookupStatus: "skipped", LookupReason: "chunk plan lookup skipped",
+		ValidationStatus: "not_run", PublicationStatus: "not_requested",
+	}
 	checkpoints := input.Checkpoints
 	if checkpoints == nil {
 		checkpoints = NoopCheckpointRecorder()
@@ -174,18 +182,14 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 
 	chunker := input.Prepared.chunker
 	attachModuleManifestMetadata(&output, "chunker", chunker)
-	var canonicalChunks []source.Chunk
-	var chunkWarnings []contracts.Warning
-	chunkCheckpoint, chunkDecision := checkpointLoader.Chunk(chunker.Key(), doc.Digest)
-	recordCheckpointEvent(&output, checkpointLoader, string(StageChunk), "", chunker.Key(), chunkDecision)
 	chunkStarted := time.Now().UTC()
+	chunkMode := effectiveChunkCacheMode(input.ChunkCacheMode)
 	if err := writeDebugTimed(debugRecorder, "chunk/input.json", debugTimedEnvelope{
 		Stage:     string(StageChunk),
 		ModuleKey: chunker.Key(),
 		StartedAt: chunkStarted,
 		Payload: map[string]any{
-			"reused":       chunkDecision.Reused,
-			"decision":     chunkDecision,
+			"cache_mode":   chunkMode,
 			"source":       debugSourceDocumentEnvelope(doc),
 			"source_input": debugContentEnvelope(sourceInput.Content, sourceInput.MediaType, nil, nil),
 			"options":      redactSensitiveMap(input.pipeline.Chunk.Options),
@@ -194,84 +198,29 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 	}); err != nil {
 		return failOutput(output), fmt.Errorf("write chunk debug artifact: %w", err)
 	}
-	chunksAccepted := chunkDecision.Reused
-	var chunkRejection *contracts.RejectedOutput
-	if chunkDecision.Reused {
-		canonicalChunks = cloneSourceChunks(chunkCheckpoint.Chunks)
-		chunkWarnings = cloneWarnings(chunkCheckpoint.Warnings)
-		output.Warnings = append(output.Warnings, chunkWarnings...)
-	} else {
-		if err := checkpoints.ChunkRunning(chunker.Key(), doc.Digest); err != nil {
-			return failOutput(output), fmt.Errorf("write chunk checkpoint: %w", err)
-		}
-		chunksAccepted, chunkRejection, err = runWithRetry(ctx, input.pipeline.Chunk.Retries, func(attempt int) (bool, *contracts.RejectedOutput, error) {
-			attemptStarted := time.Now().UTC()
-			attemptPath := path.Join("chunk", fmt.Sprintf("attempt-%02d", attempt))
-			attemptCtx, llmScope := withDebugLLMScope(ctx, attemptPath)
-			terminal := newAttemptTerminalRecorder(debugRecorder, attemptPath, "chunk", llmScope, debugTimedEnvelope{Stage: string(StageChunk), ModuleKey: chunker.Key(), Attempt: attempt, StartedAt: attemptStarted})
-			chunkResult, err := chunker.Chunk(attemptCtx, contracts.ChunkRequest{
-				Source:      doc,
-				SourceInput: sourceInput.Clone(),
-				SessionID:   sessionID,
-				References:  CloneReferenceSet(input.pipeline.ChunkReferences.ReferenceSet),
-				LLMProfile:  input.pipeline.Chunk.LLMProfile,
-				Metadata:    input.Metadata,
-			})
-			if err != nil {
-				attemptErr := fmt.Errorf("chunk source with chunker %q: %w", chunker.Key(), err)
-				return false, nil, terminal.record(nil, attemptErr)
-			}
-			if len(chunkResult.Chunks) == 0 {
-				attemptErr := fmt.Errorf("chunker %q returned no chunks", chunker.Key())
-				return false, nil, terminal.record(nil, attemptErr)
-			}
-			chunks, err := validateAndCanonicalizeChunkResult(doc, chunkResult.Chunks)
-			if err != nil {
-				attemptErr := fmt.Errorf("validate chunks from chunker %q: %w", chunker.Key(), err)
-				payload := map[string]any{"warnings": debugWarningEnvelopes(chunkResult.Warnings)}
-				return false, nil, terminal.record(payload, attemptErr)
-			}
-			validationWarnings, rejection, err := r.validateChunks(attemptCtx, doc, chunker.Key(), chunks, sourceInput, sessionID, input.pipeline.ChunkReferences.ReferenceSet, input.Metadata, input.Prepared.chunkValidators, attempt, input.Debug)
-			attemptWarnings := append(cloneWarnings(chunkResult.Warnings), validationWarnings...)
-			payload := map[string]any{
-				"chunks":    debugSourceChunkEnvelopes(chunks),
-				"warnings":  debugWarningEnvelopes(attemptWarnings),
-				"rejection": debugRejectedOutputPtr(rejection),
-			}
-			if err != nil || rejection != nil {
-				return false, rejection, terminal.record(payload, err)
-			}
-			canonicalChunks = chunks
-			chunkWarnings = attemptWarnings
-			if err := terminal.record(payload, nil); err != nil {
-				return false, nil, err
-			}
-			return true, nil, nil
-		})
-		if err != nil {
-			_ = checkpoints.ChunkFailed(chunker.Key(), doc.Digest, err)
-			return failOutput(output), err
-		}
-		if !chunksAccepted {
-			output.Rejected = append(output.Rejected, *chunkRejection)
-			if err := checkpoints.ChunkRejected(chunker.Key(), doc.Digest, *chunkRejection); err != nil {
-				return failOutput(output), fmt.Errorf("write chunk checkpoint: %w", err)
-			}
-		} else {
-			output.Warnings = append(output.Warnings, chunkWarnings...)
-			if err := checkpoints.ChunkSucceeded(chunker.Key(), doc.Digest, canonicalChunks, chunkWarnings); err != nil {
-				return failOutput(output), fmt.Errorf("write chunk checkpoint: %w", err)
-			}
-		}
+	chunkResult, err := r.runChunkPlan(ctx, input, doc, sourceInput, sessionID)
+	applyChunkPlanExecution(&output, chunkResult)
+	if err != nil {
+		return failOutput(output), err
+	}
+	if chunkResult.rejection != nil {
+		output.Rejected = append(output.Rejected, *chunkResult.rejection)
+	}
+	if chunkResult.accepted || chunkResult.lookup.Status == ChunkPlanHit {
+		output.Warnings = append(output.Warnings, chunkResult.warnings...)
 	}
 	chunkDebugPayload := map[string]any{
-		"reused":   chunkDecision.Reused,
-		"accepted": chunksAccepted,
-		"chunks":   debugSourceChunkEnvelopes(canonicalChunks),
-		"warnings": chunkWarnings,
+		"cache_mode":          chunkMode,
+		"lookup":              chunkResult.lookup,
+		"accepted":            chunkResult.accepted,
+		"materialized_chunks": debugSourceChunkEnvelopes(chunkResult.chunks),
+		"warnings":            chunkResult.warnings,
 	}
-	if chunkRejection != nil {
-		chunkDebugPayload["rejection"] = debugRejectedOutputEnvelope(*chunkRejection)
+	if chunkResult.plan != nil {
+		chunkDebugPayload["plan"] = debugChunkPlanEnvelope(*chunkResult.plan)
+	}
+	if chunkResult.rejection != nil {
+		chunkDebugPayload["rejection"] = debugRejectedOutputEnvelope(*chunkResult.rejection)
 	}
 	if err := writeDebugTimed(debugRecorder, "chunk/output.json", debugTimedEnvelope{
 		Stage:     string(StageChunk),
@@ -282,8 +231,8 @@ func (r *Runner) Run(ctx context.Context, input RunInput) (output RunOutput, err
 		return failOutput(output), fmt.Errorf("write chunk debug artifact: %w", err)
 	}
 
-	if chunksAccepted {
-		laneOutput, laneErr := r.runLanes(ctx, input, checkpoints, checkpointLoader, doc, sourceInput, sessionID, canonicalChunks)
+	if chunkResult.accepted {
+		laneOutput, laneErr := r.runLanes(ctx, input, checkpoints, checkpointLoader, doc, sourceInput, sessionID, chunkResult.chunks)
 		mergeLaneOutput(&output, laneOutput)
 		if laneErr != nil {
 			return failOutput(output), laneErr
@@ -471,6 +420,13 @@ func validateRunInput(input RunInput) error {
 	if input.Prepared == nil {
 		return fmt.Errorf("prepared pipeline must not be nil")
 	}
+	mode := effectiveChunkCacheMode(input.ChunkCacheMode)
+	if err := mode.Validate(); err != nil {
+		return err
+	}
+	if mode != ChunkCacheBypass && input.ChunkPlans == nil {
+		return fmt.Errorf("chunk plan store is required for %q mode", mode)
+	}
 	return validateResolvedPipeline(input.Prepared.resolved)
 }
 
@@ -532,10 +488,14 @@ func manifestFromPipeline(input RunInput) artifacts.RunManifest {
 
 	pipeline := input.pipeline
 	manifest := artifacts.RunManifest{
-		PipelineID:      pipeline.ID,
-		PipelineDigest:  pipeline.Digest,
-		InputModule:     pipeline.Input.Module,
-		Chunker:         pipeline.Chunk.Module,
+		PipelineID:     pipeline.ID,
+		PipelineDigest: pipeline.Digest,
+		InputModule:    pipeline.Input.Module,
+		Chunker:        pipeline.Chunk.Module,
+		ChunkPlan: &artifacts.ChunkPlanManifest{
+			Mode:            string(effectiveChunkCacheMode(input.ChunkCacheMode)),
+			RequestedModule: pipeline.Chunk.Module,
+		},
 		OutputEncoder:   pipeline.Output.Module,
 		ArtifactLanes:   make([]artifacts.ArtifactLaneManifest, 0, len(pipeline.ArtifactLanes)),
 		ValidatorChains: validatorChainManifests(pipeline.ValidatorChains),
@@ -544,10 +504,6 @@ func manifestFromPipeline(input RunInput) artifacts.RunManifest {
 		References:      ReferenceProvenance(pipeline),
 		LLMProfiles:     cloneLLMProfiles(input.LLMProfiles),
 	}
-	// The runner does not currently maintain a cache or idempotency key. Reference
-	// digests are recorded in manifest provenance and intentionally kept separate
-	// from source_digests.
-
 	for _, lane := range pipeline.ArtifactLanes {
 		laneManifest := artifacts.ArtifactLaneManifest{
 			ID:         lane.ID,
@@ -728,11 +684,38 @@ func cloneMetadata(metadata map[string]any) map[string]any {
 	}
 	out := make(map[string]any, len(metadata))
 	for key, value := range metadata {
-		out[key] = value
+		out[key] = cloneMetadataValue(value)
 	}
 	return out
 }
 
+func cloneMetadataValue(value any) any {
+	switch typed := value.(type) {
+	case map[string]any:
+		return cloneMetadata(typed)
+	case []any:
+		out := make([]any, len(typed))
+		for i := range typed {
+			out[i] = cloneMetadataValue(typed[i])
+		}
+		return out
+	case json.RawMessage:
+		return append(json.RawMessage(nil), typed...)
+	case []byte:
+		return append([]byte(nil), typed...)
+	case []string:
+		return append([]string(nil), typed...)
+	case map[string]string:
+		out := make(map[string]string, len(typed))
+		for key, item := range typed {
+			out[key] = item
+		}
+		return out
+	default:
+		return value
+	}
+}
+
 func cloneLLMProfiles(profiles []artifacts.LLMProfileManifest) []artifacts.LLMProfileManifest {
 	if len(profiles) == 0 {
 		return nil
@@ -863,6 +846,8 @@ func cloneSourceChunk(chunk source.Chunk) source.Chunk {
 	chunk.Content = append([]byte(nil), chunk.Content...)
 	chunk.Units = cloneSourceUnits(chunk.Units)
 	chunk.Metadata = cloneMetadata(chunk.Metadata)
+	chunk.Annotations = source.CloneChunkAnnotations(chunk.Annotations)
+	chunk.PlanAnnotations = source.CloneChunkAnnotations(chunk.PlanAnnotations)
 	return chunk
 }
 

internal/framework/pipeline/runner_candidate_encoding_test.go

@@ -209,7 +209,7 @@ func TestRunnerFinalEncodesAcceptedCandidatesOnce(t *testing.T) {
 			for i, event := range output.CheckpointEvents {
 				gotStages[i] = event.Stage
 			}
-			wantStages := []string{"source", string(StageChunk), string(StageExtract), string(StageMerge), string(StageNormalize)}
+			wantStages := []string{"source", string(StageExtract), string(StageMerge), string(StageNormalize)}
 			if !reflect.DeepEqual(gotStages, wantStages) {
 				t.Fatalf("checkpoint event stages = %#v, want %#v", gotStages, wantStages)
 			}

internal/framework/pipeline/runner_chunk_plan.go

@@ -0,0 +1,229 @@
+package pipeline
+
+import (
+	"context"
+	"fmt"
+	"path"
+	"time"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/artifacts"
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+)
+
+type chunkPlanExecution struct {
+	accepted  bool
+	chunks    []source.Chunk
+	plan      *source.ChunkPlan
+	warnings  []contracts.Warning
+	rejection *contracts.RejectedOutput
+	lookup    ChunkPlanDecision
+	record    *ChunkPlanRecord
+	action    string
+	summary   artifacts.ChunkPlanSummary
+}
+
+func effectiveChunkCacheMode(mode ChunkCacheMode) ChunkCacheMode {
+	if mode == "" {
+		return ChunkCacheBypass
+	}
+	parsed, _ := ParseChunkCacheMode(string(mode))
+	return parsed
+}
+
+// Chunk-plan lookup and publication happen serially before lane workers start.
+// The runner therefore does not add synchronization around the store.
+func (r *Runner) runChunkPlan(ctx context.Context, input RunInput, doc *source.SourceDocument, sourceInput contracts.LLMInputMaterial, sessionID string) (chunkPlanExecution, error) {
+	mode := effectiveChunkCacheMode(input.ChunkCacheMode)
+	chunker := input.Prepared.chunker
+	result := chunkPlanExecution{
+		lookup: ChunkPlanDecision{Reason: "chunk plan lookup skipped"},
+		summary: artifacts.ChunkPlanSummary{
+			Mode: string(mode), SourceDigest: doc.Digest, RequestedModule: chunker.Key(), LookupStatus: "skipped",
+			LookupReason: "chunk plan lookup skipped", ValidationStatus: "not_run", PublicationStatus: "not_requested",
+		},
+	}
+
+	if mode == ChunkCacheAuto {
+		record, decision, err := input.ChunkPlans.Load(doc.Digest)
+		result.lookup = decision
+		result.summary.LookupStatus = string(decision.Status)
+		result.summary.LookupReason = decision.Reason
+		if err != nil {
+			result.summary.LookupStatus = "skipped"
+			result.summary.LookupReason = "chunk plan lookup failed"
+			return result, fmt.Errorf("load chunk plan: %w", err)
+		}
+		switch decision.Status {
+		case ChunkPlanHit:
+			plan, chunks, validationErr := validateAndMaterializeChunkPlan(doc, record.Plan)
+			if validationErr == nil {
+				result.setCandidate(record, "reused")
+				validationWarnings, rejection, err := r.validateChunks(ctx, doc, chunker.Key(), chunks, sourceInput, sessionID, input.pipeline.ChunkReferences.ReferenceSet, input.Metadata, input.Prepared.chunkValidators, 1, input.Debug)
+				result.plan = &plan
+				result.chunks = chunks
+				result.warnings = append(cloneWarnings(record.Warnings), validationWarnings...)
+				result.rejection = rejection
+				result.accepted = rejection == nil && err == nil
+				result.setValidation(validationWarnings, rejection, err)
+				return result, err
+			}
+			result.lookup = ChunkPlanDecision{Status: ChunkPlanInvalid, Reason: "stored chunk plan cannot be materialized against the current source"}
+			result.summary.LookupStatus = "invalid"
+			result.summary.LookupReason = result.lookup.Reason
+		case ChunkPlanMissing, ChunkPlanInvalid:
+			// Generate below.
+		default:
+			return result, fmt.Errorf("load chunk plan returned unsupported status %q", decision.Status)
+		}
+	}
+	if mode == ChunkCacheAuto || mode == ChunkCacheRefresh {
+		result.summary.PublicationStatus = "not_published"
+	}
+
+	var producerWarnings []contracts.Warning
+	accepted, rejection, err := runWithRetry(ctx, input.pipeline.Chunk.Retries, func(attempt int) (bool, *contracts.RejectedOutput, error) {
+		attemptStarted := time.Now().UTC()
+		attemptPath := path.Join("chunk", fmt.Sprintf("attempt-%02d", attempt))
+		attemptCtx, llmScope := withDebugLLMScope(ctx, attemptPath)
+		terminal := newAttemptTerminalRecorder(input.Debug, attemptPath, "chunk", llmScope, debugTimedEnvelope{Stage: string(StageChunk), ModuleKey: chunker.Key(), Attempt: attempt, StartedAt: attemptStarted})
+		chunkResult, callErr := chunker.Plan(attemptCtx, contracts.ChunkRequest{
+			Source: doc, SourceInput: sourceInput.Clone(), SessionID: sessionID,
+			References: CloneReferenceSet(input.pipeline.ChunkReferences.ReferenceSet),
+			LLMProfile: input.pipeline.Chunk.LLMProfile, Metadata: input.Metadata,
+		})
+		if callErr != nil {
+			return false, nil, terminal.record(nil, fmt.Errorf("chunk source with chunker %q: %w", chunker.Key(), callErr))
+		}
+		plan, chunks, validationErr := validateAndMaterializeChunkPlan(doc, chunkResult.Plan)
+		if validationErr != nil {
+			attemptErr := fmt.Errorf("validate chunk plan from chunker %q: %w", chunker.Key(), validationErr)
+			payload := map[string]any{"plan": debugChunkPlanEnvelope(chunkResult.Plan), "warnings": debugWarningEnvelopes(chunkResult.Warnings)}
+			return false, nil, terminal.record(payload, attemptErr)
+		}
+		planDigest, digestErr := source.DigestChunkPlan(plan)
+		if digestErr != nil {
+			return false, nil, terminal.record(nil, fmt.Errorf("digest generated chunk plan: %w", digestErr))
+		}
+		producerMetadata, _ := moduleManifestMetadata(chunker)
+		profile := ""
+		if provider, ok := chunker.(contracts.ChunkExecutionClassProvider); ok && provider.ExecutionClass() == contracts.ExecutionClassLLMBacked {
+			profile = input.pipeline.Chunk.LLMProfile
+		}
+		candidate := ChunkPlanRecord{
+			SchemaVersion: ChunkPlanSchemaVersion, SourceDigest: doc.Digest, PlanDigest: planDigest,
+			Plan: source.CloneChunkPlan(plan),
+			Producer: ChunkPlanProducer{
+				InputModule: input.Prepared.input.Key(), ChunkModule: chunker.Key(), LLMProfile: profile,
+				References: append([]artifacts.ReferenceProvenance(nil), referenceTargetProvenance(input.pipeline.ChunkReferences)...),
+				Metadata:   cloneMetadata(producerMetadata),
+			},
+			Warnings: cloneWarnings(chunkResult.Warnings), CreatedAt: time.Now().UTC(),
+		}
+		action := "generated"
+		if mode == ChunkCacheRefresh {
+			action = "refreshed"
+		}
+		if mode == ChunkCacheBypass {
+			action = "bypassed"
+		}
+		result.setCandidate(candidate, action)
+		validationWarnings, rejected, validationErr := r.validateChunks(attemptCtx, doc, chunker.Key(), chunks, sourceInput, sessionID, input.pipeline.ChunkReferences.ReferenceSet, input.Metadata, input.Prepared.chunkValidators, attempt, input.Debug)
+		attemptWarnings := append(cloneWarnings(chunkResult.Warnings), validationWarnings...)
+		payload := map[string]any{
+			"plan": debugChunkPlanEnvelope(plan), "materialized_chunks": debugSourceChunkEnvelopes(chunks),
+			"warnings": debugWarningEnvelopes(attemptWarnings), "rejection": debugRejectedOutputPtr(rejected),
+		}
+		if validationErr != nil || rejected != nil {
+			result.setValidation(validationWarnings, rejected, validationErr)
+			return false, rejected, terminal.record(payload, validationErr)
+		}
+		result.chunks = chunks
+		result.plan = &plan
+		result.warnings = attemptWarnings
+		producerWarnings = cloneWarnings(chunkResult.Warnings)
+		result.setValidation(validationWarnings, nil, nil)
+		if debugErr := terminal.record(payload, nil); debugErr != nil {
+			return false, nil, debugErr
+		}
+		return true, nil, nil
+	})
+	if err != nil {
+		if result.summary.ValidationStatus == "not_run" {
+			result.summary.ValidationStatus = "error"
+		}
+		return result, err
+	}
+	result.accepted = accepted
+	result.rejection = rejection
+	if !accepted {
+		return result, nil
+	}
+
+	if mode == ChunkCacheAuto || mode == ChunkCacheRefresh {
+		record := cloneChunkPlanRecord(*result.record)
+		record.Warnings = cloneWarnings(producerWarnings)
+		if err := input.ChunkPlans.Save(record); err != nil {
+			return result, fmt.Errorf("save chunk plan: %w", err)
+		}
+		result.summary.PublicationStatus = "published"
+	}
+	return result, nil
+}
+
+func (result *chunkPlanExecution) setCandidate(record ChunkPlanRecord, action string) {
+	cloned := cloneChunkPlanRecord(record)
+	result.record = &cloned
+	result.action = action
+	result.summary.Action = action
+	result.summary.SourceDigest = record.SourceDigest
+	result.summary.CandidateDigest = record.PlanDigest
+}
+
+func (result *chunkPlanExecution) setValidation(warnings []contracts.Warning, rejection *contracts.RejectedOutput, err error) {
+	switch {
+	case err != nil:
+		result.summary.ValidationStatus = "error"
+	case rejection != nil:
+		result.summary.ValidationStatus = "rejected"
+	case len(warnings) > 0:
+		result.summary.ValidationStatus = "approved_with_warnings"
+	default:
+		result.summary.ValidationStatus = "approved"
+	}
+}
+
+func cloneChunkPlanRecord(record ChunkPlanRecord) ChunkPlanRecord {
+	record.Plan = source.CloneChunkPlan(record.Plan)
+	record.Producer.References = append([]artifacts.ReferenceProvenance(nil), record.Producer.References...)
+	record.Producer.Metadata = cloneMetadata(record.Producer.Metadata)
+	record.Warnings = cloneWarnings(record.Warnings)
+	return record
+}
+
+func applyChunkPlanExecution(output *RunOutput, result chunkPlanExecution) {
+	if output == nil {
+		return
+	}
+	summary := result.summary
+	output.ChunkPlan = &summary
+	if output.Manifest.ChunkPlan == nil {
+		return
+	}
+	manifest := output.Manifest.ChunkPlan
+	manifest.Action = result.action
+	if result.record == nil {
+		return
+	}
+	record := result.record
+	manifest.SourceDigest = record.SourceDigest
+	manifest.PlanDigest = record.PlanDigest
+	manifest.PlanSchemaVersion = record.SchemaVersion
+	manifest.ProducerInputModule = record.Producer.InputModule
+	manifest.ProducerModule = record.Producer.ChunkModule
+	manifest.ProducerLLMProfile = record.Producer.LLMProfile
+	manifest.ProducerReferences = append([]artifacts.ReferenceProvenance(nil), record.Producer.References...)
+	manifest.ProducerMetadata = cloneMetadata(record.Producer.Metadata)
+	createdAt := record.CreatedAt
+	manifest.CreatedAt = &createdAt
+}

internal/framework/pipeline/runner_chunk_plan_test.go

@@ -0,0 +1,455 @@
+package pipeline
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"reflect"
+	"strings"
+	"testing"
+	"time"
+
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
+	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
+)
+
+type recordingChunkPlanStore struct {
+	record   ChunkPlanRecord
+	decision ChunkPlanDecision
+	loadErr  error
+	saveErr  error
+	loads    int
+	saves    int
+	saved    ChunkPlanRecord
+}
+
+func (s *recordingChunkPlanStore) Load(string) (ChunkPlanRecord, ChunkPlanDecision, error) {
+	s.loads++
+	return s.record, s.decision, s.loadErr
+}
+
+func (s *recordingChunkPlanStore) Save(record ChunkPlanRecord) error {
+	s.saves++
+	s.saved = record
+	return s.saveErr
+}
+
+type countingChunkValidator struct {
+	calls  int
+	result contracts.ValidationResult
+	err    error
+}
+
+func (*countingChunkValidator) Name() string { return "test/counting-chunks" }
+func (*countingChunkValidator) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassDeterministic
+}
+func (v *countingChunkValidator) Validate(context.Context, contracts.ChunkValidationRequest) (contracts.ValidationResult, error) {
+	v.calls++
+	return v.result, v.err
+}
+
+type manifestChunker struct {
+	terminalChunker
+	metadata map[string]any
+}
+
+func (c manifestChunker) ManifestMetadata() map[string]any { return c.metadata }
+func (manifestChunker) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassLLMBacked
+}
+
+type llmCountingChunker struct {
+	terminalChunker
+	llmCalls *int
+}
+
+func (llmCountingChunker) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassLLMBacked
+}
+
+func (c llmCountingChunker) Plan(ctx context.Context, request contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	(*c.llmCalls)++
+	return c.terminalChunker.Plan(ctx, request)
+}
+
+type deterministicChunker struct{ terminalChunker }
+
+func (deterministicChunker) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassDeterministic
+}
+
+type retryingChunker struct {
+	key   string
+	plan  source.ChunkPlan
+	calls int
+}
+
+func (c *retryingChunker) Key() string                             { return c.key }
+func (*retryingChunker) ReferenceSlots() []contracts.ReferenceSlot { return nil }
+func (c *retryingChunker) Plan(context.Context, contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	c.calls++
+	if c.calls == 1 {
+		return contracts.ChunkPlanResult{Warnings: []contracts.Warning{{Scope: "discarded", ReasonCode: "retry", Message: "discarded warning"}}}, errors.New("retry generation")
+	}
+	return contracts.ChunkPlanResult{Plan: source.CloneChunkPlan(c.plan), Warnings: []contracts.Warning{{Scope: "accepted", ReasonCode: "observed", Message: "accepted warning"}}}, nil
+}
+
+type dependencyLoader struct {
+	CheckpointLoader
+	extractDependencies []CheckpointFingerprint
+}
+
+func (l *dependencyLoader) Extract(_ string, _ string, dependencies []CheckpointFingerprint) (ExtractCheckpoint, CheckpointDecision) {
+	l.extractDependencies = append([]CheckpointFingerprint(nil), dependencies...)
+	return ExtractCheckpoint{}, CheckpointDecision{Reason: "not found"}
+}
+
+func TestRunnerChunkPlanModeMatrix(t *testing.T) {
+	tests := []struct {
+		name       string
+		mode       ChunkCacheMode
+		decision   ChunkPlanDecision
+		wantLoads  int
+		wantSaves  int
+		wantCalls  int
+		wantAction string
+	}{
+		{name: "auto hit", mode: ChunkCacheAuto, decision: ChunkPlanDecision{Status: ChunkPlanHit}, wantLoads: 1, wantAction: "reused"},
+		{name: "auto missing", mode: ChunkCacheAuto, decision: ChunkPlanDecision{Status: ChunkPlanMissing}, wantLoads: 1, wantSaves: 1, wantCalls: 1, wantAction: "generated"},
+		{name: "auto invalid", mode: ChunkCacheAuto, decision: ChunkPlanDecision{Status: ChunkPlanInvalid}, wantLoads: 1, wantSaves: 1, wantCalls: 1, wantAction: "generated"},
+		{name: "bypass", mode: ChunkCacheBypass, wantCalls: 1, wantAction: "bypassed"},
+		{name: "empty bypass", wantCalls: 1, wantAction: "bypassed"},
+		{name: "refresh", mode: ChunkCacheRefresh, wantSaves: 1, wantCalls: 1, wantAction: "refreshed"},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			prepared, plan := preparedTerminalDebugPipeline(t)
+			calls := 0
+			llmCalls := 0
+			prepared.chunker = llmCountingChunker{terminalChunker: terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, calls: &calls}, llmCalls: &llmCalls}
+			store := &recordingChunkPlanStore{record: chunkPlanRecord(t, prepared, plan), decision: tc.decision}
+			output, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: tc.mode, ChunkPlans: store})
+			if err != nil {
+				t.Fatalf("Run() error = %v", err)
+			}
+			if store.loads != tc.wantLoads || store.saves != tc.wantSaves || calls != tc.wantCalls {
+				t.Fatalf("calls = load %d save %d module %d, want %d %d %d", store.loads, store.saves, calls, tc.wantLoads, tc.wantSaves, tc.wantCalls)
+			}
+			if output.Manifest.ChunkPlan == nil || output.Manifest.ChunkPlan.Action != tc.wantAction || output.ChunkPlan == nil || output.ChunkPlan.Action != tc.wantAction {
+				t.Fatalf("chunk plan manifest = %#v summary = %#v, want action %q", output.Manifest.ChunkPlan, output.ChunkPlan, tc.wantAction)
+			}
+		})
+	}
+}
+
+func TestRunnerChunkPlanHitUsesStoredProducerProvenance(t *testing.T) {
+	prepared, plan := preparedTerminalDebugPipeline(t)
+	prepared.resolved.Chunk.Module = "chunk/requested"
+	prepared.resolved.Chunk.LLMProfile = "current-profile"
+	record := chunkPlanRecord(t, prepared, plan)
+	record.Producer.InputModule = "input/original"
+	record.Producer.ChunkModule = "chunk/original"
+	record.Producer.LLMProfile = "original-profile"
+	record.Producer.Metadata = map[string]any{"prompt": map[string]any{"id": "original"}}
+	store := &recordingChunkPlanStore{record: record, decision: ChunkPlanDecision{Status: ChunkPlanHit}}
+	output, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheAuto, ChunkPlans: store})
+	if err != nil {
+		t.Fatal(err)
+	}
+	manifest := output.Manifest.ChunkPlan
+	if manifest.RequestedModule != "chunk/requested" || manifest.ProducerModule != "chunk/original" || manifest.ProducerLLMProfile != "original-profile" {
+		t.Fatalf("chunk plan manifest = %#v", manifest)
+	}
+	storedNested := record.Producer.Metadata["prompt"].(map[string]any)
+	storedNested["id"] = "mutated"
+	if got := manifest.ProducerMetadata["prompt"].(map[string]any)["id"]; got != "original" {
+		t.Fatalf("producer metadata changed through stored alias: %v", got)
+	}
+}
+
+func TestRunnerChunkPlanManifestRetainsCandidateOnRejection(t *testing.T) {
+	prepared, _ := preparedTerminalDebugPipeline(t)
+	validator := &countingChunkValidator{result: contracts.ValidationResult{Approved: false, ReasonCode: "policy", Message: "no"}}
+	prepared.chunkValidators.validators = []preparedValidator{{resolved: ResolvedValidator{Binding: Binding(validator.Name()), Target: ValidatorTargetChunk}, chunk: validator}}
+	output, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheRefresh, ChunkPlans: &recordingChunkPlanStore{}})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if output.Manifest.ChunkPlan.Action != "refreshed" || output.Manifest.ChunkPlan.PlanDigest == "" || output.ChunkPlan.ValidationStatus != "rejected" || output.ChunkPlan.PublicationStatus != "not_published" {
+		t.Fatalf("manifest = %#v summary = %#v", output.Manifest.ChunkPlan, output.ChunkPlan)
+	}
+}
+
+func TestRunnerValidatesChunkPlanPolicyInputs(t *testing.T) {
+	for _, tc := range []struct {
+		name string
+		mode ChunkCacheMode
+		want string
+	}{
+		{name: "auto requires store", mode: ChunkCacheAuto, want: "store is required"},
+		{name: "refresh requires store", mode: ChunkCacheRefresh, want: "store is required"},
+		{name: "invalid mode", mode: "sometimes", want: "not supported"},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			prepared, _ := preparedTerminalDebugPipeline(t)
+			_, err := New().Run(context.Background(), RunInput{Prepared: prepared, ChunkCacheMode: tc.mode})
+			if err == nil || !strings.Contains(err.Error(), tc.want) {
+				t.Fatalf("Run() error = %v, want %q", err, tc.want)
+			}
+		})
+	}
+}
+
+func TestRunnerChunkPlanStoreErrorsAreFrameworkErrors(t *testing.T) {
+	for _, tc := range []struct {
+		name      string
+		mode      ChunkCacheMode
+		decision  ChunkPlanDecision
+		loadErr   error
+		saveErr   error
+		wantError string
+		wantCalls int
+	}{
+		{name: "load", mode: ChunkCacheAuto, loadErr: errors.New("read failed"), wantError: "load chunk plan", wantCalls: 0},
+		{name: "save", mode: ChunkCacheRefresh, saveErr: errors.New("write failed"), wantError: "save chunk plan", wantCalls: 1},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			prepared, plan := preparedTerminalDebugPipeline(t)
+			calls := 0
+			llmCalls := 0
+			prepared.chunker = llmCountingChunker{terminalChunker: terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, calls: &calls}, llmCalls: &llmCalls}
+			store := &recordingChunkPlanStore{decision: tc.decision, loadErr: tc.loadErr, saveErr: tc.saveErr}
+			_, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: tc.mode, ChunkPlans: store})
+			if err == nil || !strings.Contains(err.Error(), tc.wantError) || calls != tc.wantCalls {
+				t.Fatalf("Run() error = %v, module calls = %d, want %q and %d", err, calls, tc.wantError, tc.wantCalls)
+			}
+		})
+	}
+}
+
+func TestRunnerRegeneratesStructurallyInvalidHit(t *testing.T) {
+	prepared, plan := preparedTerminalDebugPipeline(t)
+	calls := 0
+	prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, calls: &calls}
+	invalid := chunkPlanRecord(t, prepared, plan)
+	invalid.Plan.Ranges[0].StartUnitID = 999
+	store := &recordingChunkPlanStore{record: invalid, decision: ChunkPlanDecision{Status: ChunkPlanHit}}
+	if _, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheAuto, ChunkPlans: store}); err != nil {
+		t.Fatal(err)
+	}
+	if calls != 1 || store.loads != 1 || store.saves != 1 {
+		t.Fatalf("calls = module %d load %d save %d, want 1 1 1", calls, store.loads, store.saves)
+	}
+}
+
+func TestRunnerReusesCrossDomainAnnotationsAsOptionalData(t *testing.T) {
+	prepared, plan := preparedTerminalDebugPipeline(t)
+	plan.Annotations = source.ChunkAnnotations{"dnd/scenes": json.RawMessage(`{"boundary_caveats":["uncertain"]}`)}
+	plan.Ranges[0].Annotations = source.ChunkAnnotations{"dnd/scenes": json.RawMessage(`{"title":"Opening"}`)}
+	record := chunkPlanRecord(t, prepared, plan)
+	record.Producer.ChunkModule = "dnd/scenes"
+	store := &recordingChunkPlanStore{record: record, decision: ChunkPlanDecision{Status: ChunkPlanHit}}
+	output, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheAuto, ChunkPlans: store})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if output.Manifest.ChunkPlan.ProducerModule != "dnd/scenes" || output.Manifest.ChunkPlan.Action != "reused" {
+		t.Fatalf("cross-domain annotation plan was not reused: %#v", output.Manifest.ChunkPlan)
+	}
+}
+
+func TestRunnerRetriesBeforePublishingAcceptedPlan(t *testing.T) {
+	prepared, plan := preparedTerminalDebugPipeline(t)
+	prepared.resolved.Chunk.Retries = 1
+	chunker := &retryingChunker{key: prepared.resolved.Chunk.Module, plan: plan}
+	prepared.chunker = chunker
+	store := &recordingChunkPlanStore{decision: ChunkPlanDecision{Status: ChunkPlanMissing}}
+	output, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheAuto, ChunkPlans: store})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if chunker.calls != 2 || store.saves != 1 {
+		t.Fatalf("module calls = %d saves = %d, want 2 and 1", chunker.calls, store.saves)
+	}
+	if len(output.Warnings) != 1 || output.Warnings[0].Scope != "accepted" || len(store.saved.Warnings) != 1 || store.saved.Warnings[0].Scope != "accepted" {
+		t.Fatalf("output warnings = %#v stored warnings = %#v", output.Warnings, store.saved.Warnings)
+	}
+}
+
+func TestRunnerAutoHitValidatesOnceWithoutRegenerationOrMutation(t *testing.T) {
+	tests := []struct {
+		name         string
+		result       contracts.ValidationResult
+		validatorErr error
+		wantError    string
+		wantReject   bool
+	}{
+		{name: "warning", result: contracts.ValidationResult{Approved: true, Warnings: []contracts.Warning{{Scope: "current", ReasonCode: "observed", Message: "current warning"}}}},
+		{name: "rejection", result: contracts.ValidationResult{Approved: false, ReasonCode: "rejected", Message: "rejected hit"}, wantReject: true},
+		{name: "error", validatorErr: errors.New("validator failed"), wantError: "validator failed"},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			prepared, plan := preparedTerminalDebugPipeline(t)
+			calls := 0
+			llmCalls := 0
+			prepared.chunker = llmCountingChunker{terminalChunker: terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, calls: &calls}, llmCalls: &llmCalls}
+			validator := &countingChunkValidator{result: tc.result, err: tc.validatorErr}
+			prepared.chunkValidators.validators = []preparedValidator{{resolved: ResolvedValidator{Binding: Binding(validator.Name()), Target: ValidatorTargetChunk}, chunk: validator}}
+			record := chunkPlanRecord(t, prepared, plan)
+			record.Warnings = []contracts.Warning{{Scope: "stored", ReasonCode: "observed", Message: "stored warning"}}
+			store := &recordingChunkPlanStore{record: record, decision: ChunkPlanDecision{Status: ChunkPlanHit}}
+			debug := newCapturedDebugRecorder()
+			output, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheAuto, ChunkPlans: store, Debug: debug})
+			if tc.wantError != "" {
+				if err == nil || !strings.Contains(err.Error(), tc.wantError) {
+					t.Fatalf("Run() error = %v, want %q", err, tc.wantError)
+				}
+			} else if err != nil {
+				t.Fatalf("Run() error = %v", err)
+			}
+			if validator.calls != 1 || calls != 0 || llmCalls != 0 || store.loads != 1 || store.saves != 0 {
+				t.Fatalf("calls = validator %d module %d llm %d load %d save %d", validator.calls, calls, llmCalls, store.loads, store.saves)
+			}
+			assertAttemptEnvelopeSequence(t, debug, "chunk")
+			if tc.wantError == "" {
+				encoded := string(debug.json["chunk/output.json"])
+				if !strings.Contains(encoded, `"status":"hit"`) || !strings.Contains(encoded, `"plan":`) || !strings.Contains(encoded, `"materialized_chunks":`) {
+					t.Fatalf("chunk hit debug = %s", encoded)
+				}
+			}
+			if tc.wantReject && (len(output.Rejected) != 1 || output.Rejected[0].ReasonCode != "rejected") {
+				t.Fatalf("rejected = %#v", output.Rejected)
+			}
+			if tc.wantError == "" && len(output.Warnings) != 1+len(tc.result.Warnings) {
+				t.Fatalf("warnings = %#v, want stored warning once plus current warnings", output.Warnings)
+			}
+		})
+	}
+}
+
+func TestRunnerPublishesOnlyAcceptedGeneratedPlans(t *testing.T) {
+	for _, tc := range []struct {
+		name       string
+		moduleErr  error
+		validator  contracts.ValidationResult
+		cancel     bool
+		wantCalls  int
+		wantReject bool
+	}{
+		{name: "module error", moduleErr: errors.New("generation failed"), wantCalls: 2},
+		{name: "validator rejection", validator: contracts.ValidationResult{Approved: false, ReasonCode: "rejected", Message: "rejected generated plan"}, wantCalls: 2, wantReject: true},
+		{name: "cancellation", cancel: true},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			prepared, plan := preparedTerminalDebugPipeline(t)
+			prepared.resolved.Chunk.Retries = 1
+			calls := 0
+			prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, calls: &calls, err: tc.moduleErr}
+			if tc.wantReject {
+				validator := &countingChunkValidator{result: tc.validator}
+				prepared.chunkValidators.validators = []preparedValidator{{resolved: ResolvedValidator{Binding: Binding(validator.Name()), Target: ValidatorTargetChunk}, chunk: validator}}
+			}
+			ctx := context.Background()
+			if tc.cancel {
+				cancelled, cancel := context.WithCancel(ctx)
+				cancel()
+				ctx = cancelled
+			}
+			store := &recordingChunkPlanStore{decision: ChunkPlanDecision{Status: ChunkPlanInvalid}}
+			output, err := New().Run(ctx, RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheAuto, ChunkPlans: store})
+			if tc.wantReject {
+				if err != nil || len(output.Rejected) != 1 {
+					t.Fatalf("Run() error = %v rejected = %#v", err, output.Rejected)
+				}
+			} else if err == nil {
+				t.Fatal("Run() error = nil")
+			}
+			if calls != tc.wantCalls || store.saves != 0 {
+				t.Fatalf("module calls = %d, saves = %d; want %d, 0", calls, store.saves, tc.wantCalls)
+			}
+		})
+	}
+}
+
+func TestRunnerStoresProducerProvenanceAndProducerWarnings(t *testing.T) {
+	prepared, plan := preparedTerminalDebugPipeline(t)
+	prepared.resolved.Chunk.LLMProfile = "chunk-profile"
+	prepared.resolved.ChunkReferences = ResolvedReferenceTarget{
+		Stage: StageChunk,
+		ReferenceSet: contracts.ReferenceSet{Slots: map[string]contracts.ResolvedReferenceSlot{
+			"guide": {Items: []contracts.ReferenceItem{{SlotName: "guide", Digest: "sha256:guide", Origin: contracts.ReferenceOrigin{Type: "file", URI: "file:///guide.txt"}, Content: []byte("sensitive")}}},
+		}},
+	}
+	prepared.chunker = manifestChunker{terminalChunker: terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, warnings: []contracts.Warning{{Scope: "producer", ReasonCode: "observed", Message: "producer warning"}}}, metadata: map[string]any{"prompt_id": "chunk/prompt"}}
+	validator := &countingChunkValidator{result: contracts.ValidationResult{Approved: true, Warnings: []contracts.Warning{{Scope: "validator", ReasonCode: "observed", Message: "validator warning"}}}}
+	prepared.chunkValidators.validators = []preparedValidator{{resolved: ResolvedValidator{Binding: Binding(validator.Name()), Target: ValidatorTargetChunk}, chunk: validator}}
+	store := &recordingChunkPlanStore{}
+	if _, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheRefresh, ChunkPlans: store}); err != nil {
+		t.Fatal(err)
+	}
+	producer := store.saved.Producer
+	if producer.InputModule != prepared.input.Key() || producer.ChunkModule != prepared.chunker.Key() || producer.LLMProfile != "chunk-profile" || producer.Metadata["prompt_id"] != "chunk/prompt" {
+		t.Fatalf("producer = %#v", producer)
+	}
+	if len(producer.References) != 1 || producer.References[0].Digest != "sha256:guide" {
+		t.Fatalf("producer references = %#v", producer.References)
+	}
+	if len(store.saved.Warnings) != 1 || store.saved.Warnings[0].Scope != "producer" {
+		t.Fatalf("stored warnings = %#v, want only producer warning", store.saved.Warnings)
+	}
+}
+
+func TestRunnerOmitsProducerProfileForDeterministicChunker(t *testing.T) {
+	prepared, plan := preparedTerminalDebugPipeline(t)
+	prepared.resolved.Chunk.LLMProfile = "configured-but-unused"
+	prepared.chunker = deterministicChunker{terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan}}
+	store := &recordingChunkPlanStore{}
+	output, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), ChunkCacheMode: ChunkCacheRefresh, ChunkPlans: store})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if store.saved.Producer.LLMProfile != "" || output.Manifest.ChunkPlan.ProducerLLMProfile != "" {
+		t.Fatalf("deterministic producer profile = stored %q manifest %q", store.saved.Producer.LLMProfile, output.Manifest.ChunkPlan.ProducerLLMProfile)
+	}
+}
+
+func TestRunnerRefreshChangesDownstreamChunkFingerprint(t *testing.T) {
+	doc := typedTestDocumentWithUnits(2)
+	prepared := preparedConcurrentPipeline(t, 1)
+	prepared.lanes = prepared.lanes[:1]
+	prepared.resolved.ArtifactLanes = prepared.resolved.ArtifactLanes[:1]
+	prepared.ArtifactLanes = prepared.ArtifactLanes[:1]
+	prepared.input = &typedTestInput{key: prepared.resolved.Input.Module, doc: doc}
+
+	run := func(plan source.ChunkPlan) []CheckpointFingerprint {
+		prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan}
+		loader := &dependencyLoader{CheckpointLoader: NoopCheckpointLoader()}
+		if _, err := New().Run(context.Background(), RunInput{Prepared: prepared, ChunkCacheMode: ChunkCacheRefresh, ChunkPlans: &recordingChunkPlanStore{}, Checkpoint: loader}); err != nil {
+			t.Fatal(err)
+		}
+		return loader.extractDependencies
+	}
+	separate := typedTestPlan(doc)
+	combined := source.ChunkPlan{SourceDigest: doc.Digest, Ranges: []source.ChunkRange{{StartUnitID: 1, EndUnitID: 2}}}
+	if first, second := run(separate), run(combined); reflect.DeepEqual(first, second) {
+		t.Fatalf("downstream fingerprints did not change: %#v", first)
+	}
+}
+
+func chunkPlanRecord(t *testing.T, prepared *PreparedPipeline, plan source.ChunkPlan) ChunkPlanRecord {
+	t.Helper()
+	digest, err := source.DigestChunkPlan(plan)
+	if err != nil {
+		t.Fatal(err)
+	}
+	return ChunkPlanRecord{
+		SchemaVersion: ChunkPlanSchemaVersion,
+		SourceDigest:  plan.SourceDigest,
+		PlanDigest:    digest,
+		Plan:          source.CloneChunkPlan(plan),
+		Producer:      ChunkPlanProducer{InputModule: prepared.input.Key(), ChunkModule: prepared.chunker.Key()},
+		CreatedAt:     time.Now().UTC(),
+	}
+}

internal/framework/pipeline/runner_concurrency_test.go

@@ -11,7 +11,6 @@ import (
 	"testing"
 	"time"
 
-	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
 	frameworkllm "gitea.maximumdirect.net/eric/notarius/internal/framework/llm"
 )
@@ -51,12 +50,13 @@ func preparedConcurrentPipeline(t *testing.T, chunkCount int) *PreparedPipeline
 	if err != nil {
 		t.Fatalf("Prepare() error = %v", err)
 	}
-	doc := typedTestDocument()
-	chunks := make([]source.Chunk, chunkCount)
-	for i := range chunks {
-		chunks[i] = source.Chunk{ID: fmt.Sprintf("chunk-%d", i+1), SourceID: doc.ID, Index: i, Ref: doc.Units[0].Ref, Content: []byte(fmt.Sprintf(`{"chunk":%d}`, i+1)), MediaType: "application/json", Units: []source.SourceUnit{doc.Units[0]}}
+	doc := typedTestDocumentWithUnits(chunkCount)
+	if adapter, ok := prepared.input.(*typedTestInput); ok {
+		adapter.doc = doc
+	} else {
+		t.Fatalf("prepared input = %T, want *typedTestInput", prepared.input)
 	}
-	prepared.chunker = &typedTestChunker{key: "typed/chunk", chunks: chunks}
+	prepared.chunker = &typedTestChunker{key: "typed/chunk", plan: typedTestPlan(doc)}
 	return prepared
 }
 

internal/framework/pipeline/runner_concurrent.go

@@ -258,7 +258,7 @@ func prepareLaneExtract(input RunInput, loader CheckpointLoader, doc *source.Sou
 }
 
 func (r *Runner) runExtractJob(ctx context.Context, input RunInput, doc *source.SourceDocument, sourceInput contracts.LLMInputMaterial, sessionID string, job extractJob) extractJobResult {
-	state, chunk := job.lane, job.chunk
+	state, chunk := job.lane, cloneSourceChunk(job.chunk)
 	lane, typed := state.prepared.resolved, state.prepared.typed
 	result := extractJobResult{laneIndex: state.index, chunkIndex: chunk.Index}
 	var accepted erasedExtractArtifact

internal/framework/pipeline/runner_extract_handoff_test.go

@@ -2,10 +2,12 @@ package pipeline
 
 import (
 	"context"
+	"encoding/json"
 	"reflect"
 	"strings"
 	"testing"
 
+	"gitea.maximumdirect.net/eric/notarius/internal/core/source"
 	"gitea.maximumdirect.net/eric/notarius/internal/framework/contracts"
 )
 
@@ -50,6 +52,31 @@ func cloneCheckpointArtifacts(values []CheckpointArtifact) []CheckpointArtifact
 	return cloned
 }
 
+func TestRunnerPassesIndependentAnnotationScopesToExtractors(t *testing.T) {
+	prepared := preparedAttemptDebugPipeline(t)
+	chunker := prepared.chunker.(*typedTestChunker)
+	chunker.plan.Ranges[0].Annotations = source.ChunkAnnotations{"same": json.RawMessage(`{"range":1}`)}
+	chunker.plan.Annotations = source.ChunkAnnotations{"same": json.RawMessage(`{"plan":2}`)}
+
+	var gotRange, gotPlan string
+	installExtractOperation(prepared, 0, func(_ context.Context, request contracts.TypedExtractionRequest) (erasedTypedResult, error) {
+		gotRange = string(request.Chunk.Annotations["same"])
+		gotPlan = string(request.Chunk.PlanAnnotations["same"])
+		request.Chunk.Annotations["same"][0] = '['
+		request.Chunk.PlanAnnotations["same"][0] = '['
+		return erasedTypedResult{Value: typedValueForLane(0, request.Chunk.Index)}, nil
+	})
+	if _, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input")}); err != nil {
+		t.Fatalf("Run() error = %v, want nil", err)
+	}
+	if gotRange != `{"range":1}` || gotPlan != `{"plan":2}` {
+		t.Fatalf("extract annotations = %q / %q", gotRange, gotPlan)
+	}
+	if string(chunker.plan.Ranges[0].Annotations["same"]) != `{"range":1}` || string(chunker.plan.Annotations["same"]) != `{"plan":2}` {
+		t.Fatal("extract request shares annotation bytes with chunker output")
+	}
+}
+
 func TestRunnerContinuesFromFreshAndReusedExtractResults(t *testing.T) {
 	prepared := preparedAttemptDebugPipeline(t)
 	extractCalls := 0

internal/framework/pipeline/runner_terminal_debug_test.go

@@ -15,7 +15,7 @@ import (
 
 type terminalChunker struct {
 	key      string
-	chunks   []source.Chunk
+	plan     source.ChunkPlan
 	warnings []contracts.Warning
 	err      error
 	calls    *int
@@ -25,11 +25,11 @@ func (c terminalChunker) Key() string { return c.key }
 
 func (terminalChunker) ReferenceSlots() []contracts.ReferenceSlot { return nil }
 
-func (c terminalChunker) Chunk(context.Context, contracts.ChunkRequest) (contracts.ChunkResult, error) {
+func (c terminalChunker) Plan(context.Context, contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
 	if c.calls != nil {
 		(*c.calls)++
 	}
-	return contracts.ChunkResult{Chunks: cloneSourceChunks(c.chunks), Warnings: cloneWarnings(c.warnings)}, c.err
+	return contracts.ChunkPlanResult{Plan: source.CloneChunkPlan(c.plan), Warnings: cloneWarnings(c.warnings)}, c.err
 }
 
 type terminalChunkValidator struct {
@@ -37,6 +37,19 @@ type terminalChunkValidator struct {
 	err    error
 }
 
+type observingChunkValidator struct {
+	request contracts.ChunkValidationRequest
+}
+
+func (*observingChunkValidator) Name() string { return "observing/chunk-validator" }
+func (*observingChunkValidator) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassDeterministic
+}
+func (v *observingChunkValidator) Validate(_ context.Context, request contracts.ChunkValidationRequest) (contracts.ValidationResult, error) {
+	v.request = request
+	return contracts.ValidationResult{Approved: true}, nil
+}
+
 func (terminalChunkValidator) Name() string { return "terminal/chunk-validator" }
 
 func (terminalChunkValidator) ExecutionClass() contracts.ExecutionClass {
@@ -71,14 +84,14 @@ func assertAttemptEnvelopeSequence(t *testing.T, debug *capturedDebugRecorder, p
 	}
 }
 
-func preparedTerminalDebugPipeline(t *testing.T) (*PreparedPipeline, []source.Chunk) {
+func preparedTerminalDebugPipeline(t *testing.T) (*PreparedPipeline, source.ChunkPlan) {
 	t.Helper()
 	prepared := preparedAttemptDebugPipeline(t)
 	chunker, ok := prepared.chunker.(*typedTestChunker)
 	if !ok {
 		t.Fatalf("prepared chunker = %T, want *typedTestChunker", prepared.chunker)
 	}
-	return prepared, cloneSourceChunks(chunker.chunks)
+	return prepared, source.CloneChunkPlan(chunker.plan)
 }
 
 func TestRunnerRecordsChunkTerminalOutcomes(t *testing.T) {
@@ -96,8 +109,8 @@ func TestRunnerRecordsChunkTerminalOutcomes(t *testing.T) {
 	}
 	for _, tc := range tests {
 		t.Run(tc.name, func(t *testing.T) {
-			prepared, chunks := preparedTerminalDebugPipeline(t)
-			prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, chunks: chunks, warnings: []contracts.Warning{{Scope: "chunk", ReasonCode: "observed", Message: "chunk warning"}}, err: tc.moduleError}
+			prepared, plan := preparedTerminalDebugPipeline(t)
+			prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, warnings: []contracts.Warning{{Scope: "chunk", ReasonCode: "observed", Message: "chunk warning"}}, err: tc.moduleError}
 			prepared.chunkValidators.validators = []preparedValidator{{resolved: ResolvedValidator{Binding: Binding("terminal/chunk-validator"), Target: ValidatorTargetChunk}, chunk: tc.validator}}
 			debug := newCapturedDebugRecorder()
 
@@ -116,10 +129,63 @@ func TestRunnerRecordsChunkTerminalOutcomes(t *testing.T) {
 					t.Fatalf("chunk rejection = envelope %#v, outputs %#v", envelope, output.Rejected)
 				}
 			}
+			if tc.name == "accepted" {
+				encoded := string(debug.json["chunk/attempt-01.json"])
+				if !strings.Contains(encoded, `"plan":`) || !strings.Contains(encoded, `"materialized_chunks":`) || strings.Contains(encoded, `"chunks":`) {
+					t.Fatalf("chunk attempt debug = %s, want separate plan and materialized_chunks", encoded)
+				}
+			}
 		})
 	}
 }
 
+func TestRunnerMaterializesAnnotatedPlanBeforeChunkValidation(t *testing.T) {
+	prepared, plan := preparedTerminalDebugPipeline(t)
+	plan.Annotations = source.ChunkAnnotations{"same": []byte(`{"plan":1}`)}
+	plan.Ranges[0].Annotations = source.ChunkAnnotations{"same": []byte(`{"range":2}`)}
+	prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan}
+	validator := &observingChunkValidator{}
+	prepared.chunkValidators.validators = []preparedValidator{{
+		resolved: ResolvedValidator{Binding: Binding(validator.Name()), Target: ValidatorTargetChunk},
+		chunk:    validator,
+	}}
+
+	if _, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input")}); err != nil {
+		t.Fatalf("Run() error = %v, want nil", err)
+	}
+	if len(validator.request.Chunks) != 1 {
+		t.Fatalf("validator chunks = %#v, want one", validator.request.Chunks)
+	}
+	chunk := validator.request.Chunks[0]
+	if chunk.ID != "chunk-000001" || chunk.Index != 0 || chunk.MediaType != "application/json" {
+		t.Fatalf("materialized chunk identity = %#v", chunk)
+	}
+	if string(chunk.Annotations["same"]) != `{"range":2}` || string(chunk.PlanAnnotations["same"]) != `{"plan":1}` {
+		t.Fatalf("materialized annotations = %s / %s", chunk.Annotations["same"], chunk.PlanAnnotations["same"])
+	}
+	if chunk.Metadata["start_unit_id"] != 1 || chunk.Metadata["end_unit_id"] != 1 || chunk.Metadata["unit_count"] != 1 {
+		t.Fatalf("materialized metadata = %#v", chunk.Metadata)
+	}
+}
+
+func TestRunnerRetriesMalformedPlanWithDebugEnabled(t *testing.T) {
+	prepared, plan := preparedTerminalDebugPipeline(t)
+	plan.Ranges[0].Annotations = source.ChunkAnnotations{"broken": []byte(`{"value":`)}
+	prepared.resolved.Chunk.Retries = 1
+	calls := 0
+	prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, calls: &calls}
+	debug := newCapturedDebugRecorder()
+
+	_, err := New().Run(context.Background(), RunInput{Prepared: prepared, RawInput: []byte("input"), Debug: debug})
+	if err == nil || !strings.Contains(err.Error(), "valid JSON") {
+		t.Fatalf("Run() error = %v, want malformed annotation error", err)
+	}
+	if calls != 2 {
+		t.Fatalf("plan calls = %d, want two attempts", calls)
+	}
+	assertAttemptEnvelopeSequence(t, debug, "chunk", 1, 2)
+}
+
 func TestRunnerRecordsExtractTerminalOutcomes(t *testing.T) {
 	tests := []struct {
 		name          string
@@ -187,9 +253,9 @@ func TestRunnerRecordsExtractTerminalOutcomes(t *testing.T) {
 
 func TestRunnerJoinsPrimaryAndAttemptWriteErrors(t *testing.T) {
 	t.Run("chunk", func(t *testing.T) {
-		prepared, chunks := preparedTerminalDebugPipeline(t)
+		prepared, plan := preparedTerminalDebugPipeline(t)
 		primary := errors.New("chunk operation failed")
-		prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, chunks: chunks, err: primary}
+		prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, err: primary}
 		debug := newCapturedDebugRecorder()
 		debug.failPath = "chunk/attempt-01.json"
 
@@ -216,10 +282,10 @@ func TestRunnerJoinsPrimaryAndAttemptWriteErrors(t *testing.T) {
 }
 
 func TestRunnerDoesNotRetryAfterTerminalAttemptWriteFailure(t *testing.T) {
-	prepared, chunks := preparedTerminalDebugPipeline(t)
+	prepared, plan := preparedTerminalDebugPipeline(t)
 	prepared.resolved.Chunk.Retries = 1
 	calls := 0
-	prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, chunks: chunks, calls: &calls}
+	prepared.chunker = terminalChunker{key: prepared.resolved.Chunk.Module, plan: plan, calls: &calls}
 	prepared.chunkValidators.validators = []preparedValidator{{
 		resolved: ResolvedValidator{Binding: Binding("terminal/chunk-validator"), Target: ValidatorTargetChunk},
 		chunk:    terminalChunkValidator{result: contracts.ValidationResult{Approved: true}},

internal/framework/pipeline/synchronized_collaborators.go

@@ -61,11 +61,6 @@ func (l *lockedCheckpointLoader) Source(key string) (SourceCheckpoint, Checkpoin
 	defer l.mu.Unlock()
 	return l.inner.Source(key)
 }
-func (l *lockedCheckpointLoader) Chunk(key, digest string) (ChunkCheckpoint, CheckpointDecision) {
-	l.mu.Lock()
-	defer l.mu.Unlock()
-	return l.inner.Chunk(key, digest)
-}
 func (l *lockedCheckpointLoader) Extract(lane, key string, deps []CheckpointFingerprint) (ExtractCheckpoint, CheckpointDecision) {
 	l.mu.Lock()
 	defer l.mu.Unlock()
@@ -107,18 +102,6 @@ func (r *lockedCheckpointRecorder) SourceSucceeded(key string, doc *source.Sourc
 func (r *lockedCheckpointRecorder) SourceFailed(key string, err error) error {
 	return r.call(func() error { return r.inner.SourceFailed(key, err) })
 }
-func (r *lockedCheckpointRecorder) ChunkRunning(key, digest string) error {
-	return r.call(func() error { return r.inner.ChunkRunning(key, digest) })
-}
-func (r *lockedCheckpointRecorder) ChunkSucceeded(key, digest string, chunks []source.Chunk, warnings []contracts.Warning) error {
-	return r.call(func() error { return r.inner.ChunkSucceeded(key, digest, chunks, warnings) })
-}
-func (r *lockedCheckpointRecorder) ChunkRejected(key, digest string, rejected contracts.RejectedOutput) error {
-	return r.call(func() error { return r.inner.ChunkRejected(key, digest, rejected) })
-}
-func (r *lockedCheckpointRecorder) ChunkFailed(key, digest string, err error) error {
-	return r.call(func() error { return r.inner.ChunkFailed(key, digest, err) })
-}
 func (r *lockedCheckpointRecorder) ExtractRunning(lane, key string, deps []CheckpointFingerprint) error {
 	return r.call(func() error { return r.inner.ExtractRunning(lane, key, deps) })
 }

internal/framework/pipeline/typed_resolution_test.go

@@ -67,14 +67,14 @@ func (v *typedTestInput) Parse(context.Context, contracts.ParseRequest) (*source
 }
 
 type typedTestChunker struct {
-	key    string
-	chunks []source.Chunk
+	key  string
+	plan source.ChunkPlan
 }
 
 func (v *typedTestChunker) Key() string                               { return v.key }
 func (v *typedTestChunker) ReferenceSlots() []contracts.ReferenceSlot { return nil }
-func (v *typedTestChunker) Chunk(context.Context, contracts.ChunkRequest) (contracts.ChunkResult, error) {
-	return contracts.ChunkResult{Chunks: v.chunks}, nil
+func (v *typedTestChunker) Plan(context.Context, contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	return contracts.ChunkPlanResult{Plan: source.CloneChunkPlan(v.plan)}, nil
 }
 
 type typedTestOutput struct{ key string }
@@ -84,12 +84,27 @@ func (v *typedTestOutput) Encode(context.Context, contracts.OutputRequest) (cont
 	return contracts.OutputResult{}, nil
 }
 func typedTestDocument() *source.SourceDocument {
-	ref := source.SourceRef{SourceID: "source", StartUnitID: 1, EndUnitID: 1}
-	doc := &source.SourceDocument{ID: "source", Kind: "document", Format: "text/plain", Units: []source.SourceUnit{{ID: 1, Kind: "line", Text: "text", Ref: ref}}}
+	return typedTestDocumentWithUnits(1)
+}
+
+func typedTestDocumentWithUnits(count int) *source.SourceDocument {
+	doc := &source.SourceDocument{ID: "source", Kind: "document", Format: "text/plain"}
+	for id := 1; id <= count; id++ {
+		ref := source.SourceRef{SourceID: doc.ID, StartUnitID: id, EndUnitID: id}
+		doc.Units = append(doc.Units, source.SourceUnit{ID: id, Kind: "line", Text: fmt.Sprintf("text-%d", id), Ref: ref})
+	}
 	doc.Digest, _ = source.DigestDocument(doc)
 	return doc
 }
 
+func typedTestPlan(doc *source.SourceDocument) source.ChunkPlan {
+	plan := source.ChunkPlan{SourceDigest: doc.Digest, Ranges: make([]source.ChunkRange, len(doc.Units))}
+	for i, unit := range doc.Units {
+		plan.Ranges[i] = source.ChunkRange{StartUnitID: unit.ID, EndUnitID: unit.ID}
+	}
+	return plan
+}
+
 func (v typedTestSerializedValidator) Name() string { return v.key }
 func (typedTestSerializedValidator) ExecutionClass() contracts.ExecutionClass {
 	return contracts.ExecutionClassDeterministic
@@ -466,7 +481,7 @@ func mustRegisterTypedTestBase(t *testing.T, catalog ModuleCatalog) {
 	}
 	if err := catalog.Chunkers.RegisterWithSpec(ModuleSpec{Key: "typed/chunk", Stage: StageChunk}, func() (contracts.Chunker, error) {
 		doc := typedTestDocument()
-		return &typedTestChunker{key: "typed/chunk", chunks: []source.Chunk{{ID: "chunk-1", SourceID: doc.ID, Index: 0, Ref: doc.Units[0].Ref, Content: []byte(`{"chunk":1}`), MediaType: "application/json", Units: []source.SourceUnit{doc.Units[0]}}}}, nil
+		return &typedTestChunker{key: "typed/chunk", plan: typedTestPlan(doc)}, nil
 	}); err != nil {
 		t.Fatalf("register chunker: %v", err)
 	}

internal/modules/dnd/chunk/scenes/chunker.go

@@ -20,9 +20,10 @@ var requiredCapabilities = []string{
 
 var providedCapabilities = []string{
 	"chunks",
-	"chunks.scenes",
 }
 
+const annotationNamespace = "dnd/scenes"
+
 var referenceSlotDescriptions = shared.ReferenceSlotDescriptions{
 	Glossary: "Optional campaign glossary reference material used only for scene disambiguation.",
 	Party:    "Optional party roster reference material used only for scene disambiguation.",
@@ -50,6 +51,10 @@ func (c *Chunker) Key() string {
 	return Key
 }
 
+func (*Chunker) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassLLMBacked
+}
+
 func (c *Chunker) ReferenceSlots() []contracts.ReferenceSlot {
 	return shared.ReferenceSlots(referenceSlotDescriptions)
 }
@@ -74,27 +79,27 @@ func (c *Chunker) ManifestMetadata() map[string]any {
 	return metadata
 }
 
-func (c *Chunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkResult, error) {
+func (c *Chunker) Plan(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
 	if c == nil {
-		return contracts.ChunkResult{}, chunkerErrorf("chunker must not be nil")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("chunker must not be nil")
 	}
 	if c.llm == nil {
-		return contracts.ChunkResult{}, chunkerErrorf("LLM client must not be nil")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("LLM client must not be nil")
 	}
 	if ctx == nil {
-		return contracts.ChunkResult{}, chunkerErrorf("context must not be nil")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("context must not be nil")
 	}
 	if err := ctx.Err(); err != nil {
-		return contracts.ChunkResult{}, chunkerErrorf("context error before chunking: %w", err)
+		return contracts.ChunkPlanResult{}, chunkerErrorf("context error before chunking: %w", err)
 	}
 	if req.Source == nil {
-		return contracts.ChunkResult{}, chunkerErrorf("source must not be nil")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("source must not be nil")
 	}
 	if len(req.Source.Units) == 0 {
-		return contracts.ChunkResult{}, chunkerErrorf("source units must not be empty")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("source units must not be empty")
 	}
 	if err := source.ValidateDocument(req.Source); err != nil {
-		return contracts.ChunkResult{}, chunkerErrorf("validate source document: %w", err)
+		return contracts.ChunkPlanResult{}, chunkerErrorf("validate source document: %w", err)
 	}
 	var response chunkResponse
 	if _, err := c.llm.CompleteStructured(ctx, contracts.StructuredCompletionRequest{
@@ -105,19 +110,19 @@ func (c *Chunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contra
 		SessionID:     req.SessionID,
 		Inputs:        shared.PromptInputs(req.SourceInput, req.References),
 	}, &response); err != nil {
-		return contracts.ChunkResult{}, chunkerErrorf("complete structured output: %w", err)
+		return contracts.ChunkPlanResult{}, chunkerErrorf("complete structured output: %w", err)
 	}
 
 	warnings, err := warningsFromCaveats(response.BoundaryCaveats)
 	if err != nil {
-		return contracts.ChunkResult{}, chunkerErrorf("malformed structured output: %w", err)
+		return contracts.ChunkPlanResult{}, chunkerErrorf("malformed structured output: %w", err)
 	}
-	chunks, err := chunksFromResponse(req.Source, response)
+	plan, err := planFromResponse(req.Source, response, warnings)
 	if err != nil {
-		return contracts.ChunkResult{}, chunkerErrorf("malformed structured output: %w", err)
+		return contracts.ChunkPlanResult{}, chunkerErrorf("malformed structured output: %w", err)
 	}
-	return contracts.ChunkResult{
-		Chunks:   chunks,
+	return contracts.ChunkPlanResult{
+		Plan:     plan,
 		Warnings: warnings,
 	}, nil
 }
@@ -154,12 +159,12 @@ func DecodeOptions(options map[string]any) (Options, error) {
 	return Options{}, nil
 }
 
-func chunksFromResponse(doc *source.SourceDocument, response chunkResponse) ([]source.Chunk, error) {
+func planFromResponse(doc *source.SourceDocument, response chunkResponse, warnings []contracts.Warning) (source.ChunkPlan, error) {
 	if response.Scenes == nil {
-		return nil, fmt.Errorf("scenes must be present")
+		return source.ChunkPlan{}, fmt.Errorf("scenes must be present")
 	}
 	if len(response.Scenes) == 0 {
-		return nil, fmt.Errorf("scenes must not be empty")
+		return source.ChunkPlan{}, fmt.Errorf("scenes must not be empty")
 	}
 
 	unitIndexes := make(map[int]int, len(doc.Units))
@@ -167,86 +172,75 @@ func chunksFromResponse(doc *source.SourceDocument, response chunkResponse) ([]s
 		unitIndexes[unit.ID] = i
 	}
 
-	chunks := make([]source.Chunk, 0, len(response.Scenes))
+	ranges := make([]source.ChunkRange, 0, len(response.Scenes))
 	previousEnd := -1
 	for i, scene := range response.Scenes {
 		normalized, err := normalizeScene(doc, i, scene)
 		if err != nil {
-			return nil, err
+			return source.ChunkPlan{}, err
 		}
 
 		startIndex, ok := unitIndexes[normalized.StartUnitID]
 		if !ok {
-			return nil, fmt.Errorf("scene[%d] start_unit_id %d was not found", i, normalized.StartUnitID)
+			return source.ChunkPlan{}, fmt.Errorf("scene[%d] start_unit_id %d was not found", i, normalized.StartUnitID)
 		}
 		endIndex, ok := unitIndexes[normalized.EndUnitID]
 		if !ok {
-			return nil, fmt.Errorf("scene[%d] end_unit_id %d was not found", i, normalized.EndUnitID)
+			return source.ChunkPlan{}, fmt.Errorf("scene[%d] end_unit_id %d was not found", i, normalized.EndUnitID)
 		}
 		if startIndex > endIndex {
-			return nil, fmt.Errorf("scene[%d] start_unit_id %d appears after end_unit_id %d", i, normalized.StartUnitID, normalized.EndUnitID)
+			return source.ChunkPlan{}, fmt.Errorf("scene[%d] start_unit_id %d appears after end_unit_id %d", i, normalized.StartUnitID, normalized.EndUnitID)
 		}
 
 		if i == 0 && startIndex != 0 {
-			return nil, fmt.Errorf("first scene must start at first source unit %d", doc.Units[0].ID)
+			return source.ChunkPlan{}, fmt.Errorf("first scene must start at first source unit %d", doc.Units[0].ID)
 		}
 		if i > 0 {
 			if startIndex <= previousEnd {
-				return nil, fmt.Errorf("scene[%d] overlaps previous scene", i)
+				return source.ChunkPlan{}, fmt.Errorf("scene[%d] overlaps previous scene", i)
 			}
 			if startIndex > previousEnd+1 {
-				return nil, fmt.Errorf("scene[%d] leaves a gap after previous scene", i)
+				return source.ChunkPlan{}, fmt.Errorf("scene[%d] leaves a gap after previous scene", i)
 			}
 		}
 		previousEnd = endIndex
 
-		units := cloneUnits(doc.Units[startIndex : endIndex+1])
-		content, err := chunkContent(units)
+		annotation, err := json.Marshal(struct {
+			ShortTitle         string   `json:"short_title"`
+			PrimaryMode        string   `json:"primary_mode"`
+			MainParticipants   []string `json:"main_participants"`
+			Summary            string   `json:"summary"`
+			BoundaryNote       string   `json:"boundary_note"`
+			BoundaryConfidence string   `json:"boundary_confidence"`
+		}{normalized.ShortTitle, normalized.PrimaryMode, normalized.MainParticipants, normalized.Summary, normalized.BoundaryNote, normalized.BoundaryConfidence})
 		if err != nil {
-			return nil, err
+			return source.ChunkPlan{}, fmt.Errorf("encode scene[%d] annotation: %w", i, err)
 		}
-		chunks = append(chunks, source.Chunk{
-			ID:       fmt.Sprintf("scene-%06d", i+1),
-			SourceID: doc.ID,
-			Index:    i,
-			Ref: source.SourceRef{
-				SourceID:    doc.ID,
-				StartUnitID: units[0].Ref.StartUnitID,
-				EndUnitID:   units[len(units)-1].Ref.EndUnitID,
-			},
-			Content:   content,
-			MediaType: "application/json",
-			Units:     units,
-			Metadata: map[string]any{
-				"scene_title":         normalized.ShortTitle,
-				"primary_mode":        normalized.PrimaryMode,
-				"main_participants":   append([]string(nil), normalized.MainParticipants...),
-				"summary":             normalized.Summary,
-				"boundary_note":       normalized.BoundaryNote,
-				"boundary_confidence": normalized.BoundaryConfidence,
-				"start_unit_id":       normalized.StartUnitID,
-				"end_unit_id":         normalized.EndUnitID,
-				"unit_count":          len(units),
-			},
+		ranges = append(ranges, source.ChunkRange{
+			StartUnitID: normalized.StartUnitID,
+			EndUnitID:   normalized.EndUnitID,
+			Annotations: source.ChunkAnnotations{annotationNamespace: annotation},
 		})
 	}
 
 	if previousEnd != len(doc.Units)-1 {
-		return nil, fmt.Errorf("final scene must end at final source unit %d", doc.Units[len(doc.Units)-1].ID)
+		return source.ChunkPlan{}, fmt.Errorf("final scene must end at final source unit %d", doc.Units[len(doc.Units)-1].ID)
 	}
-	return chunks, nil
-}
-
-func chunkContent(units []source.SourceUnit) ([]byte, error) {
-	content, err := json.Marshal(struct {
-		Units []source.SourceUnit `json:"units"`
-	}{
-		Units: units,
-	})
+	caveats := make([]string, 0, len(warnings))
+	for _, warning := range warnings {
+		caveats = append(caveats, warning.Message)
+	}
+	annotation, err := json.Marshal(struct {
+		BoundaryCaveats []string `json:"boundary_caveats"`
+	}{BoundaryCaveats: caveats})
 	if err != nil {
-		return nil, fmt.Errorf("encode chunk content: %w", err)
+		return source.ChunkPlan{}, fmt.Errorf("encode plan annotation: %w", err)
 	}
-	return content, nil
+	return source.ChunkPlan{
+		SourceDigest: doc.Digest,
+		Ranges:       ranges,
+		Annotations:  source.ChunkAnnotations{annotationNamespace: annotation},
+	}, nil
 }
 
 func normalizeScene(doc *source.SourceDocument, index int, scene sceneResponse) (normalizedScene, error) {
@@ -347,31 +341,6 @@ func warningsFromCaveats(caveats []string) ([]contracts.Warning, error) {
 	return warnings, nil
 }
 
-func cloneUnits(units []source.SourceUnit) []source.SourceUnit {
-	out := make([]source.SourceUnit, 0, len(units))
-	for _, unit := range units {
-		out = append(out, source.SourceUnit{
-			ID:       unit.ID,
-			Kind:     unit.Kind,
-			Text:     unit.Text,
-			Ref:      unit.Ref,
-			Metadata: cloneMetadata(unit.Metadata),
-		})
-	}
-	return out
-}
-
-func cloneMetadata(metadata map[string]any) map[string]any {
-	if len(metadata) == 0 {
-		return nil
-	}
-	out := make(map[string]any, len(metadata))
-	for key, value := range metadata {
-		out[key] = value
-	}
-	return out
-}
-
 func chunkerErrorf(format string, args ...any) error {
 	return fmt.Errorf("dnd scenes chunker: "+format, args...)
 }

internal/modules/dnd/chunk/scenes/chunker_test.go

@@ -25,7 +25,7 @@ func TestNewModuleSpecAndRegister(t *testing.T) {
 		Key:            Key,
 		Stage:          pipeline.StageChunk,
 		Requires:       []string{"source.transcript"},
-		Provides:       []string{"chunks", "chunks.scenes"},
+		Provides:       []string{"chunks"},
 		ReferenceSlots: wantReferenceSlots(),
 	}
 	if got := ModuleSpec(); !reflect.DeepEqual(got, want) {
@@ -110,7 +110,7 @@ func wantReferenceSlots() []contracts.ReferenceSlot {
 	}
 }
 
-func TestChunkReturnsSceneChunksFromStructuredOutput(t *testing.T) {
+func TestPlanReturnsSceneRangesAndAnnotationsFromStructuredOutput(t *testing.T) {
 	client := &fakeScenesLLMClient{
 		response: chunkResponse{
 			Scenes: []sceneResponse{
@@ -139,9 +139,9 @@ func TestChunkReturnsSceneChunksFromStructuredOutput(t *testing.T) {
 		},
 	}
 
-	result, err := newChunker(t, client).Chunk(context.Background(), chunkRequest())
+	result, err := newChunker(t, client).Plan(context.Background(), chunkRequest())
 	if err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
 
 	if len(client.requests) != 1 {
@@ -177,36 +177,41 @@ func TestChunkReturnsSceneChunksFromStructuredOutput(t *testing.T) {
 		t.Fatalf("glossary input = %q, want empty reference placeholder", got)
 	}
 
-	if got := chunkIDs(result.Chunks); !reflect.DeepEqual(got, []string{"scene-000001", "scene-000002"}) {
-		t.Fatalf("chunk IDs = %#v, want deterministic scene IDs", got)
+	if result.Plan.SourceDigest != "sha256:source" {
+		t.Fatalf("SourceDigest = %q, want source digest", result.Plan.SourceDigest)
 	}
-	gotUnits := [][]int{unitIDs(result.Chunks[0].Units), unitIDs(result.Chunks[1].Units)}
-	wantUnits := [][]int{{1, 2}, {3, 4}}
-	if !reflect.DeepEqual(gotUnits, wantUnits) {
-		t.Fatalf("chunk units = %#v, want %#v", gotUnits, wantUnits)
+	wantRanges := []source.ChunkRange{{StartUnitID: 1, EndUnitID: 2}, {StartUnitID: 3, EndUnitID: 4}}
+	if len(result.Plan.Ranges) != len(wantRanges) {
+		t.Fatalf("ranges = %#v, want two", result.Plan.Ranges)
 	}
-	first := result.Chunks[0]
-	if first.SourceID != "session-alpha" || first.Index != 0 {
-		t.Fatalf("first chunk = %#v, want source and index fields", first)
+	for i, want := range wantRanges {
+		if result.Plan.Ranges[i].StartUnitID != want.StartUnitID || result.Plan.Ranges[i].EndUnitID != want.EndUnitID {
+			t.Fatalf("range[%d] = %#v, want %#v", i, result.Plan.Ranges[i], want)
+		}
 	}
-	if first.Ref != (source.SourceRef{SourceID: "session-alpha", StartUnitID: 1, EndUnitID: 2}) {
-		t.Fatalf("first ref = %#v, want session-alpha:1-2", first.Ref)
+	var firstAnnotation map[string]any
+	if err := json.Unmarshal(result.Plan.Ranges[0].Annotations[annotationNamespace], &firstAnnotation); err != nil {
+		t.Fatalf("decode first scene annotation: %v", err)
 	}
-	if first.MediaType != "application/json" || len(first.Content) == 0 {
-		t.Fatalf("first payload = media type %q length %d, want JSON content", first.MediaType, len(first.Content))
+	wantFirst := map[string]any{
+		"short_title": "Goblin parley", "primary_mode": "Discussion",
+		"main_participants":   []any{"Aria", "Goblin scout"},
+		"summary":             "The party negotiates with a scout.",
+		"boundary_note":       "The scene covers the discussion before fighting starts.",
+		"boundary_confidence": "High",
 	}
-	if first.Metadata["scene_title"] != "Goblin parley" ||
-		first.Metadata["primary_mode"] != "Discussion" ||
-		first.Metadata["summary"] != "The party negotiates with a scout." ||
-		first.Metadata["boundary_note"] != "The scene covers the discussion before fighting starts." ||
-		first.Metadata["boundary_confidence"] != "High" ||
-		first.Metadata["start_unit_id"] != 1 ||
-		first.Metadata["end_unit_id"] != 2 ||
-		first.Metadata["unit_count"] != 2 {
-		t.Fatalf("first metadata = %#v, want scene metadata", first.Metadata)
+	if !reflect.DeepEqual(firstAnnotation, wantFirst) {
+		t.Fatalf("first scene annotation = %#v, want %#v", firstAnnotation, wantFirst)
 	}
-	if got, ok := first.Metadata["main_participants"].([]string); !ok || !reflect.DeepEqual(got, []string{"Aria", "Goblin scout"}) {
-		t.Fatalf("main_participants = %#v, want trimmed participant slice", first.Metadata["main_participants"])
+	if len(firstAnnotation) != 6 {
+		t.Fatalf("first scene annotation keys = %#v, want exact six fields", firstAnnotation)
+	}
+	var planAnnotation map[string]any
+	if err := json.Unmarshal(result.Plan.Annotations[annotationNamespace], &planAnnotation); err != nil {
+		t.Fatalf("decode plan annotation: %v", err)
+	}
+	if !reflect.DeepEqual(planAnnotation, map[string]any{"boundary_caveats": []any{"The transition into combat is gradual."}}) || len(planAnnotation) != 1 {
+		t.Fatalf("plan annotation = %#v, want normalized caveats only", planAnnotation)
 	}
 	if got := result.Warnings; len(got) != 1 ||
 		got[0].Scope != Key ||
@@ -216,7 +221,7 @@ func TestChunkReturnsSceneChunksFromStructuredOutput(t *testing.T) {
 	}
 }
 
-func TestChunkPassesReferencesAsPromptInputs(t *testing.T) {
+func TestPlanPassesReferencesAsPromptInputs(t *testing.T) {
 	client := &fakeScenesLLMClient{response: chunkResponse{
 		Scenes: []sceneResponse{
 			{
@@ -255,8 +260,8 @@ func TestChunkPassesReferencesAsPromptInputs(t *testing.T) {
 		},
 	}
 
-	if _, err := newChunker(t, client).Chunk(context.Background(), req); err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+	if _, err := newChunker(t, client).Plan(context.Background(), req); err != nil {
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
 	request := client.requests[0]
 	if got := string(request.Inputs["players"].Content); got != "Alice: Aria" {
@@ -293,7 +298,7 @@ func TestPromptInputsMapLegacyRosterReferenceToParty(t *testing.T) {
 	}
 }
 
-func TestChunkRejectsWhitespaceOnlyBoundaryCaveats(t *testing.T) {
+func TestPlanRejectsWhitespaceOnlyBoundaryCaveats(t *testing.T) {
 	client := &fakeScenesLLMClient{
 		response: chunkResponse{
 			Scenes: validSceneResponse().Scenes,
@@ -303,46 +308,38 @@ func TestChunkRejectsWhitespaceOnlyBoundaryCaveats(t *testing.T) {
 		},
 	}
 
-	_, err := newChunker(t, client).Chunk(context.Background(), chunkRequest())
+	_, err := newChunker(t, client).Plan(context.Background(), chunkRequest())
 	if err == nil {
-		t.Fatal("Chunk() error = nil, want malformed structured output error")
+		t.Fatal("Plan() error = nil, want malformed structured output error")
 	}
 	if !strings.Contains(err.Error(), "dnd scenes chunker") || !strings.Contains(err.Error(), "malformed structured output") || !strings.Contains(err.Error(), "boundary_caveats[0]") {
-		t.Fatalf("Chunk() error = %q, want malformed boundary caveat context", err.Error())
+		t.Fatalf("Plan() error = %q, want malformed boundary caveat context", err.Error())
 	}
 }
 
-func TestChunkDefensivelyCopiesSourceUnitsAndMetadata(t *testing.T) {
+func TestPlanDefensivelyCopiesAnnotationValues(t *testing.T) {
 	doc := sceneSourceDocument()
 	client := &fakeScenesLLMClient{response: validSceneResponse()}
 
-	result, err := newChunker(t, client).Chunk(context.Background(), contracts.ChunkRequest{
+	result, err := newChunker(t, client).Plan(context.Background(), contracts.ChunkRequest{
 		Source:      doc,
 		SourceInput: sceneSourceInput(),
 		SessionID:   "session-123",
 		LLMProfile:  "profile-scenes",
 	})
 	if err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
 
-	doc.Units[0].ID = 99
-	doc.Units[0].Ref.SourceID = "mutated"
-	doc.Units[0].Metadata["speaker"] = "mutated"
 	client.response.Scenes[0].MainParticipants[0] = "mutated"
-
-	if result.Chunks[0].Units[0].ID != 1 {
-		t.Fatalf("chunk unit ID changed after source mutation: %#v", result.Chunks[0].Units[0])
+	var annotation struct {
+		MainParticipants []string `json:"main_participants"`
 	}
-	if got := result.Chunks[0].Units[0].Ref.SourceID; got != "session-alpha" {
-		t.Fatalf("chunk unit ref changed after source mutation: %#v", result.Chunks[0].Units[0].Ref)
+	if err := json.Unmarshal(result.Plan.Ranges[0].Annotations[annotationNamespace], &annotation); err != nil {
+		t.Fatalf("decode annotation: %v", err)
 	}
-	if result.Chunks[0].Units[0].Metadata["speaker"] != "Alice" {
-		t.Fatalf("chunk unit metadata changed after source mutation: %#v", result.Chunks[0].Units[0].Metadata)
-	}
-	participants, ok := result.Chunks[0].Metadata["main_participants"].([]string)
-	if !ok || participants[0] != "Aria" {
-		t.Fatalf("participants = %#v, want defensive copy", result.Chunks[0].Metadata["main_participants"])
+	if !reflect.DeepEqual(annotation.MainParticipants, []string{"Aria"}) {
+		t.Fatalf("participants = %#v, want defensive copy", annotation.MainParticipants)
 	}
 }
 
@@ -375,7 +372,7 @@ func TestChunkerManifestMetadataIncludesPromptAndSchemaProvenance(t *testing.T)
 	}
 }
 
-func TestChunkRejectsInvalidRequests(t *testing.T) {
+func TestPlanRejectsInvalidRequests(t *testing.T) {
 	validClient := &fakeScenesLLMClient{response: validSceneResponse()}
 	validReq := chunkRequest()
 	canceledCtx, cancel := context.WithCancel(context.Background())
@@ -402,18 +399,18 @@ func TestChunkRejectsInvalidRequests(t *testing.T) {
 
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
-			_, err := tt.chunker.Chunk(tt.ctx, tt.req)
+			_, err := tt.chunker.Plan(tt.ctx, tt.req)
 			if err == nil {
-				t.Fatal("Chunk() error = nil, want error")
+				t.Fatal("Plan() error = nil, want error")
 			}
 			if !strings.Contains(err.Error(), "dnd scenes") || !strings.Contains(err.Error(), tt.want) {
-				t.Fatalf("Chunk() error = %q, want module context and %q", err.Error(), tt.want)
+				t.Fatalf("Plan() error = %q, want module context and %q", err.Error(), tt.want)
 			}
 		})
 	}
 }
 
-func TestChunkRejectsMalformedStructuredOutput(t *testing.T) {
+func TestPlanRejectsMalformedStructuredOutput(t *testing.T) {
 	tests := []struct {
 		name     string
 		response chunkResponse
@@ -495,26 +492,26 @@ func TestChunkRejectsMalformedStructuredOutput(t *testing.T) {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			client := &fakeScenesLLMClient{response: tt.response}
-			_, err := newChunker(t, client).Chunk(context.Background(), chunkRequest())
+			_, err := newChunker(t, client).Plan(context.Background(), chunkRequest())
 			if err == nil {
-				t.Fatal("Chunk() error = nil, want error")
+				t.Fatal("Plan() error = nil, want error")
 			}
 			if !strings.Contains(err.Error(), "dnd scenes") || !strings.Contains(err.Error(), tt.want) {
-				t.Fatalf("Chunk() error = %q, want module context and %q", err.Error(), tt.want)
+				t.Fatalf("Plan() error = %q, want module context and %q", err.Error(), tt.want)
 			}
 		})
 	}
 }
 
-func TestChunkWrapsLLMClientError(t *testing.T) {
+func TestPlanWrapsLLMClientError(t *testing.T) {
 	client := &fakeScenesLLMClient{err: errors.New("provider unavailable")}
 
-	_, err := newChunker(t, client).Chunk(context.Background(), chunkRequest())
+	_, err := newChunker(t, client).Plan(context.Background(), chunkRequest())
 	if err == nil {
-		t.Fatal("Chunk() error = nil, want LLM error")
+		t.Fatal("Plan() error = nil, want LLM error")
 	}
 	if !strings.Contains(err.Error(), "dnd scenes") || !strings.Contains(err.Error(), "provider unavailable") {
-		t.Fatalf("Chunk() error = %q, want wrapped LLM context", err.Error())
+		t.Fatalf("Plan() error = %q, want wrapped LLM context", err.Error())
 	}
 }
 

internal/modules/generic/chunk/units/chunker.go

@@ -38,81 +38,54 @@ func (c *Chunker) Key() string {
 	return Key
 }
 
+func (*Chunker) ExecutionClass() contracts.ExecutionClass {
+	return contracts.ExecutionClassDeterministic
+}
+
 func (c *Chunker) ReferenceSlots() []contracts.ReferenceSlot {
 	return nil
 }
 
-func (c *Chunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkResult, error) {
+func (c *Chunker) Plan(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
 	if c == nil {
-		return contracts.ChunkResult{}, chunkerErrorf("chunker must not be nil")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("chunker must not be nil")
 	}
 	if c.options.MaxUnits <= 0 || c.options.OverlapUnits < 0 || c.options.OverlapUnits >= c.options.MaxUnits {
-		return contracts.ChunkResult{}, chunkerErrorf("chunker options must be initialized by construction")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("chunker options must be initialized by construction")
 	}
 	if ctx == nil {
-		return contracts.ChunkResult{}, chunkerErrorf("context must not be nil")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("context must not be nil")
 	}
 	if err := ctx.Err(); err != nil {
-		return contracts.ChunkResult{}, chunkerErrorf("context error before chunking: %w", err)
+		return contracts.ChunkPlanResult{}, chunkerErrorf("context error before chunking: %w", err)
 	}
 	if req.Source == nil {
-		return contracts.ChunkResult{}, chunkerErrorf("source must not be nil")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("source must not be nil")
 	}
 	if len(req.Source.Units) == 0 {
-		return contracts.ChunkResult{}, chunkerErrorf("source units must not be empty")
+		return contracts.ChunkPlanResult{}, chunkerErrorf("source units must not be empty")
 	}
 	if err := source.ValidateDocument(req.Source); err != nil {
-		return contracts.ChunkResult{}, chunkerErrorf("validate source document: %w", err)
+		return contracts.ChunkPlanResult{}, chunkerErrorf("validate source document: %w", err)
 	}
 
 	step := c.options.MaxUnits - c.options.OverlapUnits
-	chunks := make([]source.Chunk, 0, (len(req.Source.Units)+step-1)/step)
+	ranges := make([]source.ChunkRange, 0, (len(req.Source.Units)+step-1)/step)
 	for start := 0; start < len(req.Source.Units); start += step {
 		end := start + c.options.MaxUnits
 		if end > len(req.Source.Units) {
 			end = len(req.Source.Units)
 		}
-		units := cloneUnits(req.Source.Units[start:end])
-		content, err := chunkContent(units)
-		if err != nil {
-			return contracts.ChunkResult{}, err
-		}
-		chunks = append(chunks, source.Chunk{
-			ID:       fmt.Sprintf("chunk-%06d", len(chunks)+1),
-			SourceID: req.Source.ID,
-			Index:    len(chunks),
-			Ref: source.SourceRef{
-				SourceID:    req.Source.ID,
-				StartUnitID: units[0].Ref.StartUnitID,
-				EndUnitID:   units[len(units)-1].Ref.EndUnitID,
-			},
-			Content:   content,
-			MediaType: "application/json",
-			Units:     units,
-			Metadata: map[string]any{
-				"start_unit_id": units[0].ID,
-				"end_unit_id":   units[len(units)-1].ID,
-				"unit_count":    len(units),
-			},
+		ranges = append(ranges, source.ChunkRange{
+			StartUnitID: req.Source.Units[start].ID,
+			EndUnitID:   req.Source.Units[end-1].ID,
 		})
 		if end == len(req.Source.Units) {
 			break
 		}
 	}
 
-	return contracts.ChunkResult{Chunks: chunks}, nil
-}
-
-func chunkContent(units []source.SourceUnit) ([]byte, error) {
-	content, err := json.Marshal(struct {
-		Units []source.SourceUnit `json:"units"`
-	}{
-		Units: units,
-	})
-	if err != nil {
-		return nil, chunkerErrorf("encode chunk content: %w", err)
-	}
-	return content, nil
+	return contracts.ChunkPlanResult{Plan: source.ChunkPlan{SourceDigest: req.Source.Digest, Ranges: ranges}}, nil
 }
 
 func ModuleSpec() pipeline.ModuleSpec {
@@ -251,31 +224,6 @@ func minInt() int64 {
 	return -maxInt() - 1
 }
 
-func cloneUnits(units []source.SourceUnit) []source.SourceUnit {
-	out := make([]source.SourceUnit, 0, len(units))
-	for _, unit := range units {
-		out = append(out, source.SourceUnit{
-			ID:       unit.ID,
-			Kind:     unit.Kind,
-			Text:     unit.Text,
-			Ref:      unit.Ref,
-			Metadata: cloneMetadata(unit.Metadata),
-		})
-	}
-	return out
-}
-
-func cloneMetadata(metadata map[string]any) map[string]any {
-	if len(metadata) == 0 {
-		return nil
-	}
-	out := make(map[string]any, len(metadata))
-	for key, value := range metadata {
-		out[key] = value
-	}
-	return out
-}
-
 func chunkerErrorf(format string, args ...any) error {
 	return fmt.Errorf("generic chunker: "+format, args...)
 }

internal/modules/generic/chunk/units/chunker_test.go

@@ -48,72 +48,51 @@ func TestModuleSpecAndRegister(t *testing.T) {
 	if err != nil {
 		t.Fatalf("BuildWithRequest(%q) error = %v, want nil", Key, err)
 	}
-	result, err := configured.Chunk(context.Background(), contracts.ChunkRequest{Source: testSource(2)})
-	if err != nil || len(result.Chunks) != 2 {
-		t.Fatalf("constructed chunker result = %#v, %v; want two chunks", result, err)
+	result, err := configured.Plan(context.Background(), contracts.ChunkRequest{Source: testSource(2)})
+	if err != nil || len(result.Plan.Ranges) != 2 {
+		t.Fatalf("constructed chunker result = %#v, %v; want two ranges", result, err)
 	}
 }
 
-func TestChunkUsesDefaultsForSingleChunk(t *testing.T) {
-	result, err := newChunker(t, nil).Chunk(context.Background(), contracts.ChunkRequest{Source: testSource(3)})
+func TestPlanUsesDefaultsForSingleRange(t *testing.T) {
+	result, err := newChunker(t, nil).Plan(context.Background(), contracts.ChunkRequest{Source: testSource(3)})
 	if err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
 
-	if got := chunkIDs(result.Chunks); !reflect.DeepEqual(got, []string{"chunk-000001"}) {
-		t.Fatalf("chunk IDs = %#v, want one stable ID", got)
+	if result.Plan.SourceDigest != "sha256:source" || !reflect.DeepEqual(result.Plan.Ranges, []source.ChunkRange{{StartUnitID: 1, EndUnitID: 3}}) {
+		t.Fatalf("Plan = %#v, want source digest and one complete range", result.Plan)
 	}
-	chunk := result.Chunks[0]
-	if chunk.Index != 0 || chunk.SourceID != "source-1" {
-		t.Fatalf("chunk = %#v, want source and index fields", chunk)
-	}
-	if got := unitIDs(chunk.Units); !reflect.DeepEqual(got, []int{1, 2, 3}) {
-		t.Fatalf("unit IDs = %#v, want all units", got)
-	}
-	if chunk.Ref != (source.SourceRef{SourceID: "source-1", StartUnitID: 1, EndUnitID: 3}) {
-		t.Fatalf("chunk ref = %#v, want source-1:1-3", chunk.Ref)
-	}
-	if chunk.MediaType != "application/json" || len(chunk.Content) == 0 {
-		t.Fatalf("chunk payload = media type %q length %d, want JSON content", chunk.MediaType, len(chunk.Content))
-	}
-	if chunk.Metadata["start_unit_id"] != 1 || chunk.Metadata["end_unit_id"] != 3 || chunk.Metadata["unit_count"] != 3 {
-		t.Fatalf("metadata = %#v, want chunk bounds", chunk.Metadata)
+	if len(result.Plan.Annotations) != 0 || len(result.Plan.Ranges[0].Annotations) != 0 {
+		t.Fatalf("Plan annotations = %#v / %#v, want none", result.Plan.Annotations, result.Plan.Ranges[0].Annotations)
 	}
 }
 
-func TestChunkExactBoundaries(t *testing.T) {
-	result, err := newChunker(t, map[string]any{"max_units": 2}).Chunk(context.Background(), contracts.ChunkRequest{Source: testSource(6)})
+func TestPlanExactBoundaries(t *testing.T) {
+	result, err := newChunker(t, map[string]any{"max_units": 2}).Plan(context.Background(), contracts.ChunkRequest{Source: testSource(6)})
 	if err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
 
-	if got := chunkIDs(result.Chunks); !reflect.DeepEqual(got, []string{"chunk-000001", "chunk-000002", "chunk-000003"}) {
-		t.Fatalf("chunk IDs = %#v, want stable IDs", got)
-	}
-	gotUnits := [][]int{unitIDs(result.Chunks[0].Units), unitIDs(result.Chunks[1].Units), unitIDs(result.Chunks[2].Units)}
-	wantUnits := [][]int{{1, 2}, {3, 4}, {5, 6}}
-	if !reflect.DeepEqual(gotUnits, wantUnits) {
-		t.Fatalf("chunk units = %#v, want %#v", gotUnits, wantUnits)
+	want := []source.ChunkRange{{StartUnitID: 1, EndUnitID: 2}, {StartUnitID: 3, EndUnitID: 4}, {StartUnitID: 5, EndUnitID: 6}}
+	if !reflect.DeepEqual(result.Plan.Ranges, want) {
+		t.Fatalf("ranges = %#v, want %#v", result.Plan.Ranges, want)
 	}
 }
 
-func TestChunkOverlap(t *testing.T) {
-	result, err := newChunker(t, map[string]any{"max_units": 3, "overlap_units": 1}).Chunk(context.Background(), contracts.ChunkRequest{Source: testSource(7)})
+func TestPlanOverlap(t *testing.T) {
+	result, err := newChunker(t, map[string]any{"max_units": 3, "overlap_units": 1}).Plan(context.Background(), contracts.ChunkRequest{Source: testSource(7)})
 	if err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
 
-	gotUnits := make([][]int, 0, len(result.Chunks))
-	for _, chunk := range result.Chunks {
-		gotUnits = append(gotUnits, unitIDs(chunk.Units))
-	}
-	wantUnits := [][]int{{1, 2, 3}, {3, 4, 5}, {5, 6, 7}}
-	if !reflect.DeepEqual(gotUnits, wantUnits) {
-		t.Fatalf("chunk units = %#v, want %#v", gotUnits, wantUnits)
+	want := []source.ChunkRange{{StartUnitID: 1, EndUnitID: 3}, {StartUnitID: 3, EndUnitID: 5}, {StartUnitID: 5, EndUnitID: 7}}
+	if !reflect.DeepEqual(result.Plan.Ranges, want) {
+		t.Fatalf("ranges = %#v, want %#v", result.Plan.Ranges, want)
 	}
 }
 
-func TestChunkRejectsInvalidOptions(t *testing.T) {
+func TestPlanRejectsInvalidOptions(t *testing.T) {
 	tests := []struct {
 		name    string
 		options map[string]any
@@ -141,42 +120,36 @@ func TestChunkRejectsInvalidOptions(t *testing.T) {
 	}
 }
 
-func TestChunkRejectsEmptySource(t *testing.T) {
+func TestPlanRejectsEmptySource(t *testing.T) {
 	doc := testSource(1)
 	doc.Units = nil
 
-	_, err := newChunker(t, nil).Chunk(context.Background(), contracts.ChunkRequest{Source: doc})
+	_, err := newChunker(t, nil).Plan(context.Background(), contracts.ChunkRequest{Source: doc})
 	if err == nil {
-		t.Fatal("Chunk() error = nil, want empty source error")
+		t.Fatal("Plan() error = nil, want empty source error")
 	}
 	if !strings.Contains(err.Error(), "generic chunker") || !strings.Contains(err.Error(), "units") {
-		t.Fatalf("Chunk() error = %q, want empty source context", err.Error())
+		t.Fatalf("Plan() error = %q, want empty source context", err.Error())
 	}
 }
 
-func TestChunkDefensivelyCopiesUnits(t *testing.T) {
+func TestPlanDoesNotRetainSourceUnits(t *testing.T) {
 	doc := testSource(2)
 
-	result, err := newChunker(t, map[string]any{"max_units": 1}).Chunk(context.Background(), contracts.ChunkRequest{Source: doc})
+	result, err := newChunker(t, map[string]any{"max_units": 1}).Plan(context.Background(), contracts.ChunkRequest{Source: doc})
 	if err != nil {
-		t.Fatalf("Chunk() error = %v, want nil", err)
+		t.Fatalf("Plan() error = %v, want nil", err)
 	}
-	if len(result.Chunks) != 2 {
-		t.Fatalf("len(Chunks) = %d, want 2", len(result.Chunks))
+	if len(result.Plan.Ranges) != 2 {
+		t.Fatalf("len(Ranges) = %d, want 2", len(result.Plan.Ranges))
 	}
 
 	doc.Units[0].ID = 99
 	doc.Units[0].Ref.SourceID = "changed"
 	doc.Units[0].Metadata["speaker"] = "changed"
 
-	if result.Chunks[0].Units[0].ID != 1 {
-		t.Fatalf("chunk unit ID changed after source mutation: %#v", result.Chunks[0].Units[0])
-	}
-	if got := result.Chunks[0].Units[0].Ref.SourceID; got != "source-1" {
-		t.Fatalf("chunk unit ref changed after source mutation: %#v", result.Chunks[0].Units[0].Ref)
-	}
-	if result.Chunks[0].Units[0].Metadata["speaker"] != "speaker-001" {
-		t.Fatalf("chunk unit metadata changed after source mutation: %#v", result.Chunks[0].Units[0].Metadata)
+	if result.Plan.Ranges[0].StartUnitID != 1 || result.Plan.Ranges[0].EndUnitID != 1 {
+		t.Fatalf("first range changed after source mutation: %#v", result.Plan.Ranges[0])
 	}
 }
 
@@ -214,19 +187,3 @@ func testSource(count int) *source.SourceDocument {
 func zeroPad3(value int) string {
 	return fmt.Sprintf("%03d", value)
 }
-
-func chunkIDs(chunks []source.Chunk) []string {
-	ids := make([]string, 0, len(chunks))
-	for _, chunk := range chunks {
-		ids = append(ids, chunk.ID)
-	}
-	return ids
-}
-
-func unitIDs(units []source.SourceUnit) []int {
-	ids := make([]int, 0, len(units))
-	for _, unit := range units {
-		ids = append(ids, unit.ID)
-	}
-	return ids
-}

internal/modules/generic/output/json/encoder.go

@@ -273,11 +273,32 @@ func cloneMetadata(metadata map[string]any) map[string]any {
 	}
 	out := make(map[string]any, len(metadata))
 	for key, value := range metadata {
-		out[key] = value
+		out[key] = cloneJSONMetadataValue(value)
 	}
 	return out
 }
 
+func cloneJSONMetadataValue(value any) any {
+	switch typed := value.(type) {
+	case map[string]any:
+		return cloneMetadata(typed)
+	case []any:
+		out := make([]any, len(typed))
+		for i := range typed {
+			out[i] = cloneJSONMetadataValue(typed[i])
+		}
+		return out
+	case stdjson.RawMessage:
+		return append(stdjson.RawMessage(nil), typed...)
+	case []byte:
+		return append([]byte(nil), typed...)
+	case []string:
+		return append([]string(nil), typed...)
+	default:
+		return value
+	}
+}
+
 func encoderErrorf(format string, args ...any) error {
 	return fmt.Errorf("json output encoder: "+format, args...)
 }

internal/modules/integration/concurrent_runner_test.go

@@ -4,7 +4,6 @@ import (
 	"context"
 	"encoding/json"
 	"errors"
-	"fmt"
 	"sync/atomic"
 	"testing"
 	"time"
@@ -68,12 +67,12 @@ type concurrentChunker struct{}
 
 func (concurrentChunker) Key() string                               { return concurrentChunkerKey }
 func (concurrentChunker) ReferenceSlots() []contracts.ReferenceSlot { return nil }
-func (concurrentChunker) Chunk(_ context.Context, request contracts.ChunkRequest) (contracts.ChunkResult, error) {
-	chunks := make([]source.Chunk, len(request.Source.Units))
+func (concurrentChunker) Plan(_ context.Context, request contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	ranges := make([]source.ChunkRange, len(request.Source.Units))
 	for i, unit := range request.Source.Units {
-		chunks[i] = source.Chunk{ID: fmt.Sprintf("%s:chunk:%d", request.Source.ID, i), SourceID: request.Source.ID, Index: i, Ref: unit.Ref, Content: []byte(fmt.Sprintf(`{"unit":%d}`, unit.ID)), MediaType: "application/json", Units: []source.SourceUnit{unit}}
+		ranges[i] = source.ChunkRange{StartUnitID: unit.ID, EndUnitID: unit.ID}
 	}
-	return contracts.ChunkResult{Chunks: chunks}, nil
+	return contracts.ChunkPlanResult{Plan: source.ChunkPlan{SourceDigest: request.Source.Digest, Ranges: ranges}}, nil
 }
 
 type concurrentExtractor struct {

internal/modules/integration/dnd_spells_config_test.go

@@ -271,19 +271,9 @@ func (dndSpellsChunker) ReferenceSlots() []contracts.ReferenceSlot {
 	return nil
 }
 
-func (dndSpellsChunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkResult, error) {
-	return contracts.ChunkResult{
-		Chunks: []source.Chunk{
-			{
-				ID:        req.Source.ID + ":chunk:0",
-				SourceID:  req.Source.ID,
-				Index:     0,
-				Ref:       source.SourceRef{SourceID: req.Source.ID, StartUnitID: req.Source.Units[0].ID, EndUnitID: req.Source.Units[len(req.Source.Units)-1].ID},
-				Content:   []byte(`{"units":[1,2,3]}`),
-				MediaType: "application/json",
-				Units:     append([]source.SourceUnit(nil), req.Source.Units...),
-			},
-		},
+func (dndSpellsChunker) Plan(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	return contracts.ChunkPlanResult{
+		Plan: source.ChunkPlan{SourceDigest: req.Source.Digest, Ranges: []source.ChunkRange{{StartUnitID: req.Source.Units[0].ID, EndUnitID: req.Source.Units[len(req.Source.Units)-1].ID}}},
 	}, nil
 }
 

internal/modules/seriatim/input/transcript/config_test.go

@@ -220,8 +220,8 @@ func (fakeChunker) Key() string { return "fake/chunk" }
 
 func (fakeChunker) ReferenceSlots() []contracts.ReferenceSlot { return nil }
 
-func (fakeChunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkResult, error) {
-	return contracts.ChunkResult{}, nil
+func (fakeChunker) Plan(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	return contracts.ChunkPlanResult{}, nil
 }
 
 type fakeExtractor struct{}

internal/modules/seriatim/input/transcript/runner_test.go

@@ -177,19 +177,9 @@ func (runnerSeriatimChunker) ReferenceSlots() []contracts.ReferenceSlot {
 	return nil
 }
 
-func (runnerSeriatimChunker) Chunk(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkResult, error) {
-	return contracts.ChunkResult{
-		Chunks: []source.Chunk{
-			{
-				ID:        req.Source.ID + ":chunk:0",
-				SourceID:  req.Source.ID,
-				Index:     0,
-				Ref:       source.SourceRef{SourceID: req.Source.ID, StartUnitID: req.Source.Units[0].ID, EndUnitID: req.Source.Units[len(req.Source.Units)-1].ID},
-				Content:   []byte(`{"units":[1,2]}`),
-				MediaType: "application/json",
-				Units:     append([]source.SourceUnit(nil), req.Source.Units...),
-			},
-		},
+func (runnerSeriatimChunker) Plan(ctx context.Context, req contracts.ChunkRequest) (contracts.ChunkPlanResult, error) {
+	return contracts.ChunkPlanResult{
+		Plan: source.ChunkPlan{SourceDigest: req.Source.Digest, Ranges: []source.ChunkRange{{StartUnitID: req.Source.Units[0].ID, EndUnitID: req.Source.Units[len(req.Source.Units)-1].ID}}},
 	}, nil
 }