# Generated Text Internals

`internal/generatedtext` validates the structured prose produced for generated-
text reports and turns validated prose plus rich module values into typed render
contexts. It owns the catalog that pairs a generated-text report definition
with its validator, schema ID, template ID, and context builder. The complete
maintainer-facing context fields belong to [report templates](../templates.md).

## Catalog and validation

The Daily, Today, Tomorrow, and Hourly report definitions each use structured
generated text. `LookupDefinition` rejects unknown schema or template IDs and
unsupported schema/template pairs before the run begins. A handler validates raw JSON, returns a typed
value and canonical normalized JSON, loads its canonical schema through
`internal/promptassets`, builds a render context, and renders through
`internal/reporttemplate`.

Daily, Today, and Tomorrow use a day-style value with required trimmed summary
and one or more nonblank discussion paragraphs. Hourly requires trimmed summary
and a single trimmed discussion string. Every form also requires the
`precipitation_timing` field; an empty string means there is no supported timing
prose to render. Typed decoding rejects missing required fields and unknown JSON
fields; no general-purpose JSON Schema engine is used at runtime.

## Render contexts

The catalog's report-specific builders receive briefing metadata, a rich module
snapshot, collected facts, derived facts, and the matching validated generated
text. They decode the module stanzas needed by the template and build typed
Daily, Today, Tomorrow, or Hourly contexts. Context construction validates
metadata and periods, preserves rich module values, and uses ordered slices for
template iteration rather than maps.

Optional source stanzas become nil or fallback context fields. Missing required
stanzas, type-decoding failures, invalid metadata, or a generated-text type
that does not match the chosen handler fail before template execution. Prompt
packages, raw Promptkit output handling, and template asset lookup remain
outside this package.

## Verification and invariants

Focused tests cover the catalog, each report-specific validator, normalization,
schema/template mismatches, context construction, optional modules, and typed
stanza errors:

```sh
go test ./internal/generatedtext
```

Generated text supplies prose slots only; deterministic weather facts remain in
module and fact values. Every report definition must resolve to exactly one
supported catalog pair.