Enforce generated text report identity

docs/internal/generatedtext.md

@@ -9,9 +9,10 @@ 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
+generated text. `LookupDefinition` requires the exact report, schema, and
+template triple and rejects unknown IDs, unsupported pairs, and a pair that
+belongs to another report 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`.
 
@@ -19,8 +20,9 @@ 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.
+prose to render. Typed decoding requires the exact lowercase JSON field names,
+rejects missing, duplicate, case-variant, and unknown fields, and checks field
+shapes; no general-purpose JSON Schema engine is used at runtime.
 
 ## Render contexts