Add transcript description prompt context

README.md

@@ -75,6 +75,17 @@ audita process transcript.json \
   --report-json report.json
 ```
 
+Optional transcript background context:
+
+```sh
+audita process transcript.json \
+  --glossary glossary.yaml \
+  --transcript-description "Brief context that may help resolve ambiguous terms." \
+  --output corrected.json
+```
+
+The transcript description is background context only and does not override transcript content.
+
 Write transcript JSON to stdout (no `--output`):
 
 ```sh
@@ -113,6 +124,17 @@ Precedence:
 - `AUDITA_MODULES` (CSV)
 - CLI: `--modules`
 
+### Transcript Description
+
+CLI:
+- `--transcript-description`
+
+Behavior:
+- optional background context for proposal and LLM-validator prompts;
+- trimmed and length-limited by CLI validation;
+- does not override transcript content;
+- no `AUDITA_*` environment variable is currently defined for this setting.
+
 ### Primary LLM
 
 Environment: