[Bug] Anthropic API Error: Safeguards flagged message - reasoning_extraction

**Bug Description**
Fable 5 started to look at some claude session files and got this

❯ results for experiment C:
[Image #5]
[Image #5]

Excellent — the injection worked this time, and it answered BLUEBIRD: the headless turn genuinely saw the live session's transcript, by title, while the session was open, in ~3.6s. Terminal 1 showing nothing new is the expected blind spot. Before your remaining probes, let me look at the transcript on disk — it can tell us right now whether the injection landed in the same session file or forked:

Ran 1 shell command

⏺ API Error: Fable 5's safeguards flagged this message (https://www.anthropic.com/legal/aup). This sometimes happens with safe, normal conversations. Claude Code can't respond to this message with Fable 5.

Double press esc to edit your last message, or try a different model with /model.

Send feedback with /feedback or learn more: https://support.claude.com/en/articles/15363606

Details: `[reasoning_extraction]`

Request ID: req_011CeDUH85BtB1tfz5tZz5P7

**Environment Info**
- Platform: darwin
- Terminal: ghostty
- Version: 2.1.237
- Feedback ID: 55c589d7-48e9-47bd-b8cd-d18067a5743d

**Errors**
```json
[]
```

No source file, test, or entry point is named in the report. Start by reproducing the reported Claude session interaction on darwin with Terminal 2.1.237 and inspect the resulting reasoning_extraction safeguard error; done would require identifying a project-side cause or a reproducible fix for the flagged request.

Rédigé par le modèle d'indexation à partir du texte de l'issue.