[Bug] Anthropic API Error: Fable 5 safeguards incorrectly flagged legitimate design documentation
Bug Description
I was in the middle of updating implementation plan for webApp design and we were talking about what quickstart MVP of this App should look like and after several edits this safeguard was triggered.
⏺ Update(docs/design/architecture-v1-2026-08-18.md)
Added 6 lines
(message appended, gate pending, line state, agent liveness). Actions go through plain REST
POSTs. No WebSockets — nothing here needs client→server streaming.
Step 7 consolidation (D16). The views below shipped in steps 3–5 as Board / Line / Gate /
Inbox / Agents. Step 7 reshapes them around the quickstart configuration: MainBoard
absorbs the Gate and Inbox pages, Agent Admin stays, Courtyard Admin is added
(housekeeping, defaults, health). This section is updated page by page as each design is
approved — agile, per D16 — rather than re-specified up front.
Views (v1)
- Board — all lines with liveness badges, mode dial (auto/supervised), unread and
Ran 1 shell command, wrote 4 memories
⏺ 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_011CeFQbrhHpxTUbHZ42xdoJ
Environment Info
- Platform: darwin
- Terminal: ghostty
- Version: 2.1.237
- Feedback ID: c68dc43a-6f4f-40b7-ab89-d4cf1685d6c5
Errors
[]