The fake client raises _refused() from llm.py, and the test checks the whole handback, so a change to the real message fails it (review on #165). Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01J5Utyfzw7gF7UhjRDEtjTk