[Bug] Anthropic API Error: Cannot Modify Thinking Blocks in Assistant Messages
Status Fixed / completed
Reported on v2.1.154
Maintainer reply None cached
Activity 4 comments · opened May 28, 2026 · closed May 28, 2026
Bug Description
API Error: 400 messages.1.content.8: thinking or redacted_thinking blocks in the latest assistant message
cannot be modified. These blocks must remain as they were in the original response.
I have gotten this error about six times in the last hour, and it completely interrupts my conversation and context. It will not let me proceed unless I /clear, which is super annoying.
Environment Info
- Platform: darwin
- Terminal: Apple_Terminal
- Version: 2.1.154
- Feedback ID: 10b2184e-81c7-4230-aaf5-d268db3a5e25
Errors
[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.8: `thinking` or `redacted_thinking` blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response.\"},\"request_id\":\"req_011CbVbRa54htra5z5iw2vj4\"}\n at generate (/$bunfs/root/src/entrypoints/cli.js:11:63816)\n at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n at processTicksAndRejections (native:7:39)","timestamp":"2026-05-28T20:25:38.407Z"}]
4 Comments
I'm getting this now also.
Usual low quality shit releases, when everyone is running into the same stuff.
Found 3 possible duplicate issues:
This issue will be automatically closed as a duplicate in 3 days.
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