Issue Station
Sign In
Tools hereToolbox

claude-code - 💡(How to fix) Fix [Bug] Anthropic API Error: Cannot Modify Thinking Blocks in Assistant Messages

Official PRs (…)
ON THIS PAGE

Recommended Tools

×6

Utilities matched from this issue’s tags and category — try them while you read without losing context.

GitHub issue graph ai analysis

Paste a GitHub issue URL. We fetch that issue, discover linked issues from bodies/comments/timeline, collect linked pull requests, and produce a structured English report.

The report is written in English Markdown for sharing and archival.

Helpful · Quick feedback

Loading…

Error Message

[{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.22: 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_011CbYb1NJUkBnwdCrRRw4ew"}\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":"2026-05-30T10:21:57.090Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.22: 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_011CbYb4ZGsFqVnJYP5LbTsS"}\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":"2026-05-30T10:22:40.912Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.22: 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_011CbYb4v9yNtsGFUmsX9LjE"}\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":"2026-05-30T10:22:45.313Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.22: 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_011CbYb5fEKf2nCJGCXzkDhU"}\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":"2026-05-30T10:22:55.860Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.22: 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_011CbYb8SBLLo1SAkd4jBfA2"}\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":"2026-05-30T10:23:33.240Z"}]

Code Example

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb1NJUkBnwdCrRRw4ew\"}\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":"2026-05-30T10:21:57.090Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb4ZGsFqVnJYP5LbTsS\"}\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":"2026-05-30T10:22:40.912Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb4v9yNtsGFUmsX9LjE\"}\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":"2026-05-30T10:22:45.313Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb5fEKf2nCJGCXzkDhU\"}\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":"2026-05-30T10:22:55.860Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb8SBLLo1SAkd4jBfA2\"}\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":"2026-05-30T10:23:33.240Z"}]
RAW_BUFFERClick to expand / collapse

Bug Description  API Error: 400 messages.1.content.22: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response.

Environment Info

  • Platform: darwin
  • Terminal: iTerm.app
  • Version: 2.1.154
  • Feedback ID: 2c1bc17f-6c6a-4032-ab49-ad49bc31b09a

Errors

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb1NJUkBnwdCrRRw4ew\"}\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":"2026-05-30T10:21:57.090Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb4ZGsFqVnJYP5LbTsS\"}\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":"2026-05-30T10:22:40.912Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb4v9yNtsGFUmsX9LjE\"}\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":"2026-05-30T10:22:45.313Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb5fEKf2nCJGCXzkDhU\"}\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":"2026-05-30T10:22:55.860Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.22: `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_011CbYb8SBLLo1SAkd4jBfA2\"}\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":"2026-05-30T10:23:33.240Z"}]

Vote matrix · Quick signals

Works
Did the solution work? Tap to confirm.
Easy Fix
Was it a quick fix?
Time Saver
Did it save you time?
Blocking
Was it severely blocking?
Common Issue
Are others likely hitting this too?
Flaky / Intermittent
Is it intermittent?
Verified / Reproducible
Can you reproduce it reliably?
Loading…

Still need to ship something?

×6

Another batch ranked right after the header list — different links, same matching logic.

Back to top recommendations

TRENDING