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claude-code - 💡(How to fix) Fix [Bug] Anthropic API Error: thinking blocks in assistant message cannot be modified

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Error Message

[{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.3.content.76: 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_011CbVcQP9KcjRAb2h66j44f"}\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":"2026-05-28T20:38:29.377Z"},{"error":"Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.3.content.76: 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_011CbVcn9CYa3shme98oJ75o"}\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":"2026-05-28T20:43:24.511Z"}]

Root Cause

Bug Description ⎿  API Error: 400 messages.3.content.76: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response. > no explaination of the root cause

Code Example

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.3.content.76: `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_011CbVcQP9KcjRAb2h66j44f\"}\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":"2026-05-28T20:38:29.377Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.3.content.76: `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_011CbVcn9CYa3shme98oJ75o\"}\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":"2026-05-28T20:43:24.511Z"}]
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Bug Description ⎿  API Error: 400 messages.3.content.76: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response. > no explaination of the root cause

Environment Info

  • Platform: darwin
  • Terminal: Chau7
  • Version: 2.1.154
  • Feedback ID: d10ac0d0-cf8a-463f-a7b1-f72d11681170

Errors

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.3.content.76: `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_011CbVcQP9KcjRAb2h66j44f\"}\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":"2026-05-28T20:38:29.377Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.3.content.76: `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_011CbVcn9CYa3shme98oJ75o\"}\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":"2026-05-28T20:43:24.511Z"}]

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claude-code - 💡(How to fix) Fix [Bug] Anthropic API Error: thinking blocks in assistant message cannot be modified