[Bug] Anthropic API Error: Cannot modify thinking blocks in assistant message

Bug Description
API Error: 400 messages.1.content.7: 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: zed
• Version: 2.1.154
• Feedback ID: dbc53b65-9e2a-4787-8226-87c6d70939e7

Errors

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.7: `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_011CbVvPngzKK2CaDkwPLZQw\"}\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":"2026-05-29T00:34:23.829Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.7: `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_011CbVvW6CNGi2w3d7yyRgeX\"}\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":"2026-05-29T00:35:49.425Z"}]