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

Bug Description
⎿  API Error: 400 messages.13.content.1: 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: 2.1.150
• Feedback ID: c7a81b2e-7cf7-485f-a062-6cc975588f52

Errors

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.13.content.1: `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_011Cbh8XEXPL5zpHhcawGZEL\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:63586)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-06-03T22:39:58.983Z"}]