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

Bug Description
 Allowed by auto mode classifier ⏺ Bash(printf 'L1\nL2\nL3\nL4\nL5\n' > /tmp/probe.txt echo "wc:"; wc -l < /tmp/probe.txt…) ⎿  wc: 5 node-bytes-and-knownhash: … +3 lines (ctrl+o to expand) ⎿  Allowed by auto mode classifier ⎿  Loaded CLAUDE.md ⎿  API Error: 400 messages.3.content.4: thinking or redacted_thinking blocks in the latest assistant message cannot be modified. These blocks must remain as they were in the original response. ✻ Worked for 4m 55s · 2 shells still running ※ recap: Goal: a live page comparing our optimiz

Environment Info

• Platform: darwin
• Terminal: Apple_Terminal
• Version: 2.1.152
• Feedback ID: a8438842-902b-4cd3-8e48-e665864dd55f

Errors

[{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.137: `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_011CbUvNEK3NFMLxDQHwDZwe\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:63975)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-05-28T11:53:27.022Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.137: `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_011CbUvNjbRSdPtnpoDNiwsx\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:63975)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-05-28T11:53:33.871Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.1.content.6: `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_011CbUvefr9cKEoUpyJcAEw3\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:63975)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-05-28T11:57:10.035Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.33.content.24: `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_011CbVKt9Qdh1PUsRRHcHZdU\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:63975)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-05-28T17:01:49.758Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.33.content.24: `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_011CbVKuEgAch4eVvyhG9Ru7\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:63975)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-05-28T17:02:04.682Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.33.content.24: `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_011CbVKuPcBrGSg6ikmiAC3Z\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:63975)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-05-28T17:02:06.649Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.33.content.24: `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_011CbVKuTMQwSv1WkzGKPNEr\"}\n    at generate (/$bunfs/root/src/entrypoints/cli.js:11:63975)\n    at makeRequest (/$bunfs/root/src/entrypoints/cli.js:51:7694)\n    at processTicksAndRejections (native:7:39)","timestamp":"2026-05-28T17:02…

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