[Bug] Anthropic API Error: Cannot modify thinking blocks in assistant messages during compaction

Bug Description

/compact

⎿ Error: Error during compaction: Error: API Error: 400
{"type":"error","error":{"type":"invalid_request_error","message":"messages.5.content.49: 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_011CVnKMBDQZ3Krv6jrp5NVY"}

Environment Info

• Platform: win32
• Terminal: null
• Version: 2.0.58
• Feedback ID: d60f5e7b-6e81-4ea2-b4d4-2dab01b5b295

Errors

[{"error":"AbortError: The operation was aborted\n    at abortChildProcess (node:child_process:716:27)\n    at AbortSignal.onAbortListener (node:child_process:786:7)\n    at [nodejs.internal.kHybridDispatch] (node:internal/event_target:827:20)\n    at AbortSignal.dispatchEvent (node:internal/event_target:762:26)\n    at runAbort (node:internal/abort_controller:447:10)\n    at abortSignal (node:internal/abort_controller:433:3)\n    at AbortController.abort (node:internal/abort_controller:466:5)\n    at Timeout._onTimeout (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:4275:2086)\n    at listOnTimeout (node:internal/timers:588:17)\n    at process.processTimers (node:internal/timers:523:7)","timestamp":"2025-12-04T18:24:44.725Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.49: `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_011CVnEsW5yQBZRnCF7jPkfH\"}\n    at o2.generate (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:459:9381)\n    at RT.makeStatusError (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:1319:2195)\n    at RT.makeRequest (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:1319:5419)\n    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)\n    at async a61.model (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:3966:10439)\n    at async a61 (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:2149:1872)\n    at async yH9 (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:3966:10593)\n    at async file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:3966:3869\n    at async jt1 (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:1471:2037)\n    at async CYA (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:3966:3839)","timestamp":"2025-12-04T19:59:27.494Z"},{"error":"Error: API Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.49: `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_011CVnEsW5yQBZRnCF7jPkfH\"}\n    at F91 (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:1921:1566)\n    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)\n    at async zI2 (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:1921:9754)\n    at async W$ (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:2298:2159)\n    at async W$ (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:2298:7413)\n    at async W$ (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:2298:7413)\n    at async W$ (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:2298:7413)\n    at async W$ (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:2298:7413)\n    at async W$ (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:2298:7413)\n    at async W$ (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-code/cli.js:2298:7413)","timestamp":"2025-12-04T19:59:27.512Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"messages.5.content.49: `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_011CVnEtEwvXA22xaRkZZWXJ\"}\n    at o2.generate (file:///C:/Users/wolfgang/AppData/Roaming/npm/node_modules/@anthropic-ai/claude-

Note: Error logs were truncated.