[Bug] /context command fails with: Anthropic API Error: Invalid message format with thinking blocks and tool use

[rufinus]

Bug Description using "/context" leads to:

This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). The promise rejected with the reason:
Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.33.content.0.type: Expected `thinking` or `redacted_thinking`, but found `tool_use`. When `thinking` is enabled, a final `assistant` message must start with a thinking block (preceeding the lastmost set of `tool_use` and `tool_result` blocks). We recommend you include thinking blocks from previous turns.

Environment Info

• Platform: linux
• Terminal: vte-based
• Version: 2.0.65
• Feedback ID: f6302ca8-02b4-40a5-a830-5ad350cddde4

Errors

[{"error":"ZodError: [\n  {\n    \"code\": \"invalid_type\",\n    \"expected\": \"object\",\n    \"received\": \"undefined\",\n    \"path\": [\n      \"hooks\"\n    ],\n    \"message\": \"Required\"\n  }\n]\n    at get error (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:77:27070)\n    at QJ.parse (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:77:20339)\n    at zSB (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1067:278)\n    at wSB (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1067:3214)\n    at Ld3 (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1067:7453)\n    at async qd3 (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1067:5709)\n    at async file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1067:14558","timestamp":"2025-12-11T11:03:25.328Z"},{"error":"Error: 400 {\"type\":\"error\",\"error\":{\"type\":\"invalid_request_error\",\"message\":\"max_tokens: Extra inputs are not permitted\"},\"request_id\":\"req_011CVznfbLfrGrHZ13XvKY7c\"}\n    at B9.generate (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:122:10379)\n    at MR.makeStatusError (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:860:2195)\n    at MR.makeRequest (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:860:5419)\n    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)\n    at async file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1411:3503\n    at async file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1411:2262\n    at async oc3 (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1410:354)\n    at async mxB (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:1411:2195)\n    at async xLA (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:2082:52)\n    at async kV8 (file:///home/ludwig/.nvm/versions/node/v22.20.0/lib/node_modules/@anthropic-ai/claude-code/cli.js:2082:2358)","timestamp":"2025-12-11T11:03:31.619Z"}]

[github-actions[bot]]

Found 3 possible duplicate issues:

1. https://github.com/anthropics/claude-code/issues/13401
2. https://github.com/anthropics/claude-code/issues/13648
3. https://github.com/anthropics/claude-code/issues/12311

This issue will be automatically closed as a duplicate in 3 days.

• If your issue is a duplicate, please close it and 👍 the existing issue instead
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🤖 Generated with Claude Code

[pentafive]

Confirming this issue on WSL2 (Linux 6.6.87.2-microsoft-standard-WSL2).

My error:

Error: 400 {"type":"error","error":{"type":"invalid_request_error","message":"messages.43.content.0.type: Expected \`thinking\` or \`redacted_thinking\`, but found \`tool_use\`. When \`thinking\` is enabled, a final \`assistant\` message must start with a thinking block (preceeding the lastmost set of \`tool_use\` and \`tool_result\` blocks). We recommend you include thinking blocks from previous turns. To avoid this requirement, disable \`thinking\`. Please consult our documentation at https://docs.claude.com/en/docs/build-with-claude/extended-thinking"},"request_id":"req_011CW1Vb8UZNYZUPz7xTQF1w"}

• Triggered by /context command
• Session had ~105k tokens with multiple tool_use interactions
• Claude Code version: latest
• Model: Opus 4.5