version'."},"query":{"type":"string","description":"The question or task you need help with. Be specific and include relevant details. Good: 'How to set up authentication with JWT in Express.js' or 'React useEffect cleanup function examples'. Bad: 'auth' or 'hooks'. IMPORTANT: Do not include any sensitive or confidential information such as API keys, passwords, credentials, or personal data in your query."}},"required":["libraryId","query"],"additionalProperties":false,"$schema":"http://json-schema.org/draft-07/schema#"}}],"tool_choice":{"type":"auto"},"stream":true},"statusCode":400,"responseHeaders":{"cf-cache-status":"DYNAMIC","cf-ray":"9c503405bf4c1f6e-SIN","connection":"keep-alive","content-length":"200","content-type":"application/json; charset=utf-8","date":"Wed, 28 Jan 2026 11:38:23 GMT","server":"cloudflare","strict-transport-security":"max-age=31536000; includeSubDomains"},"responseBody":"{\"error\":{\"type\":\"invalid_request_error\",\"message\":\"error, status code: 400, message: thinking is enabled but reasoning_content is missing in assistant tool call message at index 101\"},\"type\":\"error\"}","isRetryable":false,"data":{"type":"error","error":{"type":"invalid_request_error","message":"error, status code: 400, message: thinking is enabled but reasoning_content is missing in assistant tool call message at index 101"}}}} stream error
ERROR 2026-01-28T11:38:22 +3ms service=session.processor error=error, status code: 400, message: thinking is enabled but reasoning_content is missing in assistant tool call message at index 101 stack="AI_APICallError: error, status code: 400, message: thinking is enabled but reasoning_content is missing in assistant tool call message at index 101\n at <anonymous> (../../node_modules/.bun/@[email protected]+d6123d32214422cb/node_modules/@ai-sdk/provider-utils/dist/index.mjs:936:18)\n at processTicksAndRejections (native:7:39)" process
INFO 2026-01-28T11:38:22 +0ms service=bus type=session.error publishing
INFO 2026-01-28T11:38:22 +2ms service=bus type=message.updated publishing
Description
Environment
Problem
When using Kimi for Coding with thinking enabled, any session that triggers tool calls (e.g. Grep/Read) fails with HTTP 400.
Actual
OpenCode errors:
error, status code: 400, message: thinking is enabled but reasoning_content is missing in assistant tool call message at index 101
Sometimes the index changes as the conversation grows, e.g.:
... missing in assistant tool call message at index 104
Expected
Tool calls should work while thinking is enabled, or OpenCode should disable thinking / handle reasoning_content correctly for tool call messages (or provide a documented toggle/workaround).
Reproduction steps
Logs (excerpt)
From ~/.local/share/opencode/log/.log:
Notes / workaround
Disabling thinking (thinking: disabled) avoids the crash, but removes visible “thinking”.
Plugins
dcp, auth antigravity
OpenCode version
v1.1.39
Steps to reproduce
opencode auth loginand select Kimi for Codingsubject_anchorinwindows-app/story_presets.json”thinking is enabled but reasoning_content is missing in assistant tool call message at index ...Workaround
If thinking is disabled, tool calls work.
Screenshot and/or share link
Operating System
windows 11 pro, but i use WSL full opencode
Terminal
wezterm