Where does the bug appear (feature/product)? Cursor IDE Describe the Bug When I use my own API key, I get the following error. (Kimi-2.6) Request ID: f8e77e31-d5ef-49af-8b1c-e46a6d6359f3 {“error”:“ERROR_PROVIDER_ERROR”,“details”:{“title”:“Provider Error”,“detail”:“Provider returned error: {"error":{"message":"thinking is enabled but reasoning_content is missing in assistant tool call message at index 3","type":"invalid_request_error"}}”,“isRetryable”:false,“additionalInfo”:{},“buttons”:,“planChoices”:},“isExpected”:true} Provider Error Provider returned error: {“error”:{“message”:“thinking is enabled but reasoning_content is missing in assistant tool call message at index 3”,“type”:“invalid_request_error”}} des: Provider Error Provider returned error: {“error”:{“message”:“thinking is enabled but reasoning_content is missing in assistant tool call message at index 3”,“type”:“invalid_request_error”}} at g8y (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:28853:25419) at p8y (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:28853:24303) at C8y (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:28854:6490) at e4d.run (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:28854:11311) at async Ups.runAgentLoop (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:41180:14333) at async C0h.streamFromAgentBackend (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:41248:12259) at async C0h.getAgentStreamResponse (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:41248:19484) at async Mbt.submitChatMaybeAbortCurrent (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:28969:17002) at async za (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:40232:4234) Steps to Reproduce When I use my own API key, it works in agent mode as long as the K2.6 model is selected. Operating System MacOS Version Information Version: 3.3.4 (Universal) VSCode Version: 1.105.1 Commit: e7262be617643fb2bd412dfdcca2ed82b21d0fa0 Date: 2026-05-03T00:48:29.057Z Layout: editor Build Type: Stable Release Track: Nightly Electron: 39.8.1 Chromium: 142.0.7444.265 Node.js: 22.22.1 V8: 14.2.231.22-electron.0 OS: Darwin arm64 25.4.0 For AI issues: which model did you use? Kimi K2.6 Does this stop you from using Cursor Sometimes - I can sometimes use Cursor

Hey, this is a known BYOK bug for providers that require reasoning_content passback like Kimi K2.6, DeepSeek V4, and similar. The first turn works, but on the next tool calls the provider returns 400 “thinking is enabled but reasoning_content is missing”. The same issue is discussed here: Kimi 2.6 custom model - Provider returned error: {"error":{"message":"thinking is enabled but reasoning_content is missing We’re tracking it, but there’s no ETA for a fix yet. I grabbed the Request ID and I’ll link it to the ticket. As a workaround, you can temporarily use the non-thinking Kimi option where reasoning passback isn’t required, or use another model in agent mode with tool calls. I’ll follow up once there’s an update.

Kimi own key usage error

Support Bug Reports

Topic		Replies	Views
Kimi 2.6 custom model - Provider returned error: {"error":{"message":"thinking is enabled but reasoning_content is missing Bug Reports byok	1	557	May 2, 2026
Kimi/kimi-k2.5 cannot be called to execute tool calls in cursor Bug Reports chat , byok	10	1087	June 7, 2026
Kimi Custom API Key Causes "Unauthorized User API Key" Help byok	2	300	August 19, 2026
Kimi k2.5 not working? Bug Reports	5	689	June 10, 2026
BYOK + custom base URL: built-in Kimi K3 and K2.7-Code return 404, but K2.7-Code-Highspeed works Bug Reports byok	3	193	October 23, 2026

Kimi own key usage error

Related topics