Where does the bug appear (feature/product)?
Cursor IDE
Describe the Bug
Issue 1: Context window capped at 200K
DeepSeek V4 Pro has a native 1M token context window. When connected through Cursor, the context appears to be limited to only 200K tokens. Other tools (e.g., OpenCode) pass through the full 1M context without restriction. Please support the full 1M context window.
Issue 2: “reasoning_content must be passed back to the API” error
When DeepSeek V4’s thinking mode is enabled, Cursor throws:
{“error”:{“message”:“The reasoning_content in the thinking mode must be passed back to the API.”,“type”:“invalid_request_error”}}
DeepSeek’s API requires the reasoning_content from the previous response to be included unmodified in subsequent requests. Cursor’s agent loop does not preserve/relay this field, causing all follow-up requests to fail. Please implement proper reasoning_content passthrough for DeepSeek models.
Steps to Reproduce
Issue 1:
- Connect DeepSeek V4 in Cursor
- Load a codebase larger than 200K tokens
- Observe that only ~200K tokens of context are available, even though the model supports 1M
Issue 2: - Enable thinking/reasoning mode for DeepSeek V4 in Cursor settings
- Send a multi-turn conversation (2+ messages)
- Error occurs on the second request: “reasoning_content must be passed back to the API”
Operating System
MacOS
Version Information
Version: 3.2.11
VSCode Version: 1.105.1
Commit: e9ee1339915a927dfb2df4a836dd9c8337e17cc0
Date: 2026-04-24T14:36:47.933Z
Layout: editor
Build Type: Stable
Release Track: Default
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?
DeepSeekV4pro
For AI issues: add Request ID with privacy disabled
Request ID: 08ff07d7-7821-4f23-8329-4c3076ce4aab
{“error”:“ERROR_PROVIDER_ERROR”,“details”:{“title”:“Provider Error”,“detail”:“Provider returned error: {"error":{"message":"The reasoning_content in the thinking mode must be passed back to the API.","type":"invalid_request_error","param":null,"code":"invalid_request_error"}}”,“isRetryable”:false,“additionalInfo”:{},“buttons”:,“planChoices”:},“isExpected”:true}
Provider Error Provider returned error: {“error”:{“message”:“The reasoning_content in the thinking mode must be passed back to the API.”,“type”:“invalid_request_error”,“param”:null,“code”:“invalid_request_error”}}
Cvs: Provider Error Provider returned error: {“error”:{“message”:“The reasoning_content in the thinking mode must be passed back to the API.”,“type”:“invalid_request_error”,“param”:null,“code”:“invalid_request_error”}}
at Pf_ (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:29432:24260)
at Rf_ (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:29432:23144)
at Uf_ (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:29433:6490)
at q0h.run (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:29433:11307)
at async cQi.runAgentLoop (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:41748:12418)
at async Vnm.streamFromAgentBackend (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:41816:12344)
at async Vnm.getAgentStreamResponse (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:41816:19567)
at async lCt.submitChatMaybeAbortCurrent (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:29548:16906)
at async Va (vscode-file://vscode-app/Applications/Cursor.app/Contents/Resources/app/out/vs/workbench/workbench.desktop.main.js:40804:4230)
Does this stop you from using Cursor
No - Cursor works, but with this issue