Where does the bug appear (feature/product)?
Cursor IDE
Describe the Bug
I fail to authenticate via OAuth to my mcp-server
Cursor output logs -
2025-09-21 14:46:52.315 [info] Received OAuth callback with code
2025-09-21 14:46:54.309 [info] Using redirect URL {"url":"cursor://anysphere.cursor-retrieval/oauth/user-***-mcp/callback"}
2025-09-21 14:46:56.987 [info] Using redirect URL {"url":"cursor://anysphere.cursor-retrieval/oauth/user-***-mcp/callback"}
2025-09-21 14:46:57.633 [error] Failed to complete OAuth exchange authorization code does not exist
Backend logs -
"POST /token HTTP/1.1" 400 Bad Request
We’ve confirmed the auth flow works well in prev’s Cursor versions.
Steps to Reproduce
Try to authenticate via OAuth to a working mcp-server
Expected Behavior
OAuth exchange should work properly and mcp-server should load its tools and resources
Operating System
MacOS
Current Cursor Version (Menu → About Cursor → Copy)
Version: 1.6.42 (Universal)
VSCode Version: 1.99.3
Commit: 5911e9593196a000b1c00553aaf03b0b32042b90
Date: 2025-09-20T17:16:56.346Z
Electron: 34.5.8
Chromium: 132.0.6834.210
Node.js: 20.19.1
V8: 13.2.152.41-electron.0
OS: Darwin arm64 24.6.0
Does this stop you from using Cursor
No - Cursor works, but with this issue