Summary
Authenticating the official Vercel MCP (https://mcp.vercel.com) from Cursor Cloud Agents fails immediately on Vercel’s authorize page with:
The app redirect URL is invalid, please contact the app developer for support.
This happens before any consent screen. Cursor is sending a Cloud Agents callback URL that does not appear to be allowlisted on the Vercel MCP OAuth client.
Environment
- Client: Cursor Cloud Agents (web UI:
+ → MCP → Vercel connect/login)
- MCP server:
https://mcp.vercel.com (as shipped in vercel-plugin .mcp.json)
- Date observed: 2026-07-23
Steps to reproduce
- Open a Cursor Cloud Agent session with the Vercel MCP configured (via vercel-plugin or direct
https://mcp.vercel.com).
- In the agent UI, go to MCP settings and click connect / login for Vercel.
- Browser opens Vercel OAuth authorize URL.
- Page shows: “The app redirect URL is invalid”.
Expected
Vercel accepts the Cloud Agents callback, shows the consent screen, and completes OAuth so the Vercel MCP becomes usable in Cloud Agents (serverStatus: ready).
Actual
Vercel rejects the authorize request with “The app redirect URL is invalid”. In the Cloud Agent session, Vercel MCP stays needsAuth with no tools available.
Analysis
Cursor Cloud Agents / Automations use a different OAuth redirect than the desktop IDE:
| Context |
Typical redirect_uri |
| Cursor desktop IDE |
cursor://anysphere.cursor-mcp/oauth/callback (or loopback http://localhost:8787/callback) |
| Cursor Cloud Agents |
https://www.cursor.com/agents/mcp/oauth/callback |
The failure occurs on Vercel’s authorize endpoint before the callback returns to Cursor, which strongly indicates the Cloud Agents HTTPS callback is not registered on OAuth client cl_eD921KDq5R4BhfW5pRKJ6KHgY7d0JycM.
This matches the same pattern Cursor staff described for other MCP providers (e.g. Linear): desktop can work once its URI is allowlisted, while Cloud Agents fail until the provider adds https://www.cursor.com/agents/mcp/oauth/callback.
Summary
Authenticating the official Vercel MCP (
https://mcp.vercel.com) from Cursor Cloud Agents fails immediately on Vercel’s authorize page with:This happens before any consent screen. Cursor is sending a Cloud Agents callback URL that does not appear to be allowlisted on the Vercel MCP OAuth client.
Environment
+→ MCP → Vercel connect/login)https://mcp.vercel.com(as shipped in vercel-plugin.mcp.json)Steps to reproduce
https://mcp.vercel.com).Expected
Vercel accepts the Cloud Agents callback, shows the consent screen, and completes OAuth so the Vercel MCP becomes usable in Cloud Agents (
serverStatus: ready).Actual
Vercel rejects the authorize request with “The app redirect URL is invalid”. In the Cloud Agent session, Vercel MCP stays
needsAuthwith no tools available.Analysis
Cursor Cloud Agents / Automations use a different OAuth redirect than the desktop IDE:
redirect_uricursor://anysphere.cursor-mcp/oauth/callback(or loopbackhttp://localhost:8787/callback)https://www.cursor.com/agents/mcp/oauth/callbackThe failure occurs on Vercel’s authorize endpoint before the callback returns to Cursor, which strongly indicates the Cloud Agents HTTPS callback is not registered on OAuth client
cl_eD921KDq5R4BhfW5pRKJ6KHgY7d0JycM.This matches the same pattern Cursor staff described for other MCP providers (e.g. Linear): desktop can work once its URI is allowlisted, while Cloud Agents fail until the provider adds
https://www.cursor.com/agents/mcp/oauth/callback.