[General] I am trying to configure an in-house MCP server that use OAuth authentication...

**Mood:** 😊
**Category:** General

I am trying to configure an in-house MCP server that uses OAuth authentication. We use it with Copilot CLI, VS Code, Claude, Cursor, ... but in the GitHub App, the authentication fails, and there is no way to troubleshoot it; the logs are not enough to figure out what happens.

```
2026-06-03T07:10:08.360352Z DEBUG github_app::websocket: received message text={"type":"start_mcp_oauth_login","name":"semantic-code-search","client_name":"GitHub Copilot","callback_success_message":"You can close this window and return to GitHub Copilot."}
2026-06-03T07:10:11.208880Z ERROR github_app::handlers::mcp_config: failed to start MCP OAuth login error=RPC error -32603: Request session.mcp.oauth.login failed with message: Failed to register OAuth client server_name=semantic-code-search
```

I guess it's the callback URL, but I don't have a way to confirm it, and I dunno which callback URL is being used. Can you document how to troubleshoot the MCP server connection and the configuration used for OAuth authentication?

---
| Field | Value |
| --- | --- |
| App version | 0.2.22 |
| OS | macOS 26.5.1 |
| Theme | GitHub |
| Path | /health |
| Tenure | Week 3 |

similar to https://github.com/github/app/issues/587 https://github.com/github/app/issues/104 https://github.com/github/app/issues/140 https://github.com/github/app/issues/554