[BUG] GitHub MCP authenticate flow redirects to gdrive install endpoint with "Server Turned Down" page

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

When I call mcp__github__authenticate from a Claude Code (web) session, the OAuth URL it returns (https://api.anthropic.com/authorize?...&client_id=<varies>&redirect_uri=http://localhost:<port>/callback&...) does not land on a GitHub authorize page. After clicking through, the browser ends up at:

api.anthropic.com/mcp/gdrive/google/install?metadata=<hex>
…which renders a page titled "Server Turned Down" that says:

This MCP server has been turned down.
Please use https://drivemcp.googleapis.com/mcp/v1 instead — connect via Google Drive in the Claude directory.

Two things make this clearly wrong:

I'm trying to authorize GitHub, but I'm being redirected to the gdrive (Google Drive) install endpoint.
The fallback URL it suggests (drivemcp.googleapis.com/mcp/v1) is not an Anthropic-hosted endpoint.

What Should Happen?

The OAuth URL should land on the GitHub authorize page (or, if the GitHub Integration is already connected on my account, just complete silently and make mcp__github__* tools callable in the session).

Error Messages/Logs

Settings → Connectors → GitHub Integration shows Connected for my account (with a "Disconnect" button visible).
I tried disconnecting and reconnecting GitHub Integration — same result.
I tried calling mcp__github__authenticate multiple times across attempts — same result each time.

Steps to Reproduce

Have GitHub Integration connected at the account level.
Start a Claude Code (web) session in a repo scoped to a GitHub repo.
Have Claude call mcp__github__authenticate.
Open the returned authorize URL in a browser.
Expected: GitHub authorize page (or silent completion).
Actual: api.anthropic.com/mcp/gdrive/google/install?... "Server Turned Down" page.

Claude Model

Opus

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

Claude Code (web — claude.ai/code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

Other

Additional Information

Running Claude Code via the web UI at claude.ai/code (not the CLI), so several form fields above don't apply cleanly:

No claude --version available — version isn't surfaced in the web UI.
Not using the Anthropic API directly; this is the Claude Code web product.
No terminal involved.