[BUG] Cannot connect Remote GitHub MCP Server

[yamachu]

Environment

• Platform (select one):
  • [x] Anthropic API
  • [ ] AWS Bedrock
  • [ ] Google Vertex AI
  • [ ] Other:
• Claude CLI version: <!-- output of claude --version --> 1.0.27 (Claude Code)
• Operating System: macOS 15.5
• Terminal: iTerm2

Bug Description

The OAuth authentication fails for the GitHub MCP Server (https://github.com/github/github-mcp-server) added with the following command:

claude mcp add -t http github-server https://api.githubcopilot.com/mcp/

and https://docs.anthropic.com/en/docs/claude-code/mcp#authenticate-with-remote-mcp-servers

Based on the observed behavior, it seems that Claude immediately tries to connect to /.well-known/oauth-authorization-server and ignores the resource_metadata in the www-authenticate header, preventing it from properly following the GitHub MCP Server flow.

I believe GitHub MCP Server could be supported by implementing the following flow:

1. Retrieve resource_metadata from the www-authenticate header returned by GET https://api.githubcopilot.com/mcp/
2. Send a request to the URL obtained in step 1, and use authorization_servers to perform OAuth
3. Continue with the normal flow

Steps to Reproduce

1. do claude mcp add -t http github-server https://api.githubcopilot.com/mcp/
2. run claude and try /mcp command

Expected Behavior

Complete OAuth 2.0 authentication flow

Actual Behavior

Failed OAuth 2.0 authentication flow

Additional Context