MCP server at mpp.dev/api/mcp returns 401 on source code tools

[e-fu]

Summary

The MCP server at https://mpp.dev/api/mcp returns GitHub API 401 (Unauthorized) errors for all source code browsing tools, while metadata/docs tools work fine.

Working tools

Tool	Status
list_sources	Working — returns 5 repos (mppx, mpp-rs, pympp, mpp-specs, tempo)
list_pages	Working — returns empty array
search_docs	Working — returns empty array

Failing tools (all return GitHub API error: 401)

Tool	Status
get_file_tree	401
list_source_files	401
read_source_file	401
search_source	401

Steps to reproduce

1. Add MCP config:

{
  "mcpServers": {
    "mpp": {
      "type": "http",
      "url": "https://mpp.dev/api/mcp"
    }
  }
}

2. Call any source code tool, e.g. get_file_tree with source: "mpp-specs"
3. Returns: Error: GitHub API error: 401

Likely cause

The server-side GitHub API token used by the MCP server is missing, expired, or misconfigured.