auth

19 Jun 2026

The MCP OAuth Flow, Drawn: The Broker Pattern in One Diagram (2026)

Most MCP OAuth diagrams draw two boxes and miss the point. There are two OAuth relationships, not one, and the client never holds your GitHub or Google token. Here's the broker pattern in a single diagram, plus the wiring underneath it.

• mcp
• fastmcp
• oauth
• auth
• ai

18 Jun 2026

MCP Server Authentication in FastMCP: The End-to-End Version (2026)

OAuth on an MCP server is two jobs, not one. Token verification is passive; remote OAuth is active. Pick wrong and Claude Desktop won't connect. Here's the FastMCP wiring end to end, including the DCR cliff that breaks GitHub and Google.

• mcp
• fastmcp
• auth
• oauth
• ai