The Auth Episode We've Been Avoiding | FastMCP Pod Summer School

FastMCP creator and Prefect founder Jeremiah Lowin sits down with Radhika Gulati to explain authentication and authorization in MCP. Auth is who you are, versus what you're allowed to do, and why the protocol only really cares about the first one. Authentication is your passport. Authorization is your visa. MCP handles the passport check. Everything else, like what a verified identity is allowed to do once it's inside your server, is left up to you. Which is exactly where FastMCP comes in. What we cover: - Authentication vs. authorization - The first, painful version of MCP auth - Dynamic Client Registration (DCR): why it exists, and the identity problem it introduces - What's replaced DCR, and why - SEP-990 and enterprise-issued credentials - Where Horizon fits: acting as an authorization server, and federating identity across every server in a remix - OAuth was built for humans. What about agents? Timestamps: 0:00 - Cold open: did you actually read every line of that server? 0:32 - Authentication vs. authorization: the passport and the visa 3:06 - MCP only handles authentication — here's why that matters 4:54 - Usernames, passwords, and API keys 6:32 - Local MCP servers never needed auth 7:46 - Remote servers arrive and auth becomes non-optional 10:35 - The first, painful version: your server as its own authorization server 11:25 - The fix: MCP servers as protected resources only 12:48 - Dynamic Client Registration, and the identity gap it opens 19:37 - Trusted claims vs. a user just telling you their role 21:04 - FastMCP's rule: if you can't call a tool, you can't see it 22:26 - What's replacing DCR 28:08 - SEP-990: one login, not one per tool 30:24 - Where Horizon fits in all of this 32:52 - The unsolved problem: agents aren't humans, and OAuth assumes they are FastMCP is how teams build MCP servers. Horizon is how enterprises run them in production. Try it yourself, free: prefect.io Related videos: FastMCP Pod Summer School Ep. 1: MCP Gateways — [https://youtu.be/dTLSah8my8s?si=M6SJGFkmVdGUP3BE] FastMCP Pod Summer School Ep. 2: The C in MCP — [https://youtu.be/DI5pZi5gmWM?si=Aw2DLnPmZ2fdTYT1]