OAuth for MCP clients

Give consent

POST/oauth/authorize

A browser form carrying a single-use consent ticket bound to the signed-in person.

#Authentication

Session cookie

A signed-in person: the console's session cookie. Every state-changing request also carries the header x-immiscible-csrf: 1, and the member's role decides what it may do. Bearer tokens are ignored on these routes, so no machine credential can reach them.

The consent page a person sees in the browser. The POST carries a single-use consent ticket bound to the signed-in user.

Request

curl -X POST "https://immiscible.fly.dev/oauth/authorize" \
  -H "cookie: __Host-sid=$IMMISCIBLE_SESSION" \
  -H "x-immiscible-csrf: 1"

const res = await fetch('https://immiscible.fly.dev/oauth/authorize', {
  method: 'POST',
  headers: {
    cookie: `__Host-sid=${process.env.IMMISCIBLE_SESSION}`,
    'x-immiscible-csrf': '1',
  },
});
console.log(res.status, await res.text());

import os
import requests

res = requests.post(
    "https://immiscible.fly.dev/oauth/authorize",
    headers={
        "cookie": f"__Host-sid={os.environ['IMMISCIBLE_SESSION']}",
        "x-immiscible-csrf": "1",
    },
)
print(res.status_code, res.text)