I built Passport, a free iOS/macOS app that lets a human issue signed, scoped, time-bounded credentials to AI agents — and revoke them instantly.
The problem: when an agent acts on your behalf (books, buys, emails), the receiving service can't tell whether a human authorized that specific agent to do that specific thing. Today it's raw API keys (no scoping, no audit trail, no kill switch) or nothing.
A Passport credential is a standard ES256 JWT that asserts:
- which agent this is (human-readable name)
- what it may do (scopes like
browse,purchase:general) - when the grant expires
- the issuing public key, embedded in the header
The private key is generated in the device's Secure Enclave and never leaves it; every issuance requires Face ID, so each credential maps to an explicit human decision.
Verification is deliberately boring: any JWT library can verify the token offline against the embedded key. There's also a hosted endpoint (Cloudflare Worker) that does signature + expiry + scope + revocation in one POST:
POST https://passport-verify.passport-app.workers.dev/verify
{"token": "<jwt>", "scope": "purchase:general"}
Revocation went live today: revoke a credential in the app and the next verify returns 401 with "Token has been revoked by its owner" (KV-backed list, also queryable at GET /revoked?jti=). I tested the full loop on a real credential in production. If you verify offline instead, you can poll the revocation endpoint or simply rely on short expiry times.
The format choice is intentional — I wanted something existing HTTP middleware could accept with one if statement, not a new protocol. Visa TAP and Google AP2 are converging on the same three-leg shape (human grants → agent presents → merchant verifies) for payments; this is that pattern as a small open building block.
App is free on the App Store (iOS + macOS, native). Docs with drop-in Node/Python/cURL snippets: https://passport-landing.pages.dev
Curious how others handling agent auth are thinking about scoped, revocable delegation vs. just passing API keys around.
Thank you! Feel free to ask questions!
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