What Nomos is

The one-sentence version

Nomos is an authorization layer for AI agents. It sits between your agent and every SaaS API you let it touch — GitHub, Slack, Linear, Stripe, Google, Notion, your filesystem, your cloud — and makes sure the agent can only do what you said it could, before the call ever leaves your network.

Why this exists

Today, hooking an agent up to a SaaS API means dropping an OAuth token (or worse, a raw API key) into the agent's environment. That token does too much for too long:

• A token scoped to "read & write everything in your GitHub" is the same token whether the agent is closing one issue or wiping the repo.
• If the token leaks — log line, prompt injection, leaked env file — the blast radius is the entire integration.
• You have no live record of what the agent actually did with the token, only an upstream audit log scattered across a dozen vendors.

Nomos replaces the token with a single-use cryptographic delegation (a UCAN). The agent gets a delegation that's good for "one method, one resource, the next five minutes." It never sees the underlying OAuth token. Every decision goes through your policy and lands in a tamper-evident chain you control.

Three guarantees that fall out

1. 1
   Credentials never leave the broker.

   Tokens are stored encrypted in the control plane and decrypted only inside the PDP at request time. The agent gets a UCAN bound to one upstream call.

2. 2
   Policy is enforced before the call.

   Cedar policies you write (or pick from a template) run on every authorize. Denials return a 403 — there's no "fix it after the fact."

3. 3
   Every decision is provable.

   Allows, denies, and step-ups land in an Ed25519-signed Merkle chain. Anyone with the verifier CLI can audit it offline — your auditors, your customers, you.

What you'll do next

The rest of the Get started journey walks you through your first end-to-end call — about 10 minutes start to finish. By the end you'll have:

• A live connection to a SaaS provider (we use GitHub as the running example).
• An App with one API key — that's your agent's identity.
• A starter policy attached to that app.
• One real authorize call returning a UCAN you can use to make a real request.