Concepts

Roles

Your agent ──HTTPS──▶ relay.fau.run (/v1/resolve)
Your agent ──TLS──▶ <label>.relay.fau.run:443  ──(blind pipe)──▶ user's Mac node
                                                              └── POST /mcp (MCP tools)

Role	What it is
User node	On the user’s Mac. Holds Gmail credentials, encrypted store, grants, audit log. Terminates TLS for its hostname.
Relay	Blind rendezvous. Peeks SNI, forwards ciphertext. Discovers nodes by HMAC of email. No mail, no node private keys.
Agent	You. Identified only by a domain that publishes Ed25519 keys.

Identity is a domain

You are assistant.example, not an API key. The node fetches https://assistant.example/.well-known/fau-agent and verifies RFC 9421 signatures. Prompts show that verified domain.

Open addressing, closed permission

Anyone can resolve an email and attempt a signed call (like sending email). Permission is grants + phone approvals on the node (like spam/policy), not a global agent registry on the relay.

Grants and tiers

Tier	Typical tools	Phone?
`structured_read`	`get_upcoming_travel`, `order_status`, `bills_due`	Often auto after grant
`free_form_read`	`ask`	Often auto after grant
`raw_read`	`get_excerpt`	Always
`compose`	`create_draft`, `draft_reply`	Often auto after grant
`send`	`send_draft`	Always

Categories that may appear in grants: travel, orders, bills, finance, personal, work. (security_codes is never granted.) After approval the node usually stores a grant for your domain — you retry the tool; you often never hold a capability token. The relay sees metadata (HMAC of email, hostname, timing, bytes). It cannot read tool arguments or answers. Unknown emails get decoy hostnames with the same JSON shape.

Offline users

If the Mac is asleep, sealed requests can wait on the queue (24 h). Prefer live TLS when /.well-known/fau-node answers.

Start here

Connect

Call tools

Reference

Roles

Identity is a domain

Open addressing, closed permission

Grants and tiers

Blind relay

Offline users

​Roles

​Identity is a domain

​Open addressing, closed permission

​Grants and tiers

​Blind relay

​Offline users

Roles

Identity is a domain

Open addressing, closed permission

Grants and tiers

Blind relay

Offline users