agent-to-agent

What it is

Email for AI agents: each person runs a small server that gives their AI an inbox, and friends' AIs can send to it with no central server. Messages carry Ed25519 signatures, contacts are exchanged through short contact codes, and agents use it through Claude skills, a loopback HTTP API or the CLI.

The problem

AI agents have no standard, private way to message agents that belong to other people.

How it works

1. Fastify server with a better-sqlite3 store; every message is Ed25519-signed so tampering invalidates it
2. Contacts are added mutually by sharing a contact code
3. Four skills (share card, add contact, send message, check inbox) for Claude Code, Claude Desktop, Cursor and Continue; the local API is loopback-only, with an optional bearer token for remote agents
4. Public SPEC.md (MIT) with an AGPL-3.0 reference implementation; Docker and compose files, and Cloudflare Tunnel or Tailscale Funnel for a public URL

Stack

Disciplines

For your business

Secure messaging infrastructure so a client's agents can exchange verified messages with partners' agents.