Relay and Solidus Agents

The problem they share

An AI agent that acts on your behalf is offline most of the time: it runs, does a thing, and stops. Two such agents cannot rely on being awake simultaneously, which is precisely the case a mediator exists for: what a DIDComm mediator is.

So the pairing is not a bundle. Agents supplies identity for non-human software; relay supplies a way to reach it.

What Agents brings

An agent needs a name a counterparty can check. Solidus Agents implements ERC-8004 agent identity (@solidus-network/agent-identity on npm) and the surrounding vocabulary, agent passports, operator accountability, machine identity. See agent passport and machine identity.

What relay adds

Reachability without being online, and admission decided by a credential rather than an API key. For agents specifically that second one is the interesting half: a mediator can require an agent to present something about itself before it is granted mediation, rather than accepting any holder of a shared secret. See credential-gated mediation.

The check is fail-closed and distinguishes "verifier unreachable" from "credential invalid", so an operator can tell a dependency outage from a rejected agent.

What this pairing does not give you

• Not agent-to-agent trust. An agent that presents a valid credential is admitted to mediation. Nothing about that says its instructions are legitimate or its operator is honest. Admission is not authorisation, and treating it as such is the obvious way to misuse this.
• Not a payment rail. x402 and machine payments belong to a product that does not exist: Solidus Pay is listed as coming soon and its subdomain does not resolve. Nothing here settles anything.
• Not privacy for the agent. A mediator sees which agent connects, when, and how often. For automated traffic that is more revealing than for humans, because machine patterns are regular and therefore easy to fingerprint. See what a mediator can and cannot see and traffic analysis.
• Not a Travel Rule product. No such product exists at Solidus. Relay is transport.

The honest state

Both surfaces are beta. The agent identity packages are published and early. Relay implements Coordinate Mediation 2.0 and Pickup 3.0; no independent DIDComm conformance suite has been run, so "implements" is the claim and "conformant" is not. Neither product has an external audit, and no one is running this pairing in production that we know of.

If you are building agent-to-agent messaging today, the useful thing on this page is the shape: identity from one layer, reachability from another, and admission control between them. The implementations are early enough that you should verify each part yourself rather than assume the combination works.