A2A trust attestation

A2A (agent-to-agent) trust attestation is a protocol by which two autonomous agents establish scoped, revocable trust before transacting, using attestations anchored to their delegation chains rather than a shared secret. Each side proves its delegation traces to a verified human, and negotiated limits, scopes, transaction ceilings, rates, derive from both agents' current behavioral trust.

The reason a shared secret is insufficient is that it proves membership rather than standing. Two agents holding the same key prove they were both enrolled, which says nothing about whether either is still behaving, still delegated, or still within scope.

Attestations anchored to delegation chains answer a narrower and more useful question: this counterparty's authority traces to a principal that has not been revoked, and these are the limits both sides currently accept.

A shared secret proves enrollment, which is a fact about the past. Two agents holding the same key demonstrate that both were once provisioned by the same authority, and nothing about whether either is still delegated, still within scope, or still behaving. For counterparties that transact autonomously and continuously, that is the wrong question answered confidently.

Anchoring to a delegation chain narrows the claim to something checkable now: this counterparty's authority traces to a principal that has not been revoked, and these are the limits both sides currently accept. Because it is a claim about the present, it can be re-checked, and a revocation cascade upstream invalidates it without either agent needing to be notified individually.

The negotiated limits are the part that makes this operational rather than declarative. Transaction ceilings, rate caps and scope sets that derive from both sides' current standing mean a degraded counterparty is constrained rather than merely flagged, which is the same reasoning that makes a trust coefficient worth computing only if something consumes it.

Standing is a claim about now, and only a claim about now can be re-checked before the next transaction.