An agent-to-agent interaction should communicate more than a requested action. It needs the requesting party or accountable principal, the purpose, the evidence available, the permissions granted, the data that may be used, the offer or workflow version, and the conditions that require human review. A scheduling request, for example, does not prove budget, qualification, contractual intent, or authority to share confidential material. Structured fields and signed or otherwise verifiable records may help, but the control objective is semantic: every receiver must know what the request establishes and what it does not.
Interfaces will evolve, and no single protocol can be assumed to govern the future. Operators can prepare by keeping internal contracts portable and explicit: stable identifiers, time-bound grants, scoped actions, provenance references, idempotent requests, revocation, error states, and durable receipts. A safe handoff must fail closed when identity, authority, consent, entitlement, or current product capability cannot be verified. Human escalation should remain available for ambiguity, exceptions, regulated questions, and commitments that exceed delegated authority.