vision

Portable evidence across agent-to-agent handoffs

When one agent pays another for work, each operator needs a record of what was paid for and what came back, and that record has to travel with the handoff.
Originary2 min read

What an agent has to answer before it hands off work

Suppose Agent A needs a document translated by Agent B, a service another company runs, and the service charges per request. Before Agent A can hand off the work, it has to answer:

  • How to discover AI policy and pricing?
  • How to pay without human intervention?
  • How to verify work was performed?
  • How to maintain audit trails?

The A2A stack

The A2A (agent-to-agent) stack describes the layers needed for autonomous agent commerce. Each layer addresses a specific coordination problem:

  • Layer 1, AI policy discovery. Agents discover bot policy, crawling rules, and terms at /.well-known/peac.txt.
  • Layer 2, access control (HTTP 402). Gated endpoints return 402 with payment instructions (x402, Stripe).
  • Layer 3, receipts. Each transaction returns a signed, verifiable record.
  • Layer 4, provenance. Chain of records creates auditable lineage for compliance.

An A2A transaction flow

How a complete agent-to-agent transaction works with PEAC:

  1. Policy check. Agent A fetches /.well-known/peac.txt to discover crawling policy and payment options.
  2. Access request. Agent A calls Agent B's API endpoint.
  3. 402 response. Agent B returns HTTP 402 with payment details.
  4. Payment. Agent A pays via configured method (x402, Stripe).
  5. Receipt. Agent B processes request and returns a signed record in headers.
  6. Verification. Agent A or operator verifies record at the verify endpoint.

Why records matter

In human-to-business transactions, receipts are obvious: email confirmations, PDF invoices, bank statements. Agent-to-agent transactions need the same thing, but machine-readable.

  • Record of service. A signed statement from the provider about the work it reported performing.
  • Audit trail. Operators review agent spending.
  • Review and reconciliation. Shows what the provider reported delivering.
  • Compliance. Bundled for regulatory reporting.

Getting started

If you are building agent infrastructure:

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