AP2 PaymentReceipt Verification & HNP Guardrail

Note (dated 2026-08-04): a chain composes independent computations performed in an analytical order. No step's output is carried into the next step by the execution model; each step computes from its own declared inputs. This is true of every chain on this site, including chains whose per-step copy below reads as a data handoff.

W-B. PaymentReceipt-to-mandate verification + Human-Not-Present autonomy gate (ART-62) -> mandate-chain re-validation (art-01) -> receipt aggregation (cry-05). Verifies an autonomous AP2 payment after the fact: valid receipt, intact mandate chain, in-policy autonomy.

OpenChainGraph · 3 Steps cryptographic mandate Hash-Anchored §4 chain_depth:3 Client-Side · Zero PII

Chain Stages · 3 Steps

1 ROOT · D0 node

AP2 PaymentReceipt Verifier & HNP Guardrail art-62-ap2-payment-receipt-verifier

receipt_verdict and hnp_verdict (H1) feed the mandate-chain validator

MCP Call · verify_ap2_payment_receipt

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "verify_ap2_payment_receipt",
    "arguments": {}
  },
  "id": 1
}

↓

2 D2 node

AP2 Mandate-Chain Validator art-01-ap2-mandate-chain-validator

mandate-chain verdict (H2) feeds the aggregator

MCP Call · validate_ap2_mandate_chain

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "validate_ap2_mandate_chain",
    "arguments": {}
  },
  "id": 1
}

↓

3 TERMINAL · D3 node

Agent-Action Audit-Trail Aggregator cry-05-agent-action-audit-trail-aggregator

Exports composite payment-receipt artifact with execution_hash (H3), final stage

MCP Call · aggregate_execution_receipts

{
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "name": "aggregate_execution_receipts",
    "arguments": {}
  },
  "id": 1
}

Question: After an agent payment executes, what is the one session receipt root we can hand our auditor? Run the AINumbers MCP tool `run_chain` with {"chain":"agent-economy-payment-receipt"} and read `cry-05-agent-action-audit-trail-aggregator.session_receipt_root`. Re-run with `inputs` for `cry-05-agent-action-audit-trail-aggregator`, reusing the values that result echoed, with `artifacts` changed so one executed payment receipt joins the evidence. Compare the same field. Verify: call `verify_execution_hash` (https://mcp.ainumbers.co/mcp) with `claimed_hash` set to `composite_execution_hash` and the full `composite_artifact`. Ledger, for a human re-check: https://ledger.ainumbers.co/ PII rule: send synthetic or anonymised inputs only. The MCP server runs these kernels and logs no payloads. Chain page: https://ainumbers.co/chaingraph/chains/agent-economy-payment-receipt.html

AP2 PaymentReceipt Verification & HNP Guardrail

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