{
      "tool_id": "art-22-agentic-payments-protocol-comparator",
      "tool_version": "1.1.0",
      "display_name": "Agentic Payments Protocol Comparator",
      "mcp_name": "compare_agentic_rail_protocols",
      "mandate_type": "routing_policy",
      "wave": "A",
      "gpu": false,
      "url": "https://ainumbers.co/chaingraph/art-22-agentic-payments-protocol-comparator.html",
      "description": "Compares AP2, ACP, x402, Visa TAP, Mastercard Agentic Token, and Tempo MPP (Machine Payments Protocol) across 8 dimensions (backer, artifact, signing, scope, rail, identity, audit, status) and 6 agentic scenarios. Root node of the Agentic Rail Chain: routing_policy output determines Branch A (AP2/card) or Branch B (A2A/x402). Promoted from T276.",
      "input_schema_ref": "chaingraph/art-22-agentic-payments-protocol-comparator.html#manifest",
      "deadline": null,
      "deadline_note": "AP2 v0.2 live (FIDO Alliance, April 2026); Visa TAP launched; Mastercard Agent Pay announced Apr 2025",
      "consumes": [],
      "feeds": [
        "art-16-google-ap2-mandate-builder",
        "art-23-visa-trusted-agent-protocol-inspector",
        "art-24-mastercard-agentic-token-builder",
        "art-25-a2a-agent-card-validator",
        "art-26-x402-payload-decoder-flow-simulator",
        "ptg-01-ap2-prompt-template-generator"
      ],
      "status": "live",
      "conformance_fixtures": false,
      "compute_capability": "server",
      "compute_images": [{"system":"sha256-source","image_id":"sha256:0d884710ed42dd2b36075266167a7fed1219199fa4aebad015933fabc4dfdee8","valid_from":"2026-07-10"},{"system":"risc0","image_id":"sha256:a1a0bc89b5b1febaeda3519f6dbade0fa5ac16beeb143c4e1b01689573567bc6","valid_from":"2026-06-28"}],
      "compute_proof": {
        "type": "ZkVmReceipt",
        "system": "risc0",
        "receiptFormat": "groth16-bn254",
        "imageId": "sha256:a1a0bc89b5b1febaeda3519f6dbade0fa5ac16beeb143c4e1b01689573567bc6",
        "seal": "GT0ieOk3H8vvmM7ygNO7qkNsHMJ5lnQxQqiYtn0puNwl99/R/Pikb96Ea4cMu0RLyXxPSvFsbBcQRW+3NUWcAhq/zxaPKlxSrxnRUSAf1wV+vbObNyeuZG/TOMZxYKbKD/bRJQOzhOMA9APMWaGcFSobufsxEIKEMDByJOx9YHISlxBC0i/kNOUgiD0RkfAjWiGmJD14TK1I68+htJZGgA0l0mubii1AbUUXItB3LBZp4sy+0SfQM3Q/Vq543eHJHKbdv4XGIzi6oNtw264j34O0fRWQSxTRN/2MAsOWcscs7o5gn2QleupbUAxlRBl66pcvderiPKvnSyjB77BtDg==",
        "journal": {
          "chaingraph_version": "0.4.0",
          "kernel_digest": "sha256:d3389851ebca78ebd45327e99035932bc36aa53855774154bd5abcd72afe7ae8",
          "output": {
            "crosswalk": [
              {
                "concept": "Authorization artifact",
                "values": {
                  "acp": "Shared Payment Token",
                  "ap2": "Payment Mandate (VDC)"
                }
              },
              {
                "concept": "Proof of user intent",
                "values": {
                  "acp": "OAuth delegation + SPT",
                  "ap2": "Signed mandate chain"
                }
              },
              {
                "concept": "Scope unit",
                "values": {
                  "acp": "Merchant + cart total",
                  "ap2": "Cart + amount"
                }
              },
              {
                "concept": "Settlement medium",
                "values": {
                  "acp": "Card via PSP",
                  "ap2": "Card or stablecoin"
                }
              },
              {
                "concept": "Identity / trust root",
                "values": {
                  "acp": "OAuth 2.0",
                  "ap2": "FIDO / VDC"
                }
              }
            ],
            "note": "Orientation snapshot only — verify every field against the cited primary source. Specs version monthly.",
            "protocol_names": [
              "AP2",
              "ACP"
            ],
            "protocols_compared": [
              "ap2",
              "acp"
            ],
            "protocols_detail": [
              {
                "artifact": "Checkout Mandate + Payment Mandate, expressed as Verifiable Digital Credentials (VDCs)",
                "audit": "Strong — non-repudiable chained VDC audit trail",
                "backer": "Google → donated to FIDO Alliance (2026)",
                "id": "ap2",
                "identity": "FIDO / verifiable credentials; rides on A2A",
                "name": "AP2",
                "rail": "Rail-agnostic — cards today; x402/stablecoin via the A2A x402 extension",
                "scope": "Cart + amount + payment instrument, bound at the Closed stage",
                "signed": "Cryptographically signed VDCs; Open→Closed mandate chain",
                "status": "v0.2; donated to FIDO Alliance (~Apr 2026)",
                "sub": "Agent Payments Protocol"
              },
              {
                "artifact": "Shared Payment Token (SPT) + Agentic Checkout session objects",
                "audit": "Order/session objects; PSP transaction record",
                "backer": "OpenAI + Stripe",
                "id": "acp",
                "identity": "OAuth 2.0 delegated auth",
                "name": "ACP",
                "rail": "Card via any compatible PSP (Stripe first); merchant stays merchant of record",
                "scope": "Single-use SPT scoped to merchant + cart total",
                "signed": "Delegated authorization (OAuth 2.0); PSP-issued SPT",
                "status": "beta; spec dated 2026-04-17",
                "sub": "Agentic Commerce Protocol (Shared Payment Token)"
              }
            ],
            "recommendation": {
              "also_consider": [
                "acp"
              ],
              "also_names": [
                "ACP"
              ],
              "primary_names": [
                "AP2"
              ],
              "primary_pick": [
                "ap2"
              ],
              "rationale": "A rail-agnostic, non-repudiable mandate chain across merchants is AP2's core design (Checkout + Payment Mandate VDCs). ACP fits if you are standardising on the OpenAI/Stripe checkout surface."
            },
            "scenario": "cross_merchant"
          }
        }
      },
      "export_capability": [
        "xlsx",
        "csv",
        "pdf",
        "xbrl:ocg-ext"
      ]
    }