PROTOCOL EVIDENCE · V1.3.0

Versioned field projections. Explicit boundaries everywhere.

The exact strict-v2 and adapter boundary for AP2, TAP, UCP, x402, ACP, CUSTOM and MPP—without turning field decoding into inflated conformance, proof or settlement claims.

SUPPORT CONTRACT

One boundary, explicit adapter ownership.

The strict API accepts seven declared protocol profiles. A separate versioned bridge maps documented fields from an AP2 terminal closed-payment projection, x402 v2 PAYMENT-REQUIRED and an explicitly profiled MPP Payment charge challenge. Every row states who maps, what is verified and what remains outside MandateShield.

STRICT PROFILES7
RAW PARSERS3
INTEGRATOR ADAPTERS4
NOT ACCEPTED0

PROTOCOL INDEX

Acceptance, evidence format and ownership at a glance.

AP2SUPPORTED EVIDENCE PROFILE · sd-jwtACCEPTED
TAPNORMALIZED PROJECTION · http-message-signatureACCEPTED
UCPINTEGRATOR NORMALIZATION REQUIRED · jwsACCEPTED
X402NORMALIZED PROJECTION · jwsACCEPTED
ACPINTEGRATOR NORMALIZATION REQUIRED · jwsACCEPTED
CUSTOMINTEGRATOR NORMALIZATION REQUIRED · jwsACCEPTED
MPPNORMALIZED PROJECTION · jwsACCEPTED

METHODOLOGY

How support is classified

Strict profile accepted means the current v2 API accepts the declared protocol enum only with its documented evidence format. Native payload accepted means the versioned adapter directly decodes the specifically listed input shape. It never implies complete source-protocol conformance, delegated authority, payment-credential validity or settlement.

Protocol behavior is derived from the current evidence-format map, public API and conformance contract. External descriptions link to primary official protocol publishers. This matrix was reviewed on .

AP2 · SUPPORTED EVIDENCE PROFILE

AP2: Agent Payments Protocol

  • Strict v2 accepts the declared protocol: yes
  • Unadapted native protocol payload accepted: yes
  • Accepted evidence format: sd-jwt
  • Normalization owner: MandateShield

What MandateShield verifies

  • Closed mandate.payment.1 projection
  • RFC 9901 key-binding JWT
  • Payment amount and currency
  • Payee and transaction binding
  • Account-pinned issuer trust

Integrator responsibilities

  • Use the compact AP2 presentation for production; claims-object input is development-only.
  • Do not post an upstream AP2 terminal token unchanged. Re-issue the documented MandateShield strict projection with the canonical input digest and RFC 9901 holder KB-JWT, or use the documented CUSTOM JWS profile.
  • Validate the wider checkout_jwt hash and delegate chain.
  • Operate or rely on the appropriate issuer trust registry.

Limits and evidence

  • Open mandates are not accepted by the strict closed-payment profile.
  • The native adapter parses only the terminal closed-payment projection; it does not establish AP2 v0.2 conformance or verify the wider checkout/delegate chain.
  • Conformance vectors: ap2-holder-proof-required

TAP · NORMALIZED PROJECTION

TAP: Trusted Agent Protocol

  • Strict v2 accepts the declared protocol: yes
  • Unadapted native protocol payload accepted: no
  • Accepted evidence format: http-message-signature
  • Normalization owner: integrator

What MandateShield verifies

  • Normalized RFC 9421-style signature projection
  • Method, authority, path and content-digest coverage
  • Created, expiry, nonce and signature
  • Exact purchase-envelope content digest
  • Account-pinned key trust

Integrator responsibilities

  • Parse and normalize upstream Visa structured fields.
  • Apply the appropriate Visa trust-store and participant onboarding rules.
  • Supply the documented normalized components and signature input.

Limits and evidence

  • Raw Visa structured fields are not parsed natively.
  • MandateShield does not implement the full Visa trust-store profile.
  • Conformance vectors: tap-required-component-omitted

UCP · INTEGRATOR NORMALIZATION REQUIRED

UCP: Universal Commerce Protocol

  • Strict v2 accepts the declared protocol: yes
  • Unadapted native protocol payload accepted: no
  • Accepted evidence format: jws
  • Normalization owner: integrator

What MandateShield verifies

  • Normalized final purchase envelope
  • Compact JWS signature and exact input digest
  • Account-pinned issuer, audience and protocol
  • Registered mandate policy and execution state

Integrator responsibilities

  • Resolve UCP version, negotiated capabilities and checkout state.
  • Normalize the final total, merchant and checkout facts.
  • Create the documented signed JWS projection.

Limits and evidence

  • Raw UCP service messages and capability negotiation are not parsed natively.
  • UCP interoperability does not replace payment-authority or gateway controls.
  • Conformance vectors: No protocol-specific vector is claimed.

X402 · NORMALIZED PROJECTION

X402: x402 payment protocol

  • Strict v2 accepts the declared protocol: yes
  • Unadapted native protocol payload accepted: yes
  • Accepted evidence format: jws
  • Normalization owner: MandateShield

What MandateShield verifies

  • Canonical atomic-unit string
  • Asset decimal exponent
  • Asset, network, resource and merchant scope
  • Canonical payee identity network and payTo exactly match the selected offer
  • Compact JWS and exact input digest
  • Registered mandate and replay state

Integrator responsibilities

  • Supply the selected x402 v2 PAYMENT-REQUIRED offer plus canonical payee identity with a trusted merchant-mapping evidence reference and asset-decimal mapping.
  • Independently validate the merchant-mapping evidence; the projection endpoint binds but does not fetch or certify it.
  • Any context asset or resource value must exactly equal the selected offer; the adapter rejects substitutions.
  • Without the optional first-party Gate, verify PAYMENT-SIGNATURE with the appropriate official scheme implementation or facilitator and submit only after the required gateway transition.
  • With the exact/EIP-3009 Gate, supply a compatible x402 client, durable encrypted journal, local signature verifier, trusted mappings and canonical chain verifier.

Limits and evidence

  • The hosted native bridge parses the seller's x402 v2 offer but never receives or verifies PAYMENT-SIGNATURE, wallet authority or settlement.
  • The optional first-party customer-side Gate is limited to x402 v2 HTTP exact/EIP-3009; it is not a facilitator, hosted settlement service, certification or all-x402 implementation.
  • Conformance vectors: x402-exact-beyond-safe-integer, x402-one-unit-over-cap, x402-resource-substitution

ACP · INTEGRATOR NORMALIZATION REQUIRED

ACP: Agentic Commerce Protocol

  • Strict v2 accepts the declared protocol: yes
  • Unadapted native protocol payload accepted: no
  • Accepted evidence format: jws
  • Normalization owner: integrator

What MandateShield verifies

  • Normalized final checkout facts
  • Compact JWS and exact input digest
  • Registered amount, currency and merchant scope
  • Account-pinned issuer trust and replay state

Integrator responsibilities

  • Validate and resolve the current ACP checkout session.
  • Normalize the final cart, total, merchant and fulfillment context.
  • Keep payment credentials and provider submission in the existing payment stack.

Limits and evidence

  • ACP checkout sessions are not parsed natively.
  • Fulfillment and payment processing remain with the merchant and provider.
  • Conformance vectors: No protocol-specific vector is claimed.

CUSTOM · INTEGRATOR NORMALIZATION REQUIRED

CUSTOM: Integrator-defined normalized protocol

  • Strict v2 accepts the declared protocol: yes
  • Unadapted native protocol payload accepted: no
  • Accepted evidence format: jws
  • Normalization owner: integrator

What MandateShield verifies

  • Documented normalized purchase-envelope fields
  • Compact JWS and exact canonical input digest
  • Account-pinned issuer, audience and CUSTOM protocol
  • Registered mandate, replay and execution state

Integrator responsibilities

  • CUSTOM normalization is integrator work.
  • Map the source protocol into every required normalized field.
  • Sign the exact final envelope with a registered issuer key.
  • Maintain source-protocol validation outside MandateShield.

Limits and evidence

  • CUSTOM is not a universal parser or automatic adapter.
  • Source fields omitted during normalization cannot be evaluated or bound.
  • Conformance vectors: jws-final-envelope-substitution

MPP · NORMALIZED PROJECTION

MPP: Machine Payments Protocol

  • Strict v2 accepts the declared protocol: yes
  • Unadapted native protocol payload accepted: yes
  • Accepted evidence format: jws
  • Normalization owner: MandateShield

What MandateShield verifies

  • MPP Payment challenge projection fields and RFC 8785 canonical request encoding
  • Explicit charge intent under the integrator-confirmed MANDATESHIELD_PORTABLE_CHARGE_V1 mapping profile
  • Canonical payee identity service origin and method exactly match the trusted resource and challenge
  • Strict-v2 account-pinned JWS over the resulting final envelope
  • Registered mandate, replay and execution state

Integrator responsibilities

  • Supply the exact server challenge, trusted target resource, canonical payee identity and explicit portable-charge mapping profile.
  • Independently validate the same-origin identity evidence; the projection endpoint does not establish TLS or domain control.
  • Confirm that the selected method specification maps amount, currency and recipient with the documented portable-charge semantics.
  • Verify the method-specific Payment credential with the applicable MPP implementation.
  • Keep MPP payment execution and receipt/settlement processing outside MandateShield.

Limits and evidence

  • The native adapter parses only the Payment charge challenge and does not verify a method-specific credential, server-side challenge store or settlement receipt.
  • MPP wire support is a validated field projection plus an explicit integrator mapping and a separate MandateShield JWS authority profile, not generic or method-specific MPP conformance.
  • Conformance vectors: No protocol-specific vector is claimed.

GLOBAL LIMITATIONS

Protocol compatibility is not payment execution

  • The hosted authority-verification route evaluates normalized evidence and purchase facts; it does not require payment credentials, customers must not submit them, and it does not submit or settle payments.
  • Optional first-party Gate adapters run inside customer infrastructure, where they may validate payment credentials, attempt an idempotent bound provider operation and report its outcome. MandateShield does not guarantee exactly-once provider delivery.
  • Separate hosted reconciliation is deliberately narrow. For a configured Stripe PaymentIntents or x402 profile, it stores caller observations as hints and reads the exact provider API or canonical chain outcome without trusting those observations. It never creates or submits the payment.
  • Only non-conflicting PROVIDER_API_VERIFIED or CHAIN_FINALIZED evidence can autonomously finalize with independent_verification=true. Pending, unknown and conflicting evidence stays fail-closed.
  • That legacy field means caller-independent checking by MandateShield, not an independent organization, provider attestation, certification or audit.
  • The hosted normalization bridge does not submit AP2, TAP, UCP, x402, ACP or MPP payments to a provider, facilitator, network or merchant.
  • The protocol's wider trust, discovery, checkout, credential, fulfillment and settlement chain remains in the integration that owns those functions.
  • This matrix does not claim provider adoption, permit enforcement, partnership or certification.
  • CUSTOM is not automatic compatibility. CUSTOM normalization is integrator work and must include every material final-purchase fact the operator expects the boundary to enforce.

PRIMARY SOURCES

Official protocol references

The links below point to product contracts and primary protocol publishers. External specifications can change independently and may carry publisher-specific access or license terms.

Consume the support boundary as JSON

The CORS-enabled, versioned endpoint exposes the same acceptance flags, evidence formats, adapter ownership and limitations shown here.

Open protocol-support.json →