feat: 2.1.0 — A2A v1.0 canonical wire format + tests (#52)

## Summary

Align our A2A `AgentCard` builder with the canonical wire format from
`@a2a-js/sdk@0.3.13` (the TypeScript reference SDK). This is the only
behavior change in 2.1.0; the rest of the train shipped in 2.0.x.

### A2A wire format rewrite

Python attribute names stay snake_case (PEP 8); `to_dict()` emits
camelCase keys to match the canonical A2A wire format.

- Hoisted `url`, `protocol_version`, `preferred_transport` to top-level
(were per-interface)
- Demoted `supported_interfaces` → optional `additional_interfaces[]`
(only set for multi-binding agents)
- Dropped per-interface `protocol_version` and non-canonical `tenant`
- Moved `extended_agent_card` (capability) → top-level
`supports_authenticated_extended_card`
- Added `state_transition_history` capability + per-skill `security`
- Renamed `security_requirements` → `security` (typed `list[dict[str,
list[str]]]`)
- All wire JSON keys are camelCase
- New constants: `A2A_PROTOCOL_VERSION`, `A2A_DEFAULT_TRANSPORT`

### Permanent regression guards

- New `tests/test_a2a_jws_roundtrip.py` exercises sign + verify +
tamper-detection using `joserfc` EdDSA.
- Existing `tests/test_a2a.py` rewritten with an 18-key
forbidden-snake-case list scanned against the serialized output.

### Note on PyPI a2a-sdk

`a2a-sdk@1.0.3` (Google's Python A2A package, protobuf-derived) ships an
OLDER schema (`supportedInterfaces[]` + `securityRequirements`, no
top-level `url`/`protocolVersion`). We align to the newer TypeScript SDK
schema which mirrors https://a2a-protocol.org/latest/. The node-commerce
sibling pins `@a2a-js/sdk@0.3.13` as a compile-time type guard.

### Test plan

- [x] `uv run ruff check` (clean)
- [x] `uv run ty check` (clean)
- [x] `uv run vulture` (clean)
- [x] `uv run pytest` (1380 passing, 95.06% coverage)
- [x] Live validation: `core/store` booted via `TestClient`, served
`/.well-known/agent-card.json` validated structurally against the
canonical AgentCard shape — zero drift
- [ ] CI green on PR

🤖 Generated with [Claude Code](https://claude.com/claude-code)

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: vvillait88

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
         run: uv run ty check agentscore_commerce/
 
       - name: Vulture
-        run: uv run vulture agentscore_commerce/ vulture_whitelist.py --min-confidence 80
+        run: uv run vulture agentscore_commerce/ --min-confidence 80
 
       - name: Tests
         run: uv run pytest tests/ -v --cov=agentscore_commerce --cov-report=term-missing

CLAUDE.md

@@ -8,14 +8,15 @@ Every helper is extracted from a real consumer, not speculated.
 
 | Submodule | What it is |
 |---|---|
-| `agentscore_commerce` (top-level) | `Checkout` orchestrator (the 2.0 high-level surface): one config object + hooks (pre_validate, compute_pricing, mint_recipients, compose_mppx, on_settled, gate), auto-derived x402+pympp servers, per-framework adapters `handle_fastapi`/`handle_flask`/`handle_django`/`handle_aiohttp`/`handle_sanic`, signed UCP routes via `mount_ucp_routes_{fastapi,flask,django,aiohttp,sanic}`, optional `discovery_probe` config for x402-crawler auto-routing. Plus factories: `pricing_result` (cents → typed `PricingResult`), `validation_response_{fastapi,flask,django,aiohttp,sanic}` (4xx envelope per framework), `Receipt`/`ReceiptNextSteps`/`ProductInfo`/`ShippingAddress` (canonical 200-receipt dataclasses, universal across goods + API merchants) |
-| `agentscore_commerce.identity.{fastapi,flask,django,aiohttp,sanic,middleware}` | Trust gate middleware (KYC, age, sanctions on both account name and signer wallet, jurisdiction) |
+| `agentscore_commerce` (top-level) | `Checkout` orchestrator (the 2.0 high-level surface): one config object + hooks (pre_validate, compute_pricing, mint_recipients, compose_mppx, on_settled, gate), auto-derived x402+pympp servers, per-framework adapters `handle_fastapi`/`handle_flask`/`handle_django`/`handle_aiohttp`/`handle_sanic`, signed UCP routes via `mount_ucp_routes_{fastapi,flask,django,aiohttp,sanic}`, optional `discovery_probe` config for x402-crawler auto-routing. Plus `compute_first_checkout` — variable-cost pay-per-result helper (compute-first + exact-x402). Scope is exact-mode rails only (x402-exact Base, tempo/charge, solana/charge, Stripe SPT); does NOT use x402-upto (Permit2) or Settlement-Overrides — variable cost is captured by running the work pre-settle and emitting a 402 at the exact computed price. `create_quote_cache` — content-hash quote cache used by the compute-first helper (in-memory by default; pass `redis_url` for distributed deployments). `create_default_on_denied` — canonical `on_denied(reason)` factory matching `Checkout`'s gate hook (handles `wallet_signer_mismatch`, `wallet_not_trusted` unfixable fallback, `payment_required`, `token_expired`/`invalid_credential`/`api_error`); merchants pass `merchant_name` + `support_email` and override `wallet_not_trusted_message` / `payment_required_message` / `support_context` for vendor-specific copy. `has_payment_header` — discriminator that splits discovery legs (no payment credential → 402) from settle legs (`payment-signature` / `x-payment` / `Authorization: Payment <jwt>`); `has_x402_header` / `has_mppx_header` — granular dispatch helpers (x402 vs MPP credential present) for routes that branch on rail. `default_read_only_on_denied(reason)` — canonical `on_denied` for read-only resource gates (`GET /orders/:id`): collapses every denial to 401 `unauthorized` + `Cache-Control: no-store` while still spreading `denial_reason_to_body` so `agent_instructions` / `verify_url` ride through. Returns a `DefaultOnDeniedResult(body, status, headers)` dataclass; FastAPI / Flask / aiohttp / Sanic `on_denied` callbacks accept an optional 3-tuple `(body, status, headers)` — convert with `lambda req, reason: (r := default_read_only_on_denied(reason), (r.body, r.status, r.headers or {}))[1]` or a named wrapper. Django + ASGI middleware adapters return Response objects directly; construct `JsonResponse(r.body, status=r.status, headers=r.headers)` /  `JSONResponse(content=r.body, status_code=r.status, headers=r.headers)`. `extract_owner_scope(headers) -> OwnerScope` — pull canonical owner identity from `X-Wallet-Address` / `X-Operator-Token` with safe token hashing; pair with a wallet-or-token-scoped resource query so plaintext tokens never leave the request. Plus factories: `pricing_result` (cents → typed `PricingResult`), `validation_response_{fastapi,flask,django,aiohttp,sanic}` (4xx envelope per framework), `Receipt`/`ReceiptNextSteps`/`ProductInfo`/`ShippingAddress` (canonical 200-receipt dataclasses, universal across goods + API merchants) |
+| `agentscore_commerce.identity.{fastapi,flask,django,aiohttp,sanic,middleware}` | Trust gate middleware (KYC, age, sanctions on both account name and signer wallet, jurisdiction). Each adapter exports a conditional variant that wraps the gate so it fires only on settle legs (anonymous discovery flows through and gets a 402 with all rails): FastAPI / ASGI expose `ConditionalAgentScoreGate`, Django exposes `ConditionalAgentScoreMiddleware`, Flask + Sanic expose `conditional_agentscore_gate(app, ...)`, aiohttp exposes `conditional_agentscore_gate_middleware(...)`. Adapters export ONLY framework-specific surface (gate classes / fns, accessors, `capture_wallet`); shared helpers like `has_payment_header` / `denial_reason_to_body` import from their canonical home (`agentscore_commerce.payment` and `agentscore_commerce.identity` respectively). The existing `agentscore_gate(app, ...)` and `AgentScoreGate` accept an optional `condition=` callable for inline gating. |
 | `agentscore_commerce.identity.policy` | Per-product compliance helpers: `PolicyBlock`, `build_gate_from_policy`, `run_gate_with_enforcement`, `shipping_country_allowed`, `shipping_state_allowed`, `validate_shipping_against_policy` (one-call country+state validator that raises `CheckoutValidationError` with the canonical envelope on miss) |
-| `agentscore_commerce.payment` | Networks/USDC/rails registries, paymentauth.org directive builders, `create_x402_server` (wraps `x402[evm]>=2.9` + `cdp-sdk` for `facilitator="coinbase"`; install via the `coinbase` extra), `build_x402_accepts_for_402` (build the 402's `accepts[]` from the registered scheme; derives the right `extra.name` per network), `process_x402_settle` (verify+settle in one call), `create_mppx_server` (wraps `pympp[server,tempo,stripe]>=0.6`), dispatch-by-network, signer extraction, WWW-Authenticate header, Settlement-Overrides header |
+| `agentscore_commerce.payment` | Networks/USDC/rails registries, paymentauth.org directive builders, `create_x402_server` (wraps `x402[evm]>=2.9` + `cdp-sdk` for `facilitator="coinbase"`; install via the `coinbase` extra), `build_x402_accepts_for_402` (build the 402's `accepts[]` from the registered scheme; derives the right `extra.name` per network), `build_default_checkout_rails(tempo=, x402_base=, solana_mpp=, stripe=)` (canonical 4-rail `rails` dict factory: merchants pass per-rail overrides instead of redeclaring the recipient sentinel + network/chain_id/token boilerplate. When a caller flips `network` without pinning `token` / `chain_id`, the underlying dataclass derives them from the network: Base Sepolia → Sepolia USDC + chain_id 84532, Solana devnet → devnet USDC mint. Explicit overrides always win. Solana's `network` field accepts both CAIP-2 (`solana:5eykt4UsFv8…` / `solana:EtWTRABZaYq6iMfeYKouRu166VU2xqa1`) AND the raw `@solana/mpp` form (`mainnet-beta` / `devnet` / `localnet`)), `build_mppx_compose_rails(amount_usd=, tempo_recipient=, solana_recipient=, ...)` (per-call intent factory replacing the hand-rolled `[("tempo/charge", {...}), ("solana/charge", {...}), ("stripe/charge", {...})]` list; auto-handles USD→atomic conversion for Solana), `process_x402_settle` (verify+settle in one call), `create_mppx_server` (wraps `pympp[server,tempo,stripe]>=0.6`), `is_evm_network`/`is_solana_network` (CAIP-2 discriminators that hide the `startswith("eip155:")` / `startswith("solana:")` prefix matching), `has_payment_header` (settle-leg vs discovery-leg discriminator), `parse_did_pkh_address` (parses ``did:pkh:<family>:<chain>:<addr>`` into a `PaymentSigner`), dispatch-by-network, signer extraction, WWW-Authenticate header, Settlement-Overrides header |
 | `agentscore_commerce.discovery` | Discovery probe (`is_discovery_probe_request`, `build_discovery_probe_response`), Bazaar wrapper, `/.well-known/mpp.json`, `llms.txt` builder, `skill.md` builder (Claude-Skill-compatible agent-discovery manifest), `build_redemption_skill_md` (delivery-neutral; printed/emailed/API-trial codes all covered via `delivery_intro`/`body_shape`/`body_rules`/`extra_recovery_rows` overrides), `build_merchant_index_json` + `standard_endpoint_descriptions(kind=)` (canonical `/` discovery body for goods or API merchants), `build_success_next_steps` (universal Passport-active success block), `build_agentscore_onboarding_steps`, OpenAPI snippets, `NoindexNonDiscoveryMiddleware` ASGI middleware. Plus the UCP/JWKS publish surface: `build_signed_ucp_response`, `build_signed_jwks_response`, `well_known_preflight_response`, `default_a2a_services`, `bootstrap_ucp_signing_key`, framework-neutral `SignedDiscoveryResponse` + per-framework wrappers `signed_response_{fastapi,flask,django,aiohttp,sanic}` |
 | `agentscore_commerce.challenge` | 402-body builders: accepted_methods, identity_metadata (auto-attached by `Checkout` when wallet header present), how_to_pay, agent_instructions, build_402_body, pricing, agent_memory, `build_validation_error` (4xx body builder), `Receipt`/`ReceiptNextSteps`/`ProductInfo`/`ShippingAddress` (canonical 200-receipt dataclasses) |
-| `agentscore_commerce.stripe_multichain` | Multichain PaymentIntent helper (`create_multichain_payment_intent` returns `MultichainPaymentIntentResult`; read `result.deposit_addresses[network]` directly), testnet simulator (`simulate_crypto_deposit`, `simulate_deposit_if_test_mode`), `create_pi_cache`, `create_mppx_stripe` |
+| `agentscore_commerce.stripe_multichain` | Multichain PaymentIntent helper (`create_multichain_payment_intent` returns `MultichainPaymentIntentResult`; read `result.deposit_addresses[network]` directly), `create_pay_to_address_from_stripe_pi(authorization_header=, amount_cents=, stripe=, pi_cache=, networks=, metadata=, order_id=, preferred_network=)` — one-call per-order payTo resolver matching `Checkout.mint_recipients`: on the settle leg, reuses the buyer's signed-against payTo from the MPP credential (after `pi_cache.has_address` check); on the discovery leg, mints a fresh PI via `create_multichain_payment_intent` and caches the addresses + PI mapping. Testnet simulator (`simulate_crypto_deposit`, `simulate_deposit_if_test_mode`), `simulate_deposit_for_outcome(outcome=, deposit_address=, get_payment_intent_id=, stripe_secret_key=, stripe_version=)` (dispatches the simulator based on a Checkout / compute_first_checkout settle outcome; replaces the per-merchant rail-switch + thin `simulate_deposit_if_testnet(addr, network)` wrapper), `network_for_outcome` (outcome → simulator network arg, handles both Checkout-shaped `rail_key` and compute-first-shaped `mpp_method`, accepts bare scheme names AND `<scheme>/charge` forms), `create_pi_cache`, `create_mppx_stripe` |
 | `agentscore_commerce.api` | Re-exports `AgentScore` from `agentscore` SDK |
+| `agentscore_commerce.middleware.{fastapi,flask,django,aiohttp,sanic,asgi}` | Framework-specific rate-limit middleware. FastAPI exposes `rate_limit_fastapi(...)` (FastAPI dependency) plus the ASGI `RateLimitMiddleware` re-export; Flask exposes `rate_limit_flask(app, ...)` (installs a `before_request` hook); Django exposes a class-based async `RateLimitMiddleware` configured via `settings.AGENTSCORE_RATE_LIMIT`; aiohttp exposes `rate_limit_aiohttp(...)` middleware factory; Sanic exposes `rate_limit_sanic(app, ...)` installer; `asgi.RateLimitMiddleware` is a generic ASGI middleware that works with any starlette-compatible app. Shared options: `window_seconds` (default 60), `max_requests` (default 60), `key_resolver` (default first hop of `x-forwarded-for`), `redis_url` (lazy-imports `redis.asyncio` when set, in-memory `dict` fallback otherwise), `key_prefix`. `redis` is an optional peer dep (install via the `redis` extra). |
 
 ## Architecture
 
@@ -44,7 +45,7 @@ Peer-dep pattern: payment/x402/mppx/stripe modules import lazily at runtime; ven
 | `identity_only.py` | Compliance gate without payment (vendor handles their own) |
 | `multi_rail_merchant.py` | Full agent-commerce: identity + Tempo MPP + x402 + Stripe SPT |
 | `stripe_multichain_merchant.py` | Stripe-anchored multichain (PaymentIntent → tempo/base/solana deposit addresses) |
-| `variable_cost_merchant.py` | Pay-per-actual-usage on **two protocols**: x402 upto (Permit2 + Settlement-Overrides) AND MPP tempo session (channel + SSE + mid-stream vouchers) |
+| `compute_first_merchant.py` | Pay-per-result variable-cost merchant via the compute-first + exact-x402 helper (`compute_first_checkout`). Exact-mode rails only (x402-exact Base, tempo/charge, solana/charge, Stripe SPT); deliberately scoped out of x402-upto (Permit2) and Settlement-Overrides. Probe runs the work + caches by body content-hash; settle replays the cached result at the computed exact price. Pairs with `rate_limit_fastapi` since the probe leg runs work pre-payment. |
 | `compliance_merchant.py` | Regulated-goods merchant: full compliance gate + custom `on_denied` composing the denial helpers (`verification_agent_instructions`, `is_fixable_denial`, `build_signer_mismatch_body`, `build_contact_support_next_steps`, `denial_reason_to_body`/`denial_reason_status`) |
 | `per_product_policy_merchant.py` | Multi-product merchant where each row carries its own compliance policy. One product hard-gates KYC + age + state; another is anonymous; a third uses `enforcement="soft"` (request KYC but don't block sale). Demonstrates `PolicyBlock`, `build_gate_from_policy`, `run_gate_with_enforcement`, `shipping_country_allowed`, `shipping_state_allowed`. |
 | `signed_ucp_merchant.py` | Signed UCP profile (`/.well-known/ucp`) + JWKS endpoint (`/.well-known/jwks.json`). AgentScore's `agentscore-profile+jws` is a vendor extension on top of UCP for trust-mode verifiers (regulated-commerce, AP2-aware) that opt into auditable cryptographic provenance — UCP §6 itself does NOT mandate signing; production UCP merchants commonly ship unsigned. Wires ephemeral-for-dev / env-JWK-for-prod signing, kid rotation, and `Cache-Control` posture. Uses `generate_ucp_signing_key`, `sign_ucp_profile`, `build_jwks_response`, `UCPSigningKey.from_jwk`, `UCPVerificationError`. Demonstrates the payment-handler builders (`mpp_payment_handler`, `x402_payment_handler`, `stripe_spt_payment_handler` — see "Payment-handler builders" below). |
@@ -94,15 +95,12 @@ Wallet-signer-match + signer-sanctions: the gate adapter calls `extract_payment_
 `AgentScoreGate(...)` (or `agentscore_gate(app, ...)` on Flask/Sanic) is mounted directly when the route is AgentScore-only; every request runs identity + policy. To support **anonymous discovery by any spec-compliant x402 wallet** (Coinbase awal, Phantom, Solflare, ...), wrap the gate so it fires only when a payment credential is attached:
 
 ```python
+from agentscore_commerce.payment import has_payment_header
+
 _gate = AgentScoreGate(api_key=..., require_kyc=True, ...)
 
 async def gate_on_settle(request: Request) -> None:
-    has_payment_header = bool(
-        request.headers.get("payment-signature")
-        or request.headers.get("x-payment")
-        or (request.headers.get("authorization") or "").startswith("Payment ")
-    )
-    if not has_payment_header:
+    if not has_payment_header(request):
         return None
     return await _gate(request)