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Version: 1.0.5

A2A Cart Store (AP2 + Skyfire)

A minimal, runnable example that demonstrates AP2 ↔ uAgents Payment Protocol bridging using the A2A Outbound adapter.

Repo: a2a-cart-store

Overview​

  • A2A/AP2 store (JSON‑RPC) with: list, add, remove, cart, checkout
  • uAgent adapter (SingleA2AAdapter) forwards chat and bridges payments
  • Payment handshake (uAgents): RequestPayment → Commit/Reject → Complete/Cancel
  • Skyfire method is used at checkout so UI offers Skyfire Pay

AP2 ↔ PaymentProtocol mapping

Note: Use a unique agent name and description when starting your adapter/uAgent to derive a unique address and avoid collisions.

Prerequisites​

  • Python 3.10+

Installation​

python3 -m venv .venv && source .venv/bin/activate
pip install "uagents-adapter[a2a-outbound]==0.6.0" "a2a-sdk[http-server]"
# example deps
pip install -r /Users/abhi/Desktop/a2p\ protocol/examples-a2a/requirements.txt \
            -r /Users/abhi/Desktop/a2p\ protocol/examples-a2a/a2a-cart-store/requirements.txt

Environment​

Create .env (examples root or cart-store folder):

# Ports
STORE_A2A_PORT=10031
STORE_UAGENT_PORT=8230

# Skyfire (to show Skyfire Pay)
JWKS_URL=https://app.skyfire.xyz/.well-known/jwks.json
JWT_ISSUER=https://app.skyfire.xyz
SELLER_ACCOUNT_ID=YOUR_SKYFIRE_ACCOUNT_ID
SELLER_SERVICE_ID=YOUR_SKYFIRE_SERVICE_ID
SKYFIRE_TOKENS_CHARGE_API_URL=https://api.skyfire.xyz/api/v1/tokens/charge
SELLER_SKYFIRE_API_KEY=YOUR_SKYFIRE_API_KEY

Run​

cd /Users/abhi/Desktop/a2p\ protocol/examples-a2a/a2a-cart-store
python3 av_adapter.py

By default this starts:

Commands to test on ASI1 or other uAgents Client​

  • list or catalog
  • add <sku> [qty] [<sku> [qty]] ... (e.g., add book 1 pen 2 watch 1)

AP2 ↔ PaymentProtocol mapping

  • remove <sku>
  • cart

AP2 ↔ PaymentProtocol mapping

  • checkout

Expected Output​

  • After checkout the adapter returns a RequestPayment with payment_method="skyfire" and the UI shows a Skyfire Pay option.
  • On payment approval the adapter emits CompletePayment; on failure it emits CancelPayment.

AP2 ↔ PaymentProtocol mapping

How it works (AP2 ↔ PaymentProtocol mapping)​

  • CartMandate → RequestPayment (amount/currency from AP2 total; payment_method from AP2 method_data; include cart_hash)
  • CommitPayment → PaymentMandate (token from transaction_id; total from funds)
  • PaymentSuccess → CompletePayment; PaymentFailure → CancelPayment; RejectPayment → DenyCartMandate

Files​

  • av_adapter.py: boots SingleA2AAdapter, loads .env, forwards chat, bridges payments.
  • store_executor.py: store logic; builds AP2 CartMandate on checkout; validates/charges on PaymentMandate.
  • skyfire_payment.py: Skyfire JWT verify (JWKS) + charge helper; returns a transaction_id on success.
  • requirements.txt: pins adapter and A2A SDK plus libraries used by the executor.

Troubleshooting​

  • Variable URLs in docs: use fixed defaults instead of ${VAR} in MDX.
  • Skyfire errors: confirm all env values and network reachability to JWKS/charge endpoints.
  • Ensure payment_request.method_data is non‑empty (example sets supported_methods="skyfire").