a2a-payments

# A2A Payments (APay) Blockchain-native USDC payments for AI agents on Base chain. Pay for services, manage budgets, and handle micropayments. ## Quick Start Check your balance: ``` Use apay_check_balance to see my USDC balance ``` Pay a service: ``` Use apay_pay_service with serviceId "svc-123" and amount "0.50" ``` ## Available Tools ### Balance & Budget | Tool | Description | |------|-------------| | `apay_check_balance` | Check USDC balance, daily budget, spending limits | | `apay_budget_check` | Verify if a specific amount is affordable | | `apay_spending_history` | Get spending analytics and history | ### Payments | Tool | Description | |------|-------------| | `apay_pay_service` | Pay a service (agent pays gas) | | `apay_pay_signed` | Gasless signed payment (server submits on-chain) | | `apay_estimate_cost` | Estimate cost including 0.5% platform fee | ### Services | Tool | Description | |------|-------------| | `apay_list_services` | List available APay services | | `apay_get_service` | Get detailed service info | ### Payment Channels (Streaming) | Tool | Description | |------|-------------| | `apay_channel_status` | Check channel status | | `apay_stream_open` | Open channel with USDC deposit | | `apay_stream_pay` | Sign off-chain micropayment | | `apay_stream_close` | Close channel (refund unspent) | ### x402 Protocol | Tool | Description | |------|-------------| | `apay_x402_fetch` | Fetch URL with automatic x402 payment on HTTP 402 | ## Workflows ### Pay for a tool execution 1. `apay_budget_check` — verify affordability 2. `apay_estimate_cost` — see total with fees 3. `apay_pay_service` — execute payment 4. Receive payment receipt with tx hash ### Streaming micropayments For services that charge per-request (API calls, data feeds): 1. `apay_stream_open` — deposit USDC into channel 2. `apay_stream_pay` — sign micropayments (off-chain, instant) 3. `apay_stream_close` — settle on-chain, refund remainder ### x402 auto-payment For services using the HTTP 402 payment protocol: ``` Use apay_x402_fetch with url "https://api.example.com/premium/data" and maxPayment "1.00" ``` The tool automatically detects 402 responses, pays the required amount, and retries the request. ## Network - **Chain**: Base (Coinbase L2) - **Stablecoin**: USDC (6 decimals) - **Model**: Escrow-based sessions with spending limits - **Testnet**: base-sepolia for development