> For the complete documentation index, see [llms.txt](https://docs.abapays.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.abapays.com/protocols/a2a.md).

# A2A

> Peer protocol

A peer agent discovers AbaPay via its Agent Card, then sends structured tool calls over A2A JSON-RPC — no browser, no human account-creation step, for either side.

|                   |                                           |
| ----------------- | ----------------------------------------- |
| Agent Card        | `abapays.com/.well-known/agent-card.json` |
| JSON-RPC endpoint | `abapays.com/api/a2a`                     |

## Skills (10)

`describe_capabilities` `check_balance` `list_plans` `list_international_options` `transaction_history` `pay_bill` `pay_bill_batch` `schedule_bill` `list_schedules` `cancel_schedule`

## Can an agent set and use a PIN without visiting abapays.com? Yes.

The PIN is a field in a JSON body, not something entered into a web form. Linking and every payment after it are both plain API calls:

* `POST /api/agent/link` — a wallet-signature-authenticated call (the same `personal_sign` scheme x402 signing uses elsewhere) that picks the PIN *in that same request* and mints an Agent Hub api\_key back. One HTTP call, no session, no browser.
* Every `pay_bill` / `pay_bill_batch` / `schedule_bill` call after that sends the same PIN back as another JSON field — still just an HTTP request.

`POST /api/agent/link` — real fields, verified live:

```
headers: {
  "x-wallet-address": "0xYourAgentWallet...",
  "x-wallet-signature": "<personal_sign over the request>",
  "x-wallet-timestamp": "1234567890"
}
body: {
  "wallet_address": "0xYourAgentWallet...",
  "channel": "MCP",
  "pin": "1234",
  "approved_chain": "CELO"
}
-> { "success": true, "api_key": "aba_mcp_..." }
```

Full runnable version: [examples/agent-quickstart.mjs](https://github.com/investorphem/AbaPay/blob/main/examples/agent-quickstart.mjs). Or skip the wire format entirely: `AbaPayAgent.link()` in [the SDK](/build/sdk.md) does this in one line.

> The PIN itself is still real security, not a formality: it's the one thing separate from the signature that has to be right on *every* payment call — unlike x402, which needs neither a PIN nor a link step at all. Two different trust models, both entirely API-driven.


---

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