> ## Documentation Index
> Fetch the complete documentation index at: https://docs.snack.money/llms.txt
> Use this file to discover all available pages before exploring further.

# A2A Protocol

> Agent-to-Agent protocol integration with Snack Money

## What is A2A?

**A2A (Agent-to-Agent)** is a JSON-RPC 2.0 based protocol that enables AI agents to discover and communicate with each other. Snack Money implements A2A with the **X402 extension**, combining agent discovery with cryptocurrency payments.

## Key Features

* **Agent Discovery** - Automatic service discovery via agent cards
* **JSON-RPC 2.0** - Standard protocol for agent communication
* **X402 Extension** - Integrated crypto payment capabilities
* **Multi-Network** - Support for both Base and Solana networks
* **Task-Based Flow** - Asynchronous payment processing
* **6 Payment Platforms** - Twitter, Farcaster, GitHub, Email, Web, Instagram

## How A2A Works with Snack Money

### 1. Discovery Phase

Agents discover Snack Money's capabilities through the agent card:

```bash theme={null}
GET https://api.snack.money/a2a/.well-known/agent-card
```

The agent card describes:

* Available payment skills (e.g., `snack-money.pay.twitter`)
* Required parameters and schemas
* Supported X402 extension

### 2. Payment Request

Agents send JSON-RPC requests to initiate payments:

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "snack-money.pay.twitter",
  "params": {
    "receiver": "username",
    "amount": 0.01,
    "description": "Payment via A2A",
    "meta": {
      "agent_name": "my-agent"
    }
  }
}
```

### 3. Payment Requirements

Snack Money responds with payment requirements:

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "taskId": "task_abc123",
    "status": "PAYMENT_REQUIRED",
    "payment": {
      "network": "eip155:8453",
      "amount": "10000",
      "token": "0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913",
      "recipient": "0x..."
    }
  }
}
```

### 4. On-Chain Payment

The agent executes the USDC transfer on the specified network (Base or Solana).

### 5. Payment Proof Submission

After blockchain confirmation, the agent resubmits with proof:

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "snack-money.pay.twitter",
  "params": {
    "receiver": "username",
    "amount": 0.01,
    "taskId": "task_abc123",
    "payment": {
      "network": "eip155:8453",
      "transactionHash": "0x..."
    }
  }
}
```

### 6. Completion

Snack Money verifies the payment and returns success:

```json theme={null}
{
  "jsonrpc": "2.0",
  "id": 2,
  "result": {
    "taskId": "task_abc123",
    "status": "PAYMENT_CONFIRMED",
    "metadata": {
      "x402:transactionId": "1234567890",
      "x402:receipt": "https://snack.money/x/username?txn=1234567890"
    }
  }
}
```

## Available Skills

Snack Money exposes the following A2A skills:

### Single Payments

* `snack-money.pay.twitter` - Send to Twitter/X users
* `snack-money.pay.farcaster` - Send to Farcaster users
* `snack-money.pay.github` - Send to GitHub users
* `snack-money.pay.email` - Send to email addresses
* `snack-money.pay.web` - Send to web domains
* `snack-money.pay.instagram` - Send to Instagram users

### Batch Payments

* `snack-money.batch-pay.twitter` - Batch payments to Twitter users
* `snack-money.batch-pay.farcaster` - Batch payments to Farcaster users
* `snack-money.batch-pay.github` - Batch payments to GitHub users
* `snack-money.batch-pay.email` - Batch payments to email addresses
* `snack-money.batch-pay.web` - Batch payments to web domains
* `snack-money.batch-pay.instagram` - Batch payments to Instagram users

## Required Headers

When making A2A requests, include:

```http theme={null}
Content-Type: application/json
X-A2A-Extensions: https://a2a.dev/spec/extensions/x402/v0
```

## Network Support

### Base (EVM)

* Network ID: `eip155:8453`
* Token: USDC (`0x833589fCD6eDb6E08f4c7C32D4f71b54bdA02913`)
* Use EVM private key for signing

### Solana (SVM)

* Network ID: `solana:mainnet`
* Token: USDC SPL token
* Use Solana private key for signing

## Integration Example

For complete working examples, see the [A2A Examples](/examples/a2a) page or check out the [snack-money-examples/a2a](https://github.com/snack-money/snack-money-examples/tree/main/a2a) repository.

## Why A2A + X402?

The combination of A2A and X402 protocols provides:

1. **Agent Interoperability** - Agents can discover and use services automatically
2. **Payment Integration** - Native crypto payments without manual setup
3. **Standardized Communication** - JSON-RPC 2.0 ensures compatibility
4. **Decentralized** - No central authority or intermediary required
5. **Multi-Chain** - Support for different blockchain networks

## Learn More

* [A2A Protocol Specification](https://a2a-protocol.org/)
* [X402 Protocol](/introduction/x402) - Payment protocol details
* [A2A Examples](/examples/a2a) - Implementation examples
* [Agent Card API](https://api.snack.money/a2a/.well-known/agent-card) - Live agent card