> For the complete documentation index, see [llms.txt](https://documentation.justbeep.it/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://documentation.justbeep.it/product-overview/agent-to-agent-payments-a402/developer-guide-a402-less-than-greater-than-mcp-pay.md).

# Developer guide a402 <> mcp-pay

## 📡 a402 <> MCP-Pay Integration

This package provides the **Model Context Protocol (MCP)** integration layer for **Beep SDK**, enabling seamless connections between **AI agents**, **backends**, and **on-chain payment workflows** on the **Sui network**.

Beep’s MCP integration allows **LLMs and autonomous agents** (ChatGPT, Claude, custom agents, etc.) to:

* Initiate or verify stablecoin payments
* Automate invoicing and settlement
* Embed on-chain context into reasoning flows
* Be discoverable and callable through **AEO (Answer Engine Optimization)**

***

### 📦 What’s Inside

* Reference **MCP server** implementations
* Transport adapters (`HTTP`, `SSE`, `stdio`)
* Authentication and schema definitions
* AEO-compatible metadata for agent discovery
* Best practices and integration examples

***

### 🚀 Why MCP Matters for Beep

Beep bridges **AI agents ↔ Sui payments** using self-custodial USDC infrastructure.

| Capability                  | Description                                                |
| --------------------------- | ---------------------------------------------------------- |
| **Agentic Payments**        | Agents can autonomously send, request, and verify payments |
| **Context-Aware Reasoning** | Payment data feeds directly into LLM reasoning graphs      |
| **AEO Discoverability**     | Endpoints can be indexed for direct LLM use                |
| **Composable Workflows**    | Integrate Beep payments into any AI or SaaS product        |

***

### 🔄 Supported Transports

| Transport | Use Case                     | Description                                     |
| --------- | ---------------------------- | ----------------------------------------------- |
| `http`    | Web services / REST APIs     | Standard HTTP-based MCP endpoints               |
| `sse`     | Streaming / real-time agents | Push updates via Server-Sent Events             |
| `stdio`   | Local / CLI agents           | For Claude Desktop or local agent communication |

Each transport adapter includes:

* JSON message serialization/parsing
* Lifecycle hooks (`onOpen`, `onClose`, `onError`)
* API key–based authentication middleware

***

### Beep MCP Server - Client Integration Guide

A Model-Context-Protocol (MCP) server that provides secure access to Beep platform capabilities through multiple transport protocols.

### Quick Start

#### Prerequisites

* Valid API key from Beep platform (if **not authenticated**)

#### HTTP Transport

The HTTP transport is ideal for web applications, remote clients, and production use.

**Initialize a Session**

Send an initialize request without a session ID:

```sh
curl -X POST https://api.justbeep.it/mcp \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": "1",
    "method": "initialize",
    "params": {
      "clientInfo": {
        "name": "my-client",
        "version": "1.0.0"
      }
    }
  }'
```

The server will respond with a session ID in the `mcp-session-id` header. Use this ID for all subsequent requests:

```sh
curl -X POST https://api.justbeep.it/mcp \
  -H "Content-Type: application/json" \
  -H "mcp-session-id: your-session-id" \
  -d '{
    "jsonrpc": "2.0",
    "id": "2",
    "method": "tools/list",
    "params": {}
  }'
```

**Call Tools with Authentication**

```sh
curl -X POST https://api.justbeep.it/mcp \
  -H "Content-Type: application/json" \
  -H "mcp-session-id: your-session-id" \
  -d '{
    "jsonrpc": "2.0",
    "id": "3",
    "method": "tools/call",
    "params": {
      "name": "requestAndPurchaseAsset",
      "arguments": {
        "apiKey": "your-api-key",
        "amount": 1000000,
        "currency": "USDT",
        "referenceId": "payment-123"
      }
    }
  }'
```

### Available Tools

#### Authentication Tools

* **`initiateDeviceLogin`**: Start OAuth device flow for CLI tools and apps
* **`createMerchantAccountFromSSO`**: Create new merchant accounts via Google SSO

#### Resource Access

* **`getPaidResource`**: Access premium features and paid content

### Integration Examples

#### JavaScript/Node.js

```javascript
const McpClient = require('@modelcontextprotocol/sdk/client');

const client = new McpClient({
  transport: 'http',
  endpoint: 'https://api.justbeep.it/mcp',
  auth: {
    type: 'bearer',
    token: 'your-access-token',
  },
});

await client.initialize();
const tools = await client.listTools();
```

#### Python

```python
import requests

session = requests.Session()
session.headers.update({
    'Authorization': 'Bearer your-access-token',
    'Content-Type': 'application/json'
})

# Initialize session
response = session.post('https://api.justbeep.it/mcp', json={
    'method': 'initialize',
    'params': {'clientInfo': {'name': 'python-client', 'version': '1.0.0'}}
})

session_id = response.headers.get('mcp-session-id')
session.headers.update({'mcp-session-id': session_id})

# List available tools
tools = session.post('https://api.justbeep.it/mcp', json={
    'method': 'tools/list'
}).json()
```

### Error Handling

The server returns standard HTTP status codes:

* **200**: Success
* **401**: Authentication required
* **402**: Payment required (for paid resources)
* **404**: Resource not found
* **500**: Server error

### Example apps

<br>