Overview OKX.AI Wallet Payment Trade Market Exchange OS X Layer

A2MCP Integration Guide#

What is A2MCP?#

A2MCP (Agent-to-MCP) is a service type on OKX.AI through which ASPs provide standardized services that Agents can call. Services can be free or charge per call through x402.

A2MCP services fall into two categories based on endpoint type:

Endpoint type	Use case	Source of call definitions
MCP endpoint	Supports the MCP protocol and enables discovery and invocation of one or more Tools	Tool definitions returned by `tools/list`
HTTP endpoint	A regular HTTP API	Endpoint, request method, parameter definitions, and request examples

Confirm that your service is suitable for integration#

Services suitable for A2MCP can usually be clearly expressed as “input parameters → explicit results,” with invocation and delivery handled programmatically.

Characteristic	Description	Examples
Structured data or capabilities	Returns explicit results through an interface rather than purely manual processing	Weather, exchange rates, maps, market data, company information
Can be exposed as tools	Each capability can be broken down into a function with parameters	Order queries, invoice generation, translation
Verifiable results and relatively low risk	Return values are relatively deterministic	Query and read-only services
Ongoing value	Users may make repeated calls	Data APIs, industry knowledge bases, vertical search

Preparation before integration#

Choose the endpoint type you want to integrate, then complete the corresponding 4 preparation steps.

MCP

HTTP API

Build an MCP Server

Use an official MCP SDK to create a Server and register your business capabilities as Tools. If you already have a database, HTTP API, or SaaS service, you can call these capabilities from the Tool handler.

Recommended learning order:

Official resource	What it helps you understand
Build an MCP server	The basic workflow for Servers, Tool definitions, and client calls
Official SDK index	Choosing a programming language and its SDK
Python SDK v1 documentation	Tool definitions and Streamable HTTP examples
TypeScript SDK v1 Server documentation	Tool registration and Streamable HTTP Server examples

Note on protocol versions and transports

Official tutorials and SDKs are continuously updated. Examples may use local stdio or different protocol versions. The OKX.AI integration workflow in this guide includes the initialize handshake. Choose an implementation that can negotiate a compatible protocol version with the platform.

Define tools and configure pricing

Define MCP Tools

Tool field	Purpose
name	Identifier used to invoke the tool programmatically
title	Service name displayed on the platform
description	Describes the service purpose, capabilities, and returned results
inputSchema	Defines parameter structure, types, required fields, and constraints

OKX.AI requires title and description to be non-empty. One Tool can correspond to one Service, and multiple Services can share the same MCP Endpoint.

Configure pricing

Price information for paid Tools should also be maintained in the MCP Tool / endpoint and must be parsable by the platform.

Option 1: Free services

Return business results directly when the Tool is called. No x402 implementation is required.

Option 2: Pay-per-call services (x402)

Payment should be triggered at the tools/call stage. We recommend using the OKX Payment SDK: OKX provides server-side SDKs (@okxweb3/x402-* supports Node.js, Go, Rust, Java, and Python). Attach payment middleware to the endpoint and configure the receiving address, network, and price. The SDK handles 402 responses and onchain verification. For the full process, see Integrate through the SDK.

⚠️ x402 v2 payment challenges must be base64-encoded and placed in the PAYMENT-REQUIRED response header. The marketplace validates the response header, not the response body. Using the SDK is recommended to avoid errors in the challenge format or placement.

json

{
  "x402Version": 2,
  "resource": {
    "url": "https://<your-public-endpoint>/...",
    "description": "<service-description>",
    "mimeType": "application/json"
  },
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:196",
      "asset": "0x779ded0c9e1022225f8e0630b35a9b54be713736",
      "amount": "10000",
      "payTo": "0x<your-x-layer-wallet>",
      "maxTimeoutSeconds": 300,
      "extra": { "name": "USD₮0", "version": "1" }
    }
  ]
}

Paid endpoints should validate required parameters before returning payment requirements, to avoid users paying for invalid requests. The network, payment scheme, asset, token name and version, amount, and receiving address in the payment challenge must be complete. The actual amount must match the price parsed by the platform.

3
Deploy and verify the MCP service
After deployment, use the official MCP Inspector or a compatible MCP Client to connect to the public HTTPS MCP address, such as https://你的域名/mcp, and verify the following workflow:
text
Client initialize → Server returns the initialization result → Client notifications/initialized → tools/list retrieves tool definitions → tools/call invokes the specified tool with valid arguments
Confirm that the tools you want to list can be discovered and called, that title, description, and parameter definitions are accurate, and that the business results match the stated capabilities. For paid Tools, also verify the payment requirements for business calls and whether replaying the same call after payment authorization delivers the results correctly.
Do not treat a webpage loading, HTTP 200, or progress messages alone as evidence of a successful call. Refer to the SDK documentation for tool discovery and invocation, and the official MCP debugging guide for connection troubleshooting.
4
Register on OKX.AI
Submit the Endpoint following the ASP registration process.

1
Build an HTTP API
Provide a business API that can be called through GET or POST. If you already have an API, skip this step. If developing from scratch, refer to the official FastAPI tutorial or use a Web framework you are familiar with.
Databases, internal systems, and SaaS services can all serve as server-side sources of data and capabilities, but internal addresses cannot be used directly as external Endpoints.

Prepare call information and configure pricing

Information	Preparation requirement
Service name	A name that users can understand
Service description	Describe the service purpose, capabilities, and returned results
Request method	GET or POST, consistent with the actual API
Input parameter format	Specify each parameter's name, type, meaning, and whether it is required; if there are no parameters, state “No parameters”

Parameter types include string, number, boolean, array, and object. Describe the contents of objects and arrays. For example: city (string, required): Name of the city to query.

Registration does not additionally require a complete cURL command, default values or example values for every parameter, location, or hand-written Schema JSON. Provide valid business inputs needed for verification as prompted by the Agent.

Configure pricing

After completing the call definitions, choose free or pay-per-call:

Option 1: Free services

Return business results directly when the API is called (HTTP 200). No x402 implementation is required.

Option 2: Pay-per-call services (x402)

The price comes from the endpoint's x402 settings. We recommend using the OKX Payment SDK: OKX provides server-side SDKs (@okxweb3/x402-* supports Node.js, Go, Rust, Java, and Python). Attach payment middleware to the endpoint and configure the receiving address, network, and price. The SDK handles 402 responses and onchain verification. For the full process, see Integrate through the SDK.

⚠️ x402 v2 payment challenges must be base64-encoded and placed in the PAYMENT-REQUIRED response header. The marketplace validates the response header, not the response body. Using the SDK is recommended to avoid errors in the challenge format or placement.

json

{
  "x402Version": 2,
  "resource": {
    "url": "https://<your-public-endpoint>/...",
    "description": "<service-description>",
    "mimeType": "application/json"
  },
  "accepts": [
    {
      "scheme": "exact",
      "network": "eip155:196",
      "asset": "0x779ded0c9e1022225f8e0630b35a9b54be713736",
      "amount": "10000",
      "payTo": "0x<your-x-layer-wallet>",
      "maxTimeoutSeconds": 300,
      "extra": { "name": "USD₮0", "version": "1" }
    }
  ]
}

3
Deploy and verify the HTTP API
Deploy the HTTP API and configure HTTPS for the domain. Ensure that third-party dependencies, network access, and server-side credentials are configured.
Use curl or an equivalent client to call the public HTTPS business route with the actual request method and valid parameters, and check the response and business results. The following shows only the structure of a POST JSON request. Replace the API and inputs with your own:
bash
curl -i -X POST 'https://你的域名/业务路由' \ -H 'Content-Type: application/json' \ -d '{"city":"Shanghai"}'
For paid services, also check the x402 payment requirements when no payment has been made, and complete delivery when the request is replayed with valid payment credentials.
4
Register on OKX.AI
Submit the Endpoint following the ASP registration process.

Table of contents

What is A2MCP?

Confirm that your service is suitable for integration

Preparation before integration