What is OpenAPI Schema Model Context Protocol

The OpenAPI Schema Model Context Protocol (MCP) server is a tool designed to expose OpenAPI schema information to Large Language Models (LLMs) like Claude. It facilitates exploration and understanding of OpenAPI specifications by providing specialized tools for querying API paths, operations, parameters, and schemas.

Use cases

This server is useful for developers and API consumers looking to understand API specifications in detail, including exploring endpoints, request and response structures, components, and examples. It can aid in tasks such as API documentation, testing, and integration development.

How to use

To use the MCP server, run it from the command line with a specified OpenAPI schema file in either JSON or YAML format. Configure it in the Claude Desktop or Claude Code environments to integrate with the LLM, allowing it to access various tools for querying and interacting with the API schema.

Key features

Key features of the MCP server include the ability to load any OpenAPI schema file, detailed exploration of API paths and operations, overview of components, request and response schemas, and search functionality across the specification. It also outputs responses in YAML format for better understanding by LLMs.

Where to use

The MCP server can be used in environments where OpenAPI documentation is needed, such as API design and development tools, client applications needing dynamic documentation, and integrated into frameworks like Claude for enhanced interaction with APIs.

OpenAPI Schema Model Context Protocol Server

A Model Context Protocol (MCP) server that exposes OpenAPI schema information to Large Language Models (LLMs) like Claude. This server allows an LLM to explore and understand OpenAPI specifications through a set of specialized tools.

Features

• Load any OpenAPI schema file (JSON or YAML) specified via command line argument
• Explore API paths, operations, parameters, and schemas
• View detailed request and response schemas
• Look up component definitions and examples
• Search across the entire API specification
• Get responses in YAML format for better LLM comprehension

Usage

Command Line

Run the MCP server with a specific schema file:

# Use the default openapi.yaml in current directory
npx -y mcp-openapi-schema

# Use a specific schema file (relative path)
npx -y mcp-openapi-schema ../petstore.json

# Use a specific schema file (absolute path)
npx -y mcp-openapi-schema /absolute/path/to/api-spec.yaml

# Show help
npx -y mcp-openapi-schema --help

Claude Desktop Integration

To use this MCP server with Claude Desktop, edit your claude_desktop_config.json configuration file:

{
  "mcpServers": {
    "OpenAPI Schema": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-openapi-schema",
        "/ABSOLUTE/PATH/TO/openapi.yaml"
      ]
    }
  }
}

Location of the configuration file:

• macOS/Linux: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: $env:AppData\Claude\claude_desktop_config.json

Claude Code Integration

To use this MCP server with Claude Code CLI, follow these steps:

1. Add the OpenAPI Schema MCP server to Claude Code

   # Basic syntax
   claude mcp add openapi-schema npx -y mcp-openapi-schema
   
   # Example with specific schema
   claude mcp add petstore-api npx -y mcp-openapi-schema ~/Projects/petstore.yaml
   

2. Verify the MCP server is registered

   # List all configured servers
   claude mcp list
   
   # Get details for your OpenAPI schema server
   claude mcp get openapi-schema
   

3. Remove the server if needed

   claude mcp remove openapi-schema
   

4. Use the tool in Claude Code

   Once configured, you can invoke the tool in your Claude Code session by asking questions about the OpenAPI schema.

Tips:

• Use the -s or --scope flag with project (default) or global to specify where the configuration is stored
• Add multiple MCP servers for different APIs with different names

MCP Tools

The server provides the following tools for LLMs to interact with OpenAPI schemas:

• list-endpoints: Lists all API paths and their HTTP methods with summaries in a nested object structure
• get-endpoint: Gets detailed information about a specific endpoint including parameters and responses
• get-request-body: Gets the request body schema for a specific endpoint and method
• get-response-schema: Gets the response schema for a specific endpoint, method, and status code
• get-path-parameters: Gets the parameters for a specific path
• list-components: Lists all schema components (schemas, responses, parameters, etc.)
• get-component: Gets detailed definition for a specific component
• list-security-schemes: Lists all available security schemes
• get-examples: Gets examples for a specific component or endpoint
• search-schema: Searches across paths, operations, and schemas

Examples

Example queries to try:

What endpoints are available in this API?
Show me the details for the POST /pets endpoint.
What parameters does the GET /pets/{petId} endpoint take?
What is the request body schema for creating a new pet?
What response will I get from the DELETE /pets/{petId} endpoint?
What schemas are defined in this API?
Show me the definition of the Pet schema.
What are the available security schemes for this API?
Are there any example responses for getting a pet by ID?
Search for anything related to "user" in this API.