OpenAPI to MCP Generator

This project provides a powerful tool for automatically converting OpenAPI/Swagger specifications into Model Context Protocol (MCP) servers, allowing LLMs to interact with any REST API through standardized tools.

Components

SwaggerToMcpGenerator.java

A comprehensive utility that converts any OpenAPI/Swagger specification into a fully functional MCP server:
- Parses OpenAPI specification files
- Converts API endpoints to MCP tools
- Handles path parameters, query parameters, and request bodies
- Supports multiple HTTP methods (GET, POST, PUT, DELETE, PATCH)
- Provides authentication support (API keys, Bearer tokens, Basic auth)
- Formats JSON responses for readability
- Generates robust error handling
- Includes parameter documentation with valid values and defaults

Generating an MCP Server from OpenAPI

To generate an MCP server from any OpenAPI specification:

jbang SwaggerToMcpGenerator.java path/to/swagger.json GeneratedMcpServer [options]

Parameters:
- path/to/swagger.json: Path to the OpenAPI/Swagger specification file
- GeneratedMcpServer: Name of the output Java file (without .java extension)

Options:
- --server-index <index>: Index of the server to use from the OpenAPI specification (0-based)
- --server-url <url>: URL of the server to use (overrides server-index)

This will create a new file GeneratedMcpServer.java that implements an MCP server with tools for each API endpoint defined in the swagger file. The generator will emit a warning if multiple servers are defined in the OpenAPI specification and none is explicitly selected.

Running the Generated MCP Server

To run the generated MCP server:

jbang GeneratedMcpServer.java

Server Selection

The generated MCP server includes constants for all servers defined in the OpenAPI specification, allowing you to choose which server to use at runtime. By default, the first server in the list is used, but you can select a specific server using environment variables:

```bash