OpenAPI Endpoint Discovery MCP Server

Overview

OpenAPI Endpoint Discovery is a powerful tool that enables Claude to discover and call any API endpoint through semantic search. It intelligently chunks OpenAPI specifications to handle large API documentation, with built-in request execution capabilities. This makes it perfect for integrating private APIs with Claude Desktop.

Key Features

• Uses remote OpenAPI JSON files as source, eliminating the need for local file system access or updates when APIs change
• Performs semantic search using an optimized MiniLM-L3 model (43MB vs original 90MB)
• Built on FastAPI with async support for high performance
• Implements endpoint-based chunking of OpenAPI specs to handle documents over 100KB without losing endpoint context
• Utilizes in-memory FAISS vector search for instant endpoint discovery

Installation

Using Docker (Recommended)

The easiest way to get started is with Docker:

docker run -i --rm buryhuang/mcp-server-any-openapi:latest

Using Smithery

You can install via Smithery with:

npx -y @smithery/cli install @baryhuang/mcp-server-any-openapi --client claude

Using pip

Alternatively, install via pip:

pip install mcp-server-any-openapi

Configuration

Customize the server through environment variables:

• OPENAPI_JSON_DOCS_URL: URL to the OpenAPI specification JSON (defaults to https://api.staging.readymojo.com/openapi.json)
• MCP_API_PREFIX: Customizable tool namespace (default "any_openapi")
• GLOBAL_TOOL_PROMPT: Optional text to prepend to all tool descriptions (crucial for accurate tool selection)
• API_REQUEST_BASE_URL: Optional override for the base URL extracted from OpenAPI docs

Example Docker Configuration

docker run -i --rm \
  -e OPENAPI_JSON_DOCS_URL=https://api.finance.com/openapi.json \
  -e MCP_API_PREFIX=finance \
  -e GLOBAL_TOOL_PROMPT="Access to insights APIs for ACME Financial Services abc.com." \
  buryhuang/mcp-server-any-openapi:latest

Multi-instance Configuration

You can run multiple instances to support different API sets:

{
  "mcpServers": {
    "finance_openapi": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e",
        "OPENAPI_JSON_DOCS_URL=https://api.finance.com/openapi.json",
        "-e",
        "MCP_API_PREFIX=finance",
        "-e",
        "GLOBAL_TOOL_PROMPT=Access to insights apis for ACME Financial Services abc.com.",
        "buryhuang/mcp-server-any-openapi:latest"
      ]
    },
    "healthcare_openapi": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "-e",
        "OPENAPI_JSON_DOCS_URL=https://api.healthcare.com/openapi.json",
        "-e",
        "MCP_API_PREFIX=healthcare",
        "-e",
        "GLOBAL_TOOL_PROMPT=Access to insights apis for Healthcare API services efg.com.",
        "buryhuang/mcp-server-any-openapi:latest"
      ]
    }
  }
}

Usage in Claude Desktop

Add a project prompt like:

You should get the API spec details from tools financial_api_request_schema

Your task is to use financial_make_request tool to make the requests to get responses. You should follow the API spec to add authorization header:
Authorization: Bearer <xxxxxxxxx>

Note: The base URL will be returned in the api_request_schema response, you don't need to specify it manually.

Then in chat, you can simply ask: "Get prices for all stocks"

Limitations

• Not supporting linux/arm/v7 (build fails on Transformer library)
• Cold start penalty (~15s for model loading) if not using docker image
• The docker image is large (3.76GB with pre-downloaded models)