mcp-api-reference

日本語版 (Japanese)

An MCP (Model Context Protocol) server that automatically crawls, indexes, and serves API reference documentation for LLMs.

Problem & Solution

When LLMs generate code that uses APIs, the following problems occur:

• Hallucination: Generating non-existent endpoints or parameters
• Stale information: Unable to reference the latest API specs not included in training data
• Inefficient context consumption: Passing entire documentation wastes tokens

This tool automatically crawls, parses, and indexes API reference sites just by specifying a URL, then provides token-efficient search results via MCP tools.

MCP Tools

Tool	Description	Main Inputs
search_docs	Full-text search by keyword	query, api (optional), limit (1-20)
get_endpoint	Get details of a specific endpoint	api, endpoint (path), method
list_apis	List available APIs and categories	api (optional)

Requirements

• Node.js >= 18.0.0

Installation

npm install
npm run build

Usage

Start as MCP Server

node dist/index.js

CLI Options

# Specify a custom config file
node dist/index.js --config ./my-sites.json

# Refresh cache for a specific API
node dist/index.js --refresh kintone

# Clear all cache
node dist/index.js --clear-cache

Option	Short	Description
--config <path>	-c	Path to custom site config file
--refresh <api-id>	-r	Re-fetch documentation for the specified API
--clear-cache	-	Clear all cache and exit

Claude Desktop Integration

Add the following to claude_desktop_config.json:

{
  "mcpServers": {
    "api-reference": {
      "command": "node",
      "args": ["/path/to/mcp-reference-doc/dist/index.js"]
    }
  }
}

Presets

kintone REST API

A parser for the kintone REST API is built in as a preset. No additional configuration required.

Backlog API

A parser for the Backlog API is also available as a preset. No additional configuration required.

SmartHR API

A parser for the SmartHR API is also available as a preset. No additional configuration required.

Custom Sites

You can add any API documentation site by specifying a JSON file with the --config option.

{
  "sites": [
    {
      "id": "my-api",
      "name": "My API",
      "baseUrl": "https://api.example.com",
      "crawl": {
        "startUrl": "https://api.example.com/docs",
        "includePatterns": ["https://api.example.com/docs/**"],
        "excludePatterns": [],
        "maxPages": 500,
        "delayMs": 500
      },
      "parser": {
        "type": "generic",
        "selectors": {
          "endpointContainer": ".endpoint",
          "method": ".http-method",
          "path": ".api-path",
          "title": "h3",
          "description": ".description",
          "parameters": ".parameters",
          "responseFields": ".response"
        }
      }
    }
  ]
}

Project Structure

src/
├── index.ts              # CLI entry point
├── server.ts             # MCP server initialization and tool registration
├── core/
│   ├── crawler.ts        # Web crawler with robots.txt support
│   ├── parser.ts         # Parser registry
│   ├── generic-parser.ts # Generic HTML parser (CSS selector-based)
│   ├── indexer.ts        # Full-text search index via MiniSearch
│   ├── store.ts          # Document store
│   ├── cache.ts          # TTL-based cache management
│   └── pipeline.ts       # Crawl → parse → index pipeline
├── tools/
│   ├── search-docs.ts    # search_docs tool
│   ├── get-endpoint.ts   # get_endpoint tool
│   └── list-apis.ts      # list_apis tool
├── presets/
│   ├── kintone/          # kintone preset
│   ├── backlog/          # Backlog preset
│   └── smarthr/          # SmartHR preset
├── formatters/
│   └── response.ts       # MCP response formatter
├── types/                # Type definitions
└── utils/                # Utilities (logger, glob, hash)

Development

# Build in watch mode
npm run dev

# Run tests
npm test

# Run tests (watch mode)
npm run test:watch

# Type check
npm run typecheck

# Lint
npm run lint

Tech Stack

• @modelcontextprotocol/sdk - MCP server implementation
• cheerio - HTML parser
• minisearch - Full-text search engine (with Japanese tokenization support)
• zod - Schema validation
• tsup - TypeScript bundler
• vitest - Test framework

Environment Variables

Variable	Description	Default
MCP_API_REF_CACHE_DIR	Path to cache directory	~/.mcp-api-reference/cache/
MCP_API_REF_CONFIG	Path to site config file	-

License

MIT