Package Documentation MCP Server

An MCP (Model Context Protocol) server that provides LLMs with efficient access to package documentation across multiple programming languages and language server protocol (LSP) capabilities.

Note: I am not actively maintaining the codebase at present. While it doesn't provide access to private package documentation - the Context7 MCP server and service meets my needs which are mostly for public package documentation. I personally use Context7 via my mcp-devtools MCP server which is actively maintained.

Features

• Multi-Language Support:

  • Go packages via go doc
  • Python libraries via built-in help()
  • NPM packages via registry documentation (including private registries)
  • Rust crates via crates.io and docs.rs

• Smart Documentation Parsing:

  • Structured output with description, usage, and examples
  • Focused information to avoid context overload
  • Support for specific symbol/function lookups
  • Fuzzy and exact search capabilities across documentation

• Advanced Search Features:

  • Search within package documentation
  • Fuzzy matching for flexible queries
  • Context-aware results with relevance scoring
  • Symbol extraction from search results

• Language Server Protocol (LSP) Support:

  • Hover information for code symbols
  • Code completions
  • Diagnostics (errors and warnings)
  • Currently supports TypeScript/JavaScript
  • Extensible for other languages

• Performance Optimised:

  • Built-in caching
  • Efficient parsing
  • Minimal memory footprint

Installation

Note: I do not recommend using npx -y to run your MCP servers in production as you're esentially trusting whatever package you're downloading off the internet at that moment in time. I highly recommend cloning the repository locally or building into a container image.

npx -y mcp-package-docs

Usage

As an MCP Server

1. Add to your MCP settings configuration:

{
  "mcpServers": {
    "package-docs": {
      "command": "npx",
      "args": ["-y", "mcp-package-docs"],
      "env": {
        "ENABLE_LSP": "true" // Optional: Enable Language Server Protocol support
      }
    }
  }
}

1. The LSP functionality includes default configurations for common language servers:

• TypeScript/JavaScript: typescript-language-server --stdio
• HTML: vscode-html-language-server --stdio
• CSS: vscode-css-language-server --stdio
• JSON: vscode-json-language-server --stdio

You can override these defaults if needed:

{
  "mcpServers": {
    "package-docs": {
      "command": "npx",
      "args": ["-y", "mcp-package-docs"],
      "env": {
        "ENABLE_LSP": "true",
        "TYPESCRIPT_SERVER": "{"command":"/custom/path/typescript-language-server","args":["--stdio"]}"
      }
    }
  }
}

1. The server provides the following tools:

lookup_go_doc / describe_go_package

Fetches Go package documentation

{
  "name": "describe_go_package",
  "arguments": {
    "package": "encoding/json", // required
    "symbol": "Marshal"        // optional
  }
}

lookup_python_doc / describe_python_package

Fetches Python package documentation

{
  "name": "describe_python_package",
  "arguments": {
    "package": "requests",    // required
    "symbol": "get"          // optional
  }
}

describe_rust_package

Fetches Rust crate documentation from crates.io and docs.rs

{
  "name": "describe_rust_package",
  "arguments": {
    "package": "serde",      // required: crate name
    "version": "1.0.219"     // optional: specific version
  }
}

search_package_docs

Search within package documentation

{
  "name": "search_package_docs",
  "arguments": {
    "package": "requests",    // required: package name
    "query": "authentication", // required: search query
    "language": "python",     // required: "go", "python", "npm", "swift", or "rust"
    "fuzzy": true            // optional: enable fuzzy matching (default: true)
  }
}

lookup_npm_doc / describe_npm_package

Fetches NPM package documentation from both public and private registries. Automatically uses the appropriate registry based on your .npmrc configuration.

{
  "name": "describe_npm_package",
  "arguments": {
    "package": "axios",      // required - supports both scoped (@org/pkg) and unscoped packages
    "version": "1.6.0"       // optional
  }
}

The tool reads your ~/.npmrc file to determine the correct registry for each package:

• Uses scoped registry configurations (e.g., @mycompany:registry=...)
• Supports private registries (GitHub Packages, GitLab, Nexus, Artifactory, etc.)
• Falls back to the default npm registry if no custom registry is configured

Example .npmrc configurations:

registry=https://nexus.mycompany.com/repository/npm-group/
@mycompany:registry=https://nexus.mycompany.com/repository/npm-private/
@mycompany-ct:registry=https://npm.pkg.github.com/

Language Server Protocol (LSP) Tools

When LSP support is enabled, the following additional tools become available:

get_hover

Get hover information for a position in a document

{
  "name": "get_hover",
  "arguments": {
    "languageId": "typescript", // required: language identifier (e.g., "typescript", "javascript")
    "filePath": "src/index.ts", // required: path to the source file
    "content": "const x = 1;",  // required: content of the file
    "line": 0,                  // required: zero-based line number
    "character": 6,             // required: zero-based character position
    "projectRoot": "/path/to/project" // optional: project root directory
  }
}

get_completions

Get completion suggestions for a position in a document

{
  "name": "get_completions",
  "arguments": {
    "languageId": "typescript", // required: language identifier
    "filePath": "src/index.ts", // required: path to the source file
    "content": "const arr = []; arr.",  // required: content of the file
    "line": 0,                  // required: zero-based line number
    "character": 16,            // required: zero-based character position
    "projectRoot": "/path/to/project" // optional: project root directory
  }
}

get_diagnostics

Get diagnostic information (errors, warnings) for a document

{
  "name": "get_diagnostics",
  "arguments": {
    "languageId": "typescript", // required: language identifier
    "filePath": "src/index.ts", // required: path to the source file
    "content": "const x: string = 1;",  // required: content of the file
    "projectRoot": "/path/to/project" // optional: project root directory
  }
}

Example Usage in an LLM

Looking up Documentation

// Looking up Go documentation
const goDocResult = await use_mcp_tool({
  server_name: "package-docs",
  tool_name: "describe_go_package",
  arguments: {
    package: "encoding/json",
    symbol: "Marshal"
  }
});

// Looking up Python documentation
const pythonDocResult = await use_mcp_tool({
  server_name: "package-docs",
  tool_name: "describe_python_package",
  arguments: {
    package: "requests",
    symbol: "post"
  }
});

// Looking up Rust documentation
const rustDocResult = await use_mcp_tool({
  server_name: "package-docs",
  tool_name: "describe_rust_package",
  arguments: {
    package: "serde"
  }
});

// Searching within documentation
const searchResult = await use_mcp_tool({
  server_name: "package-docs",
  tool_name: "search_package_docs",
  arguments: {
    package: "serde",
    query: "serialize",
    language: "rust",
    fuzzy: true
  }
});

// Using LSP for hover information (when LSP is enabled)
const hoverResult = await use_mcp_tool({
  server_name: "package-docs",
  tool_name: "get_hover",
  arguments: {
    languageId: "typescript",
    filePath: "src/index.ts",
    content: "const axios = require('axios');
axios.get",
    line: 1,
    character: 7
  }
});

Requirements

• Node.js >= 20
• Go (for Go package documentation)
• Python 3 (for Python package documentation)
• Internet connection (for NPM package documentation and Rust crate documentation)
• Language servers (for LSP functionality):
  • TypeScript/JavaScript: npm install -g typescript-language-server typescript
  • HTML/CSS/JSON: npm install -g vscode-langservers-extracted

Development

# Install dependencies
npm i

# Build
npm run build

# Watch mode
npm run watch

Contributing

1. Fork the repository
2. Create your feature branch (git checkout -b feature/amazing-feature)
3. Commit your changes (git commit -m 'Add some amazing feature')
4. Push to the branch (git push origin feature/amazing-feature)
5. Open a Pull Request

License

This project is licensed under the MIT License - see the LICENSE file for details.