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
- Go packages via
-
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
- 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
}
}
}
}
- 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\"]}"
}
}
}
}
- 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');\naxios.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
- TypeScript/JavaScript:
Development
# Install dependencies
npm i
# Build
npm run build
# Watch mode
npm run watch
Contributing
- Fork the repository
- Create your feature branch (
git checkout -b feature/amazing-feature) - Commit your changes (
git commit -m 'Add some amazing feature') - Push to the branch (
git push origin feature/amazing-feature) - Open a Pull Request
License
This project is licensed under the MIT License - see the LICENSE file for details.