MCP Language Server

This is an MCP server that runs and exposes a language server to LLMs. Not a language server for MCP, whatever that would be.

Demo

mcp-language-server helps MCP enabled clients navigate codebases more easily by giving them access semantic tools like get definition, references, rename, and diagnostics.

Setup

1. Install Go: Follow instructions at https://golang.org/doc/install
2. Install or update this server: go install github.com/isaacphi/mcp-language-server@latest
3. Install a language server: follow one of the guides below
4. Configure your MCP client: follow one of the guides below

Go (gopls)

<strong>Install gopls</strong>: <code>go install golang.org/x/tools/gopls@latest</code>
<strong>Configure your MCP client</strong>: This will be different but similar for each client. For Claude Desktop, add the following to <code>~/Library/Application\ Support/Claude/claude_desktop_config.json</code>

{ "mcpServers": { "language-server": { "command": "mcp-language-server", "args": ["--workspace", "/Users/you/dev/yourproject/", "--lsp", "gopls"], "env": { "PATH": "/opt/homebrew/bin:/Users/you/go/bin", "GOPATH": "/users/you/go", "GOCACHE": "/users/you/Library/Caches/go-build", "GOMODCACHE": "/Users/you/go/pkg/mod" } } } }

Note: Not all clients will need these environment variables. For Claude Desktop you will need to update the environment variables above based on your machine and username:

Rust (rust-analyzer)

<strong>Install rust-analyzer</strong>: <code>rustup component add rust-analyzer</code>
<strong>Configure your MCP client</strong>: This will be different but similar for each client. For Claude Desktop, add the following to <code>~/Library/Application\ Support/Claude/claude_desktop_config.json</code>

{ "mcpServers": { "language-server": { "command": "mcp-language-server", "args": [ "--workspace", "/Users/you/dev/yourproject/", "--lsp", "rust-analyzer" ] } } }

Python (pyright)

<strong>Install pyright</strong>: <code>npm install -g pyright</code>
<strong>Configure your MCP client</strong>: This will be different but similar for each client. For Claude Desktop, add the following to <code>~/Library/Application\ Support/Claude/claude_desktop_config.json</code>

{ "mcpServers": { "language-server": { "command": "mcp-language-server", "args": [ "--workspace", "/Users/you/dev/yourproject/", "--lsp", "pyright-langserver", "--", "--stdio" ] } } }