MCP Language Server

This MCP server runs a language server locally and exposes tools to interact with your codebase, enabling precise symbol understanding, references, and diagnostics to assist you when working with large projects.

How to use

Connect your MCP-enabled client to the language server by configuring a local stdio MCP endpoint. You will run the server locally and point the client to use it via the standard MCP workflow, enabling features like symbol definitions, references, diagnostics, code lenses, and edits.

How to install

Prerequisites: install Go and a suitable MCP client setup.

Install the MCP language server locally.

go install github.com/isaacphi/mcp-language-server@latest

Configuration and usage notes

Configure your MCP client to launch the language server as a local stdio process. Use the following configuration snippet to connect the client to the server. This starts the server with the workspace you specify and enables the LSP interface.

{
  "mcpServers": {
    "language-server": {
      "command": "go",
      "args": [
        "run",
        "github.com/isaacphi/mcp-language-server@latest",
        "--workspace",
        "/Users/you/dev/yourpythoncodebase",
        "--lsp",
        "/opt/homebrew/bin/pyright",
        "--",
        "--stdio"
      ],
      "env": {
        "DEBUG": "1"
      }
    }
  }
}

Development

Build and run commands are shown for local development. Rebuild after making changes to ensure the latest code is used by your client.

# Build the server after cloning
go mod download

go build -o server

Available tools

read_definition

Retrieves the complete source code definition of any symbol (function, type, constant, etc.) from your codebase.

find_references

Locates all usages and references of a symbol throughout the codebase.

get_diagnostics

Provides diagnostic information for a specific file, including warnings and errors.

get_codelens

Retrieves code lens hints for additional context and actions on your code.

execute_codelens

Runs a code lens action.

apply_text_edit

Allows making multiple text edits to a file programmatically.