lsp-mcp MCP Server

An MCP server that bridges LLMs and Language Server Protocol (LSP) servers, enabling LLMs to request hover information, code completions, diagnostics, and code actions for more accurate code suggestions.

Installation

NPX

npx tritlo/lsp-mcp <language-id> <path-to-lsp> <lsp-args>

From Source

git clone https://github.com/your-username/lsp-mcp.git
cd lsp-mcp
npm install
npm run build

Configuration

MCP Configuration

{
  "mcpServers": {
    "lsp-mcp": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "tritlo/lsp-mcp",
        "<language-id>",
        "<path-to-lsp>",
        "<lsp-args>"
      ]
    }
  }
}

Available Tools

Tool	Description
get_info_on_location	Get hover information at a specific location in a file
get_completions	Get code completion suggestions at a specific location in a file
get_code_actions	Get code actions for a specific range in a file
open_document	Open a file on the LSP server for analysis
close_document	Close a file on the LSP server
get_diagnostics	Get diagnostic messages (errors, warnings) for open files
start_lsp	Start the LSP server with the specified root directory
restart_lsp_server	Restart the LSP server without restarting the MCP server
set_log_level	Change the server logging verbosity level at runtime

Features

• Bridge between LLMs and Language Server Protocol servers
• Real-time diagnostic updates via subscriptions
• Code hover information and code completion suggestions
• Code actions and error handling
• Comprehensive logging system with 8 severity levels
• Runtime-configurable logging level
• Language-specific extensions (Haskell support included)
• Integration tests for TypeScript LSP
• MCP resources for diagnostics, hover, and completions
• Resource subscriptions for real-time updates

Usage Examples

Get hover information for a function at line 3, column 5 in a Haskell file

Get code completion suggestions at a specific position in a file

Get diagnostic errors and warnings for all open files

Get code actions to fix errors in a specific code range

Start the LSP server for a project directory before analyzing code

Resources

• GitHub Repository

Notes

Requires Node.js v16+ and npm. The LSP server must be explicitly started using the start_lsp tool before using other LSP functionality. Supports extensions for language-specific capabilities. Files must be opened with open_document before accessing diagnostics or other file-specific operations.