lsmcp - Language Service Protocol MCP

A unified MCP (Model Context Protocol) server that provides advanced code manipulation and analysis capabilities for multiple programming languages through Language Server Protocol integration.

• 🌍 Multi-Language Support

• 🔍 Semantic Code Analysis

• 🤖 AI-Optimized

See examples/ for working examples of each supported language configuration.

Requirements

• Node.js 22.0.0 or higher (required for built-in SQLite support)

Quick Start

RECOMMENDED WORKFLOW

🎯 Core Flow: Overview → Search → Details

📋 When to Use Each Tool

Initial Exploration:

• get_project_overview - First tool to understand any codebase

• list_dir - Browse directory structure

• get_symbols_overview - High-level view of file symbols

Finding Code:

• search_symbols - Primary search for functions, classes, interfaces

• lsp_get_document_symbols - List all symbols in a specific file

• lsp_get_workspace_symbols - Alternative workspace-wide search

Understanding Code:

• get_symbol_details - Complete information in one call (recommended)

• lsp_get_definitions - Jump to definition (use includeBody: true for full code)

• lsp_find_references - Find all usages

• lsp_get_hover - Quick type information

Code Quality:

• lsp_get_diagnostics - Check for errors

• lsp_get_code_actions - Get available fixes

Code Modification:

• lsp_rename_symbol - Safe renaming across codebase

• lsp_format_document - Format code

• replace_range / replace_regex - Text replacements

Example Workflows

1. EXPLORING A NEW CODEBASE

2. INVESTIGATING A BUG

3. REFACTORING CODE

4. ADDING NEW FEATURES

FALLBACK TOOLS (USE ONLY WHEN NECESSARY):

• ⚠️ Read - Only when you need to see non-code files or LSMCP tools fail

• ⚠️ Grep - For text pattern searches in files

• ⚠️ Glob - Only when LSMCP file finding doesn't work

• ⚠️ LS - Only for basic directory listing when LSMCP fails

• ⚠️ Bash commands - Only for non-code operations or troubleshooting

WHEN TO USE FALLBACK TOOLS

Use standard tools ONLY in these situations:

1. Non-code files: README, documentation, configuration files

2. LSMCP tool failures: When LSMCP tools return errors or no results

3. Debugging: When troubleshooting why LSMCP tools aren't working

4. Special file formats: Files that LSMCP doesn't support

5. Quick verification: Double-checking LSMCP results when needed

Memory System

You have access to project memories stored in .lsmcp/memories/. Use these tools:

• mcp__lsmcp__list_memories - List available memory files

• mcp__lsmcp__read_memory - Read specific memory content

• mcp__lsmcp__write_memory - Create or update memories

• mcp__lsmcp__delete_memory - Delete a memory file

Memories contain important project context, conventions, and guidelines that help maintain consistency.

Available Presets

lsmcp includes built-in presets for popular language servers:

• tsgo - TypeScript (Recommended)

• typescript - typescript-language-server

• rust-analyzer - Rust Analyser

• moonbit - MoonBit

• fsharp - F# (fsautocomplete)

• deno - Deno TypeScript/JavaScript

• gopls - Go (Official Go language server)

• hls - Haskell Language Server (requires ghcup setup, see docs/HASKELL_SETUP.md)

• ocaml - OCaml Language Server

Configuration

.lsmcp/config.json

For a comprehensive configuration example, see examples/full-lsmcp-config.json.

Tools

lsmcp provides comprehensive MCP tools for code analysis and manipulation:

Note: Tool names listed below are the raw MCP tool names (snake_case, e.g. get_hover). Some clients display them with a server-qualified prefix (e.g. mcplsmcpget_hover). For naming conventions and module boundaries, see docs/TOOL_REFERENCE.md.

Core LSP Tools

• lsp_get_hover - Get type information and documentation for symbols

• lsp_find_references - Find all references to a symbol across the codebase

• lsp_get_definitions - Navigate to symbol definitions with optional code body

• lsp_get_diagnostics - Check for errors and warnings in files

• lsp_get_all_diagnostics - Get diagnostics for entire project

• lsp_get_document_symbols - List all symbols in a file

• lsp_get_workspace_symbols - Search symbols across the entire workspace

• lsp_get_completion - Get code completion suggestions

• lsp_get_signature_help - Get parameter hints for function calls

• lsp_format_document - Format entire documents using language server

• lsp_rename_symbol - Rename symbols across the codebase

• lsp_get_code_actions - Get available quick fixes and refactorings

• lsp_delete_symbol - Delete a symbol and optionally all its references

• lsp_check_capabilities - Check supported LSP features

High-Level Tools

• get_project_overview - Quick project structure and component analysis

• search_symbols - Fast symbol search using pre-built index (auto-creates index if needed)

• get_symbol_details - Get comprehensive details about a symbol (hover, definition, references)

External Library Tools

• index_external_libraries - Index TypeScript declaration files from node_modules

• get_typescript_dependencies - List available TypeScript dependencies

• search_external_library_symbols - Search symbols in indexed external libraries

• resolve_symbol - Resolve symbols to their definitions in external libraries

• get_available_external_symbols - Get symbols available from imported libraries

• parse_imports - Parse and analyze import statements

Code Editing Tools

• replace_range - Replace specific text ranges in files

• replace_regex - Advanced regex-based replacements

File System Tools

• list_dir - List directories with gitignore support

• get_symbols_overview - High-level symbol overview by file

Memory Management

• list_memories - List project memories

• read_memory - Read specific memory content

• write_memory - Create or update memories

• delete_memory - Remove memories

Performance Optimization

LSMCP includes several performance optimizations:

• Incremental Indexing: Only modified files are re-indexed

• Memory Monitoring: Automatic garbage collection when memory usage is high

• Batch Processing: Efficient concurrent file processing

• Smart Caching: 15-minute cache for frequently accessed data

Configuration options in .lsmcp/config.json:

Development

See CONTRIBUTING.md for detailed development setup, testing instructions, and contribution guidelines.

Debug Logging

LSMCP has separate logging systems for MCP server and LSP client that can be controlled independently:

MCP Server Logging

Enable MCP server debug output with either environment variable:

LSP Client Logging

Enable LSP client debug output separately:

Combined Logging

Enable both MCP and LSP debug output:

License

MIT - See LICENSE file for details.