Function Lookup MCP

Code Declaration Lookup MCP Server

An MCP server that provides full text search for code declarations. Uses SQLite with FTS5 and universal ctags to index and search functions, classes, structures, enums, and other code elements. Supports all languages that ctags supports including Python, C, Go, C++, JavaScript, Rust, Java, and many others.

Requirements

• Python 3.13
• Universal Ctags 6.2.0
• SQLite with FTS5 support (included in Python 3.13)

Installation

git clone git@github.com:osinmv/function-lookup-mcp.git
cd function-lookup-mcp
claude mcp add api-lookup $(pwd)/run.sh -s user

Extending the Index

Just ask your coding agent to index your header folder. The indexing process respects your project's .gitignore file to avoid indexing unwanted files. Alternatively, you can generate ctags files manually using universal ctags:

ctags --output-format=json --fields=+Sf --kinds-C=+p -R -f apis/your_api.ctags /path/to/your/headers

Or drop existing ctags files into the apis/ folder and restart the MCP server to update the index.

MCP functions

search_declarations(name: str, offset: int = 0, limit: int = 10) - Search for code declarations by name

list_indexed_apis() - List all indexed API files

list_api_files(api_name: str, offset: int = 0, limit: int = 100) - List all unique file paths for a specific API

list_functions_by_file(file_path: str, offset: int = 0, limit: int = 100) - List all functions found in a specific file

generate_ctags(include_directory: str) - Generate ctags from source files and add to index