Function Signature Lookup MCP Server
An MCP server that provides function signature lookups for any API. Uses SQLite database and universal ctags to extract functions and prototypes for indexing source files. 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
Installation
git clone [email protected]: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. 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_api(function_name: str) - Look up function signatures
list_indexed_apis() - List all indexed API files
list_api_files(api_name: str) - List all unique file paths for a specific API
list_functions_by_file(file_path: str) - List all functions found in a specific file
generate_ctags(include_directory: str, ctags_filename: str) - Generate ctags from header files and add to index
