osinmv/funciton-lookup-mcp

Overview

An MCP server that lets AI agents look up function signatures from any API by indexing source files with universal ctags and storing them in SQLite. It supports multiple languages including Python, C, Go, C++, JS, Rust, and Java, and helps prevent hallucination on unknown or recently updated source files by providing accurate signatures.

Best for

Best for
Developers building AI agents that need accurate function signatures from existing codebases

Use cases

• Provide correct function signatures to an AI coding assistant during code generation
• Validate API calls in an agent by cross-referencing against indexed source files
• Reduce hallucination when an AI agent references functions from a large or unfamiliar codebase

How to use

Install

claude mcp add api-lookup $(pwd)/run.sh -s user

Tools exposed

• universal ctags
• sqlite

Notes

An MCP server that lets AI agents look up function signatures from any API by indexing source files with universal ctags and storing them in SQLite. It supports multiple languages including Python, C, Go, C++, JS, Rust, and Java, and helps prevent hallucination on unknown or recently updated source files by providing accurate signatures.

3 stars on GitHub. Last updated 2025-11-10.

Use cases

• Provide correct function signatures to an AI coding assistant during code generation
• Validate API calls in an agent by cross-referencing against indexed source files
• Reduce hallucination when an AI agent references functions from a large or unfamiliar codebase

Pros

• Supports a wide range of programming languages via universal ctags
• Uses local SQLite for fast, offline signature lookups
• Directly addresses hallucination by returning real function signatures

Cons

• Requires source files to be present and indexed before use
• Depends on universal ctags, which may not cover all language features or custom syntax
• Limited to function signatures only, not full documentation or usage examples

Indexed from awesome-mcp-servers-punkpeye and enriched against its public facts.