How does AST-Grep differ from standard grep?

Unlike standard grep which uses regex to find text patterns, AST-Grep parses your code into an Abstract Syntax Tree (AST), allowing it to find patterns based on code structure and syntax rather than just characters.

How do I define custom security rules?

You can create YAML-based rule files that define specific patterns to look for, the severity of the issue, and even suggested fixes for automated remediation.

Which languages are supported by this skill?

It supports over 40 languages, including popular ones like JavaScript, TypeScript, Python, Go, Rust, Java, C++, Ruby, and many more.

Can I use this for automated code migrations?

Yes, the skill supports powerful rewrite rules that allow you to transform code patterns across your entire project safely using structural understanding.

AST-Grep Structural Code Search & Refactoring

Name: AST-Grep Structural Code Search & Refactoring
Author: modu-ai

bymodu-ai

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Security & Testing

Automates structural code search, security scanning, and large-scale refactoring using AST analysis across 40+ programming languages.

This skill integrates ast-grep into Claude Code, enabling developers to perform semantic code searches and transformations that surpass traditional regex capabilities. By understanding the Abstract Syntax Tree (AST), it allows for precise pattern matching, automated code migrations (codemods), and the enforcement of complex security rules. Whether you are migrating deprecated APIs, identifying SQL injection risks, or refactoring nested function calls, this tool provides the structural awareness needed for safe and efficient code manipulation in polyglot environments.

Key Features

01Advanced security scanning with customizable YAML-based rules

02Automated code transformation and large-scale refactoring (codemods)

03Structural pattern matching using meta-variables and variadic arguments

0416 GitHub stars

05Relational search capabilities to find patterns within specific scopes or function contexts

06Support for over 40 programming languages including TypeScript, Python, and Rust

Use Cases

01Performing complex API migrations by rewriting function calls across an entire codebase

02Enforcing project-specific architectural patterns or linting rules that require AST context

03Scanning for security vulnerabilities like SQL injection or XSS using syntax-aware rules

What are Skills?·How to Install

Install with 🐟 Skill.Fish

npx skillfish add modu-ai/cc-plugins moai-tool-ast-grep

For use in Claude.ai and ChatGPT

Download Skill