Agent skill · writing content · ast-grep
ast-grep
Guide for writing ast-grep rules to perform structural code search and analysis. Use when users need to search codebases using Abstract Syntax Tree (AST) patterns, find specific code structures, or perform complex code queries that go beyond simple text search. This skill should be used when users ask to search for code patterns, find specific language constructs, or locate code with particular structural characteristics.
Why this skill is useful
Provides specific AST pattern matching rules and testing procedures that the AI wouldn't reliably generate on its own.
What it needs
Requires ast-grep installed locally. About 6k tokens when loaded. Last updated 2026-07-03. 829 stars on the source repository.
What this skill does
ast-grep Code Search Overview This skill helps translate natural language queries into ast-grep rules for structural code search. ast-grep uses Abstract Syntax Tree (AST) patterns to match code based on its structure rather than just text, enabling powerful and precise code search across large codebases. When to Use This Skill Use this skill when users: Need to search for code patterns using structural matching (e.g., "find all async functions that don't have error handling") Want to locate specific language constructs (e.g., "find all function calls with specific parameters") Request searches that require understanding code structure rather than just text Ask to search for code with particular AST characteristics Need to perform complex code queries that traditional text search cannot handle General Workflow Follow this process to help users write effective ast-grep rules: Step 1: Understand the Query Clearly understand what the user wants to find. Ask clarifying questions if needed: What specific code pattern or structure are they looking for? Which programming language? Are there specific edge cases or variations to consider? What should be included or excluded from matches? Step 2: Create Example Code Write a simple code snippet that represents what the user wants to match. Save this to a temporary file for testing. Example: If searching for "async functions that use await", create a test file: Step 3: Write the ast-grep Rule Translate the pattern into an ast-grep rule. Start simple and add complexity as needed. Key principles: Always use stopBy: end for relational rules (inside, has) to ensure search goes to the end of the direction Use pattern for simple structures Use kind with has/inside for complex structures Break complex queries into smaller sub-rules using all, any, or not Example rule file (testrule.yml): See references/rulereference.md for comprehensive rule documentation. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills ast-grep/ast-grep