ast-grep-find

SKILL.md

AST-Grep Find

Structural code search that understands syntax. Find patterns like function calls, imports, class definitions - not just text.

When to Use

Find code patterns (ignores strings/comments)

Search for function calls, class definitions, imports

Refactor code with AST precision

Rename variables/functions across codebase

Usage

Search for a pattern

uv run python -m runtime.harness scripts/ast_grep_find.py \
    --pattern "import asyncio" --language python

Search in specific directory

uv run python -m runtime.harness scripts/ast_grep_find.py \
    --pattern "async def \$FUNC(\$\$\$)" --language python --path "./src"

Refactor/replace pattern

uv run python -m runtime.harness scripts/ast_grep_find.py \
    --pattern "console.log(\$MSG)" --replace "logger.info(\$MSG)" \
    --language javascript

Dry run (preview changes)

uv run python -m runtime.harness scripts/ast_grep_find.py \
    --pattern "print(\$X)" --replace "logger.info(\$X)" \
    --language python --dry-run

Parameters

Parameter
Description

--pattern
AST pattern to search (required)

--language
Language: python, javascript, typescript, go, etc.

--path
Directory to search (default: .)

--glob
File glob pattern (e.g., **/*.py)

--replace
Replacement pattern for refactoring

--dry-run
Preview changes without applying

--context
Lines of context (default: 2)

Pattern Syntax

Syntax
Meaning

$NAME
Match single node (variable, expression)

$$$
Match multiple nodes (arguments, statements)

$_
Match any single node (wildcard)

Examples

# Find all function definitions
uv run python -m runtime.harness scripts/ast_grep_find.py \
    --pattern "def \$FUNC(\$\$\$):" --language python

# Find console.log calls
uv run python -m runtime.harness scripts/ast_grep_find.py \
    --pattern "console.log(\$\$\$)" --language javascript

# Replace print with logging
uv run python -m runtime.harness scripts/ast_grep_find.py \
    --pattern "print(\$X)" --replace "logging.info(\$X)" \
    --language python --dry-run

vs morph/warpgrep

Tool
Best For

ast-grep
Structural patterns (understands code syntax)

warpgrep
Fast text/regex search (20x faster grep)

Use ast-grep when you need syntax-aware matching. Use warpgrep for raw speed.

MCP Server Required

Requires ast-grep server in mcp_config.json.