| name | ast-grep-find |
| description | AST-based code search and refactoring via ast-grep MCP |
| allowed-tools | Bash, Read |
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.