ast-grep

# ast-grep `sg` (also installed as `ast-grep`) is an **AST-aware search and rewrite tool** across 25 languages. It treats your pattern as code, parses it the same way it parses your project, and matches structurally. It is the right tool whenever your question depends on **code shape** rather than text bytes. This skill ships a Python wrapper at `scripts/ast_grep_helper.py` and platform install scripts at `install.sh` (POSIX) and `install.ps1` (Windows). The helper adds offline pattern validation, the two-pass write trick, and binary auto-resolution. Use it as your default entry point. --- ## OmO native: the ast-grep MCP tools (fastest path, no CLI needed) OmO native also registers a bundled ast-grep MCP server. Its three tools are **deferred**: they are absent from the resident tool list and activate automatically the first time you call them by name — no `tool_search` round trip needed. - `mcp__ast_grep_search({ pattern, language, paths })` — AST-shape search, the MCP equivalent of `sg run -p`. Prefer this over shelling out to `sg` for one-off lookups: no install, no PATH issues. - `mcp__ast_grep_rewrite({ pattern, rewrite, language, paths, apply })` — preview matches (`apply: false`, the default) or apply the rewrite (`apply: true`). Same two-pass discipline as `sg run -r`: preview first, then apply. - `mcp__ast_grep_scan({ paths })` — run project YAML rules (`sgconfig.yml`, `rules/`), the MCP equivalent of `sg scan`. Same pattern language as the CLI: `$VAR` matches...