ast-grep

name	ast-grep
description	Use ast-grep MCP tools for syntax-aware structural search, AST inspection, rule testing, and structural verification. Triggers: code-shape queries, structural invariants, pattern debugging, AST inspection, and multi-file syntax matching.

ast-grep MCP Workflow

When to use this skill

Use this skill when the question depends on code structure rather than plain text.

Good fits:

• Find all code matching a syntax shape.
• Verify a structural invariant across files.
• Debug why a pattern does or does not match.
• Inspect the AST or pattern structure before writing a rule.
• Plan or verify structural rewrite targets before editing.

Do not use ast-grep as the default repo navigation tool when cymbal can answer the question more directly.

Tool map

This local setup uses the official ast-grep/ast-grep-mcp server. Do not assume extra MCP tools exist beyond the four tools below.

• ast_grep_dump_syntax_tree

  • Use to inspect target code or understand how a pattern is parsed.
  • format: cst shows concrete syntax.
  • format: ast shows named syntax nodes.
  • format: pattern shows how ast-grep interprets your search pattern.

• ast_grep_test_match_code_rule

  • Use to test a YAML rule against example code before searching the repo.

• ast_grep_find_code

  • Use for simple single-pattern searches when one AST pattern is enough.

• ast_grep_find_code_by_rule

  • Use for complex searches that need relational rules like , , , , or composite rules like , , .