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ast-grep is an open-source static analysis tool that uses abstract syntax trees (AST) to find patterns in your codebase, helping identify security vulnerabilities and enforce code quality standards.

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Configuration Options

You can configure ast-grep in your .coderabbit.yaml file or through CodeRabbit’s settings page under “Review → Tools → ast-grep”. The following options are available:
  • rule_dirs: List of directories containing your custom ast-grep rules (relative to repository root)
  • util_dirs: List of directories containing utility configs to support rule management (relative to repository root)
  • essential_rules: Enable the ast-grep essentials package (default: true)
  • packages: List of GitHub packages to use (format: owner/repo)

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Example Configuration

reviews:
  tools:
    ast-grep:
      rule_dirs:
        - "rules/javascript"
        - "rules/python"
      util_dirs:
        - "utils"
      essential_rules: true
      packages:
        - "owner/custom-rules"
CodeRabbit will only run ast-grep if you have configured at least one of the following:
  • Custom rule directories (rule_dirs)
  • Custom utility directories (util_dirs)
  • Essential rules enabled (essential_rules: true)
  • Custom packages (packages)

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Files

ast-grep will run on the following file types:
  • C/C++ (.c, .cpp, .h, .hpp)
  • C# (.cs)
  • CSS (.css)
  • Elixir (.ex, .exs)
  • Go (.go)
  • Haskell (.hs)
  • HTML (.html)
  • Java (.java)
  • JavaScript (.js, .jsx)
  • JSON (.json)
  • Kotlin (.kt)
  • Lua (.lua)
  • PHP (.php)
  • Python (.py)
  • Ruby (.rb)
  • Rust (.rs)
  • Scala (.scala)
  • Shell (.sh, .bash)
  • SQL (.sql)
  • Swift (.swift)
  • TypeScript (.ts, .tsx)
  • YAML (.yaml, .yml)