Codemod Executor Skill

Executes automated code transformations using AST-based tools for large-scale refactoring, framework migrations, and language version upgrades.

Purpose

Enable automated code transformations for:

• Framework migration (React, Angular, Vue)
• Language version upgrades
• API deprecation handling
• Pattern standardization
• Large-scale refactoring

Capabilities

1. AST-Based Transformations

• Parse source code to AST
• Apply transformation rules
• Generate modified source
• Preserve code style

2. Pattern Matching and Replacement

• Define source patterns
• Specify target patterns
• Handle edge cases
• Support wildcards and captures

3. Multi-File Transformations

• Apply across entire codebase
• Handle import updates
• Coordinate cross-file changes
• Manage side effects

4. Dry-Run Preview

• Preview changes before applying
• Generate diff reports
• Estimate impact scope
• Identify risky transformations

5. Rollback Support

• Create transformation checkpoints
• Enable selective rollback
• Track applied codemods
• Maintain change history

6. Custom Codemod Creation

• Define new transformation rules
• Test codemods in isolation
• Document transformation logic
• Share across teams

Tool Integrations

Tool	Language	Integration Method
jscodeshift	JavaScript/TypeScript	CLI
ts-morph	TypeScript	Library
Rector	PHP	CLI
Scalafix	Scala	CLI
OpenRewrite	Java	CLI / Maven
Bowler	Python	CLI
ast-grep	Multi-language	CLI / MCP
gofmt -r	Go	CLI

Output Schema

{
  "executionId": "string",
  "timestamp": "ISO8601",
  "codemod": {
    "name": "string",
    "version": "string",
    "description": "string"
  },
  "results": {
    "filesProcessed": "number",
    "filesModified": "number",
    "filesSkipped": "number",
    "transformations": "number"
  },
  "changes": [
    {
      "file": "string",
      "transformations": [
        {
          "type": "string",
          "line": "number",
          "before": "string",
          "after": "string"
        }
      ]
    }
  ],
  "errors": [],
  "warnings": []
}

Integration with Migration Processes

• code-refactoring: Large-scale refactoring
• framework-upgrade: Framework migrations
• language-version-migration: Syntax upgrades
• code-translation: Language conversion assist

Related Skills

• refactoring-assistant: Suggests transformations
• static-code-analyzer: Pre-transformation analysis

Related Agents

• code-transformation-executor: Orchestrates codemods
• framework-upgrade-specialist: Framework-specific codemods