migrating-rules

---

name: migrating-rules description: Helps migrate code when updating to new rule versions. Compares rule versions from the index and generates migration plans. Use when rules are updated or when migrating between framework versions. version: 1.0.0 allowed-tools: read, grep, glob, search, codebase_search, edit, write

Step 1: Identify Migration Context

Determine what needs migration:

• Rule version update: Same framework, updated rules
• Framework migration: Different framework (e.g., Pages Router → App Router)
• Standard update: Coding standards changed
• Technology change: New technology added to stack

Step 2: Load Rule Index

Load the rule index to find relevant rules:

• @.claude/context/config/rule-index.json

Step 3: Identify Source and Target Rules

Find the rules involved in migration:

• Source rule: Current rule being used
• Target rule: New rule to migrate to
• Both rules: If migrating between frameworks

Step 4: Load Rule Files

Load both source and target rule files:

• Read source rule file
• Read target rule file
• Compare differences

Step 5: Analyze Differences

Compare rules to identify:

• Removed patterns: What's no longer allowed
• New patterns: What's now required
• Changed patterns: What's been modified
• Breaking changes: Incompatible changes

See reference/migration-patterns.md for common migration patterns.

Step 6: Generate Migration Plan

Create step-by-step migration plan:

• Inventory: List all files affected
• Priority: Order of migration (critical first)
• Steps: Specific code changes needed
• Verification: How to verify migration success </execution_process>

<best_practices>

1. Be Comprehensive: Identify all affected code
2. Prioritize: Critical changes first
3. Show Examples: Before/after code for each change
4. Step-by-Step: Break complex migrations into clear steps
5. Verify: Include verification steps </best_practices>

Structure migration plan clearly:

Copy## Migration Plan: [Source] → [Target]

**Migration Type**: [Rule update / Framework migration / Standard update]
**Affected Files**: [count]
**Estimated Effort**: [low/medium/high]

### Overview

**Source Rule**: [rule name and path]
**Target Rule**: [rule name and path]
**Key Changes**: [summary of main differences]

### Breaking Changes

#### [Change 1]

**Impact**: [high/medium/low]
**Description**: [what changed]

**Before**:
\`\`\`[language]
[old code pattern]
\`\`\`

**After**:
\`\`\`[language]
[new code pattern]
\`\`\`

**Migration Steps**:

1. [Step 1]
2. [Step 2]
3. [Step 3]

---

### New Requirements

#### [Requirement 1]

**Description**: [new requirement]

**Action Required**:
[What needs to be done]

**Example**:
\`\`\`[language]
[code example]
\`\`\`

---

### Deprecated Patterns

#### [Pattern 1]

**Status**: Deprecated
**Replacement**: [new pattern]

**Migration**:
\`\`\`[language]
// Old (deprecated)
[old code]

// New (recommended)
[new code]
\`\`\`

---

### Migration Checklist

- [ ] Step 1: [action]
- [ ] Step 2: [action]
- [ ] Step 3: [action]
- [ ] Verification: [how to verify]

### Verification

[How to verify migration is complete and correct]

</formatting_example>

Next.js 14 → 15:

• App Router changes
• React 19 features
• Server Component patterns

Pages Router → App Router:

• Route structure changes
• Data fetching patterns
• Layout changes

TypeScript Strict Mode:

• Type safety improvements
• any → proper types
• Null checking

Python 3.10 → 3.12:

• Type hint improvements
• Pattern matching
• Performance optimizations

For each scenario, see migration-patterns.md for detailed patterns. </code_example>