sonar_get_duplication_summary

Get ranked list of files with code duplication, sortable by density, lines, or blocks.

Description

Identifies files with the most code duplication in your project. Shows priority indicators and refactoring recommendations to help focus cleanup efforts on high-impact areas.

Parameters

Parameter	Type	Required	Default	Description
sortBy	string	No	density	Sort method: density, lines, blocks
pageSize	number	No	100	Files to analyze (1-500)
maxResults	number	No	10	Limit output to top N files (1-50)

Sort Options

Option	Description	Best For
density	Percentage of file that's duplicated	Finding worst offenders
lines	Total duplicate line count	Finding biggest impact
blocks	Number of duplicate blocks	Finding scattered duplication

Usage

Basic Usage

Show me files with the most duplication

Tool call:

{}

By Impact (Lines)

Which files have the most duplicated code by volume?

Tool call:

{
  "sortBy": "lines",
  "maxResults": 15
}

Top Offenders Only

Show me the 5 worst duplicated files

Tool call:

{
  "sortBy": "density",
  "maxResults": 5
}

Response Format

DUPLICATION SUMMARY
━━━━━━━━━━━━━━━━━━━

Project: my-awesome-app
Overall Duplication: 4.2%

📊 TOP FILES BY DENSITY:

┌─────┬────────────────────────────────────────┬─────────┬───────┬────────┐
│ Rank│ File                                   │ Density │ Lines │ Blocks │
├─────┼────────────────────────────────────────┼─────────┼───────┼────────┤
│ 🔴 1│ src/utils/validators.ts                │  45.2%  │  234  │   12   │
│ 🔴 2│ src/services/PaymentService.ts         │  38.7%  │  189  │    8   │
│ 🟠 3│ src/api/handlers/userHandler.ts        │  28.3%  │  156  │    6   │
│ 🟠 4│ src/api/handlers/orderHandler.ts       │  25.1%  │  142  │    5   │
│ 🟡 5│ src/components/DataTable.tsx           │  18.4%  │   98  │    4   │
│ 🟡 6│ src/components/UserTable.tsx           │  17.9%  │   92  │    4   │
│ 🟢 7│ src/hooks/useApi.ts                    │   8.2%  │   34  │    2   │
│ 🟢 8│ src/hooks/useFetch.ts                  │   7.8%  │   31  │    2   │
│ 🟢 9│ src/config/routes.ts                   │   5.1%  │   22  │    1   │
│ 🟢10│ src/types/api.ts                       │   3.4%  │   15  │    1   │
└─────┴────────────────────────────────────────┴─────────┴───────┴────────┘

PRIORITY INDICATORS:
🔴 HIGH (>25%)   - Immediate refactoring recommended
🟠 MEDIUM (15-25%) - Should refactor soon
🟡 LOW (10-15%)  - Consider refactoring
🟢 MINIMAL (<10%) - Acceptable levels

📋 REFACTORING RECOMMENDATIONS:

High Priority:
1. src/utils/validators.ts (45.2%)
   → Extract common validation logic to shared module
   → Estimated cleanup: 234 lines reducible

2. src/services/PaymentService.ts (38.7%)
   → Abstract payment processing patterns
   → Consider strategy pattern for payment types

Pattern Detected:
• userHandler.ts and orderHandler.ts share similar patterns
  → Extract base handler class or shared utilities

SUMMARY:
  Files analyzed: 89
  Files with duplication: 10
  Total duplicate lines: 1,013
  Potential reduction: ~650 lines (64%)

Priority Levels

Level	Density	Action
🔴 HIGH	More than 25%	Refactor immediately
🟠 MEDIUM	15-25%	Plan refactoring
🟡 LOW	10-15%	Consider when touching
🟢 MINIMAL	Less than 10%	Acceptable

Examples

Example 1: Sprint Planning

Prompt:

What duplication should we tackle this sprint?

Tool Call:

{
  "sortBy": "lines",
  "maxResults": 10
}

Example 2: Code Review Focus

Prompt:

Show me the worst duplicate offenders

Tool Call:

{
  "sortBy": "density",
  "maxResults": 5
}

Example 3: Large Codebase Analysis

Prompt:

Analyze duplication across our entire codebase

Tool Call:

{
  "pageSize": 500,
  "maxResults": 50
}

Refactoring Strategies

Pattern	Solution
Similar handlers	Extract base class
Repeated validation	Create validator utility
Copy-pasted configs	Use shared constants
Similar components	Create generic component
Repeated API calls	Create service abstraction

Best Practices

1. Start with high density - Files with 25%+ duplication
2. Consider impact - High line count = bigger savings
3. Look for patterns - Similar files often share code
4. Don't over-abstract - Some duplication is acceptable

Common Issues

"No duplication data"

Cause: Project hasn't been scanned with duplication detection.

Solution: Run sonar_scan_project first.

"Results seem incomplete"

Cause: Page size too small for large projects.

Solution: Increase pageSize parameter.

Related Tools

• sonar_get_duplication_details - Detailed block analysis
• sonar_get_project_metrics - Overall metrics
• sonar_analyze_patterns - Issue patterns