SKILL-014: Detect Duplicate Files

Overview

Scans the workspace for identical files (by content, not name) to detect redundancy, copy-paste errors, or accidental forks. Generates a report suggesting deduplication actions.

Trigger Phrases

• find duplicates
• check for duplicate files
• scan redundancy

Inputs

Parameter	Type	Required	Default	Description
--workspace-path	string	No	Current directory	Root to scan
--min-size	int	No	0	Minimum file size in bytes to check
--exclude	string[]	No	node_modules, .git, bin, obj	Directories to ignore

Outputs

1. DUPLICATE_REPORT.md

Summary of found duplicates:

# Duplicate File Report

**Total Duplicates:** 12
**Wasted Space:** 4.5 MB

## Group 1 (Hash: a1b2...)
- `src/utils/math.ts` (Original?)
- `src/legacy/math_copy.ts`

## Group 2 (Hash: c3d4...)
- `config/settings.json`
- `deploy/settings.prod.json`

Implementation

Script: find_duplicates.ps1

1. recurses through directory (respecting excludes).
2. Calculates SHA256 hash of every file.
3. Groups by hash.
4. Filters groups with count < 2.
5. Generates Markdown report.

Use Cases

1. Cleanup: Reducing repo size by removing accidental copies of large assets.
2. Refactoring: Finding code that was copy-pasted instead of shared.