setup-dry

name	setup-dry
description	One-time setup skill that adds structural duplication detection via pre-commit hook and CI. Configures DRY violation checks using AST fingerprinting and Jaccard similarity. Use when user wants automated duplicate code detection.

Setup DRY

One-time guided setup. Adds DRY violation detection at both CI and pre-commit hook level. Defaults to setting up both -- confirms with user before proceeding.

Workflow

Step 1 -- Detect project setup

• Identify primary language(s) from file extensions and config files
• Identify source directories (e.g. src/, lib/, app/)
• Check for existing duplication detection tools (e.g. jscpd, PMD CPD)
• Check if .github/workflows/ already exists

Present findings to user for confirmation before proceeding.

If detection is ambiguous, use AskUserQuestion to clarify:

• If language can't be determined: ask what language(s) the project uses
• If no clear source directories: ask which directories contain production code (vs. config, scripts, etc.)
• If existing duplication tools found: ask if they want to replace or run alongside

Step 2 -- Ask user preferences

Use AskUserQuestion for each:

1. Where to enforce -- default is both, confirm with user:
   • Both CI and pre-commit hook (recommended)
   • CI only -- GitHub Actions workflow
   • Pre-commit hook only -- local enforcement
2. Similarity threshold -- minimum Jaccard similarity to flag as duplicate
   • Suggest 0.8 (80% structural similarity)
   • User can raise/lower
3. Minimum block size -- smallest code block to consider
   • Suggest 5 lines -- ignore trivially small matches
   • User can adjust
4. CI enforcement mode (if CI selected):
   • Fail the check (recommended) -- PR cannot merge on new duplicates
   • Warn only -- post a comment but don't block

Step 3 -- Generate files

• If CI selected: generate .github/workflows/dry-check.yml
• If pre-commit hook selected: write hook script to .git/hooks/pre-commit (or append to existing) and make it executable
• Hook should run DRY analysis on staged files against the existing codebase

Step 4 -- Verify

• Read back generated files and sanity-check them
• Show the user what was generated for review
• Run a sample DRY check as a smoke test

Key rules

• Never overwrite existing workflow files or hooks without asking
• Idempotent -- running again detects existing setup and skips