Multi Version Behavior Comparator

arabelatso/multi-version-behavior-comparator

Compare behavior across multiple versions of programs or repositories. Use when you need to analyze how functionality changes between versions, identify regressions, compare outputs and exceptions, or validate upgrades. The skill compares execution behavior, test results, outputs, exceptions, and observable states across versions, generating detailed reports showing behavioral divergences, potential regressions, added/removed functionality, and areas requiring validation. Supports multiple programming languages and can work with test suites or execution traces.

531 tokens

context cost

the whole folder, loaded on every use

files

instructions only

copies elsewhere

how many repositories repackaged it

141

stars on the repo

on the repository, not the skill itself

Install

one command, takes just this skill from the repository

npx skills add https://github.com/ArabelaTso/Skills-4-SE --skill multi-version-behavior-comparator

The instruction itself

7 sections, as written by the author

Multi-Version Behavior Comparator

Overview

This skill compares behavior across multiple versions of programs, identifying functional changes, regressions, and behavioral divergences to guide safe upgrades and validation.

Quick Start

# Compare two versions
python scripts/compare.py v1.0/ v2.0/

# Compare multiple versions with test suite
python scripts/compare.py v1.0/ v2.0/ v3.0/ --tests tests/

# Generate detailed report
python scripts/compare.py old/ new/ --output report.json

What Gets Compared

Functionality - Added, removed, or modified features
Outputs - Return values, printed output, file changes
Exceptions - Error handling and exception types
Test Results - Pass/fail status across versions
Observable States - Side effects, state changes

Comparison Report

Generates JSON report with:

Behavioral Divergences: Where versions behave differently
Potential Regressions: Functionality that may have broken
Added Features: New functionality in newer versions
Removed Features: Functionality no longer present
Validation Areas: Code requiring manual review

Usage

python scripts/compare.py <version1> <version2> [version3...] [--tests <test_dir>] [--output <report.json>]

Tips

Run before deploying new versions
Use with existing test suites for comprehensive comparison
Review regressions carefully before upgrading
Validate high-risk areas identified in report

How to use it

Copy the folder

Take arabelatso/multi-version-behavior-comparator from the repository into ~/.claude/skills for personal use, or into .claude/skills inside a project.

Check the name does not clash

The agent identifies a skill by the name field in its header. Two skills with the same name cannot sit side by side — one of them will be ignored.