prompt-regression-tester

Compare old and new prompt outputs to generate regression reports with diffs and stability metrics.

Updated Jan 21, 2026
One-click install
npx skills add https://github.com/vecear/Nipponverb --skill prompt-regression-tester-vecear
Or copy as Structured Prompt for Agent
Please help me install this Agent Skill.
Skill: prompt-regression-tester
Source: https://github.com/vecear/Nipponverb/tree/main/.claude/skills/prompt-regression-tester
Command: npx skills add https://github.com/vecear/Nipponverb --skill prompt-regression-tester-vecear

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

This Skill identifies and mitigates regressions when prompts are updated by comparing outputs from older and newer prompts across a curated suite of test cases, surfacing diffs and stability concerns.

Core Features & Use Cases

  • Automated comparison of old vs new prompts across multiple test cases
  • Diff summaries, stability metrics, and breakage analysis
  • Actionable fix suggestions to prevent future regressions
  • Use cases include prompt versioning, A/B testing prompts, and quality regression workflows

Quick Start

Provide two prompts (old and new) and a test case suite to generate a regression report with diffs, stability metrics, and fix suggestions.

Frequently Asked Questions about prompt-regression-tester

High-intent search queries and answers about installing and using this skill.

FAQPage Schema
How do I detect prompt regressions when updating prompt versions?

To detect prompt regressions, compare outputs from old and new prompts across a curated set of test cases. This generates structured diff summaries, stability metrics, and actionable fix suggestions to prevent quality degradation.

What is prompt A/B testing and how does diff analysis work?

Prompt A/B testing evaluates prompt behavior by comparing outputs from two prompt versions across test cases. Diff analysis identifies variations in responses, calculates stability scores, and highlights breakages to ensure versioning quality.

How do I calculate stability metrics for prompt versioning?

Calculate stability metrics by running both old and new prompts against a curated test case suite. The process compares output pairs to generate stability scores, structured diff reports, and breakage analysis for automated quality workflows.

Can I integrate prompt testing into CI pipelines for automated evaluation?

Yes, prompt testing can integrate into CI pipelines. The process generates a structured regression report containing diff summaries and stability metrics, satisfying constraints required by automated CI workflows to catch prompt breakages.

What is the best way to prevent regressions during prompt A/B testing?

The best way to prevent regressions during A/B testing is to compare old and new prompt outputs across a comprehensive test case suite. This yields structured stability metrics and actionable fix suggestions to mitigate identified breakages.

Why does my updated prompt produce inconsistent outputs across test cases?

Your updated prompt likely introduces regressions detected by comparing its outputs against the old prompt across a test case suite. This comparison generates diff summaries and stability metrics to pinpoint exact behavioral breakages.