visual-regression-testing

visual-regression-testing is a skill for Claude Code, Codex from hoangatg/ai-agent-toolkit. It costs 37 tokens per session (310 once invoked), scanned A, original, MIT.

Visual regression testing guidance for comparing application screenshots over time. It covers tools such as Playwright, Chromatic, Percy, BackstopJS, and Loki.

In plain words
What is it for?
Use it to check UI changes across pull requests, screen sizes, and pages while accounting for changing content and minor rendering differences.
Why use it?
It helps detect accidental changes to a page's appearance that ordinary functional tests may miss.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to check UI changes across pull requests, screen sizes, and pages while accounting for changing content and minor rendering differences.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/hoangatg/ai-agent-toolkit/visual-regression-testing
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add hoangatg/ai-agent-toolkit --skill visual-regression-testing
Clone the repo
git clone --depth 1 https://github.com/hoangatg/ai-agent-toolkit

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for visual-regression-testing

README.md
[![agentmods](https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/visual-regression-testing/github.svg)](https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/visual-regression-testing)
Your own site
<a href="https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/visual-regression-testing"><img src="https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/visual-regression-testing/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for visual-regression-testing

Your own site · 80×15
<a href="https://agentmods.dev/skills/hoangatg/ai-agent-toolkit/visual-regression-testing"><img src="https://agentmods.dev/badge/skills/hoangatg/ai-agent-toolkit/visual-regression-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 37 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 310 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00037 $0.00310
Opus 5 $0.00018 $0.00155
Sonnet 5 $0.00007 $0.00062
Haiku 4.5 $0.00004 $0.00031

Measured 8d ago against content hash 556d3d03f5d1, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-11, from the pricing page.

Security

Grade A, and why

visual-regression-testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 8d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.agent/skills/visual-regression-testing/SKILL.md · 45 lines

What it actually says

Visual Regression Testing

Catch unintended UI changes before users do. Screenshot comparison for every PR.

Tool Comparison

Tool Type CI Integration Cost
Playwright Screenshots Open source Any CI Free
Chromatic Cloud service GitHub/GitLab Freemium
Percy Cloud service Any CI Paid
BackstopJS Open source Any CI Free
Loki Storybook-based Any CI Free

Playwright Visual Testing

import { test, expect } from '@playwright/test'

test('homepage visual', async ({ page }) => {
  await page.goto('/')
  await expect(page).toHaveScreenshot('homepage.png', {
    maxDiffPixels: 100,
    threshold: 0.2,
  })
})

Best Practices

Practice Why
Stable test environment Prevent flaky snapshots
Mask dynamic content Dates, avatars, ads change
Test multiple viewports Mobile, tablet, desktop
Use threshold Allow anti-aliasing differences
Review in CI Approve/reject visual changes in PRs
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 8d ago First seen · 45 lines · 37 tokens per session scan A 556d3d03f5d1

Subscribe to this mod's changes

visual-regression-testing is a skill published in the GitHub repository hoangatg/ai-agent-toolkit (1 stars, last pushed 5mo ago), licensed MIT. It adds 37 tokens to every session and 310 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-03.