What is visual-testing?

A visual regression checker for rendered web pages and app screens. It takes screenshots and compares them with a previously approved baseline image to find unintended visual changes.

Compare screenshots of static HTML pages or running apps, manage baseline images, and create reports showing visual differences.

It catches layout and styling problems that ordinary functional tests may miss, such as shifted buttons, overflowing tables, or missing shadows.

visual-testing — Skill for Claude Code by arozumenko/sdlc-skills

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 arozumenko/sdlc-skills --skill visual-testing

Clone the repo

git clone --depth 1 https://github.com/arozumenko/sdlc-skills

Made for: Claude Code.

Or install sdlc-skills, the plugin that ships this one along with the rest of its 60 skills.

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.

README.md

[![agentmods](https://agentmods.dev/badge/skills/arozumenko/sdlc-skills/visual-testing/github.svg)](https://agentmods.dev/skills/arozumenko/sdlc-skills/visual-testing)

Your own site

<a href="https://agentmods.dev/skills/arozumenko/sdlc-skills/visual-testing"><img src="https://agentmods.dev/badge/skills/arozumenko/sdlc-skills/visual-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.

Your own site · 80×15

<a href="https://agentmods.dev/skills/arozumenko/sdlc-skills/visual-testing"><img src="https://agentmods.dev/badge/skills/arozumenko/sdlc-skills/visual-testing.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 176 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,222 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. Third-party audits

NVIDIA SkillSpector warn 7 Sept 2026

SkillSpector: 1 finding, up to medium

These are SkillSpector’s own severities. On a checked sample its high-severity flags on skills were ~96% false positives — a documented command, a public API, a “never do X” rule — so we show them as a caution to read, not a verdict. Why →

medium MCP Rug Pull · line 22
npx commands without a version suffix (e.g. @1.0.0) create a rug-pull risk if the upstream server is compromised and publishes a malicious update.

Fix: Pin the version: npx @scope/[email protected]

How audits are shown

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.

Model	Per session	Once invoked
Fable 5.1	$0.00176	$0.01222
Opus 5.5	$0.00070	$0.00489
Sonnet 5.5	$0.00035	$0.00244
Haiku 4.5	$0.00018	$0.00122

Measured 1mo ago against content hash b4a530c92175, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

visual-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 1mo ago.

The scan reads SKILL.md. This mod also ships 2 executable files (scripts/visual-diff.mjs, scripts/visual-diff.test.mjs), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

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.

skills/visual-testing/SKILL.md · 85 lines

How it starts

The opening of the file, as written. The whole thing — 85 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Visual testing

Catch unintended visual change. Rendered UI is deterministic enough that a pixel which moved without an intended cause is worth seeing — a card that lost its shadow, a table that overflows on tablet, a button that drifted but still works. This skill screenshots each screen and diffs it against a baseline captured when the UI was last correct.

Two halves, kept separate on purpose:

Capture is agent-driven. You open the thing under test in whatever browser or device tool you already have and save a PNG. No headless browser is bundled or installed — capture rides on the tooling that already exists (a connected browser, a Playwright/Appium session, a running app's automation).
Diff is browser-free. scripts/visual-diff.mjs shells out to reg-cli (resolved local-first, else npx --yes reg-cli@latest, so nothing is added to package.json) to compare, manage baselines, and write a report.

Workflow

Render the thing under test.
- A generated static page → build it, then open the HTML from disk (file://); the pages are self-contained, no server needed.
- A running app → drive it to the screen/state with the automation you already use (Playwright for web, the device tooling for mobile). This is the same navigation a functional check performs — the visual diff is an extra assertion, not a separate run.
Capture each screen into a current/ directory, one PNG per variant, named by the scheme below. See references/capturing.md for driving each source and controlling the noise that makes diffs flaky.
Diff against the baseline:
```
node scripts/visual-diff.mjs --current <current/> --baseline <baselines/> --diff <out/>
```
Exit 0 = no change; exit 1 = something changed (report at <out/>/report.html).
Review the report. An intended change (a redesign, a shipped restyle) → promote it: node scripts/visual-diff.mjs --current <current/> --baseline <baselines/> --diff <out/> --update then commit the updated baselines. An unintended change → a finding: fix the cause (or file the defect with the diff image); do not update the baseline.

Read the full file on GitHub · 85 lines

Files

What ships with it

4 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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.

1mo ago First seen · 85 lines · 176 tokens per session scan A b4a530c92175

Subscribe to this mod's changes

visual-testing is a skill published in the GitHub repository arozumenko/sdlc-skills (25 stars, last pushed yesterday), licensed MIT. It adds 176 tokens to every session and 1,222 once invoked, about $0.0007 per session on Opus 5.5. 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 2026-08-30.

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