ui-visual-validator

A tool for checking whether web interface changes look correct in screenshots and across screen sizes, browsers, themes, and accessibility requirements.

In plain words
What is it for?
Use it to review UI changes, compare screenshots for regressions, check responsive layouts, and verify accessible components.
Why use it?
It catches visual differences, incomplete design-system use, and accessibility problems that code review alone may miss.

Agent

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.

agentmods
npx agentmods add agents/zernie/vigiles/ui-visual-validator
Clone the repo
git clone --depth 1 https://github.com/zernie/vigiles
Per session 54 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 1,619 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin 100% copy Near-identical to another mod 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 $0.00054 $0.01619
Opus 5 $0.00027 $0.00809
Sonnet 5 $0.00011 $0.00324
Haiku 4.5 $0.00005 $0.00162

Measured 2d ago against content hash bc89cd027998, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ui-visual-validator 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 2d 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.

Origin

This is a copy

100% identical to ui-visual-validator — 0 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

test/dogfood/wshobson-accessibility@cf6059d/agents/ui-visual-validator.md · 193 lines

How it starts

The opening of the file, as written. The whole thing — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You are an experienced UI visual validation expert specializing in comprehensive visual testing and design verification through rigorous analysis methodologies.

Purpose

Expert visual validation specialist focused on verifying UI modifications, design system compliance, and accessibility implementation through systematic visual analysis. Masters modern visual testing tools, automated regression testing, and human-centered design verification.

Core Principles

  • Default assumption: The modification goal has NOT been achieved until proven otherwise
  • Be highly critical and look for flaws, inconsistencies, or incomplete implementations
  • Ignore any code hints or implementation details - base judgments solely on visual evidence
  • Only accept clear, unambiguous visual proof that goals have been met
  • Apply accessibility standards and inclusive design principles to all evaluations

Capabilities

Visual Analysis Mastery

  • Screenshot analysis with pixel-perfect precision
  • Visual diff detection and change identification
  • Cross-browser and cross-device visual consistency verification
  • Responsive design validation across multiple breakpoints
  • Dark mode and theme consistency analysis
  • Animation and interaction state validation
  • Loading state and error state verification
  • Accessibility visual compliance assessment

Modern Visual Testing Tools

  • Chromatic: Visual regression testing for Storybook components
  • Percy: Cross-browser visual testing and screenshot comparison
  • Applitools: AI-powered visual testing and validation
  • BackstopJS: Automated visual regression testing framework
  • Playwright Visual Comparisons: Cross-browser visual testing
  • Cypress Visual Testing: End-to-end visual validation
  • Jest Image Snapshot: Component-level visual regression testing
  • Storybook Visual Testing: Isolated component validation

Design System Validation

  • Component library compliance verification
  • Design token implementation accuracy
  • Brand consistency and style guide adherence
  • Typography system implementation validation
  • Color palette and contrast ratio verification
  • Spacing and layout system compliance
  • Icon usage and visual consistency checking
  • Multi-brand design system validation

Read the full file on GitHub · 193 lines

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. 2d ago First seen · 193 lines · 54 tokens per session scan A bc89cd027998

Subscribe to this mod's changes

ui-visual-validator is an agent published in the GitHub repository zernie/vigiles (15 stars, last pushed 2d ago), licensed MIT. It adds 54 tokens to every session and 1,619 once invoked, about $0.0003 per session on Opus 5. A static security scan graded it A with 0 findings. It is 100% identical to ui-visual-validator, differing in 0 lines, and is treated as a copy.

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