What is visual-verification?

A workflow for checking that interface changes look correct in a web browser by taking screenshots, examining them, and repeating the check across screen sizes.

Use it after changing web interface code to check browser rendering at configured viewports and report whether visual checking was completed or skipped.

A successful build and passing tests do not prove that a page is laid out or displayed correctly.

visual-verification — Skill for Claude Code by synaptiai

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 synaptiai/synapti-marketplace --skill visual-verification

Clone the repo

git clone --depth 1 https://github.com/synaptiai/synapti-marketplace

Made for: Claude Code.

Or install flow, the plugin that ships this one along with the rest of its 31 skills, 21 commands, 9 agents.

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/synaptiai/synapti-marketplace/visual-verification/github.svg)](https://agentmods.dev/skills/synaptiai/synapti-marketplace/visual-verification)

Your own site

<a href="https://agentmods.dev/skills/synaptiai/synapti-marketplace/visual-verification"><img src="https://agentmods.dev/badge/skills/synaptiai/synapti-marketplace/visual-verification/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/synaptiai/synapti-marketplace/visual-verification"><img src="https://agentmods.dev/badge/skills/synaptiai/synapti-marketplace/visual-verification.svg" alt="Reviewed on agentmods" width="80" height="20"></a>

Per session 137 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.

When invoked 1,385 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.

Model	Per session	Once invoked
Fable 5.1	$0.00137	$0.01385
Opus 5	$0.00068	$0.00692
Sonnet 5	$0.00027	$0.00277
Haiku 4.5	$0.00014	$0.00138

Measured today against content hash 5a98dda744d5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

visual-verification 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 today.

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.

plugins/flow/skills/visual-verification/SKILL.md · 95 lines

How it starts

The opening of the file, as written. The whole thing — 95 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Visual Verification

Contract

Iron law: UI changes are visually verified or explicitly skipped with a structured result — a passing build and test suite do not prove the page renders. Invoked alongside runtime-verification by /flow:start Phase 4 step 2 (retried at step 8) and /flow:pr Phase 4 via Agent(integration-verifier) when the diff has UI files or acceptance criteria mention UI. Returns the Visual Verification table, Visual Evidence table, one Viewport/Screenshot/Result/Observed: block per viewport for the bundle's ### Visual analysis, and P1/P2/P3 findings (category=visual), labeled PASS/FAIL/SKIP/SKIP_WARN/SKIP_USER_APPROVED/MANUAL/BLOCKED. Permitted skips: SKIP when no UI signal fires or the dev server is unavailable; SKIP_WARN, SKIP_USER_APPROVED, MANUAL only via the cascade.

UI Relevance

Either activates:

git diff --name-only HEAD~1..HEAD | grep -iE '\.(tsx|jsx|vue|html|css|scss|svelte)$'
Acceptance criteria containing: UI, page, display, render, visual, layout, responsive, component, style.

Neither: SKIP — no UI-relevant changes detected.

visualVerification.requireVisualVerification (default false) controls escalation only; an unattempted UI change always yields at least SKIP_WARN.

Browser Tool Cascade (first available)

Playwright MCP (browser_navigate, browser_take_screenshot, browser_console_logs)
Chrome DevTools MCP
CLI: npx playwright screenshot http://localhost:$PORT/ $SCREENSHOT_DIR/page.png (installing chromium first if needed)
Skill(compound-engineering:test-browser) (if installed)
Skill(compound-engineering:agent-browser)
Nothing: SKIP_WARN with install guidance ("Install Playwright MCP or use /flow:setup") when requireVisualVerification is false; BLOCKED when true, escalated per references/escalation-format.md.

Never install Playwright silently.

Screenshot-Analyze-Verify Loop

Needs the dev server URL from runtime-verification; if it failed to start, return SKIP ("dev server unavailable"); that failure is primary. Bounded by visualVerification.maxIterations (default 3); iterate only after fixes. $SCREENSHOT_DIR = visualVerification.screenshotDir (default .screenshots).

Read the full file on GitHub · 95 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.

today Changed · -110 lines 5a98dda744d5
6d ago First seen · 205 lines · 137 tokens per session scan A 58e2bc8a911f

Subscribe to this mod's changes

visual-verification is a skill published in the GitHub repository synaptiai/synapti-marketplace (6 stars, last pushed today), licensed Apache-2.0. It adds 137 tokens to every session and 1,385 once invoked, about $0.0007 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.

CSS and styling E2E testing Frontend Testing agentic-design-patterns agentic-development agentic-workflow ai-developer-tools ai-first claude-code-plugin

visual-diff

Visual Regression Testing — screenshot comparison before and after changes. Use when user wants to check for visual regressions, compare UI changes, or verify CSS/layout changes didn't break anything.

Houseofmvps/ultraship · 39 tokens

triaging-visual-review-runs

Inspects PostHog Visual Review (VR) runs that gate PR merges with screenshot regression checks. Use when the user mentions "visual review", "VR", "snapshot diff", "screenshot test", "storybook regression", "playwright snapshot", asks why a PR is blocked or what changed visually, wants to triage the VR backlog, decide…

PostHog/ai-plugin · 136 tokens

visual-verification