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.
npx skills add Houseofmvps/ultraship --skill visual-diffgit clone --depth 1 https://github.com/Houseofmvps/ultrashipWrote 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.
[](https://agentmods.dev/skills/houseofmvps/ultraship/visual-diff)<a href="https://agentmods.dev/skills/houseofmvps/ultraship/visual-diff"><img src="https://agentmods.dev/badge/skills/houseofmvps/ultraship/visual-diff/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.
<a href="https://agentmods.dev/skills/houseofmvps/ultraship/visual-diff"><img src="https://agentmods.dev/badge/skills/houseofmvps/ultraship/visual-diff.svg" alt="Reviewed on agentmods" width="80" height="20"></a>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 | $0.00039 | $0.00732 |
| Opus 5.5 | $0.00016 | $0.00293 |
| Sonnet 5.5 | $0.00008 | $0.00146 |
| Haiku 4.5 | $0.00004 | $0.00073 |
Grade A, and why
visual-diff 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.
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.
How it starts
The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Visual Regression Testing
Automated screenshot comparison using Playwright. Catch visual bugs before they ship.
Process
Phase 1: Determine Test Scope
Ask the user:
- What URL(s) to test? (localhost, staging, or production)
- What changed? (CSS update, component refactor, dependency upgrade, etc.)
If the user already described what changed, skip asking.
Phase 2: Take "Before" Screenshots
If comparing against the current state (before making changes):
Use the Playwright MCP to capture screenshots:
-
Navigate to the URL:
- Use
browser_navigateto go to the target URL
- Use
-
Take full-page screenshot:
- Use
browser_take_screenshotto capture the current state
- Use
-
Capture key viewports:
- Desktop (1920x1080):
browser_resizethenbrowser_take_screenshot - Tablet (768x1024):
browser_resizethenbrowser_take_screenshot - Mobile (375x812):
browser_resizethenbrowser_take_screenshot
- Desktop (1920x1080):
-
Save screenshots with descriptive names noting they are "before" state.
Phase 3: Make Changes
Let the user make their changes, or make them yourself if that's the task.
Phase 4: Take "After" Screenshots
Repeat the same screenshot process for the same URLs and viewports.
Phase 5: Visual Comparison
Compare before and after screenshots:
- Layout shifts — did any elements move unexpectedly?
- Color changes — did colors, gradients, or shadows change?
- Typography — did font sizes, weights, or spacing change?
- Responsive issues — does it look correct on all viewports?
- Missing elements — did anything disappear?
- Overflow issues — is content clipping or overflowing?
Use browser_snapshot to get the accessibility tree and compare DOM structure between before/after.
Phase 6: Report
Present findings in a clear format:
No Visual Regressions Found:
- "All pages look identical across desktop, tablet, and mobile viewports."
Regressions Detected: For each regression:
- Page: URL where the issue appears
- Viewport: Which screen size is affected
- What changed: Description of the visual difference
- Severity: Critical (broken layout), High (noticeable shift), Medium (minor difference), Low (pixel-level)
- Suggested fix: How to resolve the regression
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 · 97 lines · 39 tokens per session scan A dfc0e64a3ddb
visual-diff is a skill published in the GitHub repository Houseofmvps/ultraship (123 stars, last pushed 3mo ago), licensed MIT. It adds 39 tokens to every session and 732 once invoked, about $0.0002 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 2026-09-03.
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