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 sergekostenchuk/ui-ux-agent-skill-system --skill webapp-ui-skillgit clone --depth 1 https://github.com/sergekostenchuk/ui-ux-agent-skill-systemWrote 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/sergekostenchuk/ui-ux-agent-skill-system/webapp-ui-skill)<a href="https://agentmods.dev/skills/sergekostenchuk/ui-ux-agent-skill-system/webapp-ui-skill"><img src="https://agentmods.dev/badge/skills/sergekostenchuk/ui-ux-agent-skill-system/webapp-ui-skill/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/sergekostenchuk/ui-ux-agent-skill-system/webapp-ui-skill"><img src="https://agentmods.dev/badge/skills/sergekostenchuk/ui-ux-agent-skill-system/webapp-ui-skill.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 | $0.00097 | $0.00686 |
| Opus 5 | $0.00048 | $0.00343 |
| Sonnet 5 | $0.00019 | $0.00137 |
| Haiku 4.5 | $0.00010 | $0.00069 |
Grade A, and why
webapp-ui-skill 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 7d 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 — 62 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Web App UI Skill
Use this specialist for product UI surfaces: dashboards, admin tools, internal workflows, CRM screens, settings, data tables, and state-heavy app screens.
Operating Modes
build: create or refactor app UI.audit: review an existing app screen and produce a fix brief.state-coverage: inspect loading, empty, error, disabled, focus, selected, submitting, and success states.verify: run available local evidence checks and report gaps.
Required Workflow
- Read references/dashboard-patterns.md for product UI layout decisions.
- Read references/state-model.md before changing app flows or components.
- Use assets/state-matrix.template.md and assets/implementation-report.template.md when a stable output artifact is useful.
- Use
../../shared/privacy-policy.mdbefore any external service or screenshot handling. - Use
../../shared/visual-verification.mdfor material UI changes. - If source files are available, run scripts/check_state_coverage.ts or report why it was skipped.
- If a URL is available, run scripts/visual_smoke_test.mjs or report why it was skipped.
- Return concise implementation notes with
Ran,Skipped,Planned, andManual.
Design Doctrine
- Prioritize scanning, comparison, and repeated action over marketing composition.
- Use compact headings, stable grids, predictable navigation, and explicit state handling.
- Keep cards for repeated items, modals, and genuinely framed tools.
- Do not add decorative hero sections, nested cards, one-note palettes, or viewport-scaled typography.
- Buttons, controls, and tables must have stable dimensions and readable labels.
Tool Contracts
- State coverage:
node scripts/check_state_coverage.ts --root "$PROJECT_ROOT" --out reports/state-coverage.json. - Visual smoke:
node scripts/visual_smoke_test.mjs --url "$URL" --out reports/visual-smoke. - Optional cloud generation is never default. It requires explicit approval and a data-transfer note.
What ships with it
12 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.
- agents/openai.yaml 406 B
- assets/design-tokens.json 354 B
- assets/implementation-report.template.md 150 B
- assets/state-matrix.template.md 290 B
- evals/evals.json 1.3 KB
- references/accessibility-rubric.md 533 B
- references/anti-patterns.md 407 B
- references/dashboard-patterns.md 1.0 KB
- references/form-patterns.md 646 B
- references/state-model.md 630 B
- scripts/check_state_coverage.ts 2.3 KB runs code
- scripts/visual_smoke_test.mjs 1.3 KB runs code
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.
- 7d ago First seen · 62 lines · 97 tokens per session scan A 2711a13b8410
webapp-ui-skill is a skill published in the GitHub repository sergekostenchuk/ui-ux-agent-skill-system (23 stars, last pushed 2mo ago), licensed Apache-2.0. It adds 97 tokens to every session and 686 once invoked, about $0.0005 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.
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