frontend-mockup-loop

frontend-mockup-loop is a skill for Claude Code, Codex from BlackBeltTechnology/pi-agent-dashboard. It costs 185 tokens per session (2,941 once invoked), scanned A, original, MIT.

A guided process for designing, building, testing, and refining frontend mockups. It uses documented usability and accessibility guidelines, such as WCAG.

In plain words
What is it for?
Use it to create web interface mockups, choose a design system, preview them, score screenshots, and fix issues found during review.
Why use it?
It reduces generic-looking designs and gives the agent a repeatable way to check whether a mockup works visually and for users with disabilities.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it to create web interface mockups, choose a design system, preview them, score screenshots, and fix issues found during review.

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Install with agentmods
npx agentmods add skills/blackbelttechnology/pi-agent-dashboard/frontend-mockup-loop
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 BlackBeltTechnology/pi-agent-dashboard --skill frontend-mockup-loop
Clone the repo
git clone --depth 1 https://github.com/BlackBeltTechnology/pi-agent-dashboard

Made for: Claude Code, Codex.

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.

agentmods badge for frontend-mockup-loop

README.md
[![agentmods](https://agentmods.dev/badge/skills/blackbelttechnology/pi-agent-dashboard/frontend-mockup-loop/github.svg)](https://agentmods.dev/skills/blackbelttechnology/pi-agent-dashboard/frontend-mockup-loop)
Your own site
<a href="https://agentmods.dev/skills/blackbelttechnology/pi-agent-dashboard/frontend-mockup-loop"><img src="https://agentmods.dev/badge/skills/blackbelttechnology/pi-agent-dashboard/frontend-mockup-loop/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.

agentmods 80×15 button for frontend-mockup-loop

Your own site · 80×15
<a href="https://agentmods.dev/skills/blackbelttechnology/pi-agent-dashboard/frontend-mockup-loop"><img src="https://agentmods.dev/badge/skills/blackbelttechnology/pi-agent-dashboard/frontend-mockup-loop.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 185 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 2,941 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 pass 7 Sept 2026
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.

ModelPer sessionOnce invoked
Fable 5.1 $0.00185 $0.02941
Opus 5 $0.00093 $0.01470
Sonnet 5 $0.00037 $0.00588
Haiku 4.5 $0.00018 $0.00294

Measured 6d ago against content hash bebcca20e2c5, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-09, from the pricing page.

Security

Grade A, and why

frontend-mockup-loop 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 6d 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.

packages/mockup-loop/.pi/skills/frontend-mockup-loop/SKILL.md · 220 lines

How it starts

The opening of the file, as written. The whole thing — 220 lines — stays where its author put it; the contents beside it link to each section on GitHub.

frontend-mockup-loop

A disciplined loop for designing frontend surfaces. It exists to defeat distributional convergence: an undirected agent regresses to the statistical mean of its training data — generic Inter font, a purple gradient, a centered hero. "Make it look better" just returns the average again.

The fix the whole agentic-design field converged on, and what this loop enforces every time:

  1. deliberate direction from a real reference (GROUND),
  2. a consistent token system (the ui-contract),
  3. a screenshot feedback loop (eyes on output).

This skill is paired with an extension that registers five tools: serve_mockup, score_mockup, init_ui_contract, list_design_systems, validate_mockup.

Select a design system (optional)

The loop runs design-system agnostic by default (generic anti-slop rubric). To target a specific system, pick a preset and pass its id to the tools' system param. v1 presets (list_design_systems enumerates them):

id system platform substrate
shadcn shadcn/ui + Tailwind web HTML + Tailwind
mui Material UI web HTML
material-3 Material Design 3 web HTML
fluent-2 Fluent 2 web HTML
apple-hig Apple HIG iOS HTML approximation → SwiftUI on promote

With a system selected: init_ui_contract{system} writes that system's DTCG token contract (from a bundled, offline snapshot; refresh:true re-fetches upstream), score_mockup{system} swaps in the system's boolean rubric, and validate_mockup{system,dir} runs the gated pipeline.

Gate vs advisory

Validation is layered. Gates block pass; advisory layers only score and drive the fix loop (LLM visual scores skew positive — never hard-block):

  • L1 token-lint — static; HARD GATE when a linter applies (off-token color literals fail shadcn/material-3).
  • L2 a11y floor — rendered axe + WCAG contrast; HARD GATE, every system.
  • L3 named-system auditorhig-doctor / material3-mcp etc., advisory, shelled out only if installed (absent → skipped + noted, never errors).
  • L4 vision rubric — per-preset boolean checks; score = pass/N computed in code, advisory.

Read the full file on GitHub · 220 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. 6d ago First seen · 220 lines · 185 tokens per session scan A bebcca20e2c5

Subscribe to this mod's changes

frontend-mockup-loop is a skill published in the GitHub repository BlackBeltTechnology/pi-agent-dashboard (278 stars, last pushed today), licensed MIT. It adds 185 tokens to every session and 2,941 once invoked, about $0.0009 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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