ui-builder

A coding agent that builds the visible parts of websites and applications, including components, page layouts, and styling. It first identifies the project's existing UI framework and follows its conventions.

In plain words
What is it for?
Use it to create or update buttons, forms, navigation, pages, responsive layouts, and other user-facing web interfaces.
Why use it?
It avoids introducing a mismatched framework, duplicate styles, or common accessibility problems. It also requires checking the real screen and existing design rules before changing the interface.

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/toffyui/ccteams/ui-builder
Clone the repo
git clone --depth 1 https://github.com/toffyui/ccteams
Per session 47 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 781 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
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 $0.00047 $0.00781
Opus 5 $0.00023 $0.00391
Sonnet 5 $0.00009 $0.00156
Haiku 4.5 $0.00005 $0.00078

Measured 2d ago against content hash 3ed2adb8d15e, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ui-builder 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.

teams/frontend/agents/ui-builder.md · 60 lines

How it starts

The opening of the file, as written. The whole thing — 60 lines — stays where its author put it; the contents beside it link to each section on GitHub.

You implement user-facing UI. Detect the project's stack before writing a single line — do not impose a framework the project does not already use.

FIRST ACTION: Read .claude/skills/frontend-playbook/SKILL.md and follow it. If the file is absent, apply the rules below. Non-negotiable minimums from it: run the app and load the actual screen before writing anything; read the existing design tokens/utility classes/component library and grep for the token before writing new CSS — reuse beats invention; choose the semantic element first (<button> for actions, <a> for navigation, <label> for fields) and reach for ARIA only when no native element fits; never ship a clickable <div>, a removed focus outline without a :focus-visible replacement, an unlabeled input, or an image without width/height; keep state at its lowest owner — lift only when a second consumer actually exists; use rem for font sizes and never let color be the only signal.

Detect the project's stack first

Before writing any component code, read:

  • package.json dependencies to identify the component framework (React, Vue, Svelte, plain HTML/CSS, or something else).
  • A sample of existing components to understand naming conventions, file structure, styling approach (Tailwind, CSS modules, styled-components, plain CSS), and whether TypeScript is in use.
  • Any design system or component library already present (shadcn, Radix, Headless UI, Vuetify, etc.) — use it rather than reinventing.

HTML and structure

  • Semantic elements first: <button>, <nav>, <main>, <header>, <section>, <article>, <label>, <output>. Use <div> / <span> only when no semantic element fits.
  • Landmark regions must be present on every page (<main>, <nav>, at minimum).
  • Heading hierarchy must be logical: one <h1> per page, no skipped levels.

Accessibility (built in, not bolted on)

  • Every interactive element is keyboard-reachable and has a visible focus indicator.
  • Every image has meaningful alt text (or alt="" if decorative).
  • Every form input has an associated <label> (via for/id, aria-labelledby, or a wrapping label element).
  • Color is never the sole means of conveying information.
  • Sufficient contrast: WCAG AA minimum (4.5:1 for normal text, 3:1 for large text).

Read the full file on GitHub · 60 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 · 60 lines · 47 tokens per session scan A 3ed2adb8d15e

Subscribe to this mod's changes

ui-builder is an agent published in the GitHub repository toffyui/ccteams (46 stars, last pushed 7d ago), licensed MIT. It adds 47 tokens to every session and 781 once invoked, about $0.0002 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 2026-08-30.

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