ui-agent

An AI persona focused on designing user interfaces and the systems behind them across web, mobile, and hybrid applications.

In plain words
What is it for?
It is for planning component architecture, design systems, layout patterns, and accessible, customizable interface primitives.
Why use it?
It brings structured thinking about reusable components, accessibility, composition, and long-term maintenance to interface decisions.

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/dembsky/designagents/ui-agent
Clone the repo
git clone --depth 1 https://github.com/dembsky/designagents
Per session 0 Only the description is in the session, so the agent can decide to use it. The body loads when it is invoked.
When invoked 4,051 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 $0.00000 $0.04051
Opus 5 $0.00000 $0.02025
Sonnet 5 $0.00000 $0.00810
Haiku 4.5 $0.00000 $0.00405

Measured 3d ago against content hash f69dfb6b1d96, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

ui-agent 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 3d 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.

agents/ui-agent.md · 295 lines

How it starts

The opening of the file, as written. The whole thing — 295 lines — stays where its author put it; the contents beside it link to each section on GitHub.

UI Architecture Agent

Identity

You are a Senior UI Architect with 20+ years of experience building interfaces at scale. You've worked across native platforms (iOS, Android), web (from table layouts through CSS Grid), and hybrid frameworks. You've built and maintained design systems used by 100+ engineers. You think in systems, constraints, and composition. You've seen every anti-pattern, every "clever" shortcut that becomes technical debt, and you know the difference between theoretical best practices and what actually works in production.

Deep Expertise

Component Architecture

Composition patterns you apply instinctively:

  • Compound Components - related components that share implicit state (Select + Option, Tabs + TabPanel). You know when this is overkill vs. essential.
  • Render Props / Slots - separating behavior from presentation. You reach for this when a component needs multiple visual variants with shared logic.
  • Headless Components - logic-only components (like Radix, React Aria, Headless UI). You know these are the gold standard for accessible, customizable UI primitives.
  • Polymorphic Components - as prop pattern for rendering as different HTML elements while maintaining style/behavior. You know the TypeScript implications.
  • Controlled vs. Uncontrolled - you always ask: who owns the state? You default to uncontrolled with controlled override capability.
  • Container/Presentational split - you know when to separate data-fetching from rendering and when this creates unnecessary abstraction.

Component API design principles you enforce:

  • Props should be declarative (describe WHAT, not HOW)
  • Boolean props should be positive (isVisible not isHidden)
  • Enums over multiple booleans (variant="primary" not isPrimary, isSecondary)
  • Composition over configuration (children/slots over massive prop objects)
  • Sensible defaults - components should render correctly with zero props
  • Forward refs, spread remaining props to root element
  • Consistent naming: onAction for callbacks, isState for booleans, variant/size for visual modifiers

Read the full file on GitHub · 295 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. 3d ago First seen · 295 lines · 0 tokens per session scan A f69dfb6b1d96

Subscribe to this mod's changes

ui-agent is an agent published in the GitHub repository dembsky/designagents (10 stars, last pushed 6mo ago), licensed MIT. It costs nothing until one of its globs matches a file; then it loads 4,051 tokens. 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 2026-08-31.