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 hueyexe/frontend-agent-skills --skill ux-usability-foundationsgit clone --depth 1 https://github.com/hueyexe/frontend-agent-skillsWrote 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/hueyexe/frontend-agent-skills/ux-usability-foundations)<a href="https://agentmods.dev/skills/hueyexe/frontend-agent-skills/ux-usability-foundations"><img src="https://agentmods.dev/badge/skills/hueyexe/frontend-agent-skills/ux-usability-foundations/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/hueyexe/frontend-agent-skills/ux-usability-foundations"><img src="https://agentmods.dev/badge/skills/hueyexe/frontend-agent-skills/ux-usability-foundations.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 | $0.03279 |
| Opus 5 | $0.00019 | $0.01639 |
| Sonnet 5 | $0.00008 | $0.00656 |
| Haiku 4.5 | $0.00004 | $0.00328 |
Grade A, and why
ux-usability-foundations 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 11d 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 — 294 lines — stays where its author put it; the contents beside it link to each section on GitHub.
UX Usability Foundations
Purpose
Help an agent make interfaces understandable, usable, forgiving, and aligned with user expectations. Treat usability as product behavior, not surface decoration. The agent should turn unclear or fragile UI into an interface where users can quickly answer: what is this, what can I do here, where am I, what happened, how do I recover, and is this worth the effort?
When to use this skill
Use this skill when the user asks you to critique, redesign, create, or specify a UI, flow, form, app screen, website, dashboard, onboarding, settings page, checkout, navigation model, state behavior, or component interaction for usability. Use it for affordances/signifiers, feedback, constraints, errors, empty/loading/success states, recognition over recall, task clarity, and frontend behavior.
When not to use this skill
Do not use as the primary skill for deep research operations, brand styling systems, visual polish, typography craft, frontend architecture, or persuasion/growth tactics unless those choices directly affect user understanding, control, or recovery.
Core principles
- Start with goals, not screens. Identify the user’s goal, task, context, and likely knowledge before changing controls or layout. Design requirements describe needs before widgets.
- Make the next action obvious. Prefer self-evident interfaces. If the task is inherently novel or complex, make it self-explanatory with structure, labels, examples, and feedback.
- Show what is possible. Interactive elements must look interactive. Read-only elements must not look editable. Hidden gestures need visible alternatives.
- Match the user’s mental model. Use the concepts, names, and sequence users understand; do not expose database tables, file paths, internal IDs, or arbitrary system states unless users need them.
- Favor recognition over recall. Keep needed options, context, examples, and state visible or easy to retrieve.
- Reduce work and excise. Remove tasks that serve the system rather than the user’s goal: retyping, transferring data, hunting for controls, configuring obvious defaults, or answering inferable questions.
- Guide choices without overloading users. Use progressive disclosure, sensible defaults, grouping, and prioritization.
- Give immediate, informative feedback. Every consequential action needs a response that says whether the system received it, what changed, whether waiting is required, and what can happen next.
- Prevent errors before explaining them. Use constraints, safe defaults, previews, tolerant input, inline validation, and undo where feasible.
- Blame the design, not the user. Errors reveal a mismatch in expectations or an unsupported edge case. Preserve work and guide recovery.
- Respect platform and convention. Use familiar patterns when they fit. Break convention only when the user’s goal clearly benefits and the new behavior can be discovered and recovered from.
- Accessibility is usability under pressure. Design for perceptibility, operability, simplicity, and forgiveness across varied abilities, devices, literacy, stress, and environments.
What ships with it
4 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.
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.
- 11d ago First seen · 294 lines · 39 tokens per session scan A 74bca0fdefa7
ux-usability-foundations is a skill published in the GitHub repository hueyexe/frontend-agent-skills (9 stars, last pushed 1mo ago), licensed MIT. It adds 39 tokens to every session and 3,279 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 2026-08-31.
Other skills, from other repositories
Accessibility Manual Audit
Teach agents to guide manual accessibility audits for keyboard, screen reader, zoom, reflow, focus, and WCAG 2.2 criteria that scanners miss.
interaction-design
Design meaningful interactions, microinteractions, animations, state machines, gesture patterns, error prevention, and product behavior. Specify how products respond to user input across all states and contexts using established interaction design principles.
ux-strategy
Connect design decisions to business outcomes through competitive analysis, opportunity mapping, Jobs to Be Done, outcome-driven discovery, value proposition design, and UX metrics. Shape product direction with strategic frameworks grounded in evidence.
design-ops
Run design sprints, manage handoff, establish team rituals, documentation standards, and design QA processes. Covers the operational side of design — how teams organize work, collaborate with engineering, and ship quality.
design-systems
Build, document, and maintain design systems with design tokens, component specifications, pattern libraries, naming conventions, and governance processes. Conduct system audits, define component hierarchies, and establish shared design languages.
mobile-analyzer
Mobile-specific UX analysis — touch interactions, viewport issues, scroll behavior, mobile vs desktop patterns, and responsive design validation. Use when investigating mobile experience, responsive design bugs, or mobile conversion rates.