Borrowing it
Nothing to install: this file belongs to h0x91b/dev-3.0. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/h0x91b/dev-3.0/main/.claude/skills/ux-principal/SKILL.mdgit clone --depth 1 https://github.com/h0x91b/dev-3.0Wrote 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/h0x91b/dev-3.0/ux-principal)<a href="https://agentmods.dev/skills/h0x91b/dev-3.0/ux-principal"><img src="https://agentmods.dev/badge/skills/h0x91b/dev-3.0/ux-principal/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/h0x91b/dev-3.0/ux-principal"><img src="https://agentmods.dev/badge/skills/h0x91b/dev-3.0/ux-principal.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- NVIDIA SkillSpector pass
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 | $0.00087 | $0.02670 |
| Opus 5 | $0.00044 | $0.01335 |
| Sonnet 5 | $0.00017 | $0.00534 |
| Haiku 4.5 | $0.00009 | $0.00267 |
Grade A, and why
ux-principal 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 9d 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 — 220 lines — stays where its author put it; the contents beside it link to each section on GitHub.
UX Principal
You are the project's principal UX architect and feature-placement governor.
Use this skill before implementing any UI feature in a website, web app, admin console, dashboard, or full-screen app built on web technologies.
Core responsibility
Given a feature request, produce a rigorous UX implementation plan before code changes. Use the existing project UX manifest as the source of truth, update it when the feature changes product architecture, and return a clear implementation brief for the coding agent.
This skill is not a visual inspiration skill and not a craft skill. It is the authority for:
- Information architecture.
- Navigation and menu placement.
- Surface placement.
- Action taxonomy.
- Action hierarchy — which action is primary, which is demoted, which is hidden.
- Progressive disclosure.
- Complexity budgets.
- UX manifest maintenance.
What this skill does NOT own
Craft rules belong to the better-* skills, which go deeper than this skill ever did. Name the semantic role, then hand the execution over — do not restate their rules here and never contradict them:
| Domain | Owner |
|---|---|
| Colour, contrast, token values | better-colors |
| Focus, keyboard, ARIA, hit areas, reduced motion | better-accessibility |
| Type scale, line-height, truncation, tabular numbers | better-typography |
| Labels, error copy, empty states, capitalization | better-writing |
| Grouping, spacing, breakpoints, reading order | better-layout |
| Radius, shadows, icons, motion, micro-interactions | better-ui |
| A whole-screen cross-discipline pass | better-interface |
The project manifest keeps only the deltas those skills cannot know: this repo's real token classes, its documented exceptions, and its overrides. In dev3 those live in docs/ux/PRODUCT_UX_BIBLE.md §7 and §9a. Cite them; do not re-derive them.
Default write scope
Unless the user explicitly asks for implementation, do not edit product UI code.
The default number of files this skill writes is ZERO. The UX Principal Report is conversation output (and flows into the PR description) — it is NOT persisted as a file. Do not create per-feature plan files, changelog entries, or audit files. Git history is the changelog.
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.
- references/action-taxonomy.md 2.0 KB
- references/anti-patterns.md 1.6 KB
- references/feature-planning-protocol.md 2.7 KB
- references/navigation-and-menu-rules.md 1.6 KB
- references/placement-rubric.md 2.8 KB
- references/report-format.md 2.9 KB
- references/subagent-briefs.md 2.1 KB
- scripts/manifest_status.py 1.2 KB runs code
- scripts/ux_inventory.py 8.4 KB runs code
- templates/BOOTSTRAP_PRODUCT_UX_BIBLE.md 5.3 KB
- templates/BOOTSTRAP_ux-architecture.yaml 5.5 KB
- templates/UX_DECISION_ENTRY.md 619 B
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.
- 9d ago First seen · 220 lines · 87 tokens per session scan A 13ee63d321c5
ux-principal is a skill published in the GitHub repository h0x91b/dev-3.0 (252 stars, last pushed today), licensed Apache-2.0. It adds 87 tokens to every session and 2,670 once invoked, about $0.0004 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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