Harden
Design engineering system for AI coding agents — ship UI with craft-level quality. Install as an agent skill.
npx -y skills add educlopez/ui-craft --skill hardenAssembled from the repository path, not quoted from the project. Check it against their README if it does not work.
What its author says it does
Copied from the file, not written here
Production-readiness pass — audits and implements the full non-happy-path matrix: loading skeletons, empty states, error messages, partial data, i18n, offline, permissions, and first-run guidance. Use when preparing a surface for production or when the user says "it crashes on empty data" / "there's no loading state" / "harden this". Invoke when the user asks for harden on their UI, or mentions 'harden' alongside design / UI / frontend work.
SKILL.md
3.0 KB, as published. Nobody here has run it
Context: this sub-skill is one lens of the broader ui-craft skill. If the ui-craft skill is also installed, read its SKILL.md first for Discovery + Anti-Slop + Craft Test, then apply the specific lens below.
Harden the UI at $ARGUMENTS for production. Load the ui-craft skill.
Coverage matrix — check every key surface:
- Loading — skeletons match the final layout (no CLS on resolve), shown after ~200ms to avoid flash on fast responses. Never a generic centered spinner when a skeleton is possible.
- Empty — purposeful: one line explaining why it's empty + one clear primary action. Illustration optional, CTA mandatory.
- Error — inline, actionable. "Save failed. Try again / Copy error / Contact support" — never just "Something went wrong." Surface the what and the next step.
- Partial data —
—(em dash) for missing metrics, neverN/Aornullor0when the value is truly unknown. - Long content — truncation with
titletooltip,text-overflow: ellipsis, container queries for constrained regions. Test with a 120-character name. - i18n — no hardcoded strings, ~1.3× text expansion slack for German, narrower glyphs for CJK, RTL flip consideration for icons with direction.
- Offline / slow — optimistic UI with reconciliation on failure; skeleton persists past timeout with a "still loading…" affordance.
- Permission — what happens when the user lacks access: disabled vs hidden. Always surface a "why" (tooltip, inline helper) when disabled.
- Zero-state → first-run — inline hints beat 5-step tours. Guide within the surface, not over it.
Knob-agnostic — correctness is not tunable. Run the full matrix regardless of CRAFT_LEVEL / MOTION_INTENSITY / VISUAL_DENSITY.
References to read: references/accessibility.md (keyboard + screen reader paths), references/copy.md (error and empty-state voice), references/motion.md Rendering Performance section (skeleton motion + reduced-motion).
Output: a per-surface checklist marking each of the 9 items as present / missing / partial. Then edit the code to fix what's missing. Print the Review Format table showing fixes. End with a "still at risk" list for anything you couldn't safely auto-fix (requires backend, requires design decision, requires translation files).
Next step: /finalize — the pre-ship gate (rung 3).