Produce a scored heuristic critique of the UI using Nielsen's 10 + 6 design laws + optional persona walkthroughs. Outputs a machine-parseable scorecard plus a 0-100 UsabilityScore (the judged companion to the deterministic UICraftScore). Invoke when the user asks for heuristic on their UI, or mentio

<! HARNESS MIRROR — do not edit here. Canonical source: skills/ or commands/. After editing source, copy into cli/assets/<harness / and repo root harness mirrors. 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. Score the UI at $ARGUMENTS against Nielsen's 10 + 6 design laws. Load the ui craft skill. Step 1 — Load the methodology. Read references/heuristics.md for the full rubric, scoring definitions, design law details, and the required output format. Do NOT invent a new format or a new scale. Step 2 — Walk Nielsen's 10 heuristics. Score each 1 5 per the rubric: 1 blocks users · 2 severe friction · 3 works but confusing · 4 works, minor polish · 5 best in class For every heuristic, write a concrete finding — quote text, count elements, name the broken flow. Vague findings are rejected. Step 3 — Audit the 6 design laws. PASS / FAIL each with a specific detail: Fitts's Law — touch target sizing, CTA placement Hick's Law — choice density, nav + select sizing Doherty Threshold — perceived latency, optimistic UI Cleveland McGill — chart encoding choice Miller's Law — nav depth, form section counts Tesler's Law — where complexity lives Step 4 — Persona walkthrough (if persona= present). If the args include persona=<name , load references/personas.md and run the matching walkthrough checklist. Supported: priya , jordan , adaeze , kwame , margo , all . Output the walkthrough as a Checklist item Pass/Fail Finding Impact table. Without the flag, skip this step. Step 5 — Rank findings by impact tag. Impact order: blocks conversion adds friction reduces trust minor polish . Include at most 5 findings in the ranked list; cut anything at minor polish unless there are no higher impact findings. Step 6 — Compute the UsabilityScore. Roll the scorecard into a 0 100 number + grade per the UsabilityScore formula in references/heuristics.md : heuristic base = round(((mean(nielsen scores) − 1) / 4) × 100) , minus 5 × (failed design laws) , clamped [0,100]. Same A/B/C/D/F bands as UICraftScore. Always label it (judged) — it is not deterministic and must never gate CI. If the args include json , also emit the machine readable block. If the user asks for the full picture, build the Extended quality report by fetching the deterministic UICraftScore ( node scripts/eval.mjs <path json or the score ui MCP tool) and placing both side by side — never average them. Step 7 — Output. Use the exact scorecard format in references/heuristics.md : 1. Heuristic Scorecard table 2. Design Law Audit table 3. Persona Walkthrough table (only if persona= was passed) 4. Top findings (ranked by impact) — numbered list, 3 5 items 5. UsabilityScore block — the 0 100 score + grade + component breakdown Knob awareness: knob agnostic. Usability is not a knob — a 2 is a 2 whether CRAFT LEVEL is 3 or 9. Do not soften scores based on CRAFT LEVEL . Output contract: This command produces a critique artifact , not code. No edits unless the user explicitly asks in a follow up. The scorecard is machine parseable markdown. A PM can paste it into any issue tracker and file tickets row by row. Frame it that way in any preamble. No "First Impressions" paragraph, no hedging, no praise padding. Tables + ranked list only. Do NOT edit code. This is a scored critique. Next step: Fix the findings, then /finalize — the scorecard is the input to a gated ship (rung 3).