heuristic
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 mentions 'heuristic' alongside design / UI / frontend work.
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Install
Works with every agent the skills CLI supports.
npx skills add https://github.com/educlopez/ui-craft --skill heuristic- 01
Install
Run the command in your project. The CLI asks which agents to install for.
- 02
Describe the task
Ask your agent for something this skill covers. It loads heuristic automatically when relevant.
- 03
Review the result
The agent follows the SKILL.md steps, scripts and references bundled with the skill.
SKILL.md
The instructions your agent reads when the skill is triggered.
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:
## Heuristic Scorecardtable## Design Law Audittable## Persona Walkthroughtable (only if--persona=was passed)## Top findings (ranked by impact)— numbered list, 3-5 items## UsabilityScoreblock — 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).
FAQ
What does the heuristic skill do?
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 mentions 'heuristic' alongside design / UI / frontend work.
How do I install heuristic?
Run npx skills add https://github.com/educlopez/ui-craft --skill heuristic in your project. The skills CLI detects the agents you use and copies the skill into the right folder. For Claude Code you can also place the skill folder at ~/.claude/skills/heuristic/ (personal) or .claude/skills/heuristic/ (project).
Which AI agents can use heuristic?
Any agent that supports the open Agent Skills format (a folder with a SKILL.md file), including Claude Code, Codex, Cursor, GitHub Copilot, Gemini CLI, Windsurf, Cline, OpenCode and more.
Is heuristic safe to install?
No partner security audit is available yet. Skills can run commands and scripts, so read the SKILL.md and any bundled files before installing.
Who maintains heuristic?
It is published by educlopez in educlopez/ui-craft. It has 882 recorded installs.
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