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 Uxcel-Lab/product-skills --skill heuristicsgit clone --depth 1 https://github.com/Uxcel-Lab/product-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/uxcel-lab/product-skills/heuristics)<a href="https://agentmods.dev/skills/uxcel-lab/product-skills/heuristics"><img src="https://agentmods.dev/badge/skills/uxcel-lab/product-skills/heuristics/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/uxcel-lab/product-skills/heuristics"><img src="https://agentmods.dev/badge/skills/uxcel-lab/product-skills/heuristics.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 | $0.00068 | $0.02664 |
| Opus 5 | $0.00034 | $0.01332 |
| Sonnet 5 | $0.00014 | $0.00533 |
| Haiku 4.5 | $0.00007 | $0.00266 |
Grade A, and why
ux-heuristics-audit 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 — 193 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Usability Heuristics Audit Skill
What this skill changes vs. default behavior
Without this skill, a usability review tends to produce a flat list of generic suggestions ("make it cleaner", "improve the CTA") with no framework, no severity, and no link to why something is a problem. This skill forces four things:
- Every finding names the heuristic it violates — not a vague opinion.
- Every finding gets a severity rating based on frequency × impact × persistence — so the list is prioritized, not equal-weighted.
- Every finding has a concrete, specific fix — not "consider improving."
- The audit resists over-flagging. Heuristics are principles, not a checklist to max out. A finding only earns a place if it plausibly costs a real user time, confidence, or task completion.
Scope discipline. When invoked directly (the user named this audit), review only this concern — don't pull in sibling audits. It runs alongside other lenses only when an orchestrator (ux-design-review) or a generative skill calls it under docs/orchestration-policy.md, where it sits in Tier A — always-relevant, auto-runs. Explicit scope always wins.
The 10 heuristics — what to check and what a violation looks like
Work through each. For every issue, capture: violated heuristic, severity, what's wrong, fix.
1. Visibility of system status
The system should always keep users informed about what's happening through timely feedback. A good interface answers: What just happened? Where am I? What's happening now? What's next?
Flag when: an action produces no feedback (button click with no state change, form submits with no confirmation); loading/processing has no indicator; the user's current location in a flow is unclear; background operations (saving, syncing, uploading) are silent.
- ❌ User taps "Save" and nothing visibly changes — did it work?
- ✅ "Save" shows a spinner, then a checkmark + "Saved" with a timestamp.
2. Match between the system and the real world
Speak the user's language — familiar words, phrases, concepts — not system or developer jargon. Follow real-world conventions and expected ordering.
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 · 193 lines · 68 tokens per session scan A cd0b83010b18
ux-heuristics-audit is a skill published in the GitHub repository Uxcel-Lab/product-skills (10 stars, last pushed 2mo ago), licensed MIT. It adds 68 tokens to every session and 2,664 once invoked, about $0.0003 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.
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