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 jnPiyush/AgentX --skill usability-heuristicsgit clone --depth 1 https://github.com/jnPiyush/AgentXWrote 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/jnpiyush/agentx/usability-heuristics)<a href="https://agentmods.dev/skills/jnpiyush/agentx/usability-heuristics"><img src="https://agentmods.dev/badge/skills/jnpiyush/agentx/usability-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/jnpiyush/agentx/usability-heuristics"><img src="https://agentmods.dev/badge/skills/jnpiyush/agentx/usability-heuristics.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 | $0.00072 | $0.01974 |
| Opus 5.5 | $0.00029 | $0.00790 |
| Sonnet 5.5 | $0.00014 | $0.00395 |
| Haiku 4.5 | $0.00007 | $0.00197 |
Grade A, and why
usability-heuristics 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 1mo 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 — 183 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Usability Heuristics
WHEN: A prototype, page, or flow needs an evidence-based usability check beyond accessibility and visual polish. This skill is the canonical Frontier heuristic-evaluation procedure consumed by
prototype-auditPass 7.
When to Use This Skill
- Before declaring a prototype review-ready
- During the prototype-auditor Pass 7
- When a stakeholder asks "is this actually usable?"
- When choosing between two layouts to ship
Not a replacement for user testing. It is a structured expert inspection that catches the obvious failures before they reach users.
Authoritative Sources
| Source | What it covers |
|---|---|
| Nielsen Norman Group, 10 Usability Heuristics (1994, updated) | Heuristic definitions |
| Jakob Nielsen, Severity Ratings for Usability Problems | 0-4 severity scale |
| Bruce Tognazzini, First Principles of Interaction Design | Complementary principles |
| Don Norman, The Design of Everyday Things | Affordance, mapping, feedback |
| Baymard Institute UX research | Empirical e-commerce / form data |
Cite the heuristic by number in every finding so the report is auditable.
The Ten Heuristics
| # | Heuristic | One-line test |
|---|---|---|
| H1 | Visibility of system status | Does the UI tell me what is happening within 100ms / 1s / 10s? |
| H2 | Match between system and the real world | Does the language match the user's vocabulary, not the developer's? |
| H3 | User control and freedom | Can I undo, cancel, and exit cleanly? |
| H4 | Consistency and standards | Do the same words and actions mean the same thing across pages? |
| H5 | Error prevention | Are dangerous actions guarded by confirmation or constraints? |
| H6 | Recognition rather than recall | Are options visible instead of remembered? |
| H7 | Flexibility and efficiency of use | Are there accelerators for expert users (shortcuts, bulk actions)? |
| H8 | Aesthetic and minimalist design | Is every element earning its place on screen? |
| H9 | Help users recognize, diagnose, and recover from errors | Do errors say what is wrong, where, and how to fix? |
| H10 | Help and documentation | Is task-oriented help available when needed? |
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.
- 1mo ago Changed 1d47e4e4744c
- 1mo ago First seen · 183 lines · 72 tokens per session scan A 385e767a91c6
usability-heuristics is a skill published in the GitHub repository jnPiyush/AgentX (16 stars, last pushed 3d ago), licensed Apache-2.0. It adds 72 tokens to every session and 1,974 once invoked, about $0.0003 per session on Opus 5.5. 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 2026-09-03.
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