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 fernando-bertholdo/4-successful-AI-life --skill heuristicsgit clone --depth 1 https://github.com/fernando-bertholdo/4-successful-AI-lifeWrote 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/fernando-bertholdo/4-successful-ai-life/heuristics)<a href="https://agentmods.dev/skills/fernando-bertholdo/4-successful-ai-life/heuristics"><img src="https://agentmods.dev/badge/skills/fernando-bertholdo/4-successful-ai-life/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/fernando-bertholdo/4-successful-ai-life/heuristics"><img src="https://agentmods.dev/badge/skills/fernando-bertholdo/4-successful-ai-life/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 | $0.00119 | $0.04381 |
| Opus 5.5 | $0.00048 | $0.01752 |
| Sonnet 5.5 | $0.00024 | $0.00876 |
| Haiku 4.5 | $0.00012 | $0.00438 |
Grade A, and why
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.
Copies of this mod
1 near-identical copy found in the catalogue:
- ux-heuristics — 97% identical, 10 lines differ
How it starts
The opening of the file, as written. The whole thing — 308 lines — stays where its author put it; the contents beside it link to each section on GitHub.
UX Heuristics Framework
Practical usability principles for evaluating and improving user interfaces. Based on a fundamental truth: users don't read, they scan. They don't make optimal choices, they satisfice. They don't figure out how things work, they muddle through.
Core Principle
"Don't Make Me Think" - Every page should be self-evident. If something requires thinking, it's a usability problem.
The foundation: Users have limited patience and cognitive bandwidth. The best interfaces are invisible -- they let users accomplish goals without ever stopping to wonder "What do I click?" or "Where am I?" Every question mark that pops into a user's head adds to cognitive load and increases the chance they'll leave. Design for scanning, satisficing, and muddling through -- because that's what users actually do.
Scoring
Goal: 10/10. When reviewing or creating user interfaces, rate them 0-10 based on adherence to the principles below. A 10/10 means full alignment with all guidelines; lower scores indicate gaps to address. Always provide the current score and specific improvements needed to reach 10/10.
Krug's Three Laws of Usability
1. Don't Make Me Think
Core concept: Every question mark that pops into a user's head adds to their cognitive load and distracts from the task.
Why it works: Users are on a mission. They don't want to puzzle over labels, wonder what a link does, or decode clever marketing language. The less thinking required, the more likely they complete the task.
Key insights:
- Clever names lose to clear names every time
- Marketing-speak creates friction; plain language removes it
- Unfamiliar categories and labels force users to stop and interpret
- Links that could go anywhere create uncertainty
- Buttons with ambiguous labels cause hesitation
Product applications:
| Context | Application | Example |
|---|---|---|
| Navigation labels | Use self-evident names | "Get directions" not "Calculate route to destination" |
| CTAs | Use action verbs users understand | "Sign in" not "Access your account portal" |
| E-commerce | Match user mental models | "Add to cart" not "Proceed to purchase selection" |
| Form labels | Describe what's needed plainly | "Email address" not "Electronic correspondence identifier" |
| Error states | Tell users what to do next | "Check your email format" not "Validation error" |
What ships with it
7 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.
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 First seen · 308 lines · 119 tokens per session scan A 8739a389400f
heuristics is a skill published in the GitHub repository fernando-bertholdo/4-successful-AI-life (2 stars, last pushed 10d ago), licensed MIT. It adds 119 tokens to every session and 4,381 once invoked, about $0.0005 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 2026-08-31.
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