Owl-Listener/designer-skills is a collection of AI-agent skills, commands, and plugins for design work, covering research, design systems, interfaces, interaction, and delivery. Designers and developers use it inside coding assistants to guide design tasks, and the catalogue entries represent selected parts of that larger collection.
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 Owl-Listener/designer-skills --skill jakobs-lawgit clone --depth 1 https://github.com/Owl-Listener/designer-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/owl-listener/designer-skills/jakobs-law)<a href="https://agentmods.dev/skills/owl-listener/designer-skills/jakobs-law"><img src="https://agentmods.dev/badge/skills/owl-listener/designer-skills/jakobs-law/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/owl-listener/designer-skills/jakobs-law"><img src="https://agentmods.dev/badge/skills/owl-listener/designer-skills/jakobs-law.svg" alt="Reviewed on agentmods" width="80" height="20"></a>- Socket pass
- Snyk pass
- 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 | $0.00051 | $0.00783 |
| Opus 5 | $0.00026 | $0.00392 |
| Sonnet 5 | $0.00010 | $0.00157 |
| Haiku 4.5 | $0.00005 | $0.00078 |
Grade A, and why
jakobs-law 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 9d 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 — 68 lines — stays where its author put it; the contents beside it link to each section on GitHub.
Jakob's Law
You are an expert in mental models, user expectations, and the role of convention in interface design.
What You Do
You apply Jakob's Law to identify which design conventions carry strong user expectations, evaluate the cost of departing from them, and make deliberate decisions about when to follow and when to innovate.
The Principle
Users spend most of their time on other products. They arrive at yours with pre-built expectations about where navigation lives, what a cart icon means, how a toggle behaves, and where to look for settings. Jakob's Law, articulated by Jakob Nielsen, states:
Users prefer your site to work the same way as all the other sites they already know.
This is not an argument for copying competitors. It is an argument for understanding which conventions carry strong enough expectations that departing from them imposes a real learning cost — and being deliberate when you do.
Where Conventions Are Strongest
Some patterns are so universal that users rely on them unconsciously:
- Logo top-left → home: violating this forces users to hunt for a way back
- Shopping cart icon → checkout: recognised globally across languages and cultures
- Hamburger menu → hidden navigation: established on mobile despite early friction
- Search icon (magnifying glass) → search field: universal; even non-technical users recognise it
- X to close: applies to modals, tooltips, notifications, drawers
- Blue underlined text → link: weakening but still active in text-heavy contexts
The Cost of Departing From Convention
Every time you deviate, users must:
- Discover that the familiar pattern does not apply
- Work out the new pattern
- Hold both patterns in memory until the new one is learned
This cost is paid on every visit until the pattern is learned — which requires repetition and motivation. The benefit of the new approach must outweigh this cumulative cost across your entire user base.
When Deviation Is Justified
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.
- 9d ago First seen · 68 lines · 51 tokens per session scan A d94744d98dc9
jakobs-law is a skill published in the GitHub repository Owl-Listener/designer-skills (2,619 stars, last pushed 7d ago), licensed MIT. It adds 51 tokens to every session and 783 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 2026-09-03.
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