Agent skill · owl-listener
jakobs-law
Apply Jakob's Law — users expect your product to work like the others they already use. Use when deciding whether to innovate on a familiar pattern. For OS-mandated conventions specifically, use `platform-conventions` (ui-design).
What it needs
About 2k tokens when loaded.
What this skill does
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: 1. Discover that the familiar pattern does not apply 2. Work out the new pattern 3. 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. …
How to use it
Reference it in AdaL, Claude Code, Cursor or any coding agent — nothing to install:
@skills owl-listener/jakobs-law