UX Principles
Governance knowledge base — applied automatically by the AI reviewer
Jakob's Law
Users spend most time on other sites, so they expect yours to work the same.
When to apply
When designing navigation, forms, and primary patterns.
How AI uses it
AI compares patterns against common enterprise conventions and flags deviations.
Example issue detected
Custom dropdown that doesn't open on click.
Fitts's Law
Time to acquire a target is a function of distance and size.
When to apply
When placing primary CTAs and tap targets.
How AI uses it
Detects small or distant primary actions.
Example issue detected
Tiny 'Submit' link in the corner of a form.
Hick's Law
Decision time grows with the number and complexity of choices.
When to apply
For menus, settings, and multi-option screens.
How AI uses it
Flags overloaded screens and suggests grouping.
Example issue detected
12 sort options shown at once.
Miller's Law
People can hold ~7 (±2) items in working memory.
When to apply
For lists, tables, and forms.
How AI uses it
Suggests chunking long sequences.
Example issue detected
Single 22-field form with no sections.
Law of Proximity
Objects near each other are perceived as related.
When to apply
Grouping related content and controls.
How AI uses it
Detects inconsistent spacing within groups.
Example issue detected
Form label drifts from its input.
Law of Similarity
Similar elements are perceived as a group.
When to apply
Designing repeating components.
How AI uses it
Flags visually similar items with different behavior.
Example issue detected
Two identical buttons doing different things.
Law of Common Region
Elements within a shared boundary are perceived as grouped.
When to apply
Designing cards, sections, and panels.
How AI uses it
Detects orphaned controls outside their region.
Example issue detected
Action button outside the card it acts on.
Aesthetic-Usability Effect
Users perceive aesthetic designs as more usable.
When to apply
Final polish and review.
How AI uses it
Identifies inconsistency that erodes perceived quality.
Example issue detected
Mixed icon styles in the same toolbar.
Tesler's Law
Every system has irreducible complexity — designers absorb it.
When to apply
Reducing user-facing complexity.
How AI uses it
Suggests where defaults can replace decisions.
Example issue detected
Required user to choose tax region on signup.
Peak-End Rule
People judge an experience by its peak and its end.
When to apply
Designing key moments and completion screens.
How AI uses it
Flags weak end-states (e.g. abrupt success screens).
Example issue detected
Payment success page is a blank toast.
Cognitive Load Theory
Minimize extraneous load to free working memory.
When to apply
Complex enterprise workflows.
How AI uses it
Detects screens with too many simultaneous decisions.
Example issue detected
Modal with 14 fields and 3 tabs.
Progressive Disclosure
Show only what's needed; reveal more on demand.
When to apply
Advanced settings and edge cases.
How AI uses it
Suggests collapsing rarely used options.
Example issue detected
All API settings shown to every user.
Error Prevention
Prevent problems before they occur.
When to apply
Forms, destructive actions, financial flows.
How AI uses it
Flags destructive actions without confirmation.
Example issue detected
Delete account button with no confirm.
Recognition over Recall
Make options visible instead of relying on memory.
When to apply
Search, navigation, command surfaces.
How AI uses it
Detects hidden but essential actions.
Example issue detected
Critical action only accessible via keyboard shortcut.
Nielsen — Visibility of System Status
Keep users informed about what's going on.
When to apply
Loading, async tasks, multi-step flows.
How AI uses it
Detects missing progress feedback.
Example issue detected
Upload with no progress indicator.