Interface Lab
Knowledge RAG

Design Knowledge Base

Community-maintained principles reviewed before publication and retrieved as Agent design constraints.

Submit principle
15 published principles / 192 in library
Design Systems Page Patternspublic-service / trust

Public-Service Trust Rails and Recovery

Public-service interfaces must make official identity, responsible organization, legal links, task title, form semantics, error summaries, and recovery paths into verifiable page structure instead of merely applying blue-white civic styling.

Trust in public services comes from an inspectable responsibility chain and recoverable task flow: users need to know whether the service is official, who is responsible, whether the connection is safe, why information is needed, how to fix mistakes, and where privacy/accessibility/oversight information lives.95%
Design Systems Page Patternsprogressive-disclosure / settings

Progressive Disclosure for Complexity

Complex settings, forms, and admin pages should expose common tasks first, then place advanced, risky, rare, or conditional options in predictable secondary paths.

Progressive disclosure is not hiding things. It sequences visibility by task, risk, and frequency so novices make fewer errors while expert users can still find advanced controls.95%
Interaction Responsive Motionforms / validation

Form Error State Contract

A form error state contract puts labels, helper text, validation timing, inline errors, error summaries, submit states, server failures, mobile keyboards, and ARIA wiring into one implementable model.

Form errors are not one red component; they combine field contracts, state machines, and recovery paths, and should route to narrower guidance for summaries, accessible feedback, persistent labels, and transactional recovery.95%
Interaction Responsive Motionforms / errors

Transactional Form Error Recovery

Error handling in high-trust forms is not about telling users they are wrong. It returns them to a recoverable state where they can continue without re-entering information.

Transactional service error recovery must handle visual placement, screen readers, focus, original input, error copy, and next action together.94%
Typography Color Accessibilityforms / input

Touch Keyboard and Input Purpose

Touch Keyboard and Input Purpose turns a frequent interface judgment into an executable constraint before generation.

Mobile input fields should use the right keyboard, autocomplete, and input purpose to reduce errors and effort.86%
Typography Color Accessibilityforms / labels

Persistent Form Labels

Persistent Form Labels turns a frequent interface judgment into an executable constraint before generation.

Form labels should remain visible before and after input so users can confirm meaning and context.86%
Typography Color Accessibilityauthentication / accessibility

Accessible Authentication Flow

Accessible Authentication Flow turns a frequent interface judgment into an executable constraint before generation.

Secure flows still need low cognitive load, helping users complete rather than testing them.86%
Typography Color Accessibilityforms / errors

Error Summary Pattern

Error Summary Pattern turns a frequent interface judgment into an executable constraint before generation.

Users need to know how many errors exist, where they are, and how to fix them without hunting for red text.86%
Interaction Responsive Motionfeedback / toast

Toast vs Inline Feedback

Toast vs Inline Feedback turns a frequent interface judgment into an executable constraint before generation.

Feedback placement should match the object; toast fits short global status, while inline feedback fits fields and local fixes.85%
Interaction Responsive Motionwizard / progress

Wizard Stepper Progress

Wizard Stepper Progress turns a frequent interface judgment into an executable constraint before generation.

Wizards need to show current position, remaining work, reversibility, and save state.85%
Typography Color Accessibilityforms / placeholder

Placeholder Is Not a Label

Placeholder Is Not a Label turns a frequent interface judgment into an executable constraint before generation.

Placeholders are useful for examples, not as the only instruction or critical guidance.84%
Typography Color Accessibilityforms / redundant-entry

Redundant Entry Reduction

Redundant Entry Reduction turns a frequent interface judgment into an executable constraint before generation.

Redundant entry increases cognitive load, errors, and abandonment, especially for assistive technology users.84%
Interaction Responsive Motioninputs / controls

Input Mode and Control Matching

Controls should match decision shape: toggles for binary, segmented controls for modes, menus for option sets, sliders for continuous values.

The wrong control adds cognitive cost and makes reversibility unclear.82%
Interaction Responsive Motionforms / workflow

Form Flow and Validation

Forms should follow the user's mental order and provide recoverable feedback at key moments.

Good forms split complex tasks into completeable steps rather than dumping every field at once.82%
Typography Color Accessibilityforms / accessibility

Accessible Form Feedback

Form feedback should sit near fields, explain why, and remain understandable before and after submission.

Error messages are not punishment; they guide users toward completion.82%