# Layr

> An open reference of interface design rules that people and software agents read from the same source.

Established principles are not claimed as Layr inventions. Layr provides interpretation and agent guidance.

## Product

- [Layr Design Reference](/__layr/pages/index.md): An open reference of interface design rules that people and software agents read from the same source.

## Reference

- [Reference index](/__layr/pages/reference.md): 30 established principles in 5 categories, plus 2 original Layr rules.
- [Perception & Visual Hierarchy](/__layr/pages/reference/perception-visual-hierarchy.md): Rules for making visual relationships, priority, state, and interaction meaning legible before the user has to read every detail.
- [Memory & Cognition](/__layr/pages/reference/memory-cognition.md): Rules for reducing unnecessary mental work, supporting recognition, preserving context, and helping users build reliable expectations about the system.
- [Decision, Simplicity & Familiarity](/__layr/pages/reference/decision-simplicity-familiarity.md): Rules for structuring choices, managing complexity, using familiar conventions, and helping users reach correct decisions without unnecessary interpretation.
- [Interaction, Performance & Error Tolerance](/__layr/pages/reference/interaction-performance-error-tolerance.md): Rules for responsive controls, reachable targets, resilient input, bounded tasks, and recovery patterns that keep the interface trustworthy under real-world conditions.
- [Motivation, Progress & Experience Memory](/__layr/pages/reference/motivation-progress-experience-memory.md): Rules for sustaining effort, making progress legible, supporting interrupted work, and designing the moments that shape how an experience is remembered.

## Established principles

- [Aesthetic-Usability Effect](/__layr/pages/reference/aesthetic-usability-effect.md): People often approach a polished interface with more patience and a stronger initial expectation that it will be easy to use.
- [Law of Common Region](/__layr/pages/reference/law-of-common-region.md): Elements enclosed by the same visible boundary are usually interpreted as belonging together.
- [Law of Proximity](/__layr/pages/reference/law-of-proximity.md): Items placed near one another are commonly read as a group, even when no border connects them.
- [Law of Prägnanz](/__layr/pages/reference/law-of-pragnanz.md): When a visual structure is ambiguous, people tend to resolve it into the simplest coherent interpretation available.
- [Law of Similarity](/__layr/pages/reference/law-of-similarity.md): Elements that look alike are likely to be interpreted as sharing a role, state, or category.
- [Law of Uniform Connectedness](/__layr/pages/reference/law-of-uniform-connectedness.md): Visible connections make elements feel more strongly related than elements that merely share space.
- [Selective Attention](/__layr/pages/reference/selective-attention.md): People allocate attention toward a limited subset of what is visible, usually guided by their current goal, expectations, and salient cues.
- [Von Restorff Effect](/__layr/pages/reference/von-restorff-effect.md): A distinctive item within a group is more likely to attract attention and be remembered than neighboring items that look alike.
- [Chunking](/__layr/pages/reference/chunking.md): Information becomes easier to process when related pieces are organized into meaningful units that can be understood as one structure.
- [Cognitive Bias](/__layr/pages/reference/cognitive-bias.md): Judgment is shaped by predictable mental shortcuts, prior beliefs, framing, defaults, salience, and context.
- [Cognitive Load](/__layr/pages/reference/cognitive-load.md): Every task consumes limited mental resources; interface complexity adds cost when users must remember, infer, translate, compare, or recover information unnecessarily.
- [Mental Model](/__layr/pages/reference/mental-model.md): People operate a product through an internal explanation of what the system is, what its objects mean, and what actions will cause.
- [Miller's Law](/__layr/pages/reference/millers-law.md): Human short-term information processing is limited; the famous 'seven plus or minus two' finding should be treated as historical context, not as a universal UI item limit.
- [Working Memory](/__layr/pages/reference/working-memory.md): Working memory temporarily holds and manipulates information needed for the task currently in progress.
- [Serial Position Effect](/__layr/pages/reference/serial-position-effect.md): Items near the beginning and end of a sequence often receive stronger recall than items in the middle.
- [Choice Overload](/__layr/pages/reference/choice-overload.md): A large or poorly structured set of alternatives can make selection slower, more stressful, or easier to abandon.
- [Hick's Law](/__layr/pages/reference/hicks-law.md): Decision time tends to increase as the number of plausible choices and the uncertainty between them increase.
- [Jakob's Law](/__layr/pages/reference/jakobs-law.md): Users bring expectations learned from other products and usually benefit when familiar conventions continue to behave in familiar ways.
- [Occam's Razor](/__layr/pages/reference/occams-razor.md): When several designs solve the same problem equally well, prefer the one that introduces fewer assumptions, mechanisms, and moving parts.
- [Pareto Principle](/__layr/pages/reference/pareto-principle.md): A minority of features, actions, or causes often account for a disproportionate share of use or outcomes; the exact ratio is context-dependent.
- [Paradox of the Active User](/__layr/pages/reference/paradox-of-the-active-user.md): People often prefer to begin doing the task immediately rather than first investing time in manuals or complete instruction.
- [Tesler's Law](/__layr/pages/reference/teslers-law.md): Some complexity belongs to the problem itself; design determines where that complexity is handled and who must carry it.
- [Doherty Threshold](/__layr/pages/reference/doherty-threshold.md): Interaction feels fluid when feedback arrives quickly enough that users can maintain a continuous task rhythm.
- [Fitts's Law](/__layr/pages/reference/fitts-law.md): Acquiring a target generally becomes easier as the target grows and as the required pointer travel decreases.
- [Postel's Law](/__layr/pages/reference/postels-law.md): Interfaces benefit when they accept reasonable variation in user input while producing clear, predictable output.
- [Parkinson's Law](/__layr/pages/reference/parkinsons-law.md): Work tends to expand to fill the time or space available; in product design, loose task boundaries can encourage unnecessary effort.
- [Flow](/__layr/pages/reference/flow.md): Sustained engagement is more likely when the task, feedback, difficulty, and user capability remain in a productive balance.
- [Goal-Gradient Effect](/__layr/pages/reference/goal-gradient-effect.md): Motivation can strengthen as people perceive themselves getting closer to a meaningful goal.
- [Peak-End Rule](/__layr/pages/reference/peak-end-rule.md): People often remember an experience disproportionately through its most intense moments and how it concludes.
- [Zeigarnik Effect](/__layr/pages/reference/zeigarnik-effect.md): Incomplete activity can remain mentally salient, which makes visible unfinished work a powerful cue to resume a task.

## Layr principles

- [The Intentionality Law](/__layr/pages/reference/layr-001-intentionality.md): Every visible decision should support meaning, action, identity, accessibility, or comprehension. Remove what does none of those.
- [The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow.md): A feature is complete when the user can enter, understand, act, wait, succeed, fail, recover, and continue through the surrounding task.
- [Foundation and tests — The Intentionality Law](/__layr/pages/reference/layr-001-intentionality/foundation.md): An interface should explain itself through structure before it asks copy to explain the structure.
- [Visual slop catalog — The Intentionality Law](/__layr/pages/reference/layr-001-intentionality/visual-slop.md): The following patterns are signals. Layr should combine them with project context and look for clusters before creating a finding.
- [Copy slop — The Intentionality Law](/__layr/pages/reference/layr-001-intentionality/copy-slop.md): Visual design and product writing share the same failure mode: adding material because an empty area feels unfinished.
- [Interaction slop and clusters — The Intentionality Law](/__layr/pages/reference/layr-001-intentionality/interaction-slop.md): A page can look carefully designed while loading, error, empty, disabled, partial-success, and offline states fall back to generic components.
- [The correction model — The Intentionality Law](/__layr/pages/reference/layr-001-intentionality/correction-model.md): A good anti-slop review should improve decision quality while preserving the project's own visual direction.
- [Agent execution — The Intentionality Law](/__layr/pages/reference/layr-001-intentionality/agent-execution.md): Review the interface for clusters of unchosen defaults, generic visual recipes, redundant language, and decorative behavior.
- [Review checklist and examples — The Intentionality Law](/__layr/pages/reference/layr-001-intentionality/review-examples.md): A designer or founder should be able to use this section without reading the agent schema.
- [Writing, maintenance and evidence — The Intentionality Law](/__layr/pages/reference/layr-001-intentionality/maintenance-evidence.md): Because this law will appear on the Layr website, its own copy should follow the same standard.
- [Foundation and the task unit — The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow/foundation.md): A feature is complete when its expected user task can be entered, understood, performed, interrupted, corrected, recovered from, and finished across the states that reasonably belong to the product.
- [The nine flow stages — The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow/flow-model.md): Nine stages carry a task from the moment the user arrives to the moment they move on.
- [Context layers — The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow/context.md): The nine stages are not fixed. A context layer decides which of them a task can reach at all, and a flow that is complete for one user can be unreachable for another.
- [Scope and feature creep — The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow/scope.md): Completing a task is not the same as inventing product scope. Three levels separate the work that belongs to the request from the work that belongs to a product decision.
- [Worked examples — The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow/examples.md): Four tasks, each traced from the requested surface to the states a real path reaches.
- [State completeness — The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow/state-completeness.md): Not every component needs every state. It needs the states its own task can reach, which is a shorter and more specific list.
- [Anti-patterns — The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow/anti-patterns.md): Four shapes a surface-only implementation takes. Each is a decision the flow never made.
- [Agent execution and evidence — The Complete Flow Law](/__layr/pages/reference/layr-002-complete-flow/agent-execution.md): How an agent applies this law: the order of reasoning, the evidence that supports a finding, the scope boundary that stops one, and the exact shape a report has to emit.
- [AI slop vs good design](/__layr/pages/slop.md): 19 before-and-after comparisons from LAYR-001: interface patterns shown as a generator produces them, then as a decision produces them.

## Optional

- [Complete public knowledge](https://layr.design/llms-full.txt): every page above in one file.
- [Agent skill package](https://layr.design/skill/SKILL.md): the same pages wrapped for progressive retrieval, with a route map, source metadata and the excluded routes.
- [Route map](https://layr.design/__layr/routes.toon): compact TOON index of routes to Markdown files.