design-everyday-things skill
Apply foundational design principles: affordances, signifiers, constraints, feedback, and conceptual models. Use when the user mentions "why is this confusing", "affordance", "error prevention", "discoverability", "human-centered design", "mental model", "mapping", "seven stages of action", "users keep making mistakes", "this is unintuitive", or "people cant figure out how to use it". Also trigger when reducing product complexity or feature creep. Covers the gulfs of execution and evaluation. For usability scoring, see ux-heuristics. For iOS-specific patterns, see ios-hig-design.
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Install the design-everyday-things skill
A skill is a folder. Copy it into your agent's skills folder and the agent loads it when the task matches its description.
git clone --depth 1 https://github.com/wondelai/skills.git /tmp/skills mkdir -p ~/.claude/skills cp -r /tmp/skills/plugins/ux-design/skills/design-everyday-things ~/.claude/skills/design-everyday-things
In the Claude apps, zip the folder and upload it from the Skills settings. The folder on GitHub
The instructions your agent would load
SKILL.md as published, without the frontmatter. Read it on GitHub
Design of Everyday Things Framework
Foundational design principles for creating products that are intuitive, discoverable, and understandable. The "bible of UX" — applicable to physical products, software, and any human-designed system.
Core Principle
Good design is actually a lot harder to notice than poor design, in part because good designs fit our needs so well that the design is invisible. When something fails, users blame themselves — but the fault is almost always in the design. Great design bridges the gap between what people want to do and what the product allows: it is discoverable (you can figure out what to do) and understandable (you can figure out what happened).
Scoring
Goal: 10/10. Score 2 points per satisfied row of the Quick Diagnostic (5 rows = discoverability, evaluation, error recovery, mapping, constraints). Bands: 9-10 = users act without instructions, understand every outcome, and recover from any error; 5-6 = one gulf or error path is broken; <=3 = users must consult a manual or routinely blame themselves. Report the current score and the diagnostic rows failing it.
The Two Gulfs
Every interaction with a product requires bridging two gulfs:
USER PRODUCT
│ │
├──── Gulf of Execution ────────────────→│
│ "How do I do what I want?" │
│ │
│←──── Gulf of Evaluation ──────────────┤
│ "What happened? Did it work?" │Gulf of Execution
The gap between what users want to do and what the product lets them do. Users ask: What can I do here? Which control do I use?
Bridge with: clear signifiers, natural mappings, constraints, familiar conceptual models.
Gulf of Evaluation
The gap between what the product did and what users understand happened. Users ask: What happened? Did it work? What state is the system in?
Bridge with: immediate visible feedback, clear system-state indicators, meaningful error messages, progress indicators.
Design goal: Make both gulfs as narrow as possible — action and understanding should be immediate.
See: references/two-gulfs.md for gulf analysis exercises.
Seven Fundamental Design Principles
1. Discoverability
Definition: Can users figure out what actions are possible and how to perform them? Its five components — affordances, signifiers, constraints, mappings, feedback — are detailed below.
Test: Put a new user in front of your product. If they can't figure out what to do within 10 seconds, discoverability is broken.
Anti-pattern: "The user manual explains it." If users need a manual, the design failed.
2. Affordances
Definition: The relationship between an object's properties and a user's capabilities that determines how the object could be used.
Key insight: Affordances exist whether or not they are perceived — what matters for design is perceived affordance.
Digital applications:
Common failures: flat design erasing perceived affordances (button or label?), too-small touch targets, interactive and decorative elements that look identical.
See: references/affordances.md for affordance design patterns.
3. Signifiers
Definition: Signals that communicate where the action should take place. Affordances determine what you CAN do; signifiers show you WHERE and HOW.
Digital signifiers:
Design rule: When in doubt, add a signifier — better to over-communicate than leave users guessing.
See: references/signifiers.md when deciding which signifier to add to an unclear control.
4. Mappings
Definition: The relationship between controls and their effects. Natural mapping means the spatial layout of controls matches the layout of what they control.
Digital principles: controls near what they affect, layout mirroring content, direction matching expectation (scroll down = content moves up), related controls grouped.
See: references/mappings.md for mapping analysis exercises.
5. Constraints
Definition: Limiting the possible actions to prevent errors.
Digital constraints:
Design rule: Every constraint you add is one less error the user can make — make wrong actions impossible rather than punishing them.
See: references/constraints.md for constraint design patterns.
6. Feedback
Definition: Communicating the results of an action back to the user. Feedback must be immediate (within 0.1s for direct manipulation), informative, appropriately dosed, and non-intrusive.
Digital feedback patterns:
Response times: 0.1s feels instantaneous; 1s is a noticeable delay (change cursor); 10s loses attention (show progress bar); over 10s users leave (show percentage, allow backgrounding).
Common failures: no feedback (did my click register?), delayed feedback (feels broken), unclear feedback, alert overload.
See: references/feedback.md when an action gives no clear result and you need the right feedback type and timing.
7. Conceptual Models
Definition: The user's mental model of how a product works.
Goal: The user's model should match the design model; the system image is the only bridge. Matching models let users predict outcomes and recover from errors; mismatches breed confusion, self-blame, and support calls.
Example (thermostat): design model — set a temperature, the system maintains it; common user model — higher setting heats faster (wrong), so users crank it to 90°F.
Build correct models with: familiar metaphors (desktop, trash), visible system state, clear feedback, consistent behavior, progressive disclosure.
See: references/conceptual-models.md when the user's model diverges from how the product works. For fully worked teardowns (door handles, thermostats, digital products), see references/case-studies.md.
Human Error
Norman's key insight: there is no such thing as "human error" — only bad design. When someone errs, look for the design flaw, not the person's flaw.
Types of Errors
Slips — correct intention, wrong action:
Mistakes — wrong intention, executed correctly:
Design for Error
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