Sk Interface Design

Interface Design (sk-interface-design)

Approach UI work as the design lead at a studio known for visual identities that could not be mistaken for anyone else's. Make deliberate, opinionated choices specific to the brief, take one justified aesthetic risk, and reject anything that reads as a templated default. Full guidance lives in [references/design-process/design_principles.md](references/design-process/design_principles.md). Vendored from Anthropic's frontend-design skill (Apache-2.0).

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1. WHEN TO USE

Activation Triggers

Use when the work involves:

• Building a new UI, page, component, or landing section from a brief.
• Reshaping or restyling an existing interface that feels generic or templated.
• Choosing palette, typography, layout, motion, or interface copy.
• Reviewing a design direction before code is written.

Keyword Triggers: "design", "make it look good", "redesign", "variation", "give me N variations", "show me options", "multiple directions", "hero section", "landing page", "looks templated", "looks AI-generated", "visual identity".

When NOT to Use

Skip this skill when:

• The task is pure logic, data, or back-end work with no visual surface (use sk-code).
• A brief already fully pins the visual direction and only mechanical implementation remains (follow the brief, since this skill adds nothing).
• The work is documentation or prose, not interface (use sk-doc).

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2. SMART ROUTING

Primary Detection Signal

Detect design intent and how much of the visual direction the brief fixes:

# Direction freedom (pseudo)
echo "$BRIEF" | grep -qiE 'palette|font|typography|layout|brand|look|style' && AXIS_PINNED=high
# If the brief pins the direction -> follow it exactly. If axes are free -> apply the principles.

Phase Detection

DESIGN TASK
    |
    +- STEP 0: Ground the subject (name subject, audience, the page's one job)
    +- STEP 1: Brainstorm a token system (color, type, layout, signature)
    +- STEP 2: Critique the plan against AI-default looks, then revise and justify
    +- STEP 3: Build from the revised plan, deriving every choice from it
    +- STEP 4: Self-critique (screenshot, remove one accessory, check quality floor)

Resource Loading Levels

| Level | When to Load | Resource | | ----- | ------------ | -------- | | ALWAYS | Any design task | references/design-process/design_principles.md (palette, type, structure, motion, restraint) | | CONDITIONAL | Writing UI copy | Section 6 of design_principles.md (writing in design) | | CONDITIONAL | Producing two or more design directions at once | references/design-process/variation_diversity.md (seed-of-thought debias so the directions are not N safe copies of the median) | | CONDITIONAL | Verifying the quality floor / charts | references/design-process/ux_quality_reference.md (accessibility, motion, touch, responsive, forms, charts) | | CONDITIONAL | Producing or iterating on real UI (repo recreation, code-bound, a generation run) | references/design-process/real_ui_loop.md (ground in a system, reuse before generating, fidelity check, handoff) | | ONDEMAND | Need a real design system to ground in, reuse, or name the default to deviate from | A real design system you own, read live and never copied. See references/design-grounding/design_inventory.md | | INITIATIVE / ASK | A convention-heavy category where naming the real-world default sharpens the deviation | A real shipped-UI reference via Mobbin (app/iOS screens + flows) or Refero (web pages + visual styles) through Code Mode (mobbin.* / refero.*). Take the initiative to pull ONE when the category benefits and a subscription is connected; otherwise ask the user; otherwise fall back to the generic process. See references/design-grounding/design_references_mcp.md | | ONDEMAND | Implementing in code | sk-code web-surface standards for the target stack |

Smart Router Pseudocode

# Route a design task to the right guidance.
# 1) Always load references/design-process/design_principles.md.
# 2) If the brief fixes the visual direction, follow the brief verbatim and skip default-avoidance.
# 3) If axes are free, apply Sections 2-5 (subject, principles, process, restraint).
# 3b) If the brief asks for two or more directions, load references/design-process/variation_diversity.md and run the seed-of-thought debias so the set is not N copies of the median.
# 4) If the task writes interface copy, also apply Section 6 (writing).
# 5) Hand implementation to sk-code for the detected web surface. This skill owns the look, not the build mechanics.

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3. HOW IT WORKS

The Two-Pass Process

Process Flow:

STEP 0: Ground the subject
       └─ Name one concrete subject, its audience, and the page's single job
       ↓
STEP 1: Brainstorm a compact token system
       ├─ Color: 4-6 named hex values
       ├─ Type: a display face used with restraint + a body face (+ utility face)
       ├─ Layout: a concept with one-sentence prose + ASCII wireframes
       └─ Signature: the one element the page will be remembered by
       ↓
STEP 2: Critique the plan against the brief
       └─ Anything that reads like a generic default gets revised, with a stated reason
       ↓
STEP 3: Build from the revised plan
       └─ Derive every color and type decision from the plan, mind CSS specificity
       ↓
STEP 4: Self-critique
       └─ Screenshot if possible, remove one accessory, confirm the quality floor

Calibration matters: current AI design clusters around three default looks (cream + serif + terracotta, near-black + one acid accent, broadsheet with hairline rules). They are defaults, not choices. When the brief frees an axis, do not spend it on one of these. The full calibration, two-pass detail, and writing rules are in [references/design-process/design_principles.md](references/design-process/design_principles.md).

Quality Floor

Build to it without announcing it: responsive down to mobile, visible keyboard focus, and reduced motion respected. Do most of the planning and iteration in thinking, and show the user ideas only at higher confidence.

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4. RULES

ALWAYS

1. ALWAYS ground the design in the subject before choosing anything. Name the subject, audience, and the page's single job, then draw distinctive choices from the subject's own world.
2. ALWAYS make deliberate, brief-specific choices for palette, typography, layout, and motion, and take one justifiable aesthetic risk.
3. ALWAYS critique the plan against the AI-default looks before writing code, and revise anything generic with a stated reason.
4. ALWAYS treat copy as design material, with active voice, end-user vocabulary, and consistent action names across a flow.
5. ALWAYS meet the quality floor: responsive, visible focus, reduced-motion respected.
6. ALWAYS debias multiple directions with the seed of thought from references/design-process/variation_diversity.md when a brief asks for two or more: a committed seed picks a non-median start in the grounded option space and the rest are spread to be genuinely distinct, each still grounded and critiqued. Never surface it as a style chooser.
7. ALWAYS decide, at the critique step, whether a real-world reference would sharpen the default to deviate from. Take the initiative to pull ONE Mobbin or Refero reference when the brief sits in a convention-heavy category and a subscription is connected; otherwise ask the user first; otherwise fall back to the generic anti-default process. Mobbin for app/iOS surfaces, Refero for web pages and visual style. One reference, read live, never copied, never a chooser. See references/design-grounding/design_references_mcp.md.

NEVER

1. NEVER ship a templated default (cream + serif + terracotta, near-black + one acid accent, or broadsheet hairlines) on a free axis just because it is safe.
2. NEVER add decoration that does not serve the brief, including numbered markers (01 / 02 / 03) when the content is not actually a sequence.
3. NEVER let motion pile up. Scattered animation reads as AI-generated, so prefer one orchestrated moment.
4. NEVER override a brief that pins the direction. The brief's own words always win, even when they ask for a default look.

ESCALATE IF

1. ESCALATE IF the brief is too thin to ground and you cannot reasonably pin the subject, audience, or page job yourself. State your assumed direction and confirm.
2. ESCALATE IF the requested direction conflicts with brand or accessibility (for example a palette that fails contrast). Surface the trade-off before building.

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5. REFERENCES

Core References

• [references/design-process/design_principles.md](references/design-process/design_principles.md) - Full guidance: grounding, design principles, the two-pass process with AI-default calibration, restraint and self-critique, and interface writing.
• [references/design-process/ux_quality_reference.md](references/design-process/uxqualityreference.md) - The objective quality floor (accessibility, motion, touch, responsive, forms, charts). Apply as the pass/fail gate after the direction is set.
• [references/design-grounding/design_inventory.md](references/design-grounding/design_inventory.md) - How to use a real design system you own as either reuse-ground or the named default to critique against. Never a chooser.
• [references/design-grounding/design_references_mcp.md](references/design-grounding/designreferencesmcp.md) - How to read real-world shipped UI live via Mobbin or Refero (Code Mode) to name the real-world default and deviate from it. Critique-against only, one reference, never a chooser, never copied.
• [references/mcp-tooling/mobbin_tools.md](references/mcp-tooling/mobbintools.md) - Mobbin MCP tool catalog (searchscreens, search_flows): arguments, the verified Code Mode call convention, result shape, troubleshooting.
• [references/mcp-tooling/refero_tools.md](references/mcp-tooling/refero_tools.md) - Refero MCP tool catalog (8 tools across styles, screens, flows): the styles-first model, call convention, result shape, troubleshooting.
• [references/design-process/variation_diversity.md](references/design-process/variation_diversity.md) - The seed-of-thought debias for producing two or more directions at once: a committed seed picks a non-median start in the grounded option space, the rest are spread to be distinct, and grounding plus the anti-default critique stay primary. Consult only when more than one direction is requested.
• [references/design-process/real_ui_loop.md](references/design-process/realuiloop.md) - The real-UI loop: ground in a design system, reuse before generating, check the real render against the quality floor, hand off cleanly. Consult when producing or iterating on real UI.
• [LICENSE.txt](LICENSE.txt) - Apache-2.0 terms for the vendored Anthropic frontend-design base.

Feature Catalog

The skill's features are catalogued in feature_catalog/feature_catalog.md (root index) plus per-feature files under feature_catalog/--/: the design process, the quality floor, design grounding and critique, interface writing, and the integration boundary.

Manual Testing Playbook

Manual testing scenarios live in manual_testing_playbook/manual_testing_playbook.md (root index) plus per-scenario files under manual_testing_playbook/--/. Validate structure with python3 .opencode/skills/sk-doc/scripts/validate_document.py manual_testing_playbook/manual_testing_playbook.md; execute scenarios in a real session for behavioral verification.

Reference Loading Notes

• Load design_principles.md on every design task. It is the authority for palette, type, structure, motion, and copy.
• Keep Section 2 (SMART ROUTING) as the single routing authority.
• references/design-process/ux_quality_reference.md is the objective quality-floor gate; apply it after the direction is set.
• A real design system you own is an OPTIONAL source to ground in or to name the default to deviate from, never a required step and never a style chooser. design_principles.md stays the authority.
• When the Mobbin or Refero subscriptions are connected, they are an OPTIONAL real-world critique-against reference (via Code Mode) for naming the category default to deviate from, never a chooser and never copied. references/design-grounding/design_references_mcp.md owns the rules and design_principles.md stays the authority.

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6. SUCCESS CRITERIA

A design is ready when:

• ✅ The subject, audience, and the page's single job are named.
• ✅ A token system (color, type, layout, signature) exists and was critiqued against the AI-default looks.
• ✅ Every color and type decision derives from the revised plan.
• ✅ The signature element is the one bold move, and everything else is quiet.
• ✅ The quality floor holds: responsive, visible focus, reduced motion respected.

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7. INTEGRATION POINTS

Related Skills

• sk-code owns implementation. This skill decides the look, and sk-code builds it to the detected web surface's standards and verifies it.
• sk-code-review can audit the built UI against the standards sk-code enforces.
• mcp-chrome-devtools drives a real browser to screenshot the build for the self-critique step.
• mcp-figma is the sibling transport to Figma Desktop. This skill's judgment applies whenever a Figma read or export feeds a design decision.
• Mobbin and Refero (via Code Mode, mobbin.* / refero.*) are optional real-world UI reference libraries for naming the category's real-world default so a design can deviate from it deliberately. Read live, one reference, never a chooser, never copied. references/design-grounding/design_references_mcp.md owns the discipline.

Knowledge Base Dependencies

Required: references/design-process/design_principles.md. Conditional: sk-code web-surface references for the target stack during implementation.

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8. REFERENCES AND RELATED RESOURCES

The router (Section 2) loads references/design-process/design_principles.md for every design task. Hand implementation to sk-code, use mcp-chrome-devtools for screenshot-based self-critique, and reach for system-spec-kit when the work needs packet documentation.

Upstream: vendored from anthropics/skills/skills/frontend-design under Apache-2.0. LICENSE.txt carries the full terms.

Source & license

This open-source skill is cataloged on AgentStack and links to its original source — we do not rehost the code.

• Author: MichelKerkmeester
• Source: MichelKerkmeester/opencode--skilled-agent-loops-with-spec-kit-memory
• License: MIT

Install and usage instructions live in the source repository linked above.