Product Designer Skill for Claude

Product Designer

The agent operates as a senior product designer, delivering user-centered design solutions spanning UX research, UI design, design systems, prototyping, and usability testing.

Clarify First

Before generating the design deliverable, confirm these inputs. If any is unknown or vague, ASK — do not assume:

• [ ] Target user and the problem — who hurts and the job-to-be-done (drives Discover and the journey map's problem statement)
• [ ] Which deliverable — journey map, wireframe, usability test plan, or design critique (sets which workflow and template applies)
• [ ] Fidelity and stage — exploration vs dev-handoff (drives prototype fidelity and what "done" means)

Stop rule: ask only the 2-3 that most change the output. If the user says "just draft it," proceed and list your assumptions at the top of the artifact.

Workflow

• Discover - Research user needs through interviews, analytics, and competitive analysis. Create user journey maps and identify pain points. Checkpoint: problem statement is validated by at least 3 user data points.
• Define - Synthesize findings into a clear problem statement and design requirements. Build information architecture (card sorting, site maps). Checkpoint: IA has been validated via card sort or tree test.
• Develop - Ideate solutions through sketching and wireframing. Build prototypes at appropriate fidelity. Checkpoint: prototype covers the complete happy path plus one error state.
• Test - Run usability tests with 5-8 participants. Measure task completion rate, time on task, error rate, and SUS score. Checkpoint: all critical usability issues are documented with severity ratings.
• Deliver - Refine designs based on test findings. Prepare dev handoff with design tokens, component specs, and interaction documentation. Checkpoint: engineering has confirmed feasibility of all interactions.

Design Sprint (5-Day Format)

| Day | Activity | Output |

|-----|----------|--------|

| Monday | Map problem, interview experts | Challenge map, target area |

| Tuesday | Sketch solutions, Crazy 8s | Solution sketches |

| Wednesday | Decide, storyboard | Testable hypothesis |

| Thursday | Build prototype | Realistic clickable prototype |

| Friday | Test with 5 users | Validated/invalidated hypothesis |

User Journey Map Template

PERSONA: Sarah, Product Manager, goal: find analytics insights fast

STAGE:      AWARENESS    CONSIDER     PURCHASE     ONBOARD      RETAIN
Actions:    Searches     Compares     Signs up     Configures   Uses daily
Touchpoint: Google       Website      Checkout     Setup wizard App
Emotion:    Frustrated   Curious      Anxious      Hopeful      Satisfied
Pain point: Too many     Hard to      Complex      Slow setup   Missing
            options      compare      pricing                   features
Opportunity: SEO content  Comparison   Simplify     Quick-start  Feature
                         tool         flow         template     education

Information Architecture

Card Sorting Methods:

• Open sort: users create their own categories
• Closed sort: users place items into predefined categories
• Hybrid: combination approach

Example Site Map:

Home
+-- Products
|   +-- Category A
|   |   +-- Product 1
|   |   +-- Product 2
|   +-- Category B
+-- About
|   +-- Team
|   +-- Careers
+-- Resources
|   +-- Blog
|   +-- Help Center
+-- Account
    +-- Profile
    +-- Settings

UI Design Foundations

Design Principles

• Hierarchy - Visual weight guides attention via size, color, and contrast
• Consistency - Reuse patterns and components; maintain predictable interactions
• Feedback - Acknowledge every user action; show system status and loading states
• Accessibility - 4.5:1 color contrast minimum, focus indicators, screen reader support

Design Token System

/* Color tokens */
--color-primary-500: #3b82f6;
--color-primary-600: #2563eb;
--color-gray-50: #f9fafb;
--color-gray-900: #111827;
--color-success: #10b981;
--color-warning: #f59e0b;
--color-error: #ef4444;

/* Typography scale */
--text-sm: 0.875rem;   /* 14px */
--text-base: 1rem;     /* 16px */
--text-lg: 1.125rem;   /* 18px */
--text-xl: 1.25rem;    /* 20px */
--text-2xl: 1.5rem;    /* 24px */

/* Spacing (4px base unit) */
--space-1: 0.25rem;    /* 4px */
--space-2: 0.5rem;     /* 8px */
--space-4: 1rem;       /* 16px */
--space-6: 1.5rem;     /* 24px */
--space-8: 2rem;       /* 32px */

Component Structure

Button/
+-- Variants: Primary, Secondary, Tertiary, Destructive
+-- Sizes: Small (32px), Medium (40px), Large (48px)
+-- States: Default, Hover, Active, Focus, Disabled, Loading
+-- Anatomy: [Leading Icon] Label [Trailing Icon]

Component Design Tokens (JSON)

{
  "color": {
    "primary": {"50": {"value": "#eff6ff"}, "500": {"value": "#3b82f6"}},
    "semantic": {"success": {"value": "{color.green.500}"}, "error": {"value": "{color.red.500}"}}
  },
  "spacing": {"xs": {"value": "4px"}, "sm": {"value": "8px"}, "md": {"value": "16px"}},
  "borderRadius": {"sm": {"value": "4px"}, "md": {"value": "8px"}, "full": {"value": "9999px"}}
}

Example: Usability Test Plan

# Usability Test: New Checkout Flow

## Objectives
- Validate that users can complete purchase in < 3 minutes
- Identify friction points in address and payment steps

## Participants
- 6 users (3 new, 3 returning)
- Mix of desktop and mobile

## Tasks
1. "Find a laptop under $1,000 and add it to your cart" (browse + add)
2. "Complete the purchase using a credit card" (checkout flow)
3. "Change the shipping address on your order" (post-purchase edit)

## Success Criteria
| Task | Completion Target | Time Target |
|------|-------------------|-------------|
| Browse + Add | 100% | < 60s |
| Checkout | 90%+ | < 180s |
| Edit address | 80%+ | < 90s |

## Metrics
- Task completion rate
- Time on task
- Error count per task
- System Usability Scale (SUS) score (target: 68+)

Prototype Fidelity Guide

| Fidelity | Purpose | Tools | Timeline |

|----------|---------|-------|----------|

| Paper | Quick exploration | Paper, pen | Minutes |

| Low-fi | Flow validation | Figma, Sketch | Hours |

| Mid-fi | Usability testing | Figma | Days |

| High-fi | Dev handoff, final testing | Figma | Days-Weeks |

Scripts

# Design token generator
python scripts/token_generator.py --source tokens.json --output css/

# Accessibility checker
python scripts/a11y_checker.py --url https://example.com

# Asset exporter
python scripts/asset_export.py --figma-file FILE_ID --format svg,png

# Design QA report
python scripts/design_qa.py --spec spec.figma --impl https://staging.example.com

Reference Materials

• references/design_principles.md - Core design principles
• references/component_library.md - Component guidelines
• references/accessibility.md - Accessibility checklist
• references/research_methods.md - Research techniques

Tool Reference

design_critique.py

Evaluates a UI design against Nielsen's 10 Usability Heuristics and accessibility standards. Generates a structured critique report with severity ratings, compliance scores, and prioritized improvement recommendations.

| Flag | Type | Default | Description |

|------|------|---------|-------------|

| --checklist | flag | - | Generate empty checklist for evaluation |

| --answers | string | - | Path to completed checklist JSON file |

| --json | flag | False | Output as JSON |

python scripts/design_critique.py --checklist
python scripts/design_critique.py --checklist --json > checklist.json
python scripts/design_critique.py --answers completed_checklist.json
python scripts/design_critique.py --answers completed_checklist.json --json

journey_mapper.py

Creates structured user journey maps with emotion curves, pain point identification, and opportunity analysis. Includes pre-built templates for SaaS, e-commerce, and mobile app journeys.

| Flag | Type | Default | Description |

|------|------|---------|-------------|

| --template, -t | choice | - | Pre-built template: saas, ecommerce, mobile_app |

| --stages, -s | string | - | Path to custom stages JSON file |

| --json | flag | False | Output as JSON |

python scripts/journey_mapper.py --template saas
python scripts/journey_mapper.py --template ecommerce --json
python scripts/journey_mapper.py --stages custom_journey.json

usability_scorer.py

Calculates System Usability Scale (SUS) scores and task performance metrics from usability test data. Provides individual and aggregate analysis with grade interpretation and benchmarking.

| Flag | Type | Default | Description |

|------|------|---------|-------------|

| action | positional | - | "sample" to create sample CSV files |

| --sus-responses | string | - | CSV with SUS responses (participant, q1-q10) |

| --task-data | string | - | CSV with task data (participant, task, completed, time_seconds, errors) |

| --json | flag | False | Output as JSON |

python scripts/usability_scorer.py sample
python scripts/usability_scorer.py --sus-responses responses.csv
python scripts/usability_scorer.py --task-data tasks.csv
python scripts/usability_scorer.py --sus-responses responses.csv --task-data tasks.csv --json

Troubleshooting

| Problem | Cause | Solution |

|---------|-------|----------|

| SUS score below 68 (benchmark) | Significant usability issues | Focus on critical severity findings from design_critique first |

| Low task completion rate (<80%) | Task flow too complex or unclear | Simplify flow; add progressive disclosure; reduce steps |

| Users cannot find features | Poor information architecture | Conduct card sorting; redesign navigation; add search |

| High error rate on forms | Insufficient validation and guidance | Add inline validation, smart defaults, and contextual help |

| Inconsistent design across screens | Missing or ignored design system | Audit with design_critique; enforce token usage |

| Usability test participants are unrepresentative | Poor recruitment criteria | Screen for target persona match; mix new and returning users |

| Journey map emotions are flat | Insufficient research data | Conduct deeper interviews; observe real usage sessions |

Success Criteria

| Criterion | Target | How to Measure |

|-----------|--------|----------------|

| SUS score | >68 (industry average), target >80 | usability_scorer aggregate score |

| Task completion rate | >85% for core flows | usability_scorer task metrics |

| Time on task | <2x expected duration | usability_scorer avg_time_seconds |

| Design critique compliance | >80% checklist pass rate | design_critique compliance_score |

| Accessibility compliance | WCAG AA on all screens | design_critique accessibility section |

| Journey map coverage | All key personas mapped | Count of completed journey maps |

| Usability test cadence | Test every sprint or release | Count of tests per quarter |

Scope & Limitations

In scope:

• Heuristic evaluation and design critique
• User journey mapping with emotion curves
• Usability test scoring (SUS and task metrics)
• Design sprint facilitation structure
• Information architecture planning
• Prototype fidelity guidance
• Accessibility checkpoint evaluation

Out of scope:

• Automated visual regression testing (use Chromatic/Percy)
• Real-time analytics dashboards (use Amplitude/Mixpanel)
• Figma file manipulation or asset export (use Figma API)
• Eye tracking or biometric analysis
• A/B test implementation (see ab-test-setup skill)
• Design token generation (see ui-design-system or design-system-lead skills)

Integration Points

| Tool / Platform | Integration Method | Use Case |

|-----------------|-------------------|----------|

| Figma | Journey map and critique findings as design specs | Translate research into design changes |

| Maze / UserTesting | Export task data CSV for usability_scorer | Score test results from remote testing platforms |

| Dovetail / Condens | Export interview themes for journey_mapper | Build journey maps from research repositories |

| Jira / Linear | design_critique JSON priorities as tickets | Track usability improvements in sprint backlog |

| Notion / Confluence | Human-readable output from all tools | Document research findings and design decisions |

| Miro / FigJam | journey_mapper JSON output | Collaborative journey map workshops |