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.

Workflow

1. 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.
2. 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.
3. Develop - Ideate solutions through sketching and wireframing. Build prototypes at appropriate fidelity. Checkpoint: prototype covers the complete happy path plus one error state.
4. 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.
5. 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

1. Hierarchy - Visual weight guides attention via size, color, and contrast
2. Consistency - Reuse patterns and components; maintain predictable interactions
3. Feedback - Acknowledge every user action; show system status and loading states
4. 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

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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

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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

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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)

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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