Penpot UI/UX Design Guide

Create professional, user-centered designs in Penpot using the penpot/penpot-mcp MCP server and proven UI/UX principles.

Available MCP Tools

Tool	Purpose
mcp__penpot__execute_code	Run JavaScript in Penpot plugin context to create/modify designs
mcp__penpot__export_shape	Export shapes as PNG/SVG for visual inspection
mcp__penpot__import_image	Import images (icons, photos, logos) into designs
mcp__penpot__penpot_api_info	Retrieve Penpot API documentation

MCP Server Setup

The Penpot MCP tools require the penpot/penpot-mcp server running locally. For detailed installation and troubleshooting, see setup-troubleshooting.md.

Before Setup: Check If Already Running

Always check if the MCP server is already available before attempting setup:

1. Try calling a tool first: Attempt mcp__penpot__penpot_api_info - if it succeeds, the server is running and connected. No setup needed.

2. If the tool fails, ask the user:

   "The Penpot MCP server doesn't appear to be connected. Is the server already installed and running? If so, I can help troubleshoot. If not, I can guide you through the setup."

3. Only proceed with setup instructions if the user confirms the server is not installed.

Quick Start (Only If Not Installed)

# Clone and install
git clone https://github.com/penpot/penpot-mcp.git
cd penpot-mcp
npm install

# Build and start servers
npm run bootstrap

Then in Penpot:

1. Open a design file
2. Go to Plugins → Load plugin from URL
3. Enter: http://localhost:4400/manifest.json
4. Click "Connect to MCP server" in the plugin UI

VS Code Configuration

Add to settings.json:

{
  "mcp": {
    "servers": {
      "penpot": {
        "url": "http://localhost:4401/sse"
      }
    }
  }
}

Troubleshooting (If Server Is Installed But Not Working)

Issue	Solution
Plugin won't connect	Check servers are running (npm run start:all in penpot-mcp dir)
Browser blocks localhost	Allow local network access prompt, or disable Brave Shield, or try Firefox
Tools not appearing in client	Restart VS Code/Claude completely after config changes
Tool execution fails/times out	Ensure Penpot plugin UI is open and shows "Connected"
"WebSocket connection failed"	Check firewall allows ports 4400, 4401, 4402

Quick Reference

Task	Reference File
MCP server installation & troubleshooting	setup-troubleshooting.md
Component specs (buttons, forms, nav)	component-patterns.md
Accessibility (contrast, touch targets)	accessibility.md
Screen sizes & platform specs	platform-guidelines.md

Core Design Principles

The Golden Rules

1. Clarity over cleverness: Every element must have a purpose
2. Consistency builds trust: Reuse patterns, colors, and components
3. User goals first: Design for tasks, not features
4. Accessibility is not optional: Design for everyone
5. Test with real users: Validate assumptions early

Visual Hierarchy (Priority Order)

1. Size: Larger = more important
2. Color/Contrast: High contrast draws attention
3. Position: Top-left (LTR) gets seen first
4. Whitespace: Isolation emphasizes importance
5. Typography weight: Bold stands out

Design Workflow

1. Check for design system first: Ask user if they have existing tokens/specs, or discover from current Penpot file
2. Understand the page: Call mcp__penpot__execute_code with penpotUtils.shapeStructure() to see hierarchy
3. Find elements: Use penpotUtils.findShapes() to locate elements by type or name
4. Create/modify: Use penpot.createBoard(), penpot.createRectangle(), penpot.createText() etc.
5. Apply layout: Use addFlexLayout() for responsive containers
6. Validate: Call mcp__penpot__export_shape to visually check your work

Design System Handling

Before creating designs, determine if the user has an existing design system:

1. Ask the user: "Do you have a design system or brand guidelines to follow?"
2. Discover from Penpot: Check for existing components, colors, and patterns

// Discover existing design patterns in current file
const allShapes = penpotUtils.findShapes(() => true, penpot.root);

// Find existing colors in use
const colors = new Set();
allShapes.forEach(s => {
  if (s.fills) s.fills.forEach(f => colors.add(f.fillColor));
});

// Find existing text styles (font sizes, weights)
const textStyles = allShapes
  .filter(s => s.type === 'text')
  .map(s => ({ fontSize: s.fontSize, fontWeight: s.fontWeight }));

// Find existing components
const components = penpot.library.local.components;

return { colors: [...colors], textStyles, componentCount: components.length };

If user HAS a design system:

• Use their specified colors, spacing, typography
• Match their existing component patterns
• Follow their naming conventions

If user has NO design system:

• Use the default tokens below as a starting point
• Offer to help establish consistent patterns
• Reference specs in component-patterns.md

Key Penpot API Gotchas

• width/height are READ-ONLY → use shape.resize(w, h)
• parentX/parentY are READ-ONLY → use penpotUtils.setParentXY(shape, x, y)
• Use insertChild(index, shape) for z-ordering (not appendChild)
• Flex children array order is REVERSED for dir="column" or dir="row"
• After text.resize(), reset growType to "auto-width" or "auto-height"

Positioning New Boards

Always check existing boards before creating new ones to avoid overlap:

// Find all existing boards and calculate next position
const boards = penpotUtils.findShapes(s => s.type === 'board', penpot.root);
let nextX = 0;
const gap = 100; // Space between boards

if (boards.length > 0) {
  // Find rightmost board edge
  boards.forEach(b => {
    const rightEdge = b.x + b.width;
    if (rightEdge + gap > nextX) {
      nextX = rightEdge + gap;
    }
  });
}

// Create new board at calculated position
const newBoard = penpot.createBoard();
newBoard.x = nextX;
newBoard.y = 0;
newBoard.resize(375, 812);

Board spacing guidelines:

• Use 100px gap between related screens (same flow)
• Use 200px+ gap between different sections/flows
• Align boards vertically (same y) for visual organization
• Group related screens horizontally in user flow order

Default Design Tokens

Use these defaults only when user has no design system. Always prefer user's tokens if available.

Spacing Scale (8px base)

Token	Value	Usage
spacing-xs	4px	Tight inline elements
spacing-sm	8px	Related elements
spacing-md	16px	Default padding
spacing-lg	24px	Section spacing
spacing-xl	32px	Major sections
spacing-2xl	48px	Page-level spacing

Typography Scale

Level	Size	Weight	Usage
Display	48-64px	Bold	Hero headlines
H1	32-40px	Bold	Page titles
H2	24-28px	Semibold	Section headers
H3	20-22px	Semibold	Subsections
Body	16px	Regular	Main content
Small	14px	Regular	Secondary text
Caption	12px	Regular	Labels, hints

Color Usage

Purpose	Recommendation
Primary	Main brand color, CTAs
Secondary	Supporting actions
Success	#22C55E range (confirmations)
Warning	#F59E0B range (caution)
Error	#EF4444 range (errors)
Neutral	Gray scale for text/borders

Common Layouts

Mobile Screen (375×812)

┌─────────────────────────────┐
│ Status Bar (44px)           │
├─────────────────────────────┤
│ Header/Nav (56px)           │
├─────────────────────────────┤
│                             │
│ Content Area                │
│ (Scrollable)                │
│ Padding: 16px horizontal    │
│                             │
├─────────────────────────────┤
│ Bottom Nav/CTA (84px)       │
└─────────────────────────────┘

Desktop Dashboard (1440×900)

┌──────┬──────────────────────────────────┐
│      │ Header (64px)                    │
│ Side │──────────────────────────────────│
│ bar  │ Page Title + Actions             │
│      │──────────────────────────────────│
│ 240  │ Content Grid                     │
│ px   │ ┌─────┐ ┌─────┐ ┌─────┐ ┌─────┐ │
│      │ │Card │ │Card │ │Card │ │Card │ │
│      │ └─────┘ └─────┘ └─────┘ └─────┘ │
│      │                                  │
└──────┴──────────────────────────────────┘

Component Checklist

Buttons

• Clear, action-oriented label (2-3 words)
• Minimum touch target: 44×44px
• Visual states: default, hover, active, disabled, loading
• Sufficient contrast (3:1 against background)
• Consistent border radius across app

Forms

• Labels above inputs (not just placeholders)
• Required field indicators
• Error messages adjacent to fields
• Logical tab order
• Input types match content (email, tel, etc.)

Navigation

• Current location clearly indicated
• Consistent position across screens
• Maximum 7±2 top-level items
• Touch-friendly on mobile (48px targets)

Accessibility Quick Checks

1. Color contrast: Text 4.5:1, Large text 3:1
2. Touch targets: Minimum 44×44px
3. Focus states: Visible keyboard focus indicators
4. Alt text: Meaningful descriptions for images
5. Hierarchy: Proper heading levels (H1→H2→H3)
6. Color independence: Never rely solely on color

Design Review Checklist

Before finalizing any design:

• Visual hierarchy is clear
• Consistent spacing and alignment
• Typography is readable (16px+ body text)
• Color contrast meets WCAG AA
• Interactive elements are obvious
• Mobile-friendly touch targets
• Loading/empty/error states considered
• Consistent with design system

Validating Designs

Use these validation approaches with mcp__penpot__execute_code:

Check	Method
Elements outside bounds	penpotUtils.analyzeDescendants() with isContainedIn()
Text too small (<12px)	penpotUtils.findShapes() filtering by fontSize
Missing contrast	Call mcp__penpot__export_shape and visually inspect
Hierarchy structure	penpotUtils.shapeStructure() to review nesting

Export CSS

Use penpot.generateStyle(selection, { type: 'css', includeChildren: true }) via mcp__penpot__execute_code to extract CSS from designs.

Tips for Great Designs

1. Start with content: Real content reveals layout needs
2. Design mobile-first: Constraints breed creativity
3. Use a grid: 8px base grid keeps things aligned
4. Limit colors: 1 primary + 1 secondary + neutrals
5. Limit fonts: 1-2 typefaces maximum
6. Embrace whitespace: Breathing room improves comprehension
7. Be consistent: Same action = same appearance everywhere
8. Provide feedback: Every action needs a response