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:

Try calling a tool first: Attempt mcp__penpot__penpot_api_info

• if it succeeds, the server is running and connected. No setup needed.

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."

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:

• Open a design file

• Go to Plugins → Load plugin from URL

• Enter: http://localhost:4400/manifest.json

• 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

• Clarity over cleverness: Every element must have a purpose

• Consistency builds trust: Reuse patterns, colors, and components

• User goals first: Design for tasks, not features

• Accessibility is not optional: Design for everyone

• Test with real users: Validate assumptions early

Visual Hierarchy (Priority Order)

• Size: Larger = more important

• Color/Contrast: High contrast draws attention

• Position: Top-left (LTR) gets seen first

• Whitespace: Isolation emphasizes importance

• Typography weight: Bold stands out

Design Workflow

• Check for design system first: Ask user if they have existing tokens/specs, or discover from current Penpot file

• Understand the page: Call mcp__penpot__execute_code with penpotUtils.shapeStructure() to see hierarchy

• Find elements: Use penpotUtils.findShapes() to locate elements by type or name

• Create/modify: Use penpot.createBoard() , penpot.createRectangle() , penpot.createText() etc.

• Apply layout: Use addFlexLayout() for responsive containers

• 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:

• Ask the user: "Do you have a design system or brand guidelines to follow?"

• 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

• Color contrast: Text 4.5:1, Large text 3:1

• Touch targets: Minimum 44×44px

• Focus states: Visible keyboard focus indicators

• Alt text: Meaningful descriptions for images

• Hierarchy: Proper heading levels (H1→H2→H3)

• 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

• Start with content: Real content reveals layout needs

• Design mobile-first: Constraints breed creativity

• Use a grid: 8px base grid keeps things aligned

• Limit colors: 1 primary + 1 secondary + neutrals

• Limit fonts: 1-2 typefaces maximum

• Embrace whitespace: Breathing room improves comprehension

• Be consistent: Same action = same appearance everywhere

• Provide feedback: Every action needs a response