| name | generative-ui |
| description | Design system and guidelines for Claude's built-in generative UI — the show_widget tool that renders interactive HTML/SVG widgets inline in claude.ai conversations. This skill provides the complete Anthropic "Imagine" design system so Claude produces high-quality widgets without needing to call read_me first. Use this skill whenever the user asks to visualize data, create an interactive chart, build a dashboard, render a diagram, draw a flowchart, show a mockup, create an interactive explainer, or produce any visual content beyond plain text or markdown. Triggers include: "show me", "visualize", "draw", "chart", "dashboard", "diagram", "flowchart", "widget", "interactive", "mockup", "illustrate", "explain how X works" (with visual), or any request for visual/interactive output. Also triggers when the user wants to display financial data visually, create comparison grids, or build tools with sliders, toggles, or live-updating displays.
|
Generative UI Skill
This skill contains the complete design system for Claude's built-in show_widget tool — the generative UI feature that renders interactive HTML/SVG widgets inline in claude.ai conversations. The guidelines below are the actual Anthropic "Imagine — Visual Creation Suite" design rules, extracted so you can produce high-quality widgets directly without needing the read_me setup call.
How it works: On claude.ai, Claude has access to the show_widget tool which renders raw HTML/SVG fragments inline in the conversation. This skill provides the design system, templates, and patterns to use it well.
Step 1: Pick the Right Visual Type
Route on the verb, not the noun. Same subject, different visual depending on what was asked:
| User says | Type | Format |
|---|
| "how does X work" | Illustrative diagram | SVG |
| "X architecture" | Structural diagram | SVG |
| "what are the steps" | Flowchart | SVG |
| "explain compound interest" | Interactive explainer | HTML |
| "compare these options" | Comparison grid | HTML |
| "show revenue chart" | Chart.js chart | HTML |
| "create a contact card" | Data record | HTML |
| "draw a sunset" | Art/illustration | SVG |
Step 2: Build the Widget
Structure (strict order)
<style> → HTML content → <script>
Output streams token-by-token. Styles must exist before the elements they target, and scripts must run after the DOM is ready.
Philosophy
- Seamless: Users shouldn't notice where the host UI ends and your widget begins
- Flat: No gradients, mesh backgrounds, noise textures, or decorative effects. Clean flat surfaces
- Compact: Show the essential inline. Explain the rest in text
- Text goes in your response, visuals go in the tool — all explanatory text, descriptions, and summaries must be written as normal response text OUTSIDE the tool call. The tool output should contain ONLY the visual element
Core Rules
- No
<!-- comments --> or /* comments */ (waste tokens, break streaming)
- No font-size below 11px
- No emoji — use CSS shapes or SVG paths
- No gradients, drop shadows, blur, glow, or neon effects
- No dark/colored backgrounds on outer containers (transparent only — host provides the bg)
- Typography: two weights only: 400 regular, 500 medium. Never use 600 or 700. Headings: h1=22px, h2=18px, h3=16px — all font-weight 500. Body text=16px, weight 400, line-height 1.7
- Sentence case always. Never Title Case, never ALL CAPS
- No mid-sentence bolding — entity names go in
code style not bold
- No
<!DOCTYPE>, <html>, <head>, or <body> — just content fragments
- No
position: fixed — use normal-flow layouts
- No tabs, carousels, or
display: none sections during streaming
- No nested scrolling — auto-fit height
- Corners:
border-radius: var(--border-radius-lg) for cards, var(--border-radius-md) for elements
- No rounded corners on single-sided borders (border-left, border-top)
- Round every displayed number — use
Math.round(), .toFixed(n), or Intl.NumberFormat
CDN Allowlist (CSP-enforced)
External resources may ONLY load from:
cdnjs.cloudflare.comcdn.jsdelivr.netunpkg.comesm.sh
All other origins are blocked — the request silently fails.
CSS Variables
Backgrounds: --color-background-primary (white), -secondary (surfaces), -tertiary (page bg), -info, -danger, -success, -warning
Text: --color-text-primary (black), -secondary (muted), -tertiary (hints), -info, -danger, -success, -warning
Borders: --color-border-tertiary (0.15α, default), -secondary (0.3α, hover), -primary (0.4α), semantic -info/-danger/-success/-warning
Typography: --font-sans, --font-serif, --font-mono
Layout: --border-radius-md (8px), --border-radius-lg (12px), --border-radius-xl (16px)
All auto-adapt to light/dark mode.
Dark mode is mandatory — every color must work in both modes:
- In HTML: always use CSS variables for text. Never hardcode colors like
color: #333
- In SVG: use pre-built color classes (
c-blue, c-teal, etc.) — they handle light/dark automatically
- Mental test: if the background were near-black, would every text element still be readable?
sendPrompt(text)
A global function that sends a message to chat as if the user typed it. Use it when the user's next step benefits from Claude thinking. Handle filtering, sorting, toggling, and calculations in JS instead.
Step 3: Render with show_widget
The show_widget tool is built into claude.ai — no activation needed. Pass your widget code directly:
{
"title": "snake_case_widget_name",
"widget_code": "<style>...</style>\n<div>...</div>\n<script>...</script>"
}
| Parameter | Type | Required | Description |
|---|
title | string | Yes | Snake_case identifier for the widget |
widget_code | string | Yes | HTML or SVG code. For SVG: start with <svg>. For HTML: content fragment |
For SVG output: start widget_code with <svg — it will be auto-detected and wrapped appropriately.
Step 4: Chart.js Template
For charts, use onload callback pattern to handle script load ordering:
<div style="display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); gap: 12px;">
<div style="background: var(--color-background-secondary); border-radius: var(--border-radius-md); padding: 1rem;">
<div style="font-size: 13px; color: var(--color-text-secondary);">Label</div>
<div style="font-size: 24px; font-weight: 500;" id="stat1">—</div>
</div>
</div>
<div style="position: relative; width: 100%; height: 300px; margin-top: 1rem;">
<canvas id="myChart"></canvas>
</div>
<div style="display: flex; align-items: center; gap: 12px; margin-top: 1rem;">
<label style="font-size: 14px; color: var(--color-text-secondary);">Parameter</label>
<input type="range" min="0" max="100" value= = = = />
50
Chart.js rules:
- Canvas cannot resolve CSS variables — use hardcoded hex
- Set height ONLY on the wrapper div, never on canvas itself
- Always
responsive: true, maintainAspectRatio: false
- Always disable default legend, build custom HTML legends
- Number formatting:
-$5M not $-5M (negative sign before currency symbol)
- Use
onload="initChart()" on CDN script tag + if (window.Chart) initChart(); as fallback
Step 5: SVG Diagram Template
For flowcharts and diagrams, use SVG with pre-built classes:
<svg width="100%" viewBox="0 0 680 H">
<defs>
<marker id="arrow" viewBox="0 0 10 10" refX="8" refY="5" markerWidth="6" markerHeight="6" orient="auto-start-reverse">
<path d="M2 1L8 5L2 9" fill="none" stroke="context-stroke" stroke-width="1.5" stroke-linecap="round" stroke-linejoin="round"/>
</marker>
</defs>
<g class="node c-blue" onclick="sendPrompt('Tell me more about this')">
<rect x="250" y="40" width="180" height="44" rx="8" =/>
Step one
Step two
Processes the input
SVG rules:
- ViewBox always 680px wide (
viewBox="0 0 680 H"). Set H to fit content + 40px padding
- Safe area: x=40 to x=640, y=40 to y=(H-40)
- Pre-built classes:
t (14px), ts (12px secondary), th (14px medium 500), box, node, arr, c-{color}
- Every
<text> element must carry a class (t, ts, or th)
- Use
dominant-baseline="central" for vertical text centering in boxes
- Connector paths need
fill="none" (SVG defaults to fill: black)
- Stroke width: 0.5px for borders and edges
- Make all nodes clickable:
onclick="sendPrompt('...')"
Step 6: Interactive Explainer Template
For interactive explainers (sliders, live calculations, inline SVG):
<div style="display: flex; align-items: center; gap: 12px; margin: 0 0 1.5rem;">
<label style="font-size: 14px; color: var(--color-text-secondary);">Years</label>
<input type="range" min="1" max="40" value="20" id="years" style="flex: 1;" />
<span style="font-size: 14px; font-weight: 500; min-width: 24px;" id="years-out">20</span>
</div>
<div style="display: flex; align-items: baseline; gap: 8px; margin: 0 0 1.5rem;">
<span style="font-size: 14px; color: var(--color-text-secondary);">$1,000 →</span>
<span style="font-size: 24px; font-weight: 500;" id="result">$3,870</span>
</div>
<div style="margin: 2rem 0; position: relative; height: 240px;">
Use sendPrompt() to let users ask follow-ups: sendPrompt('What if I increase the rate to 10%?')
Step 7: Respond to the User
After rendering the widget, briefly explain:
- What the widget shows
- How to interact with it (which controls do what)
- One key insight from the data
Keep it concise — the widget speaks for itself.
Reference Files
references/design_system.md — Complete color palette (9 ramps × 7 stops), CSS variables, UI component patterns, metric cards, layout rulesreferences/svg_and_diagrams.md — SVG viewBox setup, font calibration, pre-built classes, flowchart/structural/illustrative diagram patterns with examplesreferences/chart_js.md — Chart.js configuration, script load ordering, canvas sizing, legend patterns, dashboard layout
Read the relevant reference file when you need specific design tokens, SVG coordinate math, or Chart.js configuration details.
