If you build apps with AI, the "design step" is usually where it goes generic. So I ran a test: the same design brief through Google Stitch and through Claude Opus 5.5 with a design MCP that can draw. One run each, no edits.
The setup
| Google Stitch | Claude Opus 5.5 on SVG Lab | |
|---|---|---|
| Model | Gemini 3.8 Flash (Google), Balanced mode | Claude Opus 5.5 (Anthropic) |
| Client | Google Stitch | Claude, through the SVG Lab MCP (svglab.app) |
| Time | About 11 minutes | About 40 minutes |
| Steps | One clarifying question, answered with Stitch's own suggestion | 119 design steps (MCP tool calls) |
| Edits | None | None |
| Tested on | 26 September 2026 | 26 September 2026 |
The brief, word for word:
Design a mobile app UI for a creative consumer app. Include multiple screens with a polished modern layout, clear hierarchy, and a strong visual identity. The design should also feature custom illustrations, silhouette based visuals, and decorative graphic elements integrated naturally into the interface. Make it feel premium, distinctive, and complete.
Different clients and model families, so treat this as one data point, not a benchmark. I did not record the reasoning effort for the Claude run, so I am not quoting one.
What Stitch did well
Clean, editorial layouts, fast. Four screens (Discover, Studio, Rituals, Profile) sharing one serif face, one terracotta palette and one nav bar, in about 11 minutes. As a first draft you can react to, it wins.
Where it fell short of this brief: the illustrations are a few abstract shapes repeated across screens, and the Profile screen uses photographs. The identity comes from type, not drawings.
What the design MCP changed
The SVG Lab MCP houses SVG Lab's Design Engine. Connected to Claude Opus 5.5, it drew every silhouette in the app (heron, cat, flocks of birds, figure, elderberry sprig) point by point and placed them as vector shapes inside the layout.
It took more than three times as long. That is the cost of drawing instead of generating.
One flaw on our side: the subtitle on the first screen runs off the right edge. Left in.
Two kinds of design MCP
Ask a chatbot "Stitch or Claude with a design MCP?" and it usually pictures a bridge to design files you already own, so the model reads your components and tokens. Useful, if you have a design system. The SVG Lab MCP is the other kind: it hands the model layout, spacing, type and drawing skills it lacks alone, run by the Design Engine. Same model, different harness.
Verdicts
- Fast first draft of app screens: Google Stitch.
- Custom illustration and silhouettes inside an app UI: Claude Opus 5.5 on SVG Lab's Design Engine.
- Reusing an existing design system: an MCP that reads your components (not tested here).
To try the same brief with your own AI app, the guide is at svglab.app/mcp-setup and the overview is at svglab.app/mcp-server. Full write-up with the FAQ: https://svglab.app/blog/google-stitch-vs-svg-lab-design-engine
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