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“I haven’t written a single line of front-end code in 3 months”: How Notion’s design team uses Claude Code to prototype

51 min episode · 2 min read
·
Brian Levin

Episode

51 min

Read time

2 min

Topics

Design & UX, Artificial Intelligence, Crypto & Web3

AI-Generated Summary

Key Takeaways

  • Shared Prototype Repository: Build a single Next.js repo where each designer gets a namespaced directory for their prototypes. This eliminates redundant setup, surfaces teammates' work in one list, and lets anyone copy useful code across prototypes by simply instructing Claude to pull from another designer's directory.
  • Claude.md Layering Strategy: Maintain two Claude context files: a committed global claude.md defining shared tooling, project structure, and rules like "don't modify other users' files," plus a personal claude.local.md per machine that sets the current user's directory and individual preferences. This combination keeps team consistency while allowing personal customization.
  • Teach Claude to Self-Verify: Every time Claude asks the user to check something — browser output, CI status, TypeScript errors — convert that request into a permanent instruction. Connect Playwright or Chrome DevTools MCP so Claude opens the browser, clicks elements, and confirms functionality itself, reducing interruptions and enabling longer unattended runs.
  • Figma-to-Code Verification Loop: A custom slash command called `/figma` force-invokes the Figma MCP, extracts the design, implements it, then enters a verification loop comparing the browser output against the original Figma frame using Chrome DevTools MCP. The loop repeats up to three iterations with no changes before stopping, reaching roughly 80% accuracy on the first pass.
  • Icon Hallucination Fix via Scripted Skills: Claude consistently guesses wrong icon names, defaulting to generic labels like "search icon" instead of the actual codebase name like "magnifying glass icon." A Claude skill called `find-icon` runs a TypeScript script that searches all 5,000 icons programmatically, including synonyms, before any implementation — eliminating repeated broken imports without manual intervention.

What It Covers

Brian Levin, designer at Notion AI, demonstrates how he built a shared Next.js prototype playground for Notion's design team, enabling code-first prototyping via Claude Code. The system uses shared components, Claude slash commands, skills, and MCP integrations to help 5–10 designers prototype directly in the browser without writing code manually.

Key Questions Answered

  • Shared Prototype Repository: Build a single Next.js repo where each designer gets a namespaced directory for their prototypes. This eliminates redundant setup, surfaces teammates' work in one list, and lets anyone copy useful code across prototypes by simply instructing Claude to pull from another designer's directory.
  • Claude.md Layering Strategy: Maintain two Claude context files: a committed global claude.md defining shared tooling, project structure, and rules like "don't modify other users' files," plus a personal claude.local.md per machine that sets the current user's directory and individual preferences. This combination keeps team consistency while allowing personal customization.
  • Teach Claude to Self-Verify: Every time Claude asks the user to check something — browser output, CI status, TypeScript errors — convert that request into a permanent instruction. Connect Playwright or Chrome DevTools MCP so Claude opens the browser, clicks elements, and confirms functionality itself, reducing interruptions and enabling longer unattended runs.
  • Figma-to-Code Verification Loop: A custom slash command called `/figma` force-invokes the Figma MCP, extracts the design, implements it, then enters a verification loop comparing the browser output against the original Figma frame using Chrome DevTools MCP. The loop repeats up to three iterations with no changes before stopping, reaching roughly 80% accuracy on the first pass.
  • Icon Hallucination Fix via Scripted Skills: Claude consistently guesses wrong icon names, defaulting to generic labels like "search icon" instead of the actual codebase name like "magnifying glass icon." A Claude skill called `find-icon` runs a TypeScript script that searches all 5,000 icons programmatically, including synonyms, before any implementation — eliminating repeated broken imports without manual intervention.

Notable Moment

Levin reveals that prototype playground originated because he was designing Notion AI chat flows entirely in Figma, mapping out perfect golden-path conversations. Once engineers built them, models behaved unpredictably — getting stuck, asking follow-ups, producing errors — exposing how static design tools cannot capture real AI model behavior.

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Episode Transcript

Way I think about designing b to b SaaS is you want your designs to encounter reality as early as possible. I've always been into prototyping, and then all of a sudden these AI coding tools come along, and now I can prototype faster. I can prototype in production. So explain to us what this prototype playground is. It's just the Next. Js app. All of our prototypes are in one place. Seeing what other people are working on is really fun and interesting. And oftentimes, you spot cool ideas, and you're like, oh, I wanna try that. The code is all in one place. It's just in one repo, and so I can just yoink cool ideas from other people's prototypes and incorporate them into mine. Every time somebody is, like, a little anti AI assisted coding, I'm like, do you know that I used to have to walk uphill both ways for my CSS? It was not fun to do this. I mean, even just sitting here watching this, I still just find this magical. Welcome back to How I AI. I'm Claire Vell, product leader and AI obsessive here on a mission to help you build better with these new tools. Today, we have a designer centric episode with Brian Levin, designer at Notion AI, who's gonna show us how he set up a prototype playground for the entire Notion design team to vibe code using Cloud Code any prototype they need. This is a great one for someone looking to either shift their design organization into a code first prototyping mode or learn some advanced techniques with Cloud Code. Let's get to it. This episode is brought to you by WorkOS. AI has already changed how we work. Tools are helping teams write better code, analyze customer data, and even handle support tickets automatically. But there's a catch. These tools only work well when they have deep access to company systems. Your Copilot needs to see your entire code base. Your chatbot needs to search across internal docs. And for enterprise buyers, that raises serious security concerns. That's why these apps face intense IT scrutiny from day one. To pass, they need secure authentication, access controls, audit logs, the whole suite of enterprise features. Building all that from scratch, it's a massive lift. That's where Work OS comes in. Work OS gives you drop in APIs for enterprise features so your app can become enterprise ready and scale up market faster. Think of it like Stripe for enterprise features. OpenAI, Perplexity, and Cursor are already using Work OS to move faster and meet enterprise demands. Join them and hundreds of other industry leaders at workos.com. Start building today. Brian, welcome to How I AI. What I am so excited about in terms of our conversation today is you're gonna show us about how one of the best designed products out there, Notion, is being designed by people like you using these new AI tools like Cloud …

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Books, tools, and gear mentioned in this episode

SignalCast may earn commission on purchases via these links.

Tools

  • by Vercel

    Brian Levin, designer at Notion AI, demonstrates how he built a shared Next.js prototype playground for Notion's design team.
  • by Google

    Connect Playwright or Chrome DevTools MCP so Claude opens the browser, clicks elements, and confirms functionality itself.
  • by WorkOS

    💼 SPONSORS ["WorkOS", "https://workos.com"]
  • by Orkes

    💼 SPONSORS ["Orkes", "https://orkes.io"]
  • by Microsoft

    Connect Playwright or Chrome DevTools MCP so Claude opens the browser, clicks elements, and confirms functionality itself.
  • Claude CodeRecommended

    by Anthropic

    Brian Levin, designer at Notion AI, demonstrates how he built a shared Next.js prototype playground for Notion's design team, enabling code-first prototyping via Claude Code.
  • by Figma

    A custom slash command called `/figma` force-invokes the Figma MCP, extracts the design, implements it, then enters a verification loop.

company

  • Brian Levin, designer at Notion AI, demonstrates how he built a shared Next.js prototype playground for Notion's design team.

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