name

design-to-frontend

description

Pipeline for taking an existing Claude Design prototype — an in-browser React + babel-standalone HTML mockup (one HTML entry loads src/*.jsx + design tokens, no build step) — toward a polished, dev-ready frontend, in four activities: INGEST it (map pages/components/tokens, find missing assets, write a DESIGN.md); GENERATE its missing image assets (mascots/banners/icons via the OpenAI image API — gpt-image-1.5, transparent backgrounds — placed by filename convention); BUILD new pages/components/features; POLISH it (visual hierarchy, states, mobile, i18n, a11y) — each verified in a real browser. Trigger when the user works on such a prototype (or names one like "new ui 2.0.html") and asks to ingest it, find/fill its missing image assets, preview it locally, build a page or feature in it, or polish/打磨 it — even if just one. NOT for: generic image generation, building a Next.js/Vite/Vue app from scratch, web perf/SEO, backend, logo design, file conversion, or design tools like Figma.

Design → Frontend pipeline

Turn a Claude-generated design prototype into a polished, dev-ready frontend across four activities — ingest, generate, build, polish — each a standalone entry point. They map to three reference guides (build & polish share one). Figure out which the request needs, then read the matching guide.

Guide	When the request is about…	Read
1 · Ingest design	"parse this design", "what's in the prototype", building a spec/DESIGN.md, mapping pages/components/tokens, finding what assets are missing	references/1-ingest-design.md
2 · Generate assets	"generate/make the missing mascots/banners/icons", transparent-background images, filling an asset pool, gpt-image-1.5, converting to WebP	references/2-generate-assets.md
3 · Build & polish	building a new page/component/feature on the prototype, OR "polish/refine/打磨 this page" — visual hierarchy, states/validation, mobile/i18n/a11y, "make a preview and check it"	references/3-polish-frontend.md

Most real requests touch one activity. A from-scratch run goes ingest → generate → build → polish. Don't read a guide you don't need.

The substrate you're working in

Claude Design prototypes are single-file-ish in-browser React apps, not a build pipeline. Knowing this shape prevents most mistakes:

React 18 + @babel/standalone loaded from CDN. One HTML entry (e.g. new ui 2.0.html) lists every <script type="text/babel" src="src/*.jsx"> in load order. There is no bundler, no npm run build — you edit .jsx and reload.
Components are plain function declarations exported with Object.assign(window, { Foo, Bar }) and referenced as window.Foo or bare globals across files (classic-script global scope). Adding a new component = write the function, add it to a window assign, and register its file in the HTML.
Design tokens (colors, fonts, spacing) live in a tokens module (e.g. getTokens('cyber','dark')). Read tokens before styling so new work matches; never hardcode a color that a token already names.
Assets are referenced by path and often by naming convention (filename pools) so the UI auto-picks them — see phase 2. External devs are expected to drop files in by name, not edit code.

Cross-cutting rules (apply in every phase)

These are the lessons that, skipped, cost the most rework:

Babel caches transpiled JSX by URL. After editing a .jsx, a normal reload often serves the old compiled code. Bust it by serving over a no-cache server on a fresh port (bundled scripts/nocache_server.py, e.g. python nocache_server.py 8853) — a new port guarantees a clean compile. This single habit avoids hours of "my change isn't showing up".
Verify every change in a real browser before claiming it works. Use Playwright (or the available browser MCP): navigate, confirm 0 console errors (a favicon 404 is harmless), then check the change visually with a screenshot and the DOM with browser_evaluate. Searching the raw page source for text gives false positives — babel's compiled <script> still contains the old string literals, so a substring match is not proof the UI rendered. Trust the screenshot and computed DOM, not source text.
API keys go in the project .env. Create a placeholder .env (e.g. OPENAI_API_KEY=) for the user to fill; read it at runtime. Never ask the user to export env vars, never hardcode or commit a key. The bundled gen_image.py already reads .env this way.
Python deps via uv (uv venv + uv pip install pillow), not python -m venv/pip. Image conversion (PNG → web-sized WebP) via Pillow.
Keep a living spec + visual record. Maintain a DESIGN.md (pages, components, tokens, asset conventions) and a screenshots/ folder of current page captures. Refresh them when the design changes — they are the handoff artifact for downstream developers.

Working rhythm

Explore before acting (read the tokens, the target component, the data shape), make the change, then verify in the browser. For multi-item work, do a quick pass to discover the work-list (which files, which asset slots, which pages) before fanning out. State findings plainly; if a check fails, say so with the evidence rather than asserting success.

When a request is a broad "polish this", don't guess — run the review framework in references/3-polish-frontend.md to produce a prioritized, grounded list first, then implement what the user picks.

Design → Frontend pipeline

Guide

When the request is about…

Read

1 · Ingest design

"parse this design", "what's in the prototype", building a spec/DESIGN.md, mapping pages/components/tokens, finding what assets are missing

references/1-ingest-design.md

2 · Generate assets

"generate/make the missing mascots/banners/icons", transparent-background images, filling an asset pool, gpt-image-1.5, converting to WebP

references/2-generate-assets.md

3 · Build & polish

building a new page/component/feature on the prototype, OR "polish/refine/打磨 this page" — visual hierarchy, states/validation, mobile/i18n/a11y, "make a preview and check it"

references/3-polish-frontend.md

Most real requests touch one activity. A from-scratch run goes ingest → generate → build → polish. Don't read a guide you don't need.

The substrate you're working in

Claude Design prototypes are single-file-ish in-browser React apps, not a build pipeline. Knowing this shape prevents most mistakes:

React 18 + @babel/standalone loaded from CDN. One HTML entry (e.g. new ui 2.0.html) lists every <script type="text/babel" src="src/*.jsx"> in load order. There is no bundler, no npm run build — you edit .jsx and reload.

Components are plain function declarations exported with Object.assign(window, { Foo, Bar }) and referenced as window.Foo or bare globals across files (classic-script global scope). Adding a new component = write the function, add it to a window assign, and register its file in the HTML.

Design tokens (colors, fonts, spacing) live in a tokens module (e.g. getTokens('cyber','dark')). Read tokens before styling so new work matches; never hardcode a color that a token already names.

Assets are referenced by path and often by naming convention (filename pools) so the UI auto-picks them — see phase 2. External devs are expected to drop files in by name, not edit code.

Cross-cutting rules (apply in every phase)

These are the lessons that, skipped, cost the most rework:

Babel caches transpiled JSX by URL. After editing a .jsx, a normal reload often serves the old compiled code. Bust it by serving over a no-cache server on a fresh port (bundled scripts/nocache_server.py, e.g. python nocache_server.py 8853) — a new port guarantees a clean compile. This single habit avoids hours of "my change isn't showing up".

Verify every change in a real browser before claiming it works. Use Playwright (or the available browser MCP): navigate, confirm 0 console errors (a favicon 404 is harmless), then check the change visually with a screenshot and the DOM with browser_evaluate. Searching the raw page source for text gives false positives — babel's compiled <script> still contains the old string literals, so a substring match is not proof the UI rendered. Trust the screenshot and computed DOM, not source text.

API keys go in the project .env. Create a placeholder .env (e.g. OPENAI_API_KEY=) for the user to fill; read it at runtime. Never ask the user to export env vars, never hardcode or commit a key. The bundled gen_image.py already reads .env this way.

Python deps via uv (uv venv + uv pip install pillow), not python -m venv/pip. Image conversion (PNG → web-sized WebP) via Pillow.

Keep a living spec + visual record. Maintain a DESIGN.md (pages, components, tokens, asset conventions) and a screenshots/ folder of current page captures. Refresh them when the design changes — they are the handoff artifact for downstream developers.

Working rhythm

When a request is a broad "polish this", don't guess — run the review framework in references/3-polish-frontend.md to produce a prioritized, grounded list first, then implement what the user picks.