Design Builder

Greenfield design pipeline for any digital product: discover, extract content, author DESIGN.md, define layout or screen flow, preview, refine.

Workflow

discovery --> copy --> inputs --> structure --> preview --> assets --> final
                                                  ^__|  (tune / comment / apply-across loop)

Each step is independent. Can run isolated or chained (discovery.md pre-loads before every operation). Assets is optional: auto-invoked after preview approval, or triggered directly. design-builder is greenfield-first — codebase path inside inputs.md is an alternative for redesign or migration, not the primary flow. Final design can be served as HTML, pushed to an external design tool when the matching MCP is available, or handed to the implementation phase.

Triggers

• Copy extraction ("extract copy", "copy from URL", "web capture", "content from website", "brief document") → copy.md
• Visual identity (DESIGN.md authoring) ("extract design tokens", "author DESIGN.md", "refresh design tokens", "extract design from images / codebase / design tool") → inputs.md
• Layout / screen flow ("create a wireframe", "layout the page", "structure the content", "screen flow", "validate this wireframe") → structure.md
• Preview / variants ("preview the design", "visual mockup", "tune the design", "creative variants", "pivot the design", "apply across variants", "push to design tool") → preview.md
• Validation ("validate DESIGN.md", "check DESIGN.md", "audit design tokens", "lint the design system") → validate.md
• Redesign ("redesign this app", "modernize this interface", "brand refresh", "change the vibe") → redesign.md
• Asset generation ("generate hero banner", "create product image", "generate OG card", "image prompts") → assets.md

discovery.md is auto-loaded before every operation — never skipped.

aesthetics.md and web-standards.md are auto-loaded by preview.md.

validate.md is both directly callable and auto-loaded by inputs.md Step 5 as the gate before declaring done.

assets.md is both directly callable and an optional sub-phase auto-invoked by preview.md after variant approval.

Guidelines

• Ask one question at a time when gathering context from the user
• Treat <project-root>/DESIGN.md as the source of truth for visual identity
• Patch DESIGN.md section by section so each phase preserves the others' work
• Route preset and decision sets by project type (landing-page, website, web-app, mobile-app)
• Auto-load aesthetics.md and web-standards.md for every preview run
• Treat external design-tool files as user-owned — read or push only when the user asks and the matching MCP is available

Anti-Pattern: Whole-File Rewrite on Section Edit

Rewriting the entire DESIGN.md when only ## Layout or ## Components changed clobbers other sections that other phases own. Patch section by section: inputs.md owns frontmatter + most prose, structure.md owns ## Layout and ## Screen Flow, copy.md owns content payload (in copy.yaml).

Anti-Pattern: Creating External Tool Files

External design-tool files (Pencil, Paper, Figma) are user-owned. The skill never creates them — it pulls when the file already exists and the matching MCP is available, and pushes when the user explicitly asks. Creating files in someone else's tool surprises them and risks naming collisions.

Anti-Pattern: Skipping Discovery

Discovery loads before every operation, even when the user hands you images, briefs, or a codebase. Without discovery, the skill misroutes — running landing-page presets on a mobile app, or pulling tokens from a codebase the user wants to leave alone. The 30 seconds discovery costs saves the alternative of redoing the whole flow.