Prototype to Production Handoff

The handoff from prototype to production code is where most prototyping effort is either preserved or lost. A well-structured prototype — built with real components, real design tokens, and real interaction patterns — transfers cleanly to production. A prototype built with shortcuts (hardcoded values, inline styles, mock interactions) requires complete reconstruction.

The handoff package includes five deliverables. Design Token Map: every token used in the prototype, mapped to its design system source (tokens.ts). Component Inventory: every component in the prototype, mapped to existing production components or flagged as new components that need to be built. Interaction Specification: every interaction in the prototype, mapped to its pattern library entry with the implementation code snippet. Responsive Behavior: how the layout adapts at key breakpoints (desktop, tablet, mobile), documented with screenshots at each breakpoint. Edge Cases: what happens with empty states, error states, loading states, and overflow content.

The edge cases document is the most commonly missing deliverable — and the most expensive to discover in production. A prototype with a beautiful dashboard that shows no empty-state design forces the developer to invent one, usually under deadline pressure, usually badly. Design the edge cases in the prototype, not in the production codebase.