design execution — handoff and the living prototype
Handoff annotations and the living prototype
The Figma file is the handoff artifact. Each frame carries annotations: spacing values, interaction notes, state transition rules, links to the relevant scenarios. The annotations are the designer's notes to the developer — not the specification itself (the story card is the specification), but the detail that makes the specification buildable without a meeting.
The prototype from Volume III stays alive during execution. As the developer builds, the designer updates the prototype to reflect what was learned — a state that turned out to need a confirmation step, an error flow that emerged during implementation, a loading state that the developer surfaced. The prototype and the code converge toward the same experience. At the PR gate, the designer compares the two.
Design system updates
Implementation reveals new components. A table variant that doesn't exist in the library yet. A notification pattern that was never needed before. The designer adds these to the design system in Figma and the developer adds the corresponding Storybook story. Both update simultaneously — the design system has one source of truth, expressed in two tools.
The discipline: no component ships in the application without existing in both Figma and Storybook. If a developer builds a component that isn't in the design system, the designer either adds it (if it's reusable) or flags it as a one-off that should use existing components instead.
UX review — the flow-level assessment
Before the PR gate, the designer does something the visual regression test cannot: they use the feature as a person would. Not clicking through scenarios — using it. Trying to grade an exam. Trying to submit. Trying to go back and fix a mistake.
The question is not "does it match the wireframe?" but "does it feel right?" A flow that matches every wireframe but takes three extra clicks to complete a natural task has a UX problem that only using-it reveals.
This assessment is the designer's input to the PR confirmation. It may produce no changes — or it may surface a flow issue that becomes a follow-up story. Either way, it happens before merge, not after.
Resolution gate — Design Execution to Pipeline
Enough for the developer to build without inventing a UI decision.
Full-fidelity screens exist for every release-1 state. Content is written. Handoff annotations are in Figma. New components exist in both the design system and Storybook. The prototype is current.