Design Handoff When Coding Agents Ship UI All Week

The old handoff was a final Figma file, a PDF, then silence until staging. In 2026 agents open PRs while you are still in critique. Tokens, annotated components, and harness docs are the new spec. Teams that embrace that rhythm ship more consistent UI with less end-of-sprint panic on both sides.

Write what agents can actually read

• Map Figma variables to code token names for spacing, type, and color.
• List required states: hover, focus, disabled, loading, error, empty.
• Describe breakpoints, not only one mobile artboard.
• Mark what must stay human-owned: brand hero, illustrations, campaign art.

Review little and often

A ten-minute pass per PR beats a three-hour review on Friday. Use staging links, screenshot diffs, and accessibility checks. Agents often nail typography and miss the focus ring users hit first.

Push back on the instruction loop

Reject output that invents components, drops states, or leaves lorem in production paths. When the same mistake repeats, update the skill or rule, not only the developer's one-off prompt.