The Annotation Toolkit, developed by GitHub's accessibility design team, addresses the frequent breakdown in communication during the handoff between designers and developers by embedding accessibility and design intent directly into Figma files. This open-source Figma library uses annotations to document elements like interactivity and accessibility behaviors, ensuring that these considerations are part of the design process from the start rather than an afterthought. By integrating Web Content Accessibility Guidelines (WCAG) directly into design annotations, the toolkit not only prevents common accessibility issues but also educates users on best practices as they work, fostering a collaborative environment where developers and designers share a common language. The Annotation Toolkit enhances clarity and consistency across teams, reducing the knowledge gaps and accessibility oversights that often arise from scattered communication methods like Slack threads or Figma comments. By making accessibility a default part of the design workflow, the toolkit improves productivity and the quality of the final product, while also being actively maintained and open to community contributions for ongoing improvement.