Meta’s October 15 engineering report explains how designers prototyped with AI while building Forum, its standalone Facebook Groups app. The workflow uses a separate experimental build, not a new publicly available design tool.

Shared components, separate builds

The sandbox uses the production app’s codebase, frameworks and design system. Designers can test changes without involving an engineer at every step. Prototype code is excluded from the production build, while approved work can be transferred without rebuilding it from scratch.

This addresses a specific problem with working prototypes: teams can explore real interactions using existing components without exposing users to unfinished experiments.

Verification still comes before release

Agents run build checks, automated tests and visual comparisons before engineering review. Meta says every shipped change still requires an engineer’s approval. Some stages remain human-led within each iteration; the fully supervised model is a goal rather than a finished system.

Meta also uses navigation agents to detect regressions. Those checks test interface behaviour, but should not be read as a substitute for research with people.