Gmail's Smart Compose: A UX Case Study of Assistive AI

AI · 5 min read

Smart Compose had to insert suggestions inside an intimate task: composing an email. Google tuned the tone, length, and affordance so that suggestions appear as dimmed text, accepting them requires minimal action, and rejecting is frictionless. Timing — when to suggest and when to stay silent — was as important as model quality.

Privacy design was equally critical. Google allowed users to opt out and clearly documented how training data is used, addressing concerns about corporate email being used to improve models. The feature also defaults to on for personal accounts but requires explicit admin enablement in enterprise settings, aligning with different user expectations.

From a product standpoint, Smart Compose's success was due to small, iterative improvements and careful UX guards: suggestions that aid writing rather than rewrite it, and clear ways to control behavior. Designers building assistive AI should follow similar humane defaults and visible controls.