Google has updated Gmail's Gemini-powered Help Me Write feature with custom refinement capabilities that let users edit AI-generated email drafts using their own instructions. The update removes the need to rely only on preset editing options and also introduces undo and redo controls for AI edits. It is enabled by default for eligible users and is rolling out across Rapid Release and Scheduled Release domains until July 20. The feature is available across supported Google AI and Workspace plans.