On 6 October Anthropic put Claude inside Google Sheets, Docs and Slides as a beta for every paid Claude plan. It reads the file you have open and only that file, it writes formulas and builds models on the sheet in front of you, and by default it asks before it changes anything. For the many businesses here that run on Google Workspace, this is the most useful tool launch since this column began, and the most important setting is the one you should never switch off.