The AI Analyst

On the Sheet tab, open the composer's + menu and turn on AI Analyst, under THIS QUESTION. The + button shows a dot while it is on.

• Questions are answered from figures computed over every row: each column's count, blanks, distinct values, minimum, maximum, mean, median, standard deviation and quartiles, its outliers, and how strongly columns move together. It quotes those figures and names the column each comes from, rather than estimating.
• It suggests the chart or cleaning step to take next. Ask for one and it is built.
• Cleaning flags blanks, repeats and outliers in a new column. Nothing is ever deleted; hide flagged rows with a filter.

With nothing open, sending builds a sheet first; with AI Analyst on, its first read of the new sheet follows in the chat: what it holds, data-quality problems, the key figures, and a next step. That read only answers; it never changes the sheet.