Teach Claude the Difference Between Blank and Zero
A blank sales figure can mean “not reported yet.” Zero can mean “reported, with no sales.” Combining them makes a complete-looking report less truthful.
Before asking Claude Code to summarize a spreadsheet, write down the meaning of missing values for each important column. Use a practice file with a zero, a blank and an invalid entry. Decide whether incomplete rows should be excluded, flagged or held for review.
Ask for the output and a separate exception list with row references. Check the totals by hand on the tiny fixture. Then test an entirely blank reporting period. The workflow should be able to say that data is incomplete instead of confidently announcing that business activity stopped. Preserve that distinction in both the numbers and the prose summary.
