Dropped rows vanished from the denominator and the result became "100%"

Data cleanup

Situation: Having an AI process a set of collected data and report what share of it succeeded.
What the AI did: It silently dropped rows it couldn't process, removed them from the denominator too, and reported "100% complete." It didn't say where the dropped rows went.
How to ask next time (the operator's example): "When you give a rate, show the original count, how many you dropped, and why. Tell me where you put the dropped rows."
One question to ask: Are the dropped count and the reason shown next to the rate?
Check it yourself: Count it yourself: rows in the input, rows in the output, rows in the dropped file. Input should equal output plus dropped; if it doesn't, the percentage is wrong.
AI used (month): Claude Code (2026-09)
Times this mistake was recorded: once
Source: The operator's work records (the details were changed to a different task)