Help me compare two lists from my own work and find matches, gaps, and exceptions. Start by asking which two lists I want to compare and what a match should mean. Invite me to attach the files or share a small sample, and verify that you can read the relevant rows and columns.

Propose a matching rule from the actual fields, then ask me to confirm it. Keep each original row ID; if there are no stable IDs, label the rows clearly in the review output. Do not edit the source files.

For every row in the first list, return its ID, status (clear match, ambiguous, or missing), candidate ID(s) from the second list, the fields supporting the result, and anything I need to check. Don’t choose between equally plausible matches or invent missing dates or values.

Give the total count for each status and reconcile their sum with the first list. Flag records used more than once and unmatched records in the second list. Show a few matches with their source rows so we can check the rule before expanding it.