Ask what changed between two versions, not for a summary of each

A supplier sends a revised contract with "just a few small changes". Reading both versions side by side is the sort of job everyone skims, and the clause that moved is always the one that mattered.

If your document tool has compare or tracked changes, use that first. It shows every edit and can't miss one. An AI is for when you've only got two copies, and for explaining what the changes mean.

Compare VERSION A (old) and VERSION B (new) below.
List every difference in a table: section, what the old version said,
what the new version says, and the impact (High, Medium or Low).
- Quote the exact words from both versions for every row. Don't
  paraphrase.
- Always include changes to numbers, dates, names, and to words like
  may, must, shall and should, however small.
- Put pure typo and formatting fixes together in one line at the end.
- Don't summarise each document. Only the differences.
- If you're not sure whether something's a real change, say so.

VERSION A: [PASTE]
VERSION B: [PASTE]

Quoting is what makes this trustworthy, because you can check any claim in seconds. Ranking by impact puts a changed liability cap above a fixed comma. And "only the differences" stops it describing both documents back to you.

Small words matter in contracts. "May" becoming "shall", or 30 days becoming 3, vanishes in a summary, which is why the prompt names them.

It can still miss a subtle one, and it isn't legal advice. For anything with money or liability on it, use it to know where to look, then read those clauses yourself. Contracts are usually confidential, so use an approved tool or take names and amounts out first.

The same idea works for two config files: let the tool find the differences and use the AI to say what they mean.