Compare two versions of a contract

Lawyer · Time: 15 min · Documents

Tools that fit this task

• Claude $20/mo
• ChatGPT $20/mo
• NotebookLM $14/mo
• Copilot in Word $20/mo
• Adobe Acrobat AI Assistant $4.99/mo
• ChatPDF $19.99/mo

Prompt

Role: you are a corporate lawyer reviewing a counterparty's edits to a contract.
Context: I represent {{our side}}. The contract is a {{contract type}}. Below are version 1 (ours) and version 2 (from the counterparty), with parties and amounts replaced by placeholders.
Task: find all changes between the versions, including removed and added clauses and changes in numbers, deadlines and wording. For each change assess whom it favors and what risk it carries for us.
Format: a table clause | before | after | favors | risk for us | proposal. As separate lists: removed clauses, new clauses, changes in numbers and deadlines. Leave unchanged clauses out of the table.
Version 1:
{{version 1}}
Version 2:
{{version 2}}

Steps

1. Get both versions as text and replace party names, amounts and details with placeholders [Party A], [Party B], [amount]
2. Run the built-in comparison in Word (Review, Compare) or give both files to an assistant that handles long documents
3. Ask for a list of all changes by clause with an assessment of whom each change favors
4. Check every change found against the originals, especially clauses on liability, deadlines, payment and termination
5. Ask separately for the clauses removed from the new version and the new clauses that did not exist before
6. Build a table of changes with a decision on each: accept, reject, propose our own wording

How to check the result

Every change in the table is found in the original, and a spot check of three clauses the model called unchanged confirms they really match

Pitfalls

• The model misses small changes such as "within 5 days" instead of "within 5 business days", so compare deadlines and numbers in Word
• A contract with real parties under NDA goes into a public service only anonymized

Data that stays out of public AI tools

• Contracts with real parties, amounts and details under NDA: into a public service only as [Party A], [Party B], [amount]
• Case files and client correspondence covered by attorney-client privilege: never into a public service
• Personal data of employees and clients in orders, complaints and applications: anonymize before pasting

• Compare two contract versions in Word with Copilot
• Compare two versions of a contract with Claude

Other tasks for lawyers

• Run a risk review of a contract for your side
• Write a formal claim letter to a counterparty
• Write a structured legal memo
• Keep a contract register and track deadlines
• Draft a personal data processing policy
• Summarize changes in legislation for colleagues
• Translate a contract and keep the terminology consistent
• Prepare a reply to a tax authority request
• Draft an internal company order
• Summarize a long PDF
• Run a quick counterparty check before a deal
• Write a business letter

AI tools for lawyers · Prompt: Compare two versions of a contract