| Tool | Quality | Speed | Cost | Privacy | Notes | |---|---|---|---|---|---| | Claude Pro | Strong on long legal documents; holds extraction formats reliably | Fast enough for 3-5 docs weekly | Covered by existing subscription | Consumer plan — confirm whether IT has approved it for confidential contracts | Best raw fit for long-document clause extraction | | ChatGPT Plus | Good general extraction; very long contracts may need chunking | Comparable | Covered by existing subscription | Same consumer-plan caveat | No clear advantage for this document length | | M365 Copilot | Adequate clause flagging; weaker thoroughness on long files | Slower on long documents | Already paid in tenant | Strongest: stays inside your existing M365 compliance boundary | The only option that clearly inherits existing IT approval | **Best fit: Microsoft 365 Copilot** — not because it is the best model for the task (it is not; Claude handles long contracts better), but because your binding constraint is confidentiality plus IT approval, and Copilot is the only one already inside the approved boundary. When privacy is the binding constraint, the ranking is decided there, not on quality. **Watch out for:** long-document thoroughness — Copilot can summarize confidently while missing clauses buried late in the file. Mitigate with a fixed checklist prompt ("list every renewal, liability and termination clause with page references") and spot-check one contract per weekly batch. **When to switch:** if IT approves a business tier of Claude or ChatGPT with contractual data-handling terms, the privacy constraint dissolves and quality becomes the deciding axis — re-run this comparison, because the recommendation likely flips. Honesty note: Claude Pro is the strongest raw model here, and it still is not the recommendation — a consumer subscription does not meet the confidentiality constraint you stated.