AI data governance: Microsoft 365 Copilot vs third-party generative AI apps
Verdict: Copilot honours the permissions a user already has, so oversharing risk comes from SharePoint permissions, not Copilot. Sensitivity labels and Defender for Cloud Apps extend Purview's generative AI protections to bound Copilot and third-party AI apps under one governance layer.
| Criterion | Microsoft 365 Copilot | Third-party generative AI web apps |
|---|---|---|
| How access is bounded | Honours the user's existing permissions at retrieval time; the real fix for oversharing is a SharePoint permission review, not Copilot itself | Not bounded by Copilot; access to pasted data is governed separately |
| Control mechanism | Sensitivity label usage rights, honoured by Copilot when grounding responses | Purview data security for generative AI apps, extended via Defender for Cloud Apps, to detect and restrict sensitive data pasted into the app |
| Unified governance | Covered by Purview data security and compliance protections for generative AI apps | Covered by the same Purview capability area, alongside enterprise-built AI apps |
Rules
- Copilot only surfaces content a user already has at least view permission to; run a SharePoint oversharing/permission review before enabling Copilot broadly.
- Apply sensitivity labels with usage rights Copilot honours when grounding, and extend Purview data security for generative AI apps via Defender for Cloud Apps to govern third-party AI web apps.
- Anchor AI oversharing governance on Purview's data security and compliance protections for generative AI apps, which span Copilot, enterprise-built AI apps, and other AI apps.
Traps
- Copilot does not maintain a separate permission model and is not trained on tenant content; grounding is retrieval-time and permission-checked.
- Enabling Copilot does not automatically apply sensitivity labels or fix permission misconfigurations.
- Purview Data Map, Records Management and Insider Risk Management are not the documented unified control for AI oversharing across Copilot and custom AI apps.