The work that can't live in a tenant.

Microsoft 365 Copilot is the most thoroughly-distributed document AI in the world. It lives inside the apps people already use (Word, Excel, PowerPoint, Outlook, Teams), integrates with the documents they already have via Microsoft Graph, and ships under enterprise contracts that most large IT departments already understand. Microsoft has done meaningful compliance work: the EU Data Boundary, Customer Lockbox, the Service Trust Portal, defaulting paid-tier prompts to no-training. None of that is theatre.

For a salaried employee inside an enterprise tenant doing internal-facing work on documents that already live in SharePoint or OneDrive, Copilot is often the right answer. We are not arguing otherwise.

When you ask Copilot to summarise a document, the document travels through Microsoft’s services. The trust set for that operation includes:

• Microsoft Corporation, as the operator of the service.
• Microsoft’s declared subprocessors, which can change with notice.
• Your tenant administrator, who controls Copilot’s access to Graph.
• Anyone in your tenant with Graph permissions to the same content.
• Whatever third-party apps your tenant has connected to Graph.
• The Customer Lockbox approver chain, when it engages.

None of that is unusual for an enterprise SaaS. It is still the trust set. For some documents, the trust set you want is “the Mac it was opened on, and that is the entire list.”

• Internal employee work on internal documents already in your tenant.
• Outlook drafting, Teams meeting summaries, intra-team SharePoint Q&A.
• Excel modelling against existing tenant data with no external sensitivity.
• PowerPoint drafting from a corporate template that’s already in OneDrive.
• Tenant-wide rollout where everyone’s already on Microsoft 365 anyway.

• External counsel reviewing material for a client whose tenant you don’t belong to.
• Privileged drafts, opinion work, and pre-litigation materials.
• Documents under contractual confidentiality with a third party.
• Pre-publication research, peer review, IRB-restricted data.
• Government, defence, and classified work that can’t sit in a commercial tenant.
• EU practitioners with Schrems II concerns about US-cloud processing.
• Anyone working on a Mac who simply doesn’t use the Microsoft suite.

Copilot’s big advantage is that it lives inside Word and the other Office apps as a panel. Muet sits in the menu bar and reads whatever Word document is at the front of your screen. The interaction model is different; the output is the same: tracked changes attributed to you, opened in Word, accepted or rejected like any other reviewer’s edits.

For workflows already inside the M365 suite, Copilot is inside the door. For workflows where the document came in by email, was opened in Preview or Pages, or sits on a local volume that isn’t synced anywhere, Muet is already there.

Microsoft 365 Copilot is per-user-per-month on top of an existing M365 licence, with usage-based metering on agentic features. Different model. Worth comparing total cost if you’re only using Copilot for the document-drafting subset of what it does.