Access and oversharing
Both keep each person's existing permissions. The difference is what happens to sensitive content inside a file someone can partly see: Brain can withhold just that part, so the rest of the document stays useful.
vs
Brain vs Microsoft 365 Copilot
A productivity assistant inside Microsoft 365, and a governance spine across all your tools.
Microsoft 365 Copilot is a productivity assistant built into Word, Excel, Teams and Outlook, and it answers from whatever a user can already access, which is why oversharing is its most-cited risk. Brain governs retrieval across all your tools, hides the sensitive part of a document instead of blocking the whole file, and records every access in a tamper-evident, content-blind log. If your concern about Copilot is data leaving the room it should have stayed in, that is the problem Brain is built for.
Why teams compare them
Proof you can hand to security
Every access goes into a tamper-evident record that says what happened without storing what was read. When legal asks whether anything leaked, the answer arrives with receipts.
Where Copilot is the better fit
If your company lives in Microsoft 365, you want AI inside Word, Excel, Teams and Outlook, and you already run Purview, Copilot is deeply integrated and hard to beat for in-app work. Brain is not trying to write your emails.
The questions people actually ask about Microsoft 365 Copilot
We already pay for Copilot. Why would we add anything?
You probably should not, for writing and summarising inside Office. That is what Copilot is for and it is good at it.
The reason a second look comes up is narrower. Copilot answers from whatever the signed-in person can already open, so years of over-permissioned SharePoint sites and inherited access become answerable by AI overnight. The question is not whether the assistant is clever. It is whether you can show it only ever surfaced what each person was cleared to see.
Fine. But doesn't Purview already handle governance?
Purview is real governance tooling, and if it is already deployed and maintained across your tenant, much of this is covered.
It is also a separate programme: labels to design, policies to roll out, and an owner to keep it current. Brain has no equivalent rollout, because governed retrieval is not a policy applied on top of the product. It is the product.
Alright. But can you actually prove what the AI saw?
That is the part a security review turns on, and it is the part Brain is built around.
Every retrieval lands in an append-only record: who asked, what was reached, what was withheld, when. The log is content-blind, so it proves the access without storing the material, and it is tamper-evident, so a later edit is detectable rather than deniable.
And everything that isn't in Microsoft 365?
Copilot reaches the Microsoft 365 apps and what sits in Microsoft Graph. Most companies keep a good deal of what they know somewhere else.
Brain connects Slack, GitHub, Drive, Box, Confluence, Salesforce and more with their permissions intact, and governs all of it the same way. An answer can cite a Slack thread and a GitHub pull request in the same breath, and each citation still respects who is asking.
At a glance
| Attribute | Brain | Microsoft 365 Copilot |
|---|---|---|
| Scope | Any connected source: Slack, GitHub, Drive, Box, Confluence, Salesforce, Telegram and more | The Microsoft 365 apps and the data in Microsoft Graph |
| Access model | Permission-aware, plus field-level redaction: hide one salary column, not the whole file | Inherits each user's existing Microsoft 365 permissions, including access inherited from over-shared sites |
| Governed retrieval | YesThe product. On by default, with nothing to roll out | PartlyAddressed through a separate Microsoft Purview deployment you configure and maintain |
| Audit and proof | Content-blind, tamper-evident record, with an optional on-chain anchor of what the model answered over | Purview auditing, configured separately |
| Model and data | Bring your own model key. Nothing you connect trains a model | Runs on Microsoft's own AI service, under Microsoft's terms |
| How you buy | Free to start, transparent self-serve tiers | An add-on licence on top of an eligible Microsoft 365 plan |
Compared against publicly available information, last checked 20 September 2026. Products change. Tell us if something here is out of date: hello@heybrain.io
Who each one is for
Choose Brain if
- Teams whose AI rollout is stuck in security review over where data could end up
- Companies that use more than Microsoft 365 and want one governed brain across all of it
- Anyone who needs a content-blind audit trail they can hand to an auditor
- Teams that want to bring their own model key and keep data and usage their own
Choose Microsoft 365 Copilot if
- All-Microsoft shops that want AI inside the Office apps themselves
- Organisations already running Microsoft Purview
- Teams whose main need is in-app document and email productivity
What the research says
~16%
of business-critical data is overshared, an average of roughly 802,000 files at risk per organisation.
Concentric AI67%
of enterprise security teams say they are concerned about AI tools exposing sensitive information.
Metomic
Compared against publicly available information, last checked 20 September 2026. Products change. Tell us if something here is out of date: hello@heybrain.io
Tempting, but nobody has time to migrate everything.
There is nothing to migrate. Brain reads the tools you already use, in place, with their permissions intact.
No re-filing, no second home for your documents, no export. The files stay where they are and where your team expects to find them.
Join the waitlistQuestions, answered
- Is Brain a replacement for Microsoft 365 Copilot?
- Not really. Copilot is a productivity assistant inside Microsoft 365. Brain governs how AI reaches all of your company's knowledge, with proof. Plenty of teams run both, and use Brain to govern access across every tool, including the data that also lives in Microsoft 365.
- Does Brain fix the oversharing problem?
- It addresses the same concern from the governance side. Brain checks permissions at the point of retrieval, can withhold the sensitive part of a document instead of blocking the whole file, and records every access content-blind, across all your sources rather than Microsoft 365 alone.
- Does Brain work outside Microsoft 365?
- Yes. Brain connects Slack, GitHub, Google Drive, Box, Confluence, Salesforce and Telegram with their permissions intact, and more through the same governed spine.
Other comparisons
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