Microsoft is rolling out Authoritative Sites for SharePoint in Copilot this week. With a single PowerShell command you mark a site as a trusted source, so Copilot Chat and Copilot Search consistently prioritise its content over random documents elsewhere in the tenant. How it works, which sites to mark first, and how it relates to Restricted Content Discovery.
Microsoft 365 Copilot searches your entire SharePoint tenant to answer questions. That is also precisely the problem. Copilot looks at everything a user can access: older project sites, test environments, archives with outdated policies, draft documents that were never updated. The result is that Copilot sometimes gives the right answer, but also regularly picks up an outdated or incomplete document as a source, without the user being able to tell.
Microsoft has addressed this problem with a new governance feature: Authoritative Sites for SharePoint in Microsoft Copilot. The feature reaches General Availability this week and gives IT administrators a direct way to guide Copilot towards the sources the organisation considers authoritative.
When you mark a SharePoint site as authoritative, you give Copilot a signal: content from this site is reliable and relevant. That signal works in two places. In Copilot Chat, answers based on content from an authoritative site are prioritised higher than similar content from other sites. In Copilot Search, content from authoritative sites appears more prominently in the results.
The designation does not affect existing SharePoint permissions. Users only see content from an authoritative site if they already have access to it. Authoritative Sites are therefore not a way to grant access, but to raise the relevance score for Copilot for content you already deliberately share.
The feature is off by default and is not configured automatically. Without administrator action, Copilot works as it does now: all accessible content carries equal weight. The administrator fully controls which sites receive authoritative status.
Configuration runs through the SharePoint Online PowerShell module. Per site you run a single command to set the authoritative flag. The cmdlet is Set-SPOSite with the IsAuthoritative parameter set to true. The same command with false removes the status.
For larger environments you can apply it via a script that processes a list of site URLs. No limit has been announced on the number of sites you can mark as authoritative, but the value of the feature lies in selectivity: the larger the authoritative set, the less distinctive the signal becomes.
The change takes effect for new Copilot sessions after activation. Existing sessions do not refresh automatically. IT administrators can verify the configuration through the SharePoint admin centre or via the Get-SPOSite cmdlet.
The choice of which sites become authoritative is a deliberate governance decision that must be made by the organisation, not by the technology. A number of categories that are self-evident in most organisations.
HR policy sites are an obvious choice. Leave policy, expense procedures, terms of employment — this is content where Copilot must give correct answers and where an outdated document can cause harm. The same applies to IT procedures: acceptable use, password policy, steps for requesting software.
The intranet homepage or digital employee portal is often the most visited and most maintained site in the tenant. If one site can be authoritative, it is usually this one. Financial procedures, procurement and tendering policies, and compliance documentation are also good candidates for organisations in regulated sectors.
What you are better off not marking as authoritative: project sites that are no longer maintained after completion, departmental sites with mixed quality, archives, and temporary workspaces. The risk is that Copilot pulls content from there that was correct for its original context but is incorrect or misleading as a general answer.
Authoritative Sites is one of two governance levers Microsoft is making available in 2026 to guide Copilot. The other is Restricted Content Discovery, a feature that explicitly places sites outside the scope of Copilot. Together they give IT administrators both positive and negative control.
With Authoritative Sites you say: search here first. With Restricted Content Discovery you say: do not search here at all. For structured Copilot governance it makes sense to assess both at the same time. Ask yourself for each site category: should Copilot prioritise this, ignore it, or treat it as ordinary content?
A typical arrangement is that a handful of central policy sites and the intranet become authoritative, a set of sensitive or outdated sites becomes restricted, and the remainder — the bulk of project sites and team sites — remains unchanged as ordinary source material for Copilot.
The feature requires a Microsoft 365 Copilot (Premium) licence. Without that licence the setting is available but has no effect on Copilot results. The SharePoint Online PowerShell module must be up to date to support the IsAuthoritative parameter.
The General Availability rollout started in the second half of June 2026 and will be completed for all tenants worldwide over the coming weeks. If the parameter is not yet visible in your tenant, expect it within the next few days.
Three concrete steps for IT administrators and SharePoint owners. First: draw up a shortlist of five to ten sites that serve as the official source for policy and procedures in your organisation. Do not ask the IT department alone — put the question to HR, finance, and management. They know which documents employees consult most frequently.
Second: check the quality of those sites before marking them. An authoritative site whose documents have not been updated for a year does not solve the problem but moves it. Link the authoritative status to an agreed review cycle so the site owner knows that an added responsibility comes with it.
Third: run the PowerShell command for the selected sites and test the effect in Copilot Chat with a number of questions you would normally ask employees about policy or procedures. Compare the answers with what you previously got from Copilot. The difference gives you immediate insight into how strongly the signal works for your specific content.
Copilot improves the more thoughtfully it is configured. Authoritative Sites is not a major infrastructure change but a targeted governance measure that directly improves the quality of Copilot answers. Want support assessing your SharePoint governance or setting up Copilot policy? Contact Zarioh for a conversation.
