Public SharePoint RAG agent
A no-login Copilot Studio agent that answers from SharePoint documents, using Azure AI Search as the bridge.
A working pattern for letting unauthenticated users chat with a Copilot Studio agent grounded in SharePoint. I built it as a proof of concept for an IT helpdesk bot and tested it end to end in a sandbox tenant.
The catch
Copilot Studio’s native SharePoint knowledge source doesn’t work for anonymous users: it always queries as the signed-in user, and with no user it returns nothing.
The fix
Take the user out of the chain. Azure AI Search indexes the SharePoint library with a service principal, and Copilot Studio reads the index with an API key. No user identity crosses the chain at any point.
That has a cost: SharePoint permissions can’t be enforced for anonymous users, so the indexed library has to be treated as public content, with a named owner.