Copilot Studio Knowledge Source Limitation When Iterating Over Multiple SharePoint Documents

What you're hitting is a known, documented limitation, so no, you're not missing anything.

Copilot Studio knowledge sources work on a RAG pattern: they retrieve the most semantically relevant chunks for a given query, they don't iterate over every document. Microsoft explicitly calls this out as "exhaustive retrieval" in the platform quotas documentation, acknowledging that agents will struggle when a query requires scanning a large number of files.

The Copilot Retrieval API also hard-caps results at 25 per query https://learn.microsoft.com/azure/search/agentic-knowledge-source-how-to-sharepoint-remote#limitations, which explains the ~10 document ceiling in practice.

Simply put, "review each document" is enumeration, not retrieval. The platform is built for the latter.

The cleanest fix is to move structured fields like review dates into SharePoint metadata columns or a Dataverse table, and query those directly. If extraction from document content is unavoidable, a Power Automate flow as an agent action is the right place for that logic, not inside the knowledge retrieval layer. Dataverse is worth highlighting here as it has no hard ceiling in generative orchestration mode. https://learn.microsoft.com/microsoft-copilot-studio/knowledge-copilot-studio#supported-knowledge-sources