what happens when more than 20-documents are added as references in a notebook

Copilot Notebooks can have more than 20 documents added as references, but only a subset is actually used for grounding responses.

For Microsoft 365 Copilot Notebooks specifically:

• More than 100 references can be added to a notebook.
• Only up to the first 100 references are used for grounding when Copilot answers questions about the notebook.
• References beyond that first 100 are effectively ignored for grounding until earlier ones are removed or reordered so that the desired files are within the first 100.

So, the effective limit in Copilot Notebooks is 100 grounded references, not 20. Adding more than 20 documents is allowed, but only the first 100 will influence Copilot’s responses. The documentation does not indicate that this 100-reference limit is changing.

References:

• Get answers and insights about your Microsoft 365 Copilot Notebook
• How Microsoft 365 Copilot Notebooks works