Stub Files: Before and After Nutshell

3 min read

The difference Nutshell AI makes is most visible in the SharePoint stub — the small file Squirrel leaves in SharePoint after moving the original document to Azure Blob storage. This article walks through what the stub looks like with and without Nutshell, and why that difference matters for search and Copilot discoverability.

Without Nutshell

When Squirrel archives a document without Nutshell enabled, the stub carries:

The original filename
The originating SharePoint site
A Restore link that triggers the normal Squirrel rehydration flow
Preserved file metadata (author, dates, sensitivity label)

What it does not carry:

Any of the original document's content

SharePoint Search and Microsoft Copilot rely on document content to answer queries. With no content in the stub, they have nothing to index — the archived document effectively drops out of your organisation's discoverable knowledge base. Users searching for something in the document will get no result until they know to look in the archive and restore first.

With Nutshell

When Nutshell is enabled, the same stub additionally carries an embedded summary of the original document's contents. That summary is what SharePoint Search and Copilot index — it looks like ordinary text to Microsoft's indexing services, so it is treated like any other document body.

Result:

A search for phrases the document discusses returns the stub as a hit.
Copilot answers questions about the document using the summary as its source, and can link users to the stub (from which they can restore the full original if they need it).
End users see the archived document in the same search results as live documents, differentiated only by whether or not they need to click Restore to work with the original.

What the summary looks like

The summary is 200–500 words of plain-language prose describing what the document is about, its structure, key points, and (where applicable) conclusions or recommendations. Length and depth are controlled by the configured mode; style and fidelity by temperature.

Sample summaries show real output from the same source document at each mode.

The archive companion copy

A second copy of the summary is stored alongside the archived document in Azure Blob Storage. This companion copy is useful for:

Rebuilding stubs if the SharePoint index is ever regenerated
Audit trails — the summary that was written back to SharePoint is preserved even if the stub is later deleted or replaced
Bulk export or offline discovery workflows that read directly from your Azure Blob storage

Both the stub summary and the companion copy remain in your own Azure subscription. Nothing about Nutshell requires customer data to leave your tenant.

Restore behaviour is unchanged

Adding Nutshell to a stub does not change what happens when a user clicks Restore. The stub still triggers Squirrel's normal restore flow, which returns the full original document from Azure Blob storage. The summary is a discoverability aid; the restore path is the same as it has always been.