Copilot Studio (New Experience Jun 2026) - Unreliable Word Template Population Using Uploaded Files and SharePoint MCP

David Wong 5 Reputation points
2026-07-13T21:51:35.3166667+00:00

Hi,

I am testing the new Copilot Studio experience (June 2026 update) and would appreciate guidance on whether I am using the correct approach or if there are known limitations.

Scenario

I want an agent to:

  1. Accept a data Word document containing source information.
  2. Accept a Word template containing Content Controls (Structured Document Tags / SDTs).
  3. Extract information from the data document.
  4. Populate the corresponding content controls in the template.
  5. Generate and return the completed report.

Issue 1: Inconsistent Template Population

The behaviour is highly inconsistent:

  • Sometimes the agent successfully populates the Word template.
  • Sometimes it ignores the template and generates a new Word document using its own format.
  • Sometimes it returns the original template without populating any fields.
  • Sometimes it reports that the environment does not allow it to modify the template.

This occurs even when using the same agent and similar input documents.

Has anyone successfully implemented a reliable Word-template-based document generation solution using the new Copilot Studio experience?

Issue 2: Storing the Template in SharePoint

To avoid uploading the template with every conversation, I stored the template in SharePoint and provided the agent with a SharePoint MCP connection.

Again, the results are inconsistent:

  • Occasionally the agent can retrieve and use the template successfully.
  • Most of the time it retrieves what appears to be the file's Base64 or binary content and then reports that it cannot reconstruct the DOCX file.
  • In some cases I receive errors similar to:

I cannot complete the report generation because I am unable to obtain the required template document from SharePoint. I successfully located the file in the SharePoint site, but the environment does not have permission to download the document content.

or

The template was returned as a binary stream and could not be reconstructed into a usable Word document.

Questions

  1. Is Word template population using Content Controls currently a supported and reliable scenario in the new Copilot Studio experience?
  2. Is storing the template in SharePoint and retrieving it via SharePoint MCP considered a supported approach?
  3. Are there known limitations around handling DOCX files, binary streams, or Base64 content within skills/tools?
  4. Is document generation expected to be implemented through:
    • Agent skills only?
      • Power Automate flows?
        • Microsoft 365 document generation capabilities?
          • Another recommended pattern?
          1. Has anyone found a robust approach for generating Word documents from templates using Copilot Studio?

Any guidance, best practices, or confirmation of current product limitations would be greatly appreciated.

Environment

  • Copilot Studio: New experience (June 2026 update)
  • Template format: Microsoft Word (.docx) with Content Controls (SDTs)
  • Template storage: Uploaded file and SharePoint document library
  • Retrieval method: SharePoint MCP
  • Goal: Generate a completed Word report from a Word template and a source data document

Thank you.

Microsoft Copilot | Other
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  1. Sayali-MSFT 6,476 Reputation points Microsoft External Staff Moderator
    2026-09-10T09:53:09.62+00:00

    Hello David Wong •,
    This behavior is understandable because agent-driven manipulation of an uploaded DOCX template is not currently the
    most reliable pattern for production document generation.

    The recommended approach is:

    1. Use the agent to extract the required information from the source document and return it as structured fields.
    2. Pass those fields to a Power Automate or agent flow.
    3. Use Word Online (Business) → Populate a Microsoft Word template to populate supported Content Controls.
    4. Save the generated DOCX to SharePoint or OneDrive and return its link to the user.

    The Word Online connector supports plain text, dropdown, combo box, image, and repeating-section controls. It does not support every Content Control type, and its input template has a 10 MB limit.

    Retrieving a DOCX through SharePoint MCP is useful for locating documents and extracting their text or metadata, but it should not be relied upon to retrieve the binary file and reconstruct or modify the original DOCX package. This explains the inconsistent Base64, binary-stream, and permission-related responses.

    Other available options are:

    • Document output (preview): Supports generating a Word document from a predefined layout, but uses {{fieldName}} placeholders rather than existing Word SDTs.
    • Microsoft 365 structured document generation: Suitable for governed SharePoint-based templates and form-driven document creation.
    • Custom API or Azure Function: Appropriate when unsupported Content Controls, advanced formatting, or direct Open XML manipulation is required.

    Therefore, for the current scenario, the most robust design is:

    Copilot Studio agent → extract structured data → Power Automate/agent flow → populate the Word template → save to SharePoint/OneDrive → return the completed document link.

    Reference:
    1.https://learn.microsoft.com/en-us/connectors/wordonlinebusiness/
    2.https://learn.microsoft.com/en-us/microsoft-copilot-studio/mcp-word-tools
    3.https://learn.microsoft.com/en-us/microsoft-copilot-studio/generate-document-output-prompt
    4.https://learn.microsoft.com/en-us/microsoft-365/documentprocessing/automate-document-generation?view=o365-worldwide
    5.https://learn.microsoft.com/en-us/sharepoint/copilot-in-sharepoint-structured-document-generation

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