Copilot Studio Agent Tool Not Detecting File Input from Power Automate Flow

Hi everyone,

I'm facing an issue with Copilot Studio and Power Automate Agent Flows.

I created a flow using "When an agent calls the workflow" with the following inputs:

The flow saves successfully and the File input is visible in Power Automate.

However, when I add the flow as a Tool in Copilot Studio, only the text input is detected:

The File input (AttachmentFiles) does not appear in the Tool Inputs section.

What I've tried:

- Removed and re-added the tool

- Refreshed the tool schema

- Created a brand-new V2 flow

- Changed the File input name multiple times (AttachmentFiles, UploadedFiles, FuelAttachments, etc.)

- Saved and republished the agent

- Removed and re-added the flow multiple times

The result is always the same. Only the Text input is exposed in Copilot Studio.

Additionally, if I manually try to add an input named "AttachmentFiles" in the Tool configuration, Copilot Studio returns:

"There is an error: 'DuplicateItem'"

This makes it seem like Copilot Studio recognizes the input internally, but it is not rendering or exposing it in the Tool UI.

Questions:

Are File/File Collection inputs currently supported for Agent Tools in Copilot Studio?
Has anyone successfully passed uploaded files from an Agent to a Power Automate flow using Tool inputs?
Is this a known limitation or a bug?
Is there a recommended workaround for sending PDF/JPG attachments to a flow from an Agent?

Any guidance would be greatly appreciated.

Thank you.

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