Please help me on how i can connect my Copilot Studio Agent with Agent Flow

Question

Please help me on how i can connect my Copilot Studio Agent with Agent Flow

John Ng 0

I am developing an agent, which takes in files from users. Then i pass the documents into an agent flow for some data extraction and validation, and output the result as markdown text back to the agent. Finally, i trigger a child agent that takes in the result, organizes and formats the text, and return to user.

I published the agent to m365 and tried testing, however every time after i upload the files, the agent outputs "Sorry, I wasn't able to respond to that. Is there something else I can help with?". I have checked the Agent Flow run history, and it is always showing succeeded with the desired markdown text output. I have no idea how to solve this since there is no error message at all

Ashlesha Pawar (Tata Consultancy Services Limited) 395 Reputation points Microsoft External Staff

2026-08-18T09:09:53.7666667+00:00
Thank you for the detailed description.

A successful Agent Flow run does not necessarily mean the calling agent received its output. Please verify that the flow:

Uses When an agent calls the flow

Ends with Respond to the agent

Has Asynchronous response = Off

Responds within 100 seconds

Returns all expected outputs on every branch

Please also check:

Respond to the agent completes within 100 seconds. Move nonessential processing after it if needed.

Return the markdown result as a defined Text output on every branch.

In the flow tool configuration, pass files using Custom value:

ContentBytes: First(System.Activity.Attachments).Content

name: First(System.Activity.Attachments).Name

If inputs/outputs changed after adding the flow to the agent, remove and re-add the flow tool to refresh its bindings.

Temporarily bypass the child agent and use Send specific response with the flow's text output directly. This helps identify whether the issue is in the flow or the child-agent handoff.

If that works, pass the flow output explicitly to the child agent using a Text input, and configure its output/After running behavior.

Publish the flow, child agent, and parent agent, then start a new conversation before testing.

Test with a small supported file such as TXT or PDF (max 15 MB). Encrypted or sensitivity-protected files may cause generic errors.

If the flow takes longer than 100 seconds, the agent may show a generic failure even though the flow eventually succeeds.

Your answer

Ashlesha Pawar (Tata Consultancy Services Limited) 395 Reputation points Microsoft External Staff

2026-08-18T09:09:53.7666667+00:00

Thank you for the detailed description.

A successful Agent Flow run does not necessarily mean the calling agent received its output. Please verify that the flow:

Uses When an agent calls the flow

Ends with Respond to the agent

Has Asynchronous response = Off

Responds within 100 seconds

Returns all expected outputs on every branch

Please also check:

Respond to the agent completes within 100 seconds. Move nonessential processing after it if needed.

Return the markdown result as a defined Text output on every branch.

In the flow tool configuration, pass files using Custom value:

ContentBytes: First(System.Activity.Attachments).Content

name: First(System.Activity.Attachments).Name

If inputs/outputs changed after adding the flow to the agent, remove and re-add the flow tool to refresh its bindings.

Temporarily bypass the child agent and use Send specific response with the flow's text output directly. This helps identify whether the issue is in the flow or the child-agent handoff.

If that works, pass the flow output explicitly to the child agent using a Text input, and configure its output/After running behavior.

Publish the flow, child agent, and parent agent, then start a new conversation before testing.

Test with a small supported file such as TXT or PDF (max 15 MB). Encrypted or sensitivity-protected files may cause generic errors.

If the flow takes longer than 100 seconds, the agent may show a generic failure even though the flow eventually succeeds.