Unable to add workflow as a tool into Agent in Copilot Studio

Question

Unable to add workflow as a tool into Agent in Copilot Studio

Lee Jotham 0

I want to set up an agent in Copilot studio which will utilize a workflow (also in Copilot Studio). I create 2 flows to test (Agent flow - created in Copilot Studio) and 1 in Power Automate.

When i select any of the workflows here and click "Add and configure". I get this error:
User's image

How can i diagnose what is wrong?

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

2026-08-12T06:09:50.6166667+00:00
Hi Lee Jotham

Thanks for reporting this. To add to the AI's checklist above — I tested this scenario myself and found one thing worth checking that isn't obvious from the picker alone:

A flow can show "Published" and still be ineligible if its trigger/action nodes aren't the exact required types.

When I built a test workflow, it had a Start trigger and a generic Agent node (which calls a different agent) instead of the required When an agent calls the flow trigger and Respond to the agent action. It showed as Published in the Workflows list, but never appeared in the "Add a tool" picker at all — because eligibility depends on the specific node types, not just publish status.

So before digging further into the server error, could you confirm the following for both your Agent flow and your Power Automate flow:

Open each flow in the designer and click the first node — confirm it's literally named When an agent calls the flow, not Start, Manual trigger, Recurrence, or similar.

Click the last node — confirm it's literally Respond to the agent, not a generic Agent/Compose/HTTP response node.

This is especially worth checking on the Power Automate-authored flow, since its designer doesn't default to these Copilot Studio–specific node types — it's easy to build something that runs fine on its own but was never structured to be agent-callable.

If both flows genuinely have the correct trigger and action, and you still get the "unexpected server error" on Add and configure, that's a stronger signal of a platform-side issue rather than a flow configuration problem — at that point it'd be worth capturing the exact error banner text, a timestamp, and your environment/tenant ID for escalation.

Let us know what you find!

1 answer

Your answer

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

2026-08-12T06:09:50.6166667+00:00

Hi Lee Jotham

Thanks for reporting this. To add to the AI's checklist above — I tested this scenario myself and found one thing worth checking that isn't obvious from the picker alone:

A flow can show "Published" and still be ineligible if its trigger/action nodes aren't the exact required types.

When I built a test workflow, it had a Start trigger and a generic Agent node (which calls a different agent) instead of the required When an agent calls the flow trigger and Respond to the agent action. It showed as Published in the Workflows list, but never appeared in the "Add a tool" picker at all — because eligibility depends on the specific node types, not just publish status.

So before digging further into the server error, could you confirm the following for both your Agent flow and your Power Automate flow:

Open each flow in the designer and click the first node — confirm it's literally named When an agent calls the flow, not Start, Manual trigger, Recurrence, or similar.

Click the last node — confirm it's literally Respond to the agent, not a generic Agent/Compose/HTTP response node.

This is especially worth checking on the Power Automate-authored flow, since its designer doesn't default to these Copilot Studio–specific node types — it's easy to build something that runs fine on its own but was never structured to be agent-callable.

If both flows genuinely have the correct trigger and action, and you still get the "unexpected server error" on Add and configure, that's a stronger signal of a platform-side issue rather than a flow configuration problem — at that point it'd be worth capturing the exact error banner text, a timestamp, and your environment/tenant ID for escalation.

Let us know what you find!

Answer 1

Use this checklist to diagnose the failure.

Verify the flow meets the required tool criteria.
- It must have the When an agent calls the flow trigger.
- It must have a Respond to the agent action.
- It must be published.
- If using a workflow, the Respond to the agent action must be configured for a real-time response. In Respond to the agent > Networking, set Asynchronous response to Off.
Confirm the flow is actually eligible to appear as a tool.
- Copilot Studio only lists published workflows/flows that include the required trigger and response action.
- If a flow appears in the picker but fails on Add and configure, re-open the flow in the designer and validate those two nodes are still present and correctly configured.
Check the flow in the designer with flow validation.
- Most flow-related issues can be found in the flow checker on the flow designer tab.
- Open each test flow and review any validation errors or warnings there first.
Review response timing.
- The flow must respond to the agent within the 100-second action limit.
- If the flow performs long-running queries or returns too much data, simplify the logic and reduce the returned payload.
Recreate one minimal test flow.
- From Flows > New flow > Agent flow.
- Use the starter template that already includes When an agent calls the flow and Respond to the agent.
- Add no extra actions.
- Publish it.
- Try adding that minimal flow to the agent.
- If the minimal flow works, the issue is in the original flow configuration rather than the agent.
After adding, configure the tool metadata.
- In the tool configuration pane, set a clear Name and Description.
- Review Inputs and Completion settings, then Save.
Test from the agent side.
- In Test your agent or Preview, trigger the workflow and verify the tool call.
- If the tool is added but not invoked, refine the tool name, description, or agent instructions.
- In the new experience, use the activity trace to see which tool was invoked, the arguments passed, and the returned result.

A practical isolation path for this exact scenario is:

First test a brand-new minimal Agent flow created from the starter template.
If that also fails at Add and configure, the issue is likely not the flow logic itself.
If it succeeds, compare the failing flows for missing Respond to the agent configuration, unpublished changes, async response settings, or excessive runtime.

The provided documentation does not include a specific cause for the generic "Something went wrong. Please try again. An unexpected server error occurred." message, but the supported diagnostic path is to validate the flow in the designer, confirm the required trigger/response pattern, ensure publication, and test with a minimal published agent flow.