Tool (flow) call with Enhanced Task Completion turned on

Question

I am testing enhanced task completion and it is great, except it fails when it tries to call a tool that I know is working with other agents

The tool a "when agent calls" trigger and runs a power BI query. The agent is giving this error

Parameters

text: 419209

Error

Failed to resolve flow trigger URI.

I have tried turning the flow on and off again, disconnect and re-connecting changing the input parameters, checking it is authenticated. The tool works 100% of the time when I turn ATC off.

Am i missing something, is there a way to get this working or is this just a limit of current ATC even though it says it will work with tools?

Answer 1

Enhanced Task Completion relies on the same underlying trigger/connection registration that standard Power Automate tool calls use. The error Failed to resolve flow trigger URI indicates that the agent cannot find or use the trigger endpoint for the flow when ATC is enabled, even though the flow itself works.

From the available guidance, the most relevant checks are the generic trigger and connection troubleshooting steps used for Power Automate flows and tools:

1. Confirm the flow’s trigger is correctly registered and not failing
   • In Power Automate, go to My flows → select the flow used as the tool.
   • Check the Details page for trigger errors similar to the generic trigger failure screenshot described in the trigger troubleshooting article. If the trigger registration is failing, the agent cannot resolve the trigger URI.
   • If there is a trigger error, follow the guidance to fix it (for example, ensuring required endpoints/IPs are allowed) and then edit and save the flow so it re-registers the trigger.
   • After fixing, make a small change to the flow, save it, then change it back and save again so the trigger registration is refreshed.
2. Verify connections and authentication
   • Ensure all connections used by the flow (including Power BI and any others) are valid and authenticated under the account that owns the tool/flow.
   • If the flow is shared or run under different identities, confirm that the correct connection is used and that it is not broken or changed in a way that invalidates the trigger configuration.
3. Check for environment or policy issues that can block trigger registration
   • If the environment uses network restrictions, ensure the Power Automate service endpoints and IP ranges are allowed as described in the trigger troubleshooting guidance. If these endpoints are blocked, trigger registration can fail and result in errors like failure to resolve the trigger URI.
4. Re-save the flow after any environment or URL changes
   • If the environment URL or configuration has changed since the tool was created, edit and save the flow again so its trigger is re-registered with the correct URI.

Given that the tool works when ATC is off, but fails only when ATC is on, this behavior is consistent with a trigger registration or resolution issue in the specific context in which ATC invokes the tool. The supported remediation path from the documentation is to:

• Validate trigger registration (no trigger errors on the flow details page).
• Ensure all required endpoints are allowed.
• Re-save the flow to force trigger re-registration.
• Confirm all connections are valid and licensed.

If these steps do not resolve the issue, this likely reflects a current limitation or defect in how Enhanced Task Completion integrates with “when agent calls” flows, and it would require escalation through Microsoft support with the exact error and flow/agent IDs.

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References:

• Troubleshoot common issues with triggers
• Troubleshoot known issues with Dataverse
• Troubleshoot a cloud flow
• Troubleshoot cloud flows
• Troubleshoot Power Apps flow integration issues
• Tool best practices for Microsoft Foundry Agent Service