Copilot Studio consistent System Error issue

Hello,

The System Error you are receiving is most likely a FlowActionTimedOut. Microsoft documentation is explicit on this point : any flow called as a tool by a Copilot Studio agent must respond within a maximum of 100 seconds. Beyond that, the flow times out and the calling agent receives a system error.

In addition, asynchronous response mode is not supported in this context. The "Asynchronous response" toggle must be set to Off in the "Respond to the agent" node.

An execution time of 10 to 15 minutes is therefore structurally incompatible with this pattern.

There is a documented option to place long-running logic after the "Respond to the agent" node, which allows the flow to continue running in the background for up to 30 days. However, this does not solve your problem: the calling agent does not receive the result of that deferred execution, it only receives the intermediate response sent before. You cannot retrieve the output of your downstream agent and return it to the calling agent.

The architecture you describe, retrieving the result of a 10 to 15 minute operation to pass it back to the calling agent, is not supported by Copilot Studio based on the current documentation.

Hope this helps.