Power Automate Flows Created Outside Copilot Studio Not Appearing in Tools

Hello Adhonai_KOUKA​ , I've just tried to replicate your setup. It worked for me. Sharing my results and observations:-

• A flow created in Power Automate can indeed be used in Copilot Studio (it doesn't have to an agent flow created straight within Copilot Studio)
• The flow once created and added to solution in Power Automate appeared immediately in Copilot Studio - there was no lag or sync time

Looks like you've done all the right things e.g. the trigger, last action, environment. May be worth checking the below points

• In the Power Automate flow, in "Respond to the agent" action settings > Asynchronous response > Off
• In the Power Automate solution, "Publish all customizations" is clicked.
  • Note that in my case, the flow is in a separate solution of its own. For the agent, I have not even created a solution at this point.
• In Copilot Studio, look for the flow under "Add tool" > "Workflows" (not in "Add new - Workflows)

If this is still not working, I'd recommend to check if this is some kind of incompatibility with the actions inside the flow. In my case, it is a very simple flow that I set up just to test this scenario.

Below is the reference I used (probably you've done the same)

https://learn.microsoft.com/en-us/microsoft-copilot-studio/flow-modify-use-with-agent