How to set the default agent?

[yeahdongcn]

I noticed the first defined one is the default agent:

@fast.agent("You are a helpful agent")          # Create an agent with a default name.
@fast.agent("greeter","Respond cheerfully!")    # Create an agent with the name "greeter"

moon_size = await agent("the moon")             # Call the default (first defined agent) with a message

But I wish to set the default agent explicitly. Does anyone know how? Thanks.

[yeahdongcn]

Close now: #231