One agent engine. Embed it, or run a fleet.

$ agen up
agen is up: hub http://127.0.0.1:7070
web UI: http://127.0.0.1:7070/

$ agen init
wrote the hello template to hello
$ agen deploy hello --replicas 1
deployed default/hello definition 3f1c0d2a7b9e desired 1
$ agen run hello "hi"
Hello! Nice to meet you.

from agen import Agent, openrouter, tool

@tool(read_only=True)
def lookup_order(order_id: str) -> dict:
    """Look up an order by id."""
    return {"status": "shipped", "carrier": "UPS"}

agent = Agent("order-desk",
              instructions="Answer order questions using lookup_order.",
              model="deepseek/deepseek-v4-flash",
              provider=openrouter(),
              tools=[lookup_order])

with agent:
    print(agent.run("Where is my order A-1001?").output)