Step Choices Parameter

Access available choices in selector functions to dynamically route between steps.

Demonstrates using step_choices in a router selector for dynamic step selection.

step_choices_parameter.py
"""
Step Choices Parameter
======================

Demonstrates using `step_choices` in a router selector for dynamic step selection.
"""

from typing import List, Union

from agno.agent.agent import Agent
from agno.models.openai import OpenAIChat
from agno.workflow.router import Router
from agno.workflow.step import Step
from agno.workflow.types import StepInput
from agno.workflow.workflow import Workflow

# ---------------------------------------------------------------------------
# Create Agents
# ---------------------------------------------------------------------------
researcher = Agent(
    name="researcher",
    model=OpenAIChat(id="gpt-5.6-luna"),
    instructions="You are a researcher.",
)

writer = Agent(
    name="writer",
    model=OpenAIChat(id="gpt-5.6-luna"),
    instructions="You are a writer.",
)

reviewer = Agent(
    name="reviewer",
    model=OpenAIChat(id="gpt-5.6-luna"),
    instructions="You are a reviewer.",
)


# ---------------------------------------------------------------------------
# Define Router Selector
# ---------------------------------------------------------------------------
def dynamic_selector(
    step_input: StepInput,
    step_choices: list,
) -> Union[str, Step, List[Step]]:
    user_input = step_input.input.lower()
    step_map = {s.name: s for s in step_choices if hasattr(s, "name") and s.name}

    print(f"Available steps: {list(step_map.keys())}")

    if "research" in user_input:
        return "researcher"
    if "write" in user_input:
        return step_map.get("writer", step_choices[0])
    if "full" in user_input:
        return [step_map["researcher"], step_map["writer"], step_map["reviewer"]]
    return step_choices[0]


# ---------------------------------------------------------------------------
# Create Workflow
# ---------------------------------------------------------------------------
workflow = Workflow(
    name="Dynamic Routing (step_choices)",
    steps=[
        Router(
            name="Dynamic Router",
            selector=dynamic_selector,
            choices=[researcher, writer, reviewer],
        ),
    ],
)

# ---------------------------------------------------------------------------
# Run Workflow
# ---------------------------------------------------------------------------
if __name__ == "__main__":
    workflow.print_response("I need to research something", stream=True)

Run the Example

Set up your virtual environment

uv venv --python 3.12
source .venv/bin/activate

Install dependencies

uv pip install -U agno fastapi openai

Export your OpenAI API key

export OPENAI_API_KEY="your_openai_api_key_here"

Run the example

Save the code above as step_choices_parameter.py, then run:

python step_choices_parameter.py

Full source: cookbook/04_workflows/05_conditional_branching/step_choices_parameter.py