> ## Documentation Index
> Fetch the complete documentation index at: https://phidatainc-studio-tools-doc.mintlify.site/llms.txt
> Use this file to discover all available pages before exploring further.

# Nested Workflow with Router

> Inner workflow with a `Router` step that routes to specialist agents based on the topic.

```python theme={null}
from typing import List

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


def topic_router(step_input: StepInput) -> List[Step]:
    """Route to a specialist based on keywords in the input."""
    text = (step_input.input or "").lower()

    if any(kw in text for kw in ["code", "programming", "software", "api"]):
        return [Step(name="tech_research", agent=tech_specialist)]
    elif any(kw in text for kw in ["history", "war", "ancient", "century"]):
        return [Step(name="history_research", agent=history_specialist)]
    else:
        return [Step(name="general_research", agent=general_specialist)]


# Specialist agents
tech_specialist = Agent(
    name="Tech Specialist",
    model=OpenAIChat(id="gpt-4o-mini"),
    instructions="You are a technology expert. Provide detailed technical explanations.",
)

history_specialist = Agent(
    name="History Specialist",
    model=OpenAIChat(id="gpt-4o-mini"),
    instructions="You are a historian. Provide detailed historical context and analysis.",
)

general_specialist = Agent(
    name="General Specialist",
    model=OpenAIChat(id="gpt-4o-mini"),
    instructions="You are a general knowledge expert. Provide clear, informative answers.",
)

# Inner workflow: routed research
inner_workflow = Workflow(
    name="Routed Research",
    description="Routes to the right specialist based on the topic",
    steps=[
        Router(
            name="specialist_router",
            selector=topic_router,
            choices=[
                Step(name="tech_research", agent=tech_specialist),
                Step(name="history_research", agent=history_specialist),
                Step(name="general_research", agent=general_specialist),
            ],
        ),
    ],
)

# Outer workflow
editor = Agent(
    name="Editor",
    model=OpenAIChat(id="gpt-4o-mini"),
    instructions="You are an editor. Polish and improve the specialist's research into a clear article.",
)

outer_workflow = Workflow(
    name="Smart Research and Edit",
    description="Routes to the right specialist, then edits the result",
    steps=[
        Step(name="research_phase", workflow=inner_workflow),
        Step(name="editing_phase", agent=editor),
    ],
)


if __name__ == "__main__":
    outer_workflow.print_response(
        input="Explain how REST APIs work and best practices for designing them",
        stream=True,
    )
```

## Run the Example

```bash theme={null}
git clone https://github.com/agno-agi/agno.git
cd agno/cookbook/04_workflows/06_advanced_concepts/workflow_as_a_step

pip install agno openai

python nested_workflow_with_router.py
```