> ## Documentation Index
> Fetch the complete documentation index at: https://launchpad.datalumina.com/llms.txt
> Use this file to discover all available pages before exploring further.

# Nested Workflow

> Compose Launchpad workflows by delegating to a child workflow with a shared TaskContext

This deterministic example shows one Launchpad workflow calling another workflow while reusing the same `TaskContext`. It is useful when a larger workflow needs to delegate a focused sub-process without losing the parent workflow's accumulated state.

The example ships as `NestedWorkflow` in `app/launchpad/workflows/examples/nested_workflow/` and is registered as `WorkflowRegistry.NESTED_WORKFLOW`.

## What it demonstrates

* Parent workflow composition with `await ReplyDraftWorkflow().run_async(context=task_context)`
* A child workflow that writes output into the same `TaskContext`
* A runnable example that does not require LLM, tracing, database, or vector-search credentials
* The `Workflow.run_async(context=...)` path added for workflow composition

## Workflow graph

```mermaid theme={null}
flowchart TD
    A[RunReplyWorkflowNode] --> B[ReplyDraftWorkflow]
    B --> C[DraftReplyNode]
    C --> D[SendReplyNode]
```

## Parent workflow

```python theme={null}
from launchpad.core.schema import NodeConfig, WorkflowSchema
from launchpad.core.workflow import Workflow
from launchpad.workflows.examples.nested_workflow.nodes.run_reply_workflow_node import (
    RunReplyWorkflowNode,
)
from launchpad.workflows.examples.nested_workflow.nodes.send_reply_node import (
    SendReplyNode,
)
from launchpad.workflows.examples.nested_workflow.schema import (
    NestedWorkflowEventSchema,
)


class NestedWorkflow(Workflow):
    workflow_schema = WorkflowSchema(
        description="Parent workflow that delegates reply drafting to a child workflow.",
        event_schema=NestedWorkflowEventSchema,
        start=RunReplyWorkflowNode,
        nodes=[
            NodeConfig(
                node=RunReplyWorkflowNode,
                connections=[SendReplyNode],
                description="Calls ReplyDraftWorkflow with the shared context.",
            ),
        ],
    )
```

## Delegating to the child workflow

The parent node passes the current task context into the child workflow. Because the context is shared, `DraftReplyNode` can save its output and `SendReplyNode` can read it later in the parent flow.

```python theme={null}
class RunReplyWorkflowNode(Node):
    class OutputType(BaseModel):
        delegated: bool
        workflow: str

    async def process(self, task_context: TaskContext) -> TaskContext:
        await ReplyDraftWorkflow().run_async(context=task_context)
        self.save_output(self.OutputType(delegated=True, workflow="ReplyDraftWorkflow"))
        return task_context
```

## Run it

```bash theme={null}
uv run playground/nested_workflow.py
```

The script loads `app/launchpad/workflows/examples/nested_workflow/request_examples/billing_question.json`, runs `WorkflowRegistry.NESTED_WORKFLOW.value()`, and prints the final `TaskContext`.