09_workflow_hitl

Human-in-the-Loop Workflow on a Standalone Durable Task Worker

This sample demonstrates a Human-in-the-Loop (HITL) agent-framework Workflow running as a durable orchestration on a standalone Durable Task worker — no Azure Functions required. It is the durabletask counterpart to the Azure Functions sample samples/04-hosting/azure_functions/12_workflow_hitl.

Key Concepts Demonstrated

• Pausing a workflow for human input with MAF's ctx.request_info() / @response_handler pattern, hosted on a standalone worker via DurableAIAgentWorker.configure_workflow(workflow).
• Discovering pending HITL requests from a client with DurableWorkflowClient.get_pending_hitl_requests(instance_id).
• Resuming the workflow by sending a decision with DurableWorkflowClient.send_hitl_response(instance_id, request_id, response).
• Reading the final result with DurableWorkflowClient.await_workflow_output(instance_id).

The workflow is a content-moderation pipeline:

input_router -> ContentAnalyzerAgent -> content_analyzer_executor
             -> human_review_executor (HITL pause) -> publish_executor

How HITL Works Here

The HITL mechanism is host-agnostic — the same shared workflow orchestrator drives it on both Azure Functions and a standalone worker:

1. human_review_executor calls ctx.request_info(...), which pauses the workflow. The orchestrator records the open request in its custom status and waits for an external event named by the request's request_id.
2. The client reads the custom status via get_pending_hitl_requests and sends a response via send_hitl_response, which raises that external event.
3. The orchestrator routes the response back to the executor's @response_handler, and the workflow resumes.

send_hitl_response sanitizes the payload (neutralizing pickle-marker injection) before delivery, since the worker deserializes it.

Environment Setup

See the README.md in the parent directory for environment setup.

This sample uses Azure AI Foundry credentials:

• FOUNDRY_PROJECT_ENDPOINT
• FOUNDRY_MODEL

It also needs a Durable Task Scheduler. For local development, start the emulator (defaults to http://localhost:8080):

docker run -d -p 8080:8080 -p 8082:8082 mcr.microsoft.com/dts/dts-emulator:latest

Running the Sample

Start the worker in one terminal:

cd samples/04-hosting/durabletask/09_workflow_hitl
python worker.py

In a second terminal, run the client:

python client.py

The client runs two cases:

• Appropriate content → analyzed → HITL pause → client approves → "Content '...' has been APPROVED and published."
• Spammy content → analyzed → HITL pause → client rejects → "Content '...' has been REJECTED."