chore: import upstream snapshot with attribution

python/samples/03-workflows/functional/hitl_review.py

@@ -0,0 +1,84 @@
+# Copyright (c) Microsoft. All rights reserved.
+
+"""Human-in-the-loop review pipeline using functional workflows.
+
+Demonstrates ctx.request_info() for pausing the workflow to wait for
+external input and resuming with run(responses={...}).
+
+HITL works with or without @step. The difference is what happens on resume:
+- Without @step: every function re-executes from the top (fine for cheap calls).
+- With @step: completed functions return their saved result instantly.
+
+This sample uses @step on write_draft() because it simulates an expensive
+operation that shouldn't re-run just because the workflow was paused.
+"""
+
+import asyncio
+
+from agent_framework import RunContext, WorkflowRunState, step, workflow
+
+
+# @step saves the result. When the workflow resumes after the HITL pause,
+# this returns its saved result instead of running the expensive operation again.
+#
+# In a real workflow you might call an agent here instead:
+#   @step
+#   async def write_draft(topic: str) -> str:
+#       return (await writer_agent.run(f"Write a draft about: {topic}")).text
+@step
+async def write_draft(topic: str) -> str:
+    """Simulate writing a draft — expensive, shouldn't re-run on resume."""
+    print(f"  write_draft executing for '{topic}'")
+    return f"Draft document about '{topic}': Lorem ipsum dolor sit amet..."
+
+
+@step
+async def revise_draft(draft: str, feedback: str) -> str:
+    """Revise the draft based on feedback."""
+    return f"Revised: {draft[:50]}... [Applied feedback: {feedback}]"
+
+
+@workflow
+async def review_pipeline(topic: str, ctx: RunContext) -> str:
+    """Write a draft, get human review, then revise."""
+    draft = await write_draft(topic)
+
+    # ctx.request_info() suspends the workflow here. The caller gets back
+    # a WorkflowRunResult with state IDLE_WITH_PENDING_REQUESTS and can
+    # inspect the pending request via result.get_request_info_events().
+    feedback = await ctx.request_info(
+        {"draft": draft, "instructions": "Please review this draft"},
+        response_type=str,
+        request_id="review_request",
+    )
+
+    # This only executes after the caller resumes with run(responses={...}).
+    # write_draft above returns its saved result (thanks to @step),
+    # request_info returns the provided response, and we continue here.
+    return await revise_draft(draft, feedback)
+
+
+async def main():
+    # Phase 1: Run until the workflow pauses for human input
+    print("=== Phase 1: Initial run ===")
+    result1 = await review_pipeline.run("AI Safety")
+
+    # If request_info() was reached, the state is IDLE_WITH_PENDING_REQUESTS.
+    # If the workflow completed without hitting request_info(), it would be IDLE.
+    print(f"State: {(final_state := result1.get_final_state())}")
+    assert final_state == WorkflowRunState.IDLE_WITH_PENDING_REQUESTS
+
+    requests = result1.get_request_info_events()
+    print(f"Pending request: {requests[0].request_id}")
+
+    # Phase 2: Resume with the human's response
+    print("\n=== Phase 2: Resume with feedback ===")
+    print("(write_draft should NOT execute again — saved by @step)")
+    result2 = await review_pipeline.run(responses={"review_request": "Add more details about alignment research"})
+
+    print(f"State: {result2.get_final_state()}")
+    print(f"Output: {result2.get_outputs()[0]}")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())