Human In The Loop

What this lesson demonstrates

Approvals, clarifications, sign-offs — some steps can’t proceed without a human. RunContext.request_info suspends the workflow and returns a pending request to your code. You gather the human’s answer and resume by re-running with that answer keyed by request_id. Here an approval_flow asks whether to publish a release note, suspends, and on resume either publishes or rejects — pure functional workflow, zero credentials.

The code

The suspend point is a single awaited call inside a @workflow:

@workflow
async def approval_flow(draft: str, ctx: RunContext) -> str:
    decision = await ctx.request_info(
        {"draft": draft, "question": "Approve this release note? (approve/reject)"},
        response_type=str,
        request_id="review",
    )
    if decision.strip().lower().startswith("approve"):
        return f"PUBLISHED ✅ — {draft}"
    return "REJECTED ❌ — sent back for edits."

Driving it is two runs — one that suspends, one that resumes:

result = await approval_flow.run(draft)
pending = result.get_request_info_events()          # what the human must answer
final = await approval_flow.run(responses={"review": "approve"})  # resume, no new message

What to notice

• request_info returns the human’s answer on resume. On the first run it suspends; on the resume run the same await returns the supplied value directly, so the function reads like straight-line code.
• Pending requests are events. result.get_request_info_events() lists each suspension with its request_id and data — the payload you showed the human.
• Resume passes responses, not a message. run(responses={"review": human_answer}) — no draft on resume, just the keyed answer.

The gotcha

The resume key must exactly match the request_id from the suspend call — here "review" on both sides. Pass a mismatched key and the workflow won’t find the answer it’s waiting on. Note also that functional workflows are experimental in this build, so the API may shift.

How it maps to MAF and Foundry

This builds directly on checkpointing: a suspended workflow can be persisted and resumed hours later, across process restarts, once its state is snapshotted. The same request_info gate underlies tool-approval flows where a human authorizes a side effect before an agent proceeds — MAF’s uniform way to put a person in the loop.

Run it

uv run tutorial/03-workflows/04_human_in_the_loop.py

Runs offline — no Azure creds. Success: the workflow suspends, receives approve, and prints PUBLISHED.

Next: Workflow As Agent