Loop Confirmation HITL Example (AgentOS)

Pausing before a Loop starts so a human can decide whether to run the iterative work.

loop_confirmation.py

"""
Loop Confirmation HITL Example (AgentOS)

This example demonstrates pausing before a Loop starts so a human can decide
whether to run the iterative work.
"""

from agno.os import AgentOS
from agno.workflow.loop import Loop
from agno.workflow.step import Step
from agno.workflow.types import StepInput, StepOutput
from agno.workflow.workflow import Workflow
from workflow_db import db


def prepare_data(step_input: StepInput) -> StepOutput:
    topic = step_input.input or "quarterly performance"
    return StepOutput(
        content=f"Prepared data for '{topic}'.\n"
        "- Baseline metrics loaded\n"
        "- Candidate refinements identified"
    )


def refine_analysis(step_input: StepInput) -> StepOutput:
    previous_content = step_input.previous_step_content or "No previous analysis"
    return StepOutput(
        content=f"Refinement pass complete.\n\nInput considered:\n{previous_content}\n\n"
        "- Quality score improved\n"
        "- Narrative tightened"
    )


def finalize_results(step_input: StepInput) -> StepOutput:
    previous_content = step_input.previous_step_content or "No refinement output"
    return StepOutput(content=f"Final results:\n\n{previous_content}")


workflow = Workflow(
    name="loop_confirmation_workflow",
    description="Ask for human confirmation before an iterative refinement loop.",
    db=db,
    steps=[
        Step(name="prepare_data", executor=prepare_data),
        Loop(
            name="refinement_loop",
            steps=[Step(name="refine_analysis", executor=refine_analysis)],
            max_iterations=3,
            requires_confirmation=True,
            confirmation_message="Start the refinement loop?",
        ),
        Step(name="finalize_results", executor=finalize_results),
    ],
)
workflow.id = "workflow-hitl-loop-confirmation"

agent_os = AgentOS(
    name="Workflow Loop Confirmation HITL",
    description="AgentOS workflow example for loop start confirmation.",
    workflows=[workflow],
    db=db,
)
app = agent_os.get_app()


if __name__ == "__main__":
    agent_os.serve(app="loop_confirmation:app", reload=True)

The example imports this helper module from the same directory:

workflow_db.py

from agno.db.postgres import PostgresDb

db_url = "postgresql+psycopg://ai:ai@localhost:5532/ai"
db = PostgresDb(db_url=db_url)

Run the Example

1. Set up your virtual environment

   Mac

   uv venv --python 3.12
   source .venv/bin/activate
   

   uv venv --python 3.12
   .venv\Scripts\activate
   
2. Install dependencies

   uv pip install -U "agno[os]" "psycopg[binary]"
   
3. Run PgVector

   macOS / Linux

   docker run -d \
     -e POSTGRES_DB=ai \
     -e POSTGRES_USER=ai \
     -e POSTGRES_PASSWORD=ai \
     -e PGDATA=/var/lib/postgresql \
     -v pgvolume:/var/lib/postgresql \
     -p 5532:5432 \
     --name pgvector \
     agnohq/pgvector:18
   

   docker run -d `
     -e POSTGRES_DB=ai `
     -e POSTGRES_USER=ai `
     -e POSTGRES_PASSWORD=ai `
     -e PGDATA=/var/lib/postgresql `
     -v pgvolume:/var/lib/postgresql `
     -p 5532:5432 `
     --name pgvector `
     agnohq/pgvector:18
   
4. Run the example

   Save the code blocks above as loop_confirmation.py and workflow_db.py in the same directory, then run:

   python loop_confirmation.py
   

Full source: cookbook/04_workflows/08_human_in_the_loop/loop/01_loop_confirmation.py