digraph BranchLoop {
    graph [goal="Create a Python script that passes its test suite"]
    rankdir=LR

    start [shape=Mdiamond, label="Start"]
    exit  [shape=Msquare, label="Exit"]

    plan      [label="Plan", prompt="Plan a small Python script (fizzbuzz.py) and a test file (test_fizzbuzz.py) using pytest. Describe what you will create.", shape=tab, reasoning_effort="low"]
    implement [label="Implement", prompt="Create fizzbuzz.py and test_fizzbuzz.py as planned. Write the files to disk."]
    validate  [label="Validate", shape=parallelogram, script="python3 -m pytest test_fizzbuzz.py -v 2>&1 || true"]
    gate      [shape=diamond, label="Tests passing?"]

    start -> plan -> implement -> validate -> gate
    gate -> exit      [label="Pass", condition="outcome=succeeded"]
    gate -> implement [label="Fix"]
}