State Path Traceback

The problem

It is difficult to find the exact sequence of actions that causes a system to break or reach an error state. Identifying the root cause often requires checking every possible path instead of just the one that failed.

What it does

It looks at the history of inputs and traces back to pinpoint the specific sequence that leads to an invalid state. It identifies the exact path of events that caused a problem.

Why it matters

It identifies the specific error path rather than requiring a check of the entire system.

Validation

It was run inside an isolated container with no network access. This is the exact command and the real output it produced — captured process output, not written by a model.

$ python3 state_path_traceback.py
Sequence of inputs leading to invalid state: ['input1', 'input2', 'input3']

A screenshot of that run.

A clean run proves this does what is shown above, in a CPU-only sandbox. It is a small research demo — not a production tool, and nothing here was published anywhere.

The code

All of it — 30 lines, one file, standard library only.

# State Path Traceback Script

def backtrack_trace(transitions, invalid_state):
    path = []
    current_state = invalid_state
    
    # Iterate through transitions in reverse chronological order
    for i in range(len(transitions)-1, -1, -1):
        prev, curr, inp = transitions[i]
        if curr == current_state:
            path.append(inp)
            current_state = prev

    # Reverse to maintain chronological order
    path.reverse()
    return path


# Example Usage
if __name__ == "__main__":
    # Define transitions as (previous_state, current_state, input) tuples
    transitions = [
        ("Start", "A", "input1"),
        ("A", "B", "input2"),
        ("B", "Invalid", "input3")
    ]

    invalid_state = "Invalid"
    result = backtrack_trace(transitions, invalid_state)
    print(f"Sequence of inputs leading to invalid state: {result}")