Usually not. Nothing is taken when you start a run, and a task is charged only if the model finished without an error (in the API, pexit is "0").
Failed: not charged; the cost is set to $0.
Cancelled while queued: not charged. The model never ran.
Killed while running: normally not charged, because stopping the model counts as an error. If the model had already succeeded when the kill arrived, the run is charged and can show Cancelled with a cost.
Succeeded without a file: charged. Deleting files later doesn't undo a charge.
Exceptions: realtime voice sessions are charged per turn, and those charges stay if the session is killed or ends with an error. The Wiro Studio chat uses a small amount of credit even when a generation fails.
Think a failed task was charged? Send us the task ID. Details: failed tasks and when you're charged and our docs.