Core tool: the session's todo list (omp's todo), kept in todos/<session_id>.json in the app's data dir. Writing the steps of a multi-step job down and ticking them off keeps the agent from stopping halfway, or forgetting a step after a compaction; and the list survives a restart of the app. One item at a time is in progress: the first open one, moved on whenever an item is done or removed.

open_items/2 gives the items not done yet, so the loop can remind the agent when it ends a run with some left.