Save a progress checkpoint so any future agent session can resume exactly here.

Call this after EVERY concrete sub-task (a file edited, a test passing, a command run) — not only when a numbered step finishes. Frequent, small checkpoints are the point: if the session dies mid-step, the next agent resumes from the last sub-task instead of redoing the whole step.

Args: plan: The full numbered plan being executed (all steps, verbatim). current_step: 1-based number of the step currently being worked on. total_steps: Total number of steps in the plan. step_status: "in_progress", "done", or "blocked" — status of current_step. what_was_done: Everything completed so far, across all steps, specific enough that another agent will not redo any of it. what_remains: What is still missing IN THE CURRENT STEP, specific enough to be the very next action (plus any known remaining steps). project_dir: Optional project directory override; defaults to the server's working directory (walking up to the nearest .git root).

Get the latest checkpoint for this project — where to resume from.

Call this FIRST when a task looks like a continuation of earlier work (e.g. after a session was cut off). It returns the plan, the current step, what was already done (do not redo it), and the exact next action.

Args: project_dir: Optional project directory override; defaults to the server's working directory (walking up to the nearest .git root).

List the checkpoint history for this project, newest first, with timestamps.

Args: limit: Maximum number of checkpoints to return (default 20). project_dir: Optional project directory override; defaults to the server's working directory (walking up to the nearest .git root).

Delete all checkpoints for this project. Requires confirm=true.

Called without confirm, it only reports how many checkpoints would be deleted; ask the user before calling again with confirm=true.

Args: confirm: Must be true to actually delete. False = dry run. project_dir: Optional project directory override; defaults to the server's working directory (walking up to the nearest .git root).