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Subtasks

Let an agent split a task into subtasks, run them with Claude Code or Codex, and follow their results.

An agent working on a task can start subtasks: other Claude Code or Codex tasks that each take part of the job. You ask in plain words, and the agent starts the subtasks, sends them instructions, and reads their results.

In a task, tell the agent how to split the work. For example:

Example request
Split this into two subtasks: a Codex subtask that adds the CSV export endpoint, and a Claude Code subtask that writes tests for it. When both finish, review their changes and tell me what's left.

The agent writes each subtask’s title and instructions, and picks its agent and model. To choose them yourself, say so in your request.

While a subtask runs, the agent that started it can:

  • Send it more instructions, or change the instruction it’s working on.
  • Switch its model or reasoning level.
  • Interrupt it, stop it, or mark its work as done.
  • Read its results.

Hercus tells the agent when a subtask finishes a turn or fails, so it doesn’t have to keep checking.

Subtasks don’t appear on the board. You find them under the task that started them:

  • The task’s card shows how many it has, for example 2 subtasks.
  • In the open task, select the subtasks button in the title bar to show the Subtasks panel. The button’s tooltip shows how many subtasks there are and any unread updates.

The panel lists each subtask with its agent, model, and status:

StatusMeaning
WorkingThe subtask is starting up, or its agent is working.
ReadyThe subtask finished its turn and is ready for more instructions.
ErrorSomething went wrong. Open the subtask to see what happened.
TerminatedThe subtask was stopped. Its conversation is kept, so it can carry on later.
ArchivedIts work was accepted. Archived subtasks move to History at the bottom of the panel.

While a subtask launches, its status can show Queued, Waiting for system resources, or Starting… first.

Select a subtask to open it on top of its parent. You can read its work and reply to it like any task.

To tidy up, open Subtask actions in the panel. Hercus asks you to confirm each action:

  • Archive resolved archives the subtasks that finished their turn or were stopped.
  • Terminate active stops every subtask that’s still working, without accepting its work.

If a subtask shows Delivery needs attention, Hercus couldn’t pass its result to the parent task, for example because the parent was stopped. Restart the parent task, then select Retry delivery.

  • Only an agent in a task can start subtasks. Sidechat and Explore can’t.
  • Subtasks go one level deep. A subtask can’t start subtasks of its own.
  • Each subtask runs with full access, like every task, and counts toward its agent’s usage limits.