Tomorrow. Under twenty minutes.
Take a task you would normally give an agent in one go and split it in two. Run the first half, then ask the agent to write a handover note covering what it did, what it decided, and what is still open. Close the session. Open a new one, paste the note, and run the second half.
You will know it worked when you can point to something in the second session that went better than the equivalent stretch of a long session, and say why.