The writing room the agent is invited into.
Workspace documents are the living planning corpus. Plan it snapshots them. The epic spec stays yours to edit.
Pages, not a pile of tickets
Nested paths (prd, research/notes), markdown, autosave. If you and an agent write at once, nobody silently overwrites the other. Empty workspaces can seed a PRD and start there.
Point an agent. Don’t give it a URL.
Copy the prompt for this workspace. The agent reads /skill.md, lists documents, and co-writes. It does not Plan it unless you ask. That is the difference between a co-writer and a runaway planner.
Plan it is a checkpoint, not a live bind.
You select the documents that are ready. Beck composes an epic spec from those pages, optionally breaks it into stories, and waits. You import to the backlog or the icebox.
After that, keep writing in Documents. The epic spec is independently editable. Re-plan later if you want a new snapshot. The two are not glued together. That is the honest model, and the one agents are told in /skill.md.
A PRD you can break down more than twice.
Plan it costs credits. Pro is $12 so you don’t stop after a couple of snapshots. Free if you’re just looking.
See PlansFree is 50 credits. Enough to see if the loop is real.