Spec mode

For work where the plan matters more than the first patch, a thread can run in spec mode: it produces requirements, then design, then tasks as separate artifacts, and each one is gated: the next stage does not unlock until you approve the previous one. The artifacts live with the thread, so the tasks that come out the end are traceable back to the requirement that asked for them. You can leave spec mode without approving the remaining stages if the work has moved on.

Once tasks.md is approved, the checkboxes are a dispatch DAG: each line is an id, a title, and optional needs: dependencies. Dispatch forks a worker per currently unblocked task; a second click only starts work that is still open. Converge has the spec thread re-read the artifacts and the repo and append missing checkboxes. A cycle or a dangling needs: id is a parse error, not a silent skip.