Scribbles for my memory

bg-run sounds like a small shell convenience: start a command and let the agent continue. Its real contract is much larger. The command must survive the end of the current agent turn, record its result, report meaningful milestones, and wake the right session later. That is a lifecycle and delivery problem, not an ampersand problem.

A reliable implementation needs a durable owner, an isolated process group, cancellation and reaping, durable result and event records, and a callback path into the session that started the work. It also needs at-least-once delivery, because a wake-up can be retried without creating a second task.

The tmux implementation works because tmux happens to provide most of this machinery. A helper session owns the process after the caller returns, and a pane gives the result a place to wake. bg-run can write immutable milestone and final events, then the agent can consume them on its next turn. On a tmux host, this is a perfectly useful adapter.

But tmux is a hosting-specific workaround, not the underlying abstraction. A Baton driver has no pane and no TMAT_PANE, so the tmux implementation correctly refuses to run. Replacing it with setsid, disown, or another backgrounding trick would not fix the ownership problem: an external tool runner can still clean up the caller's descendant process tree, leaving a state file that names a dead worker. Detaching a process is not the same as giving it a supervisor.

Baton already has the right foundation. baton serve is a resident mailbox responder with atomic pending/claimed/done delivery, single-instance locking, stale-work reclaim, and cooperative stop. The missing piece is making that residency real for the whole integration: a host-owned baton service process, run in the foreground under something like a systemd user service, should spawn and own each session's baton serve and each asynchronous task. The client that submits work must not be its owner.

On top of that service, a generic baton task start API can return a stable task ID immediately, persist the command specification and state, run the task in its own process group, capture its output, and emit immutable milestone and terminal events to the requested Baton mailbox. task status and task cancel complete the lifecycle; session teardown cancels and reaps its tasks. The agent starts the task, ends its turn, and is woken by the mailbox when there is something worth reading. No sleep 50, PID loop, or result-file polling is needed.

That is why the Baton design is the general solution: it treats ownership and notification as a protocol rather than an accidental property of a terminal multiplexer. bg-run remains a good agent-facing name in my-ai-team because it describes the user action. Baton itself should expose a provider-neutral task or job primitive, with my-ai-team's bg-run as one adapter. Tmux can remain a useful adapter where it exists; Baton supplies the real owner where it does not.