Parallel sessions

Sessions that change the same host — two windows, or teammates on different workstations — see each other. Before its first change a session registers on the host itself, in /tmp/hostwarden/ (no root needed), with who it is, where it runs and what it is doing. Another live entry makes Hostwarden say so and ask whether the two get in each other's way; a session on the same machine can be messaged directly, to share what each has seen, never to have one do what the other may not. Sessions that only read — housekeeping, audits — register nothing.

Steps that reach other hosts

A reboot, a firewall or network change or a restart reaches more than its own host: the guests of a hypervisor, the hosts behind a jump host, the hosts that use a service it runs. Before such a step a session announces it; the sessions on this machine that work on a host it reaches are named, the ones changing something there get up to two minutes to reach a safe point, and you decide whether to go, wait or stop. A session that then reaches one of those hosts is told once what is going on.

In a team

In a team — two or more people in operators.md, not counting a handle marked (inactive since …) or (operations host) — the announcement also goes onto each host it reaches, as a register entry and a journal line, so your colleagues' sessions see it too. Alone, with or without a shared workspace, nothing is written on other hosts.

The coordinator

The first session in an operations checkout starts a coordinator in the background, one per checkout, and says so in one line. It keeps track of which session works on which host, asks a session what it is doing when it moves on to other hosts, passes an announced step on to the sessions it concerns, keeps an order of steps that spans sessions, and warns about maintenance windows. It never reaches a server and never decides anything for you or another session.

claude agents lists it as hostwarden coordinator. To turn it off, run /hostwarden-coordinator in any session: it stops the coordinator and writes Coordinator: off into your memory/user.md, so the next session does not start it again. The same skill removes the line and starts one when you want it back.