Agent Hosts

An agent host is the place an agent loop runs. Three host shapes cover practice. A session: the agent runs on your machine while you watch, and dies when the terminal closes. A gateway: a long-lived process that listens for events, a chat message, a webhook, a schedule, and wakes the agent for each one. A job runtime: durable execution, where progress is recorded at every wait and a crash resumes instead of restarting.

The cut between them is lifetime. A session lives as long as your attention. A gateway lives as long as its process. A job survives both, because its state is stored outside the process that runs it.

“The agent is always on” describes the host, because the model only exists during a call. Something is holding the loop open and catching events; a gateway can also send itself a heartbeat, a scheduled self-wake that lets it check on the world without being asked.

When an agent “cannot” do something, check the host before the model. Cannot run for an hour: session limit. Cannot react to an incoming email: no gateway. Cannot wait three days for an approval: no durable runtime. Same model in all three cases.