chat.agent: advanced and operational

chat.agent is built on Sessions: a durable, task-bound, bi-directional I/O channel pair keyed on a stable externalId (e.g. chatId) that outlives any single run. This skill covers the layers beneath and around the everyday agent: the raw sessions API, server-side AgentChat, durable sub-agents, actions / background injection, fast starts, compaction and recovery, and the wire protocol for custom transports.

Two chat namespaces are easy to confuse: the agent definition imports chat from @trigger.dev/sdk/ai; Head Start / Node-listener server entries import chat from @trigger.dev/sdk/chat-server.

Setup

Happy path: drive an agent from server-side code (task, webhook, or script) with AgentChat.

import { AgentChat } from "@trigger.dev/sdk/chat";
import type { myAgent } from "./trigger/my-agent";