Every agentic interface needs a sidebar that lets humans watch what the agent is doing—tool invocations, chat, errors, status updates—and send messages back. Without it, the agent becomes a black box: humans can't debug, learn the interaction rhythm, or intervene when things drift.

AgentPanel is a controlled-state activity feed component. The parent owns the stream (an array of AgentActivity objects with id, at timestamp, kind discriminator, source, text body, and optional detail JSON) via the activity prop. Header shows agent name and color, auto-scrolls to newest entry, and optional onSubmit callback enables textarea composer—respects busy flag during requests.

Import from @particle-academy/agent-integrations and render <AgentPanel activity={myActivity} agent={{ name, color }} onSubmit={handleMessage} busy={isWorking} />. Purely presentational: you own the state, component owns scroll and layout mechanics.