What a call carries on Ulai Docs

The agent profile

Mon, 01 Jan 0001 00:00:00 +0000

Almost nothing about a conversation is configured on the agent server. The prompt, the voice, the GCP project, the service-account key, which behaviours are on — all of it arrives with each call, in something called the agent profile, sent by the agent client.

This matters to you as an operator for three reasons.

1. It explains the short environment list

You are not missing settings. There is no PROMPT, no VOICE, no GEMINI_MODEL to set here, because those are properties of an agent, not of a host. One agent server runs many different agents at once, each with its own.

Tools

Mon, 01 Jan 0001 00:00:00 +0000

An agent can do more than talk. Mid-call it can look up a balance, an order status, an appointment slot — anything the business it belongs to can answer.

None of that work happens on this host. The agent server has no database and no idea what any of those tools mean. It carries the request out to the agent client and carries the answer back.

model asks for "check_balance"
 │
 ▼
 agent server ──▶ agent client ──▶ the business's own system
 ◀──────────── answer ◀───────────────┘
 │
 ▼
model continues the conversation

What this means operationally

Tools are configured on the agent, not here. There is nothing to install, declare or permit on this host to make a tool available.

The shape of a call

Mon, 01 Jan 0001 00:00:00 +0000

Joining

The room exists first. Whoever created it is the only party that knows which room the other participants are in, so the agent server never creates one — it is told which to join.

client ──JoinBridge──▶ server ──join──▶ control plane
 │
 ├──▶ SFU room (WebSocket, Opus)
 └──▶ AI backend (the placement on the profile)

JoinBridge returns once the agent has a seat. The backend handshake continues after that.