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Who speaks first

Who speaks first

firstTurnHow a conversation opens
"user" (default)The agent waits for the caller.
"agent"A call opens with one short greeting the model writes after the caller joins. The instruction behind it is framework-generated and hidden from the preview transcript.
{ say: "..." }Every conversation opens with exactly that line, with no model call: a call speaks it, typed chat in the preview shows it, curb say and curb test start with it.

Use { say } when the opening words must not vary, for example a notice the law requires before an AI assistant talks to someone. A greeting the model writes cannot guarantee wording; this line is said as written:

export const agent = defineAgent({
  app: MyApp,
  firstTurn: {
    say: "Ich bin Clara, die digitale Assistentin von Beispiel GmbH. Ich bin eine KI und kann Fehler machen. Wie kann ich helfen?",
  },
});

The line is the agent’s first message in the conversation, so the model knows it has already greeted and answers the caller’s first words instead of greeting again. On a call it is spoken with interruptions off, like the "agent" greeting: the caller hears all of it, and a message typed meanwhile is answered once it has played.

say can also be a function of the session info the conversation has when it opens: caller.* on a call, and client.*, the page info. It gets a read-only record and returns the words. Return words for every session, including one without the key it reads:

firstTurn: {
  say: ({ "client.event": event }) =>
    typeof event === "string"
      ? `Ich bin Clara, die digitale Assistentin von Beispiel GmbH. Schön, dass Sie vom ${event} kommen.`
      : "Ich bin Clara, die digitale Assistentin von Beispiel GmbH.",
},

client.* is what the web page the agent is embedded in says about itself (the event it advertises, the campaign it came from). It is untrusted input from that page, like a form field: use it to choose words, never to decide what the caller may see or do. Every route holds it to the same limits: a key is a letter followed by up to 39 letters, digits or underscores, and a value is a string of at most 256 characters. To try it locally, see Testing (“Page info: client.*”).

defineAgent refuses a say with no words (AGENT_INVALID_AUTHORING_PROP). A function that returns none is reported when the conversation opens, and the conversation goes on without the line.

A phone call has no page to show a notice on. To tell a caller that the call is recorded, use firstTurn: { say } for exact words, or firstTurn: "agent" and put the rule in <SystemPrompt>, where the model says it in its own words.

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