Customise an ElevenLabs session

Make conversations personal with user-specific greetings, language preferences, and agent instructions. Build on your working session from the three-step quickstart. The Anam session token API accepts additional fields that are passed through to ElevenLabs when starting the conversation. These let you personalise each session — greet users by name, switch languages, override the system prompt, or pass data to a custom LLM backend. See the ElevenLabs personalisation overview for full details. All of these fields are optional and go inside elevenLabsAgentSettings alongside signedUrl and agentId in your server route:

body: JSON.stringify({
  personaConfig: { avatarId },
  environment: {
    elevenLabsAgentSettings: {
      signedUrl,
      agentId,
      dynamicVariables: { ... },          // optional
      conversationConfigOverride: { ... }, // optional
      userId: "...",                       // optional
      customLlmExtraBody: { ... },        // optional
    },
  },
}),

Dynamic variables

Dynamic variables are the simplest way to personalise a conversation at runtime. Define placeholders like {{user_name}} in your agent’s system prompt or first message in the ElevenLabs dashboard, then fill them in when creating the session token:

body: JSON.stringify({
  personaConfig: { avatarId },
  environment: {
    elevenLabsAgentSettings: {
      signedUrl,
      agentId,
      dynamicVariables: {
        user_name: "Alice",
        account_type: "premium",
      },
    },
  },
}),

See ElevenLabs dynamic variables docs for the full syntax.

Overrides

Overrides let you change agent behaviour per conversation — things like the first message, language, system prompt, or TTS voice. Only include the fields you want to override; everything else keeps its default from the ElevenLabs dashboard.

body: JSON.stringify({
  personaConfig: { avatarId },
  environment: {
    elevenLabsAgentSettings: {
      signedUrl,
      agentId,
      conversationConfigOverride: {
        agent: {
          prompt: {
            prompt: "You are a helpful assistant. Always respond in Spanish.",
          },
          firstMessage: "¡Hola! ¿En qué puedo ayudarte hoy?",
          language: "es",
        },
      },
    },
  },
}),

See ElevenLabs overrides docs for the full list of overridable fields.

User ID

Pass userId to identify the caller in ElevenLabs analytics and conversation history:

elevenLabsAgentSettings: {
  signedUrl,
  agentId,
  userId: "user_abc123",
},

Custom LLM extra body

If your ElevenLabs agent is configured to call a custom LLM backend, customLlmExtraBody lets you pass arbitrary parameters alongside each request:

body: JSON.stringify({
  personaConfig: { avatarId },
  environment: {
    elevenLabsAgentSettings: {
      signedUrl,
      agentId,
      customLlmExtraBody: {
        session_context: { region: "eu", tier: "enterprise" },
      },
    },
  },
}),

See ElevenLabs custom LLM docs for how to set up a custom LLM backend.

Keep building

Director Notes

Add expressions that follow your agent’s voice.

Client tools

Let your agent trigger actions in your app.

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Help

Customise an ElevenLabs session

Dynamic variables

Overrides

User ID

Custom LLM extra body

Keep building

Director Notes

Client tools

​Dynamic variables

​Overrides

​User ID

​Custom LLM extra body

​Keep building

Director Notes

Client tools

Dynamic variables

Overrides

User ID

Custom LLM extra body

Keep building