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How It Works

Phoenix-4 and Phoenix-4.5 faces can dynamically express emotions like happiness, sadness, anger, and more through lifelike facial expressions while speaking and listening. For the most human-like results, emotional expression works best as part of a closed-loop system: Phoenix-4 or Phoenix-4.5 for expression, Raven-1 for perception, and Sparrow-2 for conversational flow. Each component informs the others. Tavus handles the complex interactions behind the scenes - all of this powered by our state of the art models working seamlessly with any LLM. All of this available out of the box with default Tavus settings.

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Requirements

  1. Select a face - Faces marked Pro in the Stock Face Library are a hand-picked, top-performing set. See featured Pro faces here.
  2. Emotional expression is on - Faces express emotion out of the box. There is no parameter to set.
Pair with Raven-1 as your perception model to enhance user emotion understanding. See Perception for configuration.
For best results, use a Tavus-hosted model with strong instruction-following capabilities such as tavus-gemma-4.

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Guiding Emotional Delivery

You can further shape how the PAL expresses emotion through your system_prompt. For example:
  • “Be enthusiastic when discussing new features”
  • “Speak calmly and empathetically when the user is frustrated”
  • “Show excitement when celebrating user achievements”
  • “Respond with anger if the user interrupts you mid-sentence”

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Example: Negotiation Sparring Partner

Here’s an example system prompt designed to display a range of emotions:
You are a tough but fair negotiation coach who helps users practice high-stakes conversations. When role-playing scenarios, embody the opposing party with conviction. If the user makes weak arguments or caves too easily, push back with frustration - they need to feel the pressure. When they fumble or seem lost, express concern and gently guide them. But when they land a strong point or hold their ground, show genuine satisfaction. Don’t go easy on them. Real negotiations are uncomfortable, and you’re here to prepare them for that.
This prompt naturally triggers angry responses when pushing back, scared/concerned reactions when the user struggles, and content acknowledgment when the user succeeds.

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Example PAL Configuration

You can learn more about PAL Configuration here
This minimal configuration works because emotional expression is on. Faces express emotion out of the box.

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Echo Mode

When using Echo Mode, you must manually insert emotion tags into your text echos. Valid emotion values: neutral, angry, excited, elated, content, sad, dejected, scared, contempt, disgusted, surprised