> ## Documentation Index
> Fetch the complete documentation index at: https://docs.chatzy.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Engine

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  <img src="https://mintcdn.com/chatzyai/f4zfTmwUuctQb-Q3/ai-agents/voice-ai-agent/settings/engine.png?fit=max&auto=format&n=f4zfTmwUuctQb-Q3&q=85&s=6dd2a5f2a5755aa2c5a5ef1bd11368c2" width="1723" height="789" data-path="ai-agents/voice-ai-agent/settings/engine.png" />
</Frame>

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The **Engine** tab contains advanced configuration options that shape the responsiveness, fluidity, and overall performance of your **Voice AI Agent**. Adjusting these parameters helps create a more seamless and human-like voice experience.

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#### Conversation Control

* **User Online Detection** — This toggle monitors user activity during a voice session.\
  If the system detects prolonged silence or inactivity, it will automatically **send a ping message** after a set duration to confirm whether the user is still active before gracefully ending the call.

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#### Voice Response Rate Configuration

These controls fine-tune the **latency** (response delay) of your agent, directly impacting how natural the conversation feels.

* **Endpointing (in ms)** - Defines the pause duration (in milliseconds) after the user stops speaking before the agent starts responding.
  * Lower values → Faster replies, but risk cutting off the user mid-sentence.
  * Higher values → Safer, more natural pacing, but slightly slower responses.
  > **Tip:** Experiment to balance responsiveness with natural turn-taking.

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#### Interruptions

This section governs how the agent reacts when the user speaks while it’s still talking — a behavior known as **barge-in**.

* **Number of Words to Wait Before Interrupting** - Sets the tolerance threshold for interruptions.\
  The agent will **ignore user speech until it has spoken this many words**, ensuring the start of its message isn’t instantly cut off.

  > **Note:** If the user says keywords like “Stop,” “Wait,” or “Hold on,” the agent automatically pauses, regardless of this setting.

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💡 **Best Practice:**\
Use moderate endpointing and interruption settings to maintain conversational flow - too aggressive can feel robotic, while too passive may cause delays.