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How Smart Filler Works

Expert Mode Smart Filler reduces perceived latency by generating contextual filler responses while your main AI model processes the full answer. Instead of silence during processing, your agent says something like “Let me check that for you…” before delivering the complete response.
Smart Filler uses a fast secondary AI model to generate contextual fillers in parallel with your main AI model. It reduces perceived latency but does not make the main response complete faster.

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How It Works

  1. User asks a question
  2. Smart Filler immediately generates a contextual filler phrase using a fast secondary AI model
  3. The filler plays while your main AI model processes the full response
  4. The complete response follows without interruption

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Configuration

Navigate to your agent’s General tab, switch to Expert mode, and open Sounds to configure Smart Filler.

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Enable Smart Filler

Toggle Smart Filler on or off. When disabled, the agent waits silently until the full response is ready.

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Delay Threshold

Choose how long the main response can take before the filler plays. The dashboard supports 0-2000 ms in 50 ms steps. A value of 0 ms lets the filler play as soon as it is available; higher values avoid fillers for fast responses.

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Custom Filler Prompt

Customize how your agent generates filler responses with a custom prompt. Default behavior: The agent generates appropriate acknowledgments like:
  • “Let me check that for you…”
  • “One moment while I look into that…”
  • “Good question, let me find out…”
Custom prompt examples: 
Use Austrian German expressions like "Passt" or "Jo eh"
for casual acknowledgments.

Use formal business language. Never use casual phrases.
Example: "I'll look into that right away" not "Let me check".

Be warm and friendly. Use phrases like "Great question!"
and "I'd be happy to help with that!"

Match the language the customer is speaking. If they speak
German, respond in German. If Spanish, respond in Spanish.
Custom filler prompts are limited to 2000 characters. Keep instructions concise and focused.

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Use Cases

High-latency responses

Cover wait time from advanced AI models with longer response times

Complex queries

Fill pauses during tool calls, database lookups, or multi-step reasoning

Knowledge base searches

Acknowledge the caller while knowledge base retrieval adds processing time

API integrations

Bridge latency from custom API tools

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Best Practices

Match your brand voice: Use the custom prompt to ensure fillers match your agent’s personality and brand guidelines. See the prompt engineering guide for writing effective prompts. Keep it natural: The best fillers sound like natural human acknowledgments, not robotic placeholders. Consider context: Different situations call for different filler styles. Sales calls might use energetic fillers while support calls might use reassuring ones. Test extensively: Make test calls to ensure fillers feel natural in real conversations and don’t create awkward pauses or repetition.

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Performance Impact

MetricWithout Smart FillerWith Smart Filler
Perceived latencyFull AI processing time~500ms
User experienceSilent waitingNatural conversation flow
Actual response timeUnchangedUnchanged
Smart Filler doesn’t speed up your actual response time—it makes the wait feel shorter by providing immediate acknowledgment.

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Limitations

  • Not always appropriate: Some contexts (legal disclaimers, critical information) may require silence rather than fillers
  • Language matching: Works best when filler prompt matches conversation language

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Next Steps

Thinking Sounds

Add audio feedback while processing

Voice Settings

Fine-tune voice parameters

Choose AI Model

Select the model that drives your agent

Test Your Agent

Test Smart Filler in the simulator