Barge-In Configuration

Control how users can interrupt the assistant while speaking.

Overview

Barge-in allows users to interrupt the assistant's speech. Configure it per action using the barge_in field.

Configuration

{
  "type": "speak",
  "session_id": "session-123",
  "text": "Hello!",
  "barge_in": {
    "strategy": "minimum_characters",
    "minimum_characters": 3,
    "allow_after_ms": 500
  }
}

Strategies

none

Disables barge-in completely. Audio plays fully without interruption.

{
  "barge_in": {
    "strategy": "none"
  }
}

Use cases:

• Critical information
• Legal disclaimers
• Emergency instructions

manual

Allows manual barge-in via API only (no automatic detection).

{
  "barge_in": {
    "strategy": "manual"
  }
}

Use cases:

• Custom interruption logic
• Button-triggered interruption
• External event-based interruption

minimum_characters

Automatically detects barge-in when user speech exceeds character threshold.

{
  "barge_in": {
    "strategy": "minimum_characters",
    "minimum_characters": 5,
    "allow_after_ms": 500
  }
}

Use cases:

• Natural conversation flow
• Customer service scenarios
• Interactive voice menus

immediate ⚡ NEW

Most responsive option - Interrupts immediately when user starts speaking, using Voice Activity Detection (VAD).

{
  "barge_in": {
    "strategy": "immediate",
    "allow_after_ms": 500
  }
}

How it works:

• Azure/Deepgram: Uses VAD (Voice Activity Detection) - triggers before any text is recognized
• ElevenLabs: Uses first partial transcript
• Latency: 20-100ms (2-4x faster than minimum_characters)
• No text required: Interrupts on voice detection, not transcription

Use cases:

• High-priority conversations requiring instant responsiveness
• Natural dialogue where interruptions should feel seamless
• Customer service where quick response matters
• Urgent or time-sensitive interactions

Best practices:

• Use allow_after_ms: 500-1000 to prevent accidental interruptions at start
• Test with real users to find optimal allow_after_ms value
• Consider network latency in production environments

Comparison with minimum_characters:

Feature	immediate	minimum_characters
Trigger	Voice Activity (VAD)	Text recognition (3+ characters)
Latency	20-100ms	50-200ms
User Experience	Instant interruption	Slight delay
Accuracy	May trigger on noise	More reliable (text-based)

Configuration Options

minimum_characters

Minimum number of characters before barge-in triggers.

• Default: 3
• Range: 1 to 100
• Higher values: Require more speech before interruption

allow_after_ms

Delay in milliseconds before barge-in is allowed (protection period).

• Default: 0 (immediate)
• Range: 0 to 10000 (10 seconds)
• Use: Prevent interruption during critical information

Examples

Natural Conversation

{
  "type": "speak",
  "session_id": "session-123",
  "text": "I can help you with billing, support, or sales.",
  "barge_in": {
    "strategy": "minimum_characters",
    "minimum_characters": 3
  }
}

Critical Information

{
  "type": "speak",
  "session_id": "session-123",
  "text": "Your verification code is 1-2-3-4-5-6.",
  "barge_in": {
    "strategy": "none"
  }
}

Protected Announcement

{
  "type": "speak",
  "session_id": "session-123",
  "text": "Your account number is 1234567890.",
  "barge_in": {
    "strategy": "minimum_characters",
    "minimum_characters": 10,
    "allow_after_ms": 2000
  }
}

Instant Response (Immediate) ⚡

{
  "type": "speak",
  "session_id": "session-123",
  "text": "I can help you with your order, account, or technical support. What would you like to know?",
  "barge_in": {
    "strategy": "immediate",
    "allow_after_ms": 500
  }
}

Result: Assistant stops speaking the moment user starts talking (20-100ms latency), providing the most natural conversation experience.

Best Practices

1. Use none sparingly - Only for truly critical information
2. Choose the right strategy:
   • immediate - For most natural, responsive conversations
   • minimum_characters - For balance between responsiveness and reliability
   • manual - For custom logic
   • none - For critical announcements only
3. Set protection periods - Use allow_after_ms: 500-1000 to prevent cutting off important intro
4. Test with users - Find the right balance for your use case
5. Consider noise - immediate may trigger on background noise; use allow_after_ms as buffer

Next Steps

• Speak Action - How to use barge-in
• User Speak Event with Barge-In Flag - Handle interruptions