Changelog

Flux: Configure Control Message for Dynamic Mid-Stream Configuration

Flux now supports dynamic configuration updates mid-stream with the new Configure control message, enabling voice agents to adapt speech recognition behavior as conversations evolve—without disconnecting and reconnecting.

🎯 Dynamic Configuration Updates

Real conversations aren’t static. They shift from casual confirmation to strict authentication, from general discussion to domain-specific troubleshooting. The Configure control message lets you inject the right ASR context at the right moment in the conversation.

Update these parameters mid-stream:

• Keyterms - Inject task-critical vocabulary as conversation context changes (names, medications, product terminology)
• Turn detection thresholds (eot_threshold, eager_eot_threshold) - Tighten or relax turn detection confidence requirements
• Timeout behavior (eot_timeout_ms) - Adjust silence tolerance for different conversation phases

Why This Matters

Context injection for speech recognition. Add a customer’s name to keyterms right before asking for it. Swap to medication terminology when moving to pharmacy discussion. Load product names when handling specific inquiries. You’re no longer stuck with a generic keyterm list that’s “good enough” for the entire call.

Adaptive turn detection. When collecting passwords, OTPs, or account numbers, increase eot_timeout_ms and eot_threshold to prevent premature cutoffs. Relax them when you’re back to natural conversation.

Simplified engineering. No more reconnecting mid-call (dropping audio, managing state transitions) or managing multiple concurrent streams. One connection, dynamic behavior.

Implementation

Send a Configure control message over your Flux WebSocket connection:

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{
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  "type": "Configure",
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  "thresholds": {
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    "eot_threshold": 0.8,
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    "eot_timeout_ms": 5000
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  },
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  "keyterms": ["product_name", "feature_name"]
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}

You’ll receive a ConfigureSuccess response confirming the update, and changes apply immediately in the audio stream order.

Availability: Configure is currently available via direct WebSocket connections only. SDK and self-hosted support are coming soon.

Important: Keyterms are replaced (not merged) when you send a Configure message. Include both existing and new terms if you want to add to the list.

For comprehensive documentation, examples in multiple languages, and detailed behavior specifications, see the Configure Control Message documentation.

For the full API specification, see the Flux API Reference.