---
title: AssemblyAI Keyterm and Prompt Now Available for Telnyx Voice AI Assistants
canonical: https://telnyx.com/release-notes/assemblyai-prompt-keyterm-voice-ai-assistants
---
# AssemblyAI Keyterm and Prompt Now Available for Telnyx Voice AI Assistants

[Release notes](https://telnyx.com/release-notes)

# Prompt and Keyterm Support Now Available for AssemblyAI on Telnyx Voice AI Assistants

### 20, Oct 2026

Voice AI Assistants that use AssemblyAI Universal-3.5 Pro for speech-to-text can now pass a context prompt and a list of keyterms to the model. Telnyx also sends the agent's last reply to AssemblyAI after each turn, so the model hears every caller response with the question it answers.

### What's new

* **Prompt:** Describe the call in up to 1,750 characters, such as the domain, names, and what callers usually talk about. AssemblyAI uses it to recognize the vocabulary that fits the conversation.
* **Keyterm Boost:** Add up to 100 comma-separated terms, each up to 50 characters, to improve recognition of product names, drug names, and other domain vocabulary.
* **Agent context:** After each reply, the assistant passes its last spoken reply to AssemblyAI automatically. No setting is required.

### Why it matters

* Domain vocabulary is where speech-to-text errors cost the most. A misheard product name or medication sends the whole turn down the wrong path.
* Keyterms and the prompt are optional with Universal-3.5 Pro, so an existing assistant keeps working without changes.
* Prompt, keyterms, and agent context travel through the same Telnyx pipeline as the rest of the call, so there is no separate STT vendor integration to build or maintain.

### Example use cases

* Healthcare scheduling agents that need drug names and clinic locations transcribed correctly.
* Support agents for a product catalog with part numbers and brand names callers say out loud.
* Financial services agents that handle account types, fund names, and ticker symbols.

### Getting started

1. In Mission Control, go to AI, then Assistants, and select your assistant.
2. Open the **Voice** tab and select `assemblyai/universal-3-5-pro` as the transcription model.
3. In **Prompt**, describe the content of your calls. Describe the content only, not instructions for the model.
4. In **Keyterm Boost**, enter your terms separated by commas.
5. Save your assistant.

Requests over the limits return a 400 error from the API.

**Learn more** in the [Telnyx transcription settings docs](https://developers.telnyx.com/docs/inference/ai-assistants/transcription-settings).

[Start building](https://telnyx.com/sign-up)

### Ask AI

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* [![Perplexity](https://d2efw2akbx8gaf.cloudfront.net/https://dotcom-payload-assets-prod.s3.us-east-1.amazonaws.com/cms-media/perplexity_icon-cd5b74f1.webp?width=92&format=webp)](https://www.perplexity.ai/search?q=What makes Telnyx's global network different, breakdown call quality for normal phone calls and voice AI calls.)
* [![Gemini](https://d2efw2akbx8gaf.cloudfront.net/https://dotcom-payload-assets-prod.s3.us-east-1.amazonaws.com/cms-media/gemini_icon-4ff1cbf4.webp?width=92&format=webp)](https://www.google.com/search?udm=50&aep=11&q=What makes Telnyx's global network different, breakdown call quality for normal phone calls and voice AI calls.)
* [![Grok](https://d2efw2akbx8gaf.cloudfront.net/https://dotcom-payload-assets-prod.s3.us-east-1.amazonaws.com/cms-media/grok_icon-e588e5bd.webp?width=92&format=webp)](https://x.com/i/grok?text=What makes Telnyx's global network different, breakdown call quality for normal phone calls and voice AI calls.)