---
title: Update Voice AI Assistant Variables from Webhook Tool Responses | Telnyx
canonical: https://telnyx.com/release-notes/dynamic-variables-webhook-response
---
# Update Voice AI Assistant Variables from Webhook Tool Responses | Telnyx

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

# Update assistant dynamic variables from webhook tool responses

### 24, Mar 2026

Webhook tools can now write values directly into an assistant's dynamic variables. This lets you route tool output into prompts, actions, and insights without extra middleware or post-processing.

## What's new

* **Dynamic variable assignment:** Map response fields to variables using response paths.
* **Response path mapping:** Extract values like `current.precipitation` from JSON responses.
* **Instruction injection:** Use updated variables in assistant instructions at runtime.
* **Insight integration:** Reference dynamic variables inside insight templates.
* **Tool-driven inputs:** Populate downstream fields such as transfer targets or routing logic.

## Why it matters

* Reduces glue code by removing the need for external data handling.
* Improves control over model behavior using real-time tool outputs.
* Simplifies workflows by passing data across steps without reformatting.
* Prevents inconsistencies between tool results and assistant context.
* Enables deterministic routing based on structured API responses.

## Example use cases

* Populate a call transfer destination from a CRM lookup webhook.
* Adjust assistant replies based on weather or location data.
* Store extracted addresses or IDs for later steps in a flow.
* Generate insights using structured outputs from external APIs.

## Getting started

1. Create or edit a webhook tool in your AI Assistant in the Mission Control.
2. Add a dynamic variable assignment, set a variable name.
3. Define the response path, for example `current.precipitation`.
4. Reference the variable in assistant instructions or insight templates using `{{variable_name}}`.
5. Test the tool and confirm the variable updates during execution.

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

### Ask AI

* [![GPT](https://d2efw2akbx8gaf.cloudfront.net/https://dotcom-payload-assets-prod.s3.us-east-1.amazonaws.com/cms-media/chatgpt_icon-ea55e09d.jpeg?width=92&format=webp)](https://chat.openai.com/?q=What makes Telnyx's global network different, breakdown call quality for normal phone calls and voice AI calls.)
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* [![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.)