VAPI•2mo ago

How to access and forward callId from API tools and custom function tools to external services?

VAPI Assistant - I'm trying to find a reliable way to use a unique callId to correlate all tool calls within the same Vapi call session - in API tools and custom function tools. Better if dynamic variable available.

In the logs => Tool category => I can see the callId in the attributes property, but not sure how can I use it.

Didn't find anything useful
Community thread - https://vapi.ai/community/m/1381689099240472586?utm_source=chatgpt.com
Dynamic variable - https://docs.vapi.ai/assistants/dynamic-variables#default-variables

call_id - VAPI

Is there a way in which we can also sent the call_id of the call during the tool call, while the call is ongoing??

Variables | Vapi

Personalize assistant messages with dynamic and default variables

primary-violetOP•11/17/25, 6:14 AM

Thanks @Manja manna
I’ve already tried that — {{call.id}} isn’t available in the VAPI assistant prompt or in the API tool.

I need this value as a correlation ID, because I want to pass it as a parameter to my external webhooks (via the VAPI API Tool). This will let me tag and persist some memory data against the call.

VapiAPP•11/17/25, 7:51 PM

Hi kannas1905,

To access the call ID within an API request tool, you can utilize the setup provided by Vapi's integration with tools. When configuring your assistant's model, ensure that you include the necessary context variables or metadata that expose call details, such as the call ID, which can be passed to your tools. This setup usually involves defining the appropriate placeholders or configurations in your API request settings.

If you are using the SDK, you can retrieve call details using client methods such as client.calls.list()client.calls.list(), providing you specify filters or conditions to get the specific call you're interested in.

If you need further details on API tools, you can review the API reference here.

How to access and forward callId from API tools and custom function tools to external services?

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