The toolCallId is an id that looks like the following "call_..." and when I make a request to the GET tool API call, I get the following error.

id must be a valid UUID.'

. Docs -> https://docs.vapi.ai/api-reference/calls/get#response.body.messages.ToolCallResultMessage.toolCallId

Thank you for sharing the error. To help diagnose the issue, could you please clarify which exact API endpoint you are calling and provide a sample of the full request payload or URL you are using when you receive the

id must be a valid UUID

error? This will help determine if the

toolCallId

format mismatch is due to the endpoint's requirements or something else. Example:

GET /call/{id}

or

GET /tool/{toolCallId}

This detail will help pinpoint the root cause! Sources: - [Vapi API Reference: Get Call](https://docs.vapi.ai/api-reference/calls/get-call) - [Vapi Custom Tools Troubleshooting](https://docs.vapi.ai/tools/custom-tools-troubleshooting)

Heres the full respose from

GET /call/{id}

. Take a look at messages, specifically the tool_call and the tool_call_results messages. The tool_call ids present in both start with

call_

... instead of a uuid. When i use this id and make a request to

GET /tool/{toolCallId}

I get the following error:

status_code: 400, body: {'message': ['id must be a valid UUID.'], 'error': 'Bad Request', 'statusCode': 400}

https://cdn.discordapp.com/attachments/1435852438824550450/1436039098665013388/message.txt?ex=692fc561&is=692e73e1&hm=78c380f7638c58a488448d62589ee9b1ab386d69e2fc00f20aef97bdfabf5854&

Hi mathusan, The

toolCallId

you’re seeing in the call messages represents the specific invocation of a tool during a call, not the actual UUID of the tool itself. This ID is only used to track that particular usage within the call flow — which is why it doesn’t work with the

/tool/{toolCallId}

endpoint. To retrieve the actual tool’s UUID, you’ll need to: 1. List all tools in your account using:

GET /tool

Documentation: 2. From that list, find the tool you’re looking for and get its tool ID (a valid UUID). 3. Once you have the tool’s UUID, you can call:

GET /tool/{toolId}

to fetch the tool definition or related details. Let me know if you'd like help identifying which tool maps to which call event!