The test webhook doesnt take the default values when you input multiple key values into the body of the request. https://cdn.discordapp.com/attachments/1430539375271350313/1430539375686451290/Schermafbeelding_2025-10-22_om_14.47.21.png?ex=68fa251d&is=68f8d39d&hm=e43d9afc376037ccdd23486683b541dbb461d64312db3884040fb15f81694753&

Suggestion: Check that your tool schema explicitly defines each variable with a default value. For example, your schema should look like this:

json
{
  "name": "your_tool",
  "parameters": {
    "type": "object",
    "properties": {
      "call_subject": { "type": "string", "default": "Default subject" },
      "phone_number": { "type": "string", "default": "+1234567890" },
      "customer_name": { "type": "string", "default": "John Doe" },
      "preferred_time": { "type": "string", "default": "09:00" }
    },
    "required": ["call_subject", "phone_number", "customer_name", "preferred_time"]
  }
}

After updating your schema, refresh the tool in the dashboard and try the test webhook again to ensure default values are detected and copied properly. For more details, see the [custom tools troubleshooting guide](https://docs.vapi.ai/tools/custom-tools-troubleshooting#validate-json-format). Source: - [Custom tools troubleshooting](https://docs.vapi.ai/tools/custom-tools-troubleshooting#validate-json-format)

Hi there, Our team is currently working on this issue. In the meantime, please note that the parameters may temporarily take on the values of other default fields defined within your tool configuration. We’ll share an update once a fix is deployed. Best, Kyle Vapi Support