It seems VAPI Assistance is sending a truncated argument to the API Request tool. Is there a character/payload size limit, and how can I handle this? The payload includes nested JSON (often >1000 chars), and when truncated, no values reach the external webhook. Unfortunately, I don’t have much flexibility to reduce the argument size on my end. Call ID: 80450359-edda-4e65-8a66-9fd4f0f0534e Call Time: 09/22/2025 23:15 (IST) Log Time: Sep 22, 23:17:08.537 (IST)

Suggestion: If your payload is frequently exceeding size limits and getting truncated, consider uploading the large JSON to external storage (like S3 or a file server) and passing only a reference (e.g., a URL or file ID) in your API Request tool call. This keeps the payload small and avoids truncation issues.

json
{
  "action": "processData",
  "dataUrl": "https://your-storage.com/files/large-payload-123.json"
}

This approach is recommended for large or nested data structures to ensure reliable delivery to your webhook. Source: - [Custom LLM Tool Calling Integration](https://docs.vapi.ai/customization/tool-calling-integration)

@Lordvickthor up to ~2500 characters.

VAPI Assistance → VAPI API Request Tools → External Webhook

Truncation occurs at:

VAPI Assistance → VAPI API Request Tool

and not at

VAPI API Request to  External Webhook

We will have to reach out to our team regarding the truncation issue. While we may not be able to support a payload larger than 2500 characters, you might want to consider using a knowledge base of some sort and only pulling the data you need for the one request