itchy-amethyst•3h ago
How to inject custom tools per call/session in Vapi?
Hey folks! I’m integrating Vapi into an AI agent builder platform. Users create agents with a unique set of “tools” (each tool = an HTTP API endpoint I host). In text chat I already do dynamic tool routing. Now I want the same agent to work in Vapi voice + phone calls, but:
Each call/session must get a custom tool set (based on the specific agent + tenant).
I can’t pre-save all tools in Vapi because every user/agent differs.
I’d like to inject tools at call start, and have tool calls be webhooked to my backend (I handle auth/tenancy/rate-limits).
Questions:
What’s the recommended way to send per-call tool definitions (schema + name + description) to Vapi? Is there a supported “assistant overrides” / “runtime tools” mechanism at call initialization?
Can I resolve tools server-side on call.started (or equivalent) and return a tool list for that session?
1 Reply
Hi there,
Thank you for your message. Our team is currently out of the office. We operate Monday through Friday, from 9:00 AM to 8:00 PM Pacific Standard Time (PST).
We’ll get back to you as soon as possible during our normal business hours.
If your message is urgent, please mark it accordingly or include “URGENT” in the subject line, and we’ll do our best to respond promptly.
Warm regards,
Vapi
Customer Support Team
Vapi
Customer Support Team