Hey Vapi fam — I could use a little help on this one.
I'm trying to get my assistant (Jane) to trigger a pre-call context tool before the call starts — specifically to pull metadata like name, email, LinkedIn, etc. I’ve got the tool (precall-context) set up and it works perfectly when tested manually via webhook.
The issue?
Even though the prompt explicitly says:
"Before saying anything to the user, immediately call the precall-context tool..."
…it still skips the tool call and jumps straight into the greeting. It’s ONLY this pre-call tool — other tools like booking and follow-up work fine mid-convo.
Things I’ve already checked/tried:
Tool is active and testable ✅
Tool schema is valid ✅
Assistant has the precall-context tool assigned ✅
Prompt correctly formats the tool call with tool: precall-context, input: { phone: {{phone}} } ✅
Tested with both async ON and OFF ✅
Even tried converting the logic to XML to structure the flow strictly ✅
Still… no dice. Jane keeps talking before the tool gets triggered.
Not sure if I’m missing something in how pre-call tools are handled differently — or if there’s a better way to force that tool call before anything is said.
Anyone else run into this or figured out a workaround?
Appreciate any insight 🙏
– Apollo | NovaLinQs AI