Hi there ,
I hope you guys to help me with my problem .
I setup an AI agent for a HANDY MAN services business - in Vietnamese. The main purpose for this AI is to get customer name , phone number ,and requested job. But it can’t event get through phone numbers event with the most expensive AI Setup . Some time it hangup by itself .
Is there any way to improve ? I got recommend Retell ai is the best. Hope you can provide solution
Best regards,
Tom Nguyen
Hello @tcnguye01
Could you please share the Call IDs of the most recent failed calls, along with the Agent ID? This will help us investigate the issue further.
Best Regards.
Hi
Agent ID : agent_5eee442ea32ffd5dfefafba241
call ID call_dbeb6260a06179983fa9a71dddf
Thank you for looking into this matter
Hello @tcnguye01
Thanks for the call ID — Team pulled call_dbeb…9a71dddf and can see exactly what’s happening. The good news: this isn’t a limitation of the “expensive AI setup”, it’s two fixable configuration issues.
1.Why the phone number came out wrong
Your caller’s real number is +1 509-xxx-9405, but on the call the agent locked in (509) xxx-9400. Looking at the transcript, the caller said “…chín bốn trăm không” (nine four hundred zero). The word “trăm” (hundred) is a Vietnamese numeric qualifier — the model treated the tail as “9400” instead of “9-4-0-5”. This is a known pattern for Vietnamese digit capture and can’t be reliably fixed by prompting alone.
The most reliable fixes, in order:
Enable Speech Normalization in the Agent Handbook → Accuracy & Format section. This normalizes spoken numeric expressions into digits before the LLM sees them.
Add a Post-Call Analysis field (Agent → Post-Call Analysis) named e.g. customer_phone with type string and description “Extract the customer’s 10-digit phone number in E.164 format.” PCA runs a dedicated extraction pass over the full transcript after the call, which is more robust than in-conversation confirmation for Vietnamese digit runs. Docs:
Ask the caller to read digits one at a time (“Anh vui lòng đọc từng số một”) in your prompt — this reduces the chance of grouped forms like bốn trăm appearing in the first place.
Enable Echo Verification so the agent explicitly re-reads each digit for confirmation before accepting.
2.Why the call ended by itself
The disconnect reason on this call is inactivity, not a system error or hangup. Your agent’s endCallAfterSilenceMs is set to 10,000 ms (10 seconds), and after the confirmation prompt the caller was silent for that full window, so the agent ended the call. You can raise this value in the agent settings if your callers commonly need longer to think or read a number off a screen.
Optional cost note:
I noticed your Post-Call Analysis model is set to gpt-4.1. For lead intake, gpt-4.1-mini is typically enough and meaningfully cheaper — worth trying once the PCA field above is in place.
Best Regards.
@tcnguye01 Fellow Vietnamese here and have been building AI voice agents in Vietnam, DM me if you want to discuss!