Best Practices
Phone Number Formatting
Always use E.164 format:
- ✅
+15550100000(US number) - ✅
+911234567890(India number) - ❌
555-010-0000(missing country code) - ❌
(555) 010-0000(parentheses and spaces)
Metadata Usage
Use metadata for:
- Customer identification
- Campaign tracking
- Context for the assistant
- Post-call analytics
Error Handling
Common errors and how to handle them:
| Error | Cause | Solution |
|---|---|---|
400 Invalid number |
Wrong format | Ensure E.164 format |
404 Assistant not found |
Wrong ID | Verify assistant exists and is active |
404 Trunk not found |
Wrong ID | Verify trunk exists and belongs to user |
500 Provider error |
SIP provider issue | Check provider status and credentials |
Call Hold Behavior (Exotel)
When a call is placed on hold via Exotel:
- The agent detects hold instantly through SIP re-INVITE signaling.
- All agent activity is suppressed — no filler words, no silence reprompts, no transcript processing.
- Any in-progress agent speech is immediately interrupted.
- When the call resumes, the agent returns to normal operation automatically.
- This prevents the agent from responding to hold music or generating spurious responses.
Provider coverage
Hold detection currently works for Exotel only. Twilio calls do not have hold detection — if a Twilio call is placed on hold, the agent may respond to hold music.
Next Steps
After triggering a call:
- Store the room_name for future reference
- Listen for webhook at your configured endpoint (if set)
- Check call recording in your S3 bucket (if enabled)
- Analyze transcripts for quality assurance