how do I fetch some data for agent at call start? | ElevenLabs | Page 1

AI-generated Answer for cauliflower9481

Short answer: use Conversation Initiation Client Data. There are two supported ways, depending on how the call/session starts.

Inbound Twilio calls
- Enable Twilio personalization: set your webhook URL in Agents Platform settings, then on the agent’s Security tab enable “fetching conversation initiation data.” (elevenlabs.io)
- On each inbound call ElevenLabs sends your webhook a POST with caller_id, agent_id, called_number, and call_sid. Your webhook must quickly return a JSON body of type conversation_initiation_client_data containing:
  - dynamic_variables: key–values for any dynamic variables you’ve defined, and
  - conversation_config_override: optional overrides (prompt, first_message, language, voice_id). (elevenlabs.io)
- Use HTTPS, authenticate via headers/secrets, and keep response time low to avoid delaying call setup. (elevenlabs.io)
Web, SDK, or direct WebSocket sessions
- Pass conversation_initiation_client_data when you start the session (e.g., first WebSocket message). You can include dynamic_variables, conversation_config_override, and optional custom_llm_extra_body. (elevenlabs.io)

Key concepts and requirements

Dynamic variables let you inject per-call values into prompts, first message, and tools; system variables like system__caller_id and system__call_sid are also available. (elevenlabs.io)
If you plan to override system prompt, first_message, language, or voice at start, you must first enable those overrides in the agent’s Security settings; otherwise an error is thrown. (elevenlabs.io)
React and other SDKs expose “overrides” at conversation start if you’re not using Twilio/webhooks. (elevenlabs.io)

References:

Twilio personalization (pre-call webhook, payload, response format, security). (elevenlabs.io)
Conversation Initiation Client Data structure. (elevenlabs.io)
Agent WebSockets (sending conversation_initiation_client_data at session start). (elevenlabs.io)
Dynamic variables (how to define/use; available system variables). (elevenlabs.io)
Overrides (enable in Security; fields and behavior). (elevenlabs.io)
React SDK

#how do I fetch some data for agent at call start?