Context & Variables

Lemu has a simple data model for passing information through a call. Understanding it is key to building agents that feel personalised and to extracting useful results after a call.

The three context objects#

initial_context ──► Agent ──► gathered_context
                       │
                 [template variables](/voice-agent/template-variables)
                 (used in prompts)

initial_context#

Data available to the agent before the call starts — the contact's name, account details, appointment information, anything the agent should know upfront. It can be set from several places:

API trigger — pass it in the request body when calling POST /public/agent/{uuid} or POST /telephony/initiate-call
Campaign CSV — columns beyond phone_number automatically become initial_context fields for each contact's call
Dashboard — set default template context variables on the agent, used when no external context is provided

{
  "phone_number": "+14155550100",
  "initial_context": {
    "customer_name": "Jane Smith",
    "plan": "premium",
    "renewal_date": "April 1"
  }
}

Template variables#

Values from initial_context are available in your agent's prompt using {{double_brace}} syntax.

You are calling {{customer_name}} about their {{plan}} plan,
which renews on {{renewal_date}}. Be friendly and confirm
whether they'd like to continue.

When the call starts, Lemu substitutes the values before sending the prompt to the LLM — so the agent speaks naturally as if it already knows the contact.

gathered_context#

Data the agent collects during the call. You configure what to extract in the agent node's extraction settings — each variable has a name, type, and a prompt that tells the LLM what to look for.

gathered_context is returned in the run record after the call completes and is available in webhook payloads for downstream processing.

Data flow example#

1
Your system sends initial_context (e.g. customer_name, plan)
into the call
2
Lemu substitutes placeholders into the agent prompt
conversation
3
LLM responds turn by turn
call ends
4
Lemu extracts gathered_context (e.g. renewal_confirmed)
return
5
Run record with gathered_context goes back to your system

Where variables are available#

Location	Variables available
Agent node prompts	`initial_context` fields via `{{variable_name}}`
Edge conditions	Evaluated against the live conversation — no explicit variable syntax needed
Webhook payload templates	All context objects via `{{initial_context.field}}`, `{{gathered_context.field}}` etc.
Campaign CSV columns	CSV columns beyond `phone_number` become `initial_context` fields automatically