Session variables

Every endpoint on this page requires either a Clerk-issued JWT (Authorization: Bearer <token>) or an organization API key (x-api-key: pk_…). Anonymous calls return 401 Unauthorized. See Authentication for the full setup.

Each agent has a System Prompt that defines its behaviour. You can sprinkle placeholders into the prompt that are resolved at call-start time from two sources:

System variables — populated automatically by Agentix (date/time, channel context, telephony identifiers).
Custom variables — supplied by you under session_variables in the call-trigger request.

How dynamic variable replacement works

Placeholders use double-curly syntax: {{variable_name}}. When a call starts, Agentix runs a templating pass over the system prompt before the very first message is sent to the model. Everything inside {{…}} is replaced with the resolved value. The LLM never sees the placeholder — it only sees the final, hydrated prompt. Prompt template:

Hello {{customerName}}, you are calling about {{orderInsight}}.

Sent to the LLM at runtime:

Hello Alex, you are calling about order #88291 (placed 2026-05-09, status: shipped, tracking AE998123).

Rules to remember

If a placeholder has no matching value, it is left as-is (e.g. {{customerAge}} stays literal). Instruct the LLM to ask the user for it rather than leaving the literal placeholder in dialogue.
Replacement happens once per session, at the start. Mid-call value changes are not propagated.
Values are always rendered as strings. Pass pre-formatted strings (currency, dates) if you need them styled.

System variables (provided automatically)

These keys are populated by Agentix at call-start — you don’t pass them in. They cover date / time, channel context, and telephony identifiers.

Date and time

Placeholder	How it’s computed	Example output
`{{system.year}}`	`now.getFullYear()` (UTC server)	`2026`
`{{system.date}}`	`now.toISOString().split('T')[0]` (UTC date)	`2026-05-08`
`{{system.time}}`	`now.toLocaleTimeString()` (UTC server locale)	`10:28:42 AM`
`{{system.now}}`	`now.toISOString()` (UTC)	`2026-05-08T10:28:42.123Z`
`{{system.dubai.now}}`	`now` shifted to Asia/Dubai (UTC+4) → ISO	`2026-05-08T14:28:42.000Z`

Use these for time-aware behaviour (“a viewing this week”, “the order placed 3 days ago”, “good morning/afternoon”).

Channel context

Placeholder	Resolves to	Example
`{{system.platform}}`	Session platform	`voice` / `chat` / `whatsapp`
`{{system.medium}}`	Session medium	`phone` / `web`
`{{system.direction}}`	Call direction	`inbound` / `outbound`

Telephony and session identifiers

Placeholder	Resolves to	Example
`{{system.incoming.phonenumber}}`	Incoming number (or empty)	`+97142000000`
`{{system.outgoing.phonenumber}}`	Outgoing number (or empty)	`+971501234567`
`{{system.customer.phonenumber}}`	Always points to the customer’s number, regardless of direction	`+971507654321`
`{{system.roomname}}`	LiveKit room name (or empty)	`voice-room-7f3b…`
`{{system.sessionId}}`	Session ID	`sess_abc123`

Fallback rule: any non-system.* {{key}} is pulled from session_variables. If the key is missing or empty, instruct the LLM to ask the user for it rather than leaving the literal {{key}} in dialogue.

Custom variables

You define these yourself. Anything you send under session_variables in the trigger request becomes available as {{key}} in the prompt. A typical canonical set for an outbound use case:

Variable	Purpose	Example value
`customerName`	Who the agent is calling	`"Alex Morgan"`
`contextSummary`	Pre-baked summary of the reason for the call	`"Order #88291, placed 2026-05-09, status shipped, ETA 2026-05-14"`
`objective`	What the agent should accomplish	`"Confirm delivery slot and capture preferred time"`
`crmContactId`	Mapping key back to your CRM record	`"CRM-7728"`

The CRM mapping key (crmContactId above) is critical: it’s the thread you’ll use later to map the Agentix call back to your own contact record. It is echoed back verbatim in the webhook payload under metadata.sessionVariables — see Webhook events.

Designing a system prompt that uses these variables

A prompt template that exercises both system and custom variables:

You are calling {{customerName}} on behalf of Acme Co.

Today is {{system.dubai.now}}.

Context for this call:
{{contextSummary}}

Your objective:
{{objective}}

Conversation rules:
  - Greet the customer by name.
  - Stay polite and concise — keep the call under 3 minutes.
  - If the customer is unavailable, ask for a better time to call back.

When the objective is satisfied, thank the customer and end the call.

The corresponding session_variables payload at call time:

{
  "customerName": "Alex Morgan",
  "contextSummary": "Order #88291, placed 2026-05-09, status shipped, ETA 2026-05-14",
  "objective": "Confirm delivery slot and capture preferred time",
  "crmContactId": "CRM-7728"
}

Build contextSummary server-side by concatenating relevant fields from your DB. Sending one pre-formatted string keeps the prompt readable and lets you change the surface format without touching the agent config.

Cheat sheet

Type	Pattern	Source	Example
System	`{{system.now}}`	Agentix	`2026-05-13T11:02:14Z`
System	`{{system.customer.phonenumber}}`	Agentix	`+971507654321`
Custom	`{{anyKey}}`	`session_variables.anyKey` in trigger call	`Alex Morgan`

Next steps

Trigger an outbound call

Pass session_variables in the call-start request.

Post-call analysis

Configure structured fields that get extracted from the transcript.

Getting Started

Build

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SDKs & Examples

Operate

Session variables

How dynamic variable replacement works

System variables (provided automatically)

Date and time

Channel context

Telephony and session identifiers

Custom variables

Designing a system prompt that uses these variables

Cheat sheet

Next steps

Trigger an outbound call

Post-call analysis

​How dynamic variable replacement works

​System variables (provided automatically)

​Date and time

​Channel context

​Telephony and session identifiers

​Custom variables

​Designing a system prompt that uses these variables

​Cheat sheet

​Next steps

Trigger an outbound call

Post-call analysis

How dynamic variable replacement works

System variables (provided automatically)

Date and time

Channel context

Telephony and session identifiers

Custom variables

Designing a system prompt that uses these variables

Cheat sheet

Next steps