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Glossary

Short definitions of the terms used in this documentation.

Term	Meaning
Account	A workspace as the API names it. Owns agents, numbers, calls and the wallet.
Agent	The definition of a voice assistant: prompts, models, tools and call settings.
Agent version	A snapshot of an agent, created on every save. Executions remember theirs.
API key	A long-lived token for programs. Starts with `vk-`. Acts as admin.
Barge-in	The caller speaking over the agent. The engine pauses playback and decides whether to yield.
Batch	A CSV of contacts called by one agent.
Calling hours	The window, in the recipient's time zone, in which an agent may call. Calls outside it are rescheduled.
Campaign	A workflow run for a list of contacts.
Core API	The half of the API for agents, calls, numbers and related resources.
Dead letter	A background job or webhook delivery that failed all its attempts and waits for a decision.
Disposition	A question answered about a call after it ends, to produce structured data.
Do-not-call list	Numbers the workspace must never dial. Also called the suppression list.
DTMF	The tones of a phone keypad.
Edge	A connection between two nodes of a graph agent, with a condition.
Engine	The component that holds the conversation: `mock` or `own`.
Execution	One call and everything recorded about it.
Extensions	The half of the API for login, team, billing, compliance, messaging and operations.
Extraction	Pulling structured values out of a transcript after the call.
Function tool	Something the language model may invoke during a call: an HTTP request, a transfer, ending the call.
Graph agent	An agent whose conversation is a set of nodes and edges.
Idempotency key	A header value that makes a request safe to repeat.
Knowledge base	Documents, split and indexed, that an agent searches during a call.
Ledger	The append-only list of every movement of a wallet.
Member	A person who logs in to a workspace, with a role.
Mock engine	A scripted conversation with no audio and no dialling.
Mock telephony	Simulated numbers and dialling, for development.
Node	One step of a graph agent.
Price book	The deployment's table of per-minute rates.
Provider key	A credential for a third-party service, stored encrypted for the workspace.
Session token	What a login returns. Starts with `vs-`. Lasts 7 days.
Sub-account	A workspace under another, with its own keys and data and the parent's wallet.
Suppression list	See do-not-call list.
Task	A unit of work in an agent. The conversation is a task.
Telephony provider	The company that connects calls to the phone network: Twilio, Plivo or Exotel.
Turn	One side speaking until it stops.
User data	Per-call variables that fill `{placeholders}` in prompts and messages.
Voice engine	The platform's own real-time engine (`own`).
Wallet	The prepaid balance calls are charged to.
Webhook	An HTTP request the platform sends to your URL when something changes.
Workflow	A sequence of steps (calls, waits, messages, branches) for one contact.