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This capability is in beta. Behavior can change before general availability.
A flow node is one step of a voice call, the way a gambit is one step of a chat flow. The two are not interchangeable. At the end of this page, your voice agent runs its calls as flow nodes joined by transitions.

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Before you start

Before you start, sign in to the dashboard and select the organization you want to work in.
  • A voice agent of the type Conversation flow. See Create a voice agent. A single prompt voice agent becomes a flow with Convert to conversation flow in the more actions menu.
  • Your role includes Build chat agents, voice agents, knowledge bases & tools.

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Write the global prompt

1

Open the voice agent and select the Global Settings tab

The Global Settings panel opens.
2

Write the Global prompt

Tars adds the global prompt before the instruction of every flow node. Use it to say who the voice agent is on every step.
3

Choose the Transition flexibility

Rigid mode or Flex mode decides how the voice agent moves between flow nodes.
Global Settings also holds the voice agent’s Speech settings, Transcription, Call settings, After the call, Security & storage and Webhooks. See Configure the settings.

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Add flow nodes

Every flow starts at Begin. Begin holds the Welcome message and the Pre-call tools, which look up data before the voice agent speaks. Select or drag a flow node from the Nodes palette. To join a new flow node to an existing one, use Connect to and select Create and connect. These flow nodes are available: When an Extract Variable flow node ends with a Required variable still empty, it recovers like this:
  • If extraction worked but left the value empty, only an Else transition can fire.
  • If extraction failed, no values are saved and Else is skipped, even when it exists.
  • Without a transition, the call returns to the flow node that last spoke, and the voice agent talks with the caller again to get the missing value.
  • If no flow node has spoken yet, the call stays on the Extract Variable flow node, and the voice agent asks using that flow node’s instruction.
Select a flow node to open its inspector. The inspector holds the flow node’s Instruction or Static sentence, its Transitions, and these optional sections:
  • Knowledge attaches knowledge bases to this flow node only.
  • Overrides changes the model, interruption, silence reminders or transcription mode for this flow node. In Flex mode, the voice agent’s speech settings apply instead.
  • With Global node, the caller can reach this flow node from anywhere when its Entry condition is met. With Go back afterwards, the caller then returns to where they were.
  • Fine-tune examples gives the model example conversations for its transitions and replies.

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Connect flow nodes with transitions

A transition moves the caller to another flow node. With no transitions, the caller stays in the flow node. Skip response moves on without the voice agent replying first. Confirm values before moving asks the caller to confirm the values that a transition needs.

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What a flow node knows about later flow nodes

Each flow node knows what the voice agent can do later in the call. A flow node never tells the caller that the voice agent cannot do a task that a later flow node does. It moves the call toward that flow node instead. Tars sets this when you publish. A flow published before October 30, 2026 gets it only after you publish it again. See Publish a version.

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Reuse steps with subflows

A subflow is a group of flow nodes that a Subflow flow node enters. A subflow returns to its parent flow through an Exit. A shared subflow has its own versions. Select Publish in the subflow to publish a new version. Voice agents keep the version they use until you select Take the update on their Subflow flow node. To move a subflow between local and shared, select Convert to shared or Convert to local. A subflow uses the voice agent’s voice, model, global prompt and other global settings. Only the transition flexibility can differ inside a subflow.

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Check the flow

Select Validate to list the issues that block publishing. When nothing blocks it, the banner reads No issues · ready to publish. Search nodes in the toolbar opens Voice flow commands. Search flow nodes there, or run commands such as Fit view and Toggle test panel.

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Verify

Open the test panel and select Text chat. Type what a caller says and check that the call moves through the flow nodes you expect. See Test and publish a voice agent.