Flow node reference

This is the field-level reference for the flow builder — every node type, its fields, and how it behaves during a call. For what a flow is and how edges and labels work, start with the flow builder overview.

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Start

Entry point of every flow. Defines the greeting and the greeting mode:

• agent speaks first — the greeting is spoken as soon as the call connects (typical inbound).
• user speaks first — the assistant waits for the caller (typical outbound: the callee says “Hello?” first).

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Agent

A conversational agent with its own name, instructions, and optional voice override. The conversation stays with this agent until it hands off along one of its outgoing edges.

• Each outgoing edge is a possible handoff; the assistant uses its label to decide. See why labels matter.
• Empty instructions use the assistant’s system prompt (Advanced prompt) as the base; node text is appended, not replaced.
• Voice override lets different agents speak with different voices.

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Condition

A forced decision point. You write a description of what is being decided; the assistant must choose exactly one outgoing edge based on the edge labels. Use it when routing must happen immediately.

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Tool

Runs a reusable API or built-in tool during the conversation and gives the result back to the assistant. Configure its endpoint, credentials, description, and reusable behavior under Tools.

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Transfer (blind)

Immediately transfers the call to a phone number or SIP URI (SIP REFER), optionally after a short announcement. The assistant leaves the call; there is no briefing of the receiving person.

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Warm transfer

The premium handover: the caller is put on hold music, the assistant dials the target (an employee), briefs them with an AI-generated summary of the conversation so far, and only then connects both parties. The employee can accept or decline; voicemail at the target is detected. Warm transfer outcomes (started / completed / failed) are recorded as call events.

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Collect

Structured data capture with built-in validation, re-asking, and confirmation — far more reliable than hoping the LLM transcribes an email address correctly.

• Types: name, email, phone, address, date of birth, dtmf (digits via keypad or spoken aloud), credit_card (payment card).
• Variable (required): the result is stored under this name and included in the call.completed webhook.
• Prompt: optional extra instructions on top of the built-in dialogue.
• Max attempts (default 3): after final failure, the flow takes the edge labeled failed if present.
• DTMF digits: for type dtmf, how many digits to collect.
• Timeout and stop key (dtmf, set on the assigned Collect keypad tool): how long the caller has before the attempt times out (1–30 s, default 5 s), and which key — # or * — ends input early instead of waiting it out.
• Payment card: requires the Collect payment card tool and an eligible connected Stripe account. During the call, payment details are collected securely. Only a reusable payment-method reference and non-sensitive display details are retained; the full card number and security code are never stored. Connect Stripe under Tools → Agent Connectors first.

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DTMF

Prompts the caller to enter a fixed number of digits on the phone keypad — spoken digits work too. The assigned DTMF input tool sets how many digits to collect (1–32); the caller gets about four seconds per digit, and pressing # ends input early. Use collect with type dtmf when you want validation and retries; use this simpler node for quick menu choices.

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End

Terminates the call, optionally speaking a farewell first. Always give your flows explicit endings — it produces clean call statuses and prevents the conversation from drifting after its job is done.

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Central Tool Library

Add node opens a searchable Tool Library. Reusable settings remain managed on the Tools page: Use Edit in Tools to change reusable settings. The change applies to every assistant and flow that uses the tool.