dograh/docs/voice-agent/start-call.mdx

---
title: "Start Call"
description: "You can use Start Call node to Start the call and configure how Agent greets the user when the conversation starts."
---

## Video Tutorial

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  width="560" 
  height="315" 
  src="https://www.youtube.com/embed/Bpnu7Oz-YPI" 
  title="Start Call Node Tutorial" 
  frameBorder="0" 
  allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" 
  referrerPolicy="strict-origin-when-cross-origin" 
  allowFullScreen
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<Note>
You should have only one Start Call node per Voice Agent.
</Note>

Start Call is the entry point for every conversation. It fires the moment a call connects and controls the first thing your agent says. Every workflow must have exactly one.

## When it runs

Start Call executes before any Agent Node. No other node can precede it in the call flow.

After Start Call completes, the conversation moves to the next node - typically your first Agent Node. If the caller hangs up immediately or reaches a wrong-number condition, Start Call can route directly to End Call instead.

## Fields

**Name**

Short identifier shown in the canvas and call logs. Has no runtime effect on what the agent says.

**Greeting Type**

Whether the greeting is spoken via TTS from text or played from a pre-recorded audio file. Defaults to "Text (TTS)".

**Greeting Text**

Optional fixed line spoken via TTS the moment the call connects, before the AI's conversational turn begins. Supports `{{template_variables}}`. Leave empty to skip the greeting and let the Prompt handle the opening.

For example:

```text
Hi {{initial_context.debtor_name}}, this is Alex from Apex Recovery Solutions.
```

<Note>
See [Pre-recorded Audio](./pre-recorded-audio) to use a recording file instead of TTS text.
</Note>

**Prompt** (required)

System instructions for the AI's opening conversational turn. Runs after Greeting Text (if set). Supports `{{initial_context.field_name}}` and variables from Pre-Call Data Fetch.

For example:

```text
After greeting the caller, confirm you are speaking with
{{initial_context.debtor_name}}. If they confirm, move to Debt Disclosure.
If they say wrong number, move to End Call.
```

<Warning>
If a variable referenced in Greeting Text or Prompt is missing from the API request payload, the agent speaks the raw placeholder out loud - for example, "Hi `{{initial_context.debtor_name}}`" - instead of the caller's name. Test with a complete payload before publishing.
</Warning>

**Allow Interruption**

When on, the caller can interrupt the agent mid-utterance. Off by default on Start Call.

**Add Global Prompt**

When on and a Global Node exists, the Global Prompt is prepended to this node's Prompt at runtime. On by default.

**Delayed Start**

When on, the agent waits before speaking after the call connects. Useful for outbound calls where the called party needs a moment to settle. Duration can be set between 0.1 and 10 seconds.

**Enable Variable Extraction**

When on, an LLM extraction pass runs after this node's turn to capture structured data from the conversation into `gathered_context`.

**Tools**

Functions the agent can call during the opening turn. Add via the "HTTP & Tools" tab (HTTP API and built-in tools) or the "MCP" tab (MCP server tools).

**Knowledge Base Documents**

Documents the agent can reference during this step. Attach via "Manage Documents."

**Pre-Call Data Fetch**

When on, Dograh makes a POST request to an external API before the call starts and merges the JSON response into the call context as template variables.

## Outgoing edges

Start Call can have multiple outgoing edges, each with a user-defined label and a condition written in plain language. The LLM reads the conversation and picks the edge whose condition best matches.

Each edge needs two things:

- **Label:** a short name shown on the canvas (you define this)
- **Condition:** the instruction that tells the LLM when to take this edge

A typical Start Call has two edges:

```text
Label: "caller confirmed"
Condition: "The caller confirmed they are the right person and are ready to continue."

Label: "wrong number"
Condition: "The caller says this is the wrong number, asks not to be called, or refuses to confirm their identity."
```

You can add more edges if the opening turn needs to branch further.

## Common mistakes

**Leaving Greeting Text empty with no Prompt.** If both Greeting Text and Prompt are empty, the agent says nothing at the start of the call. The caller hears silence.

**Confusing Node Name with the agent's spoken name.** Node Name is a canvas label for your own reference. The name the agent introduces itself as comes from the Greeting Text or Prompt content, or the persona you define in the [Global Node](./global).

**Adding a second Start Call node.** Each workflow has one entry point. A second Start Call node will throw an error.

## Next Steps

<CardGroup cols={2}>
  <Card title="Agent Node" href="./agent">
    Build the core conversation logic that follows the greeting.
  </Card>
  <Card title="Global Node" href="./global">
    Set persona and tone rules that apply across all nodes.
  </Card>
  <Card title="Context and Variables" href="../core-concepts/context-and-variables">
    Learn how `initial_context` variables flow through a call.
  </Card>
  <Card title="End Call Node" href="./end-call">
    Configure the agent's final message before the call drops.
  </Card>
</CardGroup>