> ## Documentation Index
> Fetch the complete documentation index at: https://dialnexa.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# DialNexa Default Variables

> Understand DialNexa default variables, fallback dynamic values, prompt placeholders, voicemail variables, transfer destinations, and batch or workflow protection.

DialNexa default variables are fallback values saved on an agent version for dynamic placeholders. You edit them in the **Fallback Settings** panel - see [Fallback Settings](/agent-settings/fallback-settings) for the how-to; this page explains what defaults are and when they apply. They protect calls when the launch surface does not provide a value for a placeholder used in the prompt, welcome message, voicemail message, transfer path, batch row, or workflow lead.

<Tip>
  A default value should sound acceptable to a caller, not just acceptable to a form validator.
</Tip>

## Default Variable Behavior

Defaults are saved per agent version.

| Behavior            | Meaning                                                                   |
| ------------------- | ------------------------------------------------------------------------- |
| Detected from text  | Placeholders in prompt, welcome, and voicemail text create variable rows. |
| Saved to version    | Defaults are patched to the selected agent version.                       |
| Used as fallback    | If launch data omits a value, the default can be used.                    |
| Transfer validation | Transfer destination variables can require a specific number format.      |
| Published state     | Editing may be blocked on published versions.                             |

## Where Defaults Prevent Bad Calls

Defaults are most useful where data quality varies.

<CardGroup cols={2}>
  <Card title="Batch CSV gaps" icon="file-spreadsheet" href="/batch-calls/recipient-files">
    Protect incomplete recipient rows.
  </Card>

  <Card title="Manual test calls" icon="phone-call" href="/agents/testing-agents">
    Avoid saying unresolved placeholders during tests.
  </Card>

  <Card title="Voicemail messages" icon="voicemail" href="/calls/voicemail-detection">
    Prevent awkward voicemail output.
  </Card>

  <Card title="Workflow leads" icon="workflow" href="/workflows/lead-variables-and-call-attributes">
    Keep workflow actions from missing important text values.
  </Card>
</CardGroup>

## Default Variable Rules

<AccordionGroup>
  <Accordion title="Do not use secrets">
    Defaults can appear in prompts, logs, or exports.
  </Accordion>

  <Accordion title="Use neutral fallback text">
    For a missing first name, a generic greeting may be safer than an incorrect name.
  </Accordion>

  <Accordion title="Retest after changing defaults">
    Published routes may still use another version.
  </Accordion>
</AccordionGroup>

## Related Reading

<CardGroup cols={2}>
  <Card title="Dynamic Variables" icon="braces" href="/agents/dynamic-variables">
    Understand call-time values.
  </Card>

  <Card title="Fallback Settings" icon="settings" href="/agent-settings/fallback-settings">
    Edit defaults in the builder.
  </Card>

  <Card title="Batch Recipient Files" icon="file-spreadsheet" href="/batch-calls/recipient-files">
    Use variables in CSVs.
  </Card>
</CardGroup>