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

# Agent Configuration

> Configure your AI phone agent — voice, language, instructions, flow builder, knowledge sources, actions, transfer destinations, and telephony routing.

Edit any agent from **[Channels → Phone → Agents](https://platform.open.cx/channels/phone/agents)**.

<Tip>
  Haven't created an agent yet? Start with [Create Phone Agent](/phone/create-agent).
</Tip>

## Voice And Language

| Setting              | Detail                                                                                                     |
| -------------------- | ---------------------------------------------------------------------------------------------------------- |
| **Voice**            | Select from the voice library. Each voice has a distinct tone and style.                                   |
| **Language**         | Set the primary language. Multi-language agents detect and switch languages automatically during the call. |
| **Background noise** | Optional ambient noise preset: `none`, `office`, `bar`, or `city-street`. Adds realism to the call.        |

## Instructions

Define what the agent does during a call. Two approaches:

<Tabs>
  <Tab title="Free text">
    Write natural-language instructions in the text field. The agent follows them as guidelines throughout the call.
  </Tab>

  <Tab title="Visual flow builder">
    Build a structured call flow using drag-and-drop nodes:

    | Node              | Purpose                                                 |
    | ----------------- | ------------------------------------------------------- |
    | **Root**          | Entry point of the flow                                 |
    | **Instruction**   | Give the agent a directive at this step                 |
    | **Collect Info**  | Ask the caller for specific information                 |
    | **Transfer Call** | Transfer to a phone number, SIP destination, or hang up |
    | **Call Action**   | Trigger a workflow or tool                              |
    | **If Condition**  | Branch based on what the caller said or data collected  |
    | **End Call**      | End the conversation                                    |

    The flow builder and free-text instructions can be used together. Flow nodes override free text when active.
  </Tab>
</Tabs>

## First Message

What the agent says when it picks up the call. Set this to a greeting that matches your brand (e.g. "Thanks for calling Acme. How can I help you today?"). Defaults to **"Hello?"** if left blank.

## Knowledge Sources

Link published knowledge documents to the agent. The AI references them during calls.

* Select **individual items** or **entire directories** from your knowledge base.
* Only **published** (non-draft) items are used.
* Selecting a directory includes all current and future published items within it.

<Note>
  Knowledge sources are managed under the **Knowledge Sources** section of the agent settings page.
</Note>

## Actions And Workflows

Select which **active AI-trigger workflows** the agent can use during calls. The AI decides when to trigger them based on the conversation context.

* A `null` selection means **all actions** are available.
* An empty selection means **no actions**.

## Transfer Destinations

<Tooltip tip="The AI hands the live call to another party — a human agent, external phone number, or SIP destination — mid-conversation.">Transfer destinations</Tooltip> are defined at the **org level** and then assigned to individual agents. Phone numbers use <Tooltip tip="The international phone number format: + country code followed by the subscriber number, e.g. +14155551234.">E.164</Tooltip> format.

| Type       | Target                                                                 |
| ---------- | ---------------------------------------------------------------------- |
| **Phone**  | Transfer to an external phone number (E.164 format)                    |
| **SIP**    | Transfer to a SIP URI with optional digest authentication              |
| **Custom** | End the call (useful as a pre-transfer or post-transfer workflow hook) |

Manage destinations under the **Transfer Destinations** section of the agent settings, or at the org level under **[Channels → Phone](https://platform.open.cx/channels/phone)**.

## Telephony And Routing

<AccordionGroup>
  <Accordion title="Inbound Numbers" icon="phone-arrow-down-left">
    Assign one or more verified phone numbers to the agent. Each number can only be assigned to **one agent**. For BYOC numbers, configure SIP trunks under **[Settings → SIP](https://platform.open.cx/settings/sip)** and assign them here.
  </Accordion>

  <Accordion title="Outbound Caller" icon="phone-arrow-up-right">
    Set the caller number for outbound calls. Choose a hosted number or configure a custom SIP trunk. See [Outbound Calls](/phone/outbound-calls).
  </Accordion>

  <Accordion title="Agent ID" icon="fingerprint">
    Each agent has a unique **Agent ID** shown on the settings page. Use it with the <Tooltip tip="A custom SIP header that tells OpenCX which agent should handle the call, enabling dynamic routing from your own infrastructure.">X-OPENCX-AGENT-ID</Tooltip> SIP header for dynamic routing from your own infrastructure. See [SIP Integration](/phone/sip-integration).
  </Accordion>
</AccordionGroup>

***

## Related Documentation

<CardGroup cols={2}>
  <Card title="Inbound Calls" icon="phone-arrow-down-left" href="/phone/inbound-calls">
    Call routing, session matching, and call behavior.
  </Card>

  <Card title="Outbound Calls" icon="phone-arrow-up-right" href="/phone/outbound-calls">
    Make calls from the dashboard, API, or workflows.
  </Card>

  <Card title="SIP Integration" icon="server" href="/phone/sip-integration">
    Inbound and outbound SIP trunks for BYOC.
  </Card>
</CardGroup>