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

# Tools

> The seven tool types a voice agent can use

A tool is an **action the agent can run during the call**: query an API, book an appointment, transfer, hang up, or send a WhatsApp.

<Info>
  **📷 Screenshot needed** — the tool builder, showing the available types.

  Save to `/images/en/voice-agents/tools-builder.png`
</Info>

## How they work

Tools are an **account-wide library**, not per agent. You create one once under **Voice → Tools**, then **attach** it to whichever agents need it. The same tool can serve many agents.

<Steps>
  <Step title="Create it">
    Under **Voice → Tools**, pick the type and configure it.
  </Step>

  <Step title="Attach it">
    In the agent editor, the **Tools** button → add.
  </Step>

  <Step title="Map the parameters">
    Connect each of the tool's parameters to a variable in your prompt.
  </Step>
</Steps>

<Warning>
  **The type can't be changed after the tool is created.** If you pick wrong, you have to create another.
</Warning>

## The description is the trigger

It's the most important field and the most underestimated: **the AI decides when to use a tool by reading its description**.

<Tip>
  Don't describe *what* the tool does, describe **when it should be used**.

  Weak: `Checks order status.` Strong: `Use when the customer asks about an order and has given an order number. Do not use
      if they're only asking about shipping times in general.`
</Tip>

## The seven types

<AccordionGroup>
  <Accordion title="API — call an external service" icon="code">
    Method, URL, parameters, headers and body. Responses are mapped with JSON paths (`customer.id`, `data[0].name`) and those values become output variables.

    Any `{{token}}` you write in the URL, parameters or headers **becomes an input variable** for the AI to fill.

    Advanced options: timeout (120 s by default), a **message while it runs**, and a **message after it finishes** (on by default).

    <Note>
      The request is always sent as `application/json`, even if you set another header.
    </Note>
  </Accordion>

  <Accordion title="Transfer — hand the call to a person" icon="phone-arrow-right">
    Destination in E.164 format (`+[country][number]`), with an optional extension.

    Two modes:

    * **Cold Transfer** — direct handoff, the agent drops out.
    * **Warm Transfer** — the agent introduces the caller and waits for a human to pick up. Supports hold music, a private message for whoever answers, and a public one for the caller.
  </Accordion>

  <Accordion title="End Call — hang up" icon="phone-slash">
    One field that matters: the **trigger prompt**, describing when the conversation should end. Optionally, a message right before hanging up.

    <Tip>
      Keep the trigger narrow. Ending too eagerly cuts customers off mid-thought — "customer confirms it's resolved" works better than "conversation seems done".
    </Tip>

    <Note>
      This tool's helper text is worded for chat ("before the chat ends") because the component is shared with WhatsApp and SMS. On a call it means hanging up.
    </Note>
  </Accordion>

  <Accordion title="Agent Swap — hand off to another agent" icon="arrows-repeat">
    Passes the call to **another voice agent**, which continues the same conversation rather than starting fresh. You can choose which agents the post-call analysis is attributed to.
  </Accordion>

  <Accordion title="Calendar — check and book" icon="calendar">
    Against Dialtu's native calendar. Eight operations, split between reads and writes:

    **Reads:** list services, list professionals, list appointment types, check availability, list the customer's appointments. **Writes:** book, reschedule and cancel an appointment.

    Settings: **times to offer** (1–20, default 5), **days to look ahead** (1–30, default 7), and whether it **sends a confirmation message**.

    <Warning>
      Booking and rescheduling only work well if the agent **can also check availability**. Enable the reads alongside the writes — nothing forces you to, but without them the agent books blind.
    </Warning>
  </Accordion>

  <Accordion title="Integration — a connected system" icon="plug">
    Today there is **one provider available: AgendaPro**, with ten operations (six reads and four that modify real data).

    <Warning>
      **There's no screen for you to connect integrations yourself.** The Dialtu team makes the connection. In the builder you'll only see a status indicator — if it says *Not connected*, ask your Dialtu contact to link it before going live.
    </Warning>

    <Tip>
      On a call the agent reads results aloud, so keep the set of operations small: every extra capability is one more thing it may reach for mid-conversation.
    </Tip>
  </Accordion>

  <Accordion title="Send WhatsApp Template" icon="whatsapp">
    A voice agent can send an **approved WhatsApp template** during the call — useful for sending a link, a confirmation or a location while talking.

    Each template variable is filled either from **server context** (automatic, never shown to the AI) or as an **AI argument**.

    <Tip>
      Use server context for anything the model shouldn't invent.
    </Tip>
  </Accordion>
</AccordionGroup>

## Attaching and mapping

The editor's **Tools** button opens the list of attached tools. Selecting one lets you map each parameter to a **prompt variable**.

Two behaviours worth knowing:

<Check>
  **Removing** a tool cleans its variables out of the prompt automatically — the words stay, but the `{{ }}` braces go.
</Check>

<Check>
  **Renaming** a variable on the tool rewrites the prompt in place.
</Check>

<Note>
  In the attached-tools panel, Calendar, Integration and WhatsApp Template tools all display an **API** label. It's a known display bug: the tool works correctly, it's just mislabelled.
</Note>

## Next step

<Card title="Test and activate" icon="circle-play" href="/en/voice-agents/test-publish">
  Test the agent before leaving it to handle calls.
</Card>