---
title: Press Keys (DTMF)
description: "Let an agent press keypad digits during a call, to get through an IVR menu or confirm a prompt, with fixed digits or digits it chooses."
---

<Badge variant="accent">Voice agents</Badge>

**Press Keys (DTMF)** lets the agent press keypad digits on the call, for example to
get through an IVR menu or to confirm a prompt. It is what an outbound agent needs
when the number it dials answers with "press 1 for sales" instead of a person.

## Adding it

1. Open the agent and choose **Tools** under **Build**.
2. Choose **Add tool**, then **Press Keys (DTMF)**.
3. Optionally fill **Fixed digits (optional)**, then choose **Add Tool** and
   **Save** the agent.

The tool's title defaults to `Press Keys`, so its ID is `press_keys`. **AI
Response** starts empty.

## Fixed digits or chosen digits

The one setting decides who picks the digits.

- **With fixed digits**, the model only decides *when* to press them. Use this when
  the path is always the same, such as the same menu option on every call.
- **Left empty**, the model chooses the digits on each call. Use this when the
  right key depends on what the menu says, and let the prompt tell the agent how to
  choose.

Digits may only contain `0` to `9`, `*`, `#` and `A` to `D`, up to 32 of them.
Lower-case `a` to `d` are accepted and saved in upper case.

## Writing the description

The tool's description is what the model reads to decide when to use it. Its
default is *Press keypad digits on the call, e.g. to navigate an IVR menu or confirm
a prompt.* Narrow it to your case, for example: *Press the key for billing when the
menu offers it. Never press keys while a person is speaking.*

## Related

- [Tools overview](/build/tools/overview)
- [Transfer Call](/build/tools/transfer-call)
- [Answering machine detection](/build/speech-pipeline/answering-machine-detection)