# 🛠️ Tools

Use an interface to answer a question or get something done. Tools can be a documented external service, a small local widget, or both.

## Start here

- [Network fee calculator](./network-fee/en.md) — turn gas units and a gas price into an estimated execution fee.

## Add a tool

Copy `network-fee/en.md` and assign a new stable ID. Explain what the tool does, its inputs, its limits, and a useful example. Widgets are optional; a good guide to an existing interface is welcome. See [Contributing](../CONTRIBUTING.md).