# Voice User Interface Design Guidelines Through these guidelines you will learn how to use principles of Voice User Interface Design to build more effective skills. These tools will help define and validate the features of the skill before diving deep into development. This guide will cover what a Skill can do, Voice Assistant Personas, the Design process we recommend, some Voice Interaction definitions, and best practices. We will also cover some methods to use that can help plan, prototype and test your skill during the early design stages. To work well with Mycroft's processes, and accelerate your skill into the Marketplace, it is best to take a [Test Driven Development approach](https://behave.readthedocs.io/en/latest/philosophy.html). By the end of this process you should have all the tools you need to begin creating a Behave test for your skill. How to create the Behave test will be covered in the next section. --- # Agent Instructions: Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter: ``` GET https://mycroft-ai.gitbook.io/docs/skill-development/voice-user-interface-design-guidelines.md?ask= ``` The question should be specific, self-contained, and written in natural language. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.