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Vaadin Copilot Hilla

Introduction to Vaadin Copilot, a visual, AI-powered development tool.

Vaadin Copilot is a handy development tool that’s ready to assist you whenever you run an application in development mode. Copilot is a visual development tool and it’s an AI-powered assistant. You can inspect and edit the UI, and use generative AI to help with a variety of tasks.

Vaadin Copilot contains all of the functionality previously found in Development Tools. However, starting in version 24.4 some of the new functionality is primarily available for Hilla projects.

Warning
Copilot functionality that makes changes to code, including but not limited to AI functionality, requires that you log in and accept the terms and conditions. This functionality is available for all subscribers.

Vaadin Copilot is designed to work seamlessly with an IDE, and fit into regular development workflow. When activated, Copilot appears in the browser, on top of your running application. You can switch between your IDE and Copilot to make changes where it’s most convenient.

Getting Started

Vaadin Copilot comes built into the development mode of your application; you don’t need to install anything. If you have an existing project, make sure it’s running Vaadin 24.4 or later.

See how to Start a Project for more information. Be sure you add a Hilla view. Also, see how to Import to an IDE, and Run an Application.

Once your application is running, click the }> button to activate or deactivate Copilot.

Quick Step-by-Step Instructions

  • Go to start.vaadin.com and click Download Project. Be sure that the platform version is at least 24.4.

  • After downloading, unzip the project.

  • Run ./mvnw in the project folder.

  • Once the project opens in your browser, click }> button.

Basic Operation

Copilot supersedes the previous development tools, and is activated via the same }> button that appears on top of your application in development mode. When activated, Copilot takes over the browser and disables interaction with the application until Copilot is deactivated.

Enable the keyboard shortcuts so that you can effortlessly enter and exit Copilot as you develop your application.

Keyboard Shortcuts

The shortcut to enable Copilot is ⇧+CTRL+CTRL or ⇧+CMD+CMD (i.e., hold SHIFT while pressing CTRL or CMD twice in quick succession).

You can deactivate Copilot using the same shortcut you used to activate it. When active, you can use ⇧+SPACE (i.e., hold SHIFT, press SPACEBAR) to open the command window. Use ESC to close it again.

Vaadin Copilot UI

The Copilot UI consists of four main parts. Referring to the numbers in the graphic that follows, the ➀ Activation Button activates and deactivates Copilot, and hosts a popup menu with some configuration options. This is the only functionality available when Copilot is not activated. Once activated, Copilot offers additional functionality.

➁ Drawers are located to the left, right, and bottom edges of the browser window, and appear when you move the mouse close enough to those edges. Drawers are where you find most of the Copilot functionality tucked away by default.

Vaadin Copilot UI overview

Each Drawer contains ➂ Panels, with each representing a specific functionality. Each panel can be turned into a ➃ Floating Panel so that it doesn’t auto-hide with the Drawer, and can be moved, collapsed, and resized.

The ➄ Spotlight is a context-sensitive popup window with an input prompt. This is where you can give commands to the AI.

Built-In Panels

Panel Default Drawer Description

Features

Right

Manage Feature Flags.

Info

Right

Application information.

Database

Right

Manage H2 development database instances.

Theme Editor

Right

Theme Editor

Outline

Left

Component/element hierarchy. Hover to highlight, click to select, and drag & drop to rearrange.

Palette

Left

A palette containing select Vaadin components. Drag to UI or Outline to add to the application.

Log

Bottom

Application debug message log.

Accessibility (a11y)

Right

Accessibility check and recommendations.

Internationalization (i18n)

Right

Internationalization tool.

Plugins

Copilot uses a plugin architecture which allows additional functionality to appear as panels. This includes tools such as Vaadin AppSec Kit, as well as third-party plugins.

Context Menu

Go to Source: Component Locator

You might have previously used the component locator in Development Tools. The same functionality is available in Copilot: Select a component by clicking on it. Then right-click to display the context menu, and choose "Go to source".

Your IDE will open the source file on the row where the component is created.

Wrap with…​

You can select a component and use "Wrap with" in the context menu to add a layout around the selected component.

Duplicate

Make a copy of the component.

Add click listener

A quick way to add a click listener stub to the source code. Your IDE will open the source file on the row where the listener has been added.

Delete

Delete the component.

Drag & Drop

You can rearrange components by using drag-and-drop. Drop zones will appear to visualize where components can be dropped. You can also use drag-and-drop on the Outline, and drag in new components from the Palette.

AI Assistant

You can ask Copilot to do things for using a natural language prompt in the Spotlight popup. The AI does its best to fulfill your request, but in this early phase its abilities are limited; it makes mistakes sometimes. Think of it as a very helpful junior developer, who remembers a lot about topics you might have forgotten or not looked into yet, but is still very inexperienced and needs supervision. It’s slower than you on small tasks if you remember exactly how to do them. It’s faster if you’d need to look up how to do a task, or if it involves a lot of typing. Basically, be ready to fix minor mistakes, undo a whole change — and be prepared to be pleasantly surprised.

Context & Selection

The AI knows a bit about your project and tech stack — and which components you’ve selected, if any. It tries to make use of that information when possible: for instance when you refer to a button, selected components, or similar items.

Example Prompts

To learn how to use Copilot, you might start by trying to perform some small tasks. Below are suggestions of common tasks.

Try to do the following to make a button primary:

> make the button primary

This type of task can be slow compared to making the change manually. However, it can be very useful when you don’t remember how to do it in the code.

Bootstrapping a new form or generating placeholder content can be very convenient. Try this:

> add comprehensive fields for contact details and international shipping and billing

Prompts can affect multiple components, and take context into account without being very specific in the prompt. To make those changes and addition, try these:

> make the width of each field match the expected input

> add a placeholder to each field

The AI may be able to help with UX considerations. Try these tasks:

> follow UX best practices for placeholders

> group fields into natural sections

Undo & IDE Integration

When developing UIs, there’s a tendency to switch repeatedly between code and the browser to verify and tweak the results. You should be able to code when needed, and do changes directly in the UI when that feels more appropriate.

Vaadin Copilot aims to integrate seamlessly into your regular development workflow. This way you can switch back and forth between the code in your IDE and Copilot, depending on which is appropriate. However, this can pose a problem with being able to undo when two applications are changing the same files. Copilot considers the file on disk to be the source of truth. All changes are made to the file, then hot deployed to the browser.

To get full-fledged undo support, though, use the Vaadin plugin for IntelliJ. It makes all Copilot changes appear as if they were made within your IDE.

As a stop-gap when you’re not using the plugin, make sure the file being changed by Copilot is open in your IDE: the changes will be reloaded from the disk. This adds the operation to the undo stack so you can go back to the previous version. This approach can be difficult to manage when changing multiple files, and it’s easy to forget to open relevant files before using Copilot. Use version management (e.g., git) to revert changes. This requires you to commit often. Otherwise, undoing operations will be very coarse-grained.

Limitations

These are some known limitations with using Copilot with Vaadin:

  • Vaadin Flow (i.e., Java) UI editing is not supported in version 24.4.

  • Not all views or hierarchies can be edited via drag-and-drop. In particular, parts of the UI created programmatically (e.g., loops) can cause problems.

  • AI makes mistakes.

  • AI is currently limited to smaller one-view tasks.