How to Get Started with MPS 2026.1 Early Access and Its New Features

Introduction

Welcome to the MPS 2026.1 Early Access Program (EAP)! This guide will walk you through downloading, installing, and exploring the key improvements in the first EAP build. Whether you're a seasoned MPS user or just curious about the latest updates, these step-by-step instructions will help you take full advantage of the new platform migration, enhanced language checking, editor capabilities, and build language improvements. By the end, you'll be ready to test drive the new features and provide valuable feedback to the JetBrains team.

What You Need

• MPS 2026.1 EAP build – Download from the official JetBrains website (link provided in Step 1).
• Supported operating system – Windows, macOS, or Linux (64-bit).
• JDK 25 – The EAP now requires JDK 25 for runtime; ensure you have it installed or allow the installer to manage it.
• IntelliJ Platform 2026.1 – This build is built on the latest IntelliJ platform, so a compatible environment is needed.
• Kotlin 2.3.0 – Embedded Kotlin version; no separate installation required.
• Optional: Grazie language support plugins – For natural language features, install additional language packs from JetBrains Marketplace.

Step-by-Step Guide

1. Step 1: Download the MPS 2026.1 EAP Build

   Visit the MPS EAP download page and obtain the installer for your operating system. The first 2026.1 EAP release is available now. Click the download button and save the file to your computer.

2. Step 2: Install MPS 2026.1 EAP

   Run the downloaded installer. On Windows, use the executable; on macOS, mount the DMG and drag MPS to Applications; on Linux, extract the tarball to your preferred location. Follow the on-screen prompts. The installer will automatically configure the bundled JDK 25 and Kotlin 2.3.0. Once installation is complete, launch MPS from your applications menu.

3. Step 3: Verify Platform Migration and New Features

   After launching, check the About MPS dialog (Help > About) to confirm you are running on IntelliJ Platform 2026.1 with JDK 25 and Kotlin 2.3.0. Notice that MPS now builds and ships its own kotlinx-metadata-klib and kotlin-metadata-jvm artifacts at the matching 2.3.0 tag. This restores KLib-based Kotlin stub support that was missing in the last public kotlinx-metadata-klib:0.0.6. You can now open projects that rely on Kotlin stubs without compatibility issues.

4. Step 4: Configure Natural Language Checking for ICheckedNamePolicy

   MPS now integrates with the IntelliJ Platform’s natural language support via Grazie. This allows you to check capitalization rules for intentions, actions, and tools. To use this feature:

   • Install language support packs: Go to Settings > Plugins, search for "Grazie" and install the language packs you need (e.g., English, German, French).
   • In your project, find an instance of ICheckedNamePolicy (e.g., an intention or action).
   • MPS will automatically detect the language used in string values and verify proper capitalization. You can also bypass detection by explicitly specifying the desired language in the policy.
   • Choose from four capitalization rule options: Title-case (default), Sentence-case (follows IntelliJ Platform rules), Inherited (uses ancestor’s rules), or No capitalization rules.

5. Step 5: Split Binary Operations into Multiple Lines

   Long binary operations can now be split across multiple lines for better readability. To use this:

   • In the editor, place the cursor on a BinaryOperation expression.
   • Press Alt+Enter (or click the light bulb) to open the intention actions list.
   • Select Split binary operation into multiple lines (or the corresponding toggle for multi-line to single-line).
   • The operation will be reformatted with line breaks at each operator. Use the same intention to collapse back to a single line.

6. Step 6: Apply the New Read-Only-Inspector Style

   A new boolean editor style read-only-inspector helps enforce read-only properties for inspector cells. Follow these steps:

   

   • Open an editor definition in your language.
   • Add the read-only-inspector style to a cell in the main editor (e.g., style="read-only-inspector").
   • By default, this style is disabled. When applied, the inspector becomes read-only for the inspected node only when the cell with this style is selected in the main editor.
   • The style is inheritable and overridable, similar to the regular read-only style. It has no effect on main editor cells themselves. You can override the read-only behavior in child cells of the inspector.

7. Step 7: Manage Transitive Dependencies in Build Language

   Build Language scripts now automatically handle transitive dependencies. Previously, you had to list every transitively-reachable build script. Now, if BuildA depends on BuildB, and BuildB depends on BuildC, BuildA can reach BuildC without explicitly listing it. The generator emits Ant properties like ${artifacts.BuildC} for such cases, which can be supplied from outer build tools (Gradle, Maven, etc.). To use this:

   • In your build script, declare direct dependencies only.
   • Ensure that the transitive build scripts are in the same project or accessible via the Ant properties.
   • If you use an external build tool, pass the properties (e.g., -Dartifacts.BuildC=path) to the build.

Tips and Best Practices

• Back up your projects before installing an EAP build, as it may contain experimental features or minor incompatibilities.
• Report bugs and feedback via the JetBrains bug tracker or community forums; the EAP period is the perfect time to shape the final release.
• Explore each feature in isolation – try the natural language checking on a small set of intentions before rolling out to your entire base language.
• Use the split binary operation intention often to improve code readability in generators and editors.
• Combine the read-only-inspector style with the existing read-only style to create fine-grained access control in your language editors.
• Leverage transitive dependencies in Build Language to reduce boilerplate and simplify your build scripts – but be mindful of implicit dependencies that might cause confusion.
• Keep an eye on the EAP release notes for updates, bug fixes, and additional changes throughout the program.

We hope this guide helps you get started with MPS 2026.1 EAP. Happy modeling and language engineering!