MPS 2026.1 Early Access: What’s New in the First Preview Release

Overview of MPS 2026.1 EAP

The MPS 2026.1 Early Access Program (EAP) has officially launched, offering developers an early look at the next generation of JetBrains’ domain-specific language environment. This first preview build is packed with significant platform updates, new editor features, and streamlined dependency handling. Download the EAP release now to test these improvements yourself.

MPS 2026.1 Early Access: What’s New in the First Preview Release — Source: blog.jetbrains.com

Platform Upgrades: IntelliJ 2026.1, JDK 25, and Kotlin 2.3

MPS completes its transition to the latest IntelliJ Platform (2026.1), bringing full compatibility with the newest tooling and performance enhancements. Under the hood, the runtime now uses JDK 25, and the embedded Kotlin version has been upgraded to 2.3.0. A notable improvement is the restoration of KLib-based Kotlin stubs support. MPS now builds and ships its own kotlinx-metadata-klib and kotlin-metadata-jvm artifacts from the Kotlin repository at the matching 2.3.0 tag, replacing the outdated kotlinx-metadata-klib:0.0.6 that could no longer provide this functionality.

Enhanced Natural Language Checking with Grazie

MPS integrates the IntelliJ Platform’s natural language engine (Grazie) to offer smarter string validation. Developers can now check whether string values in ICheckedNamePolicy instances—such as intention names, action descriptions, or tool labels—follow proper capitalization rules for a specific language.

You can install language support packs for various languages, and MPS will automatically detect the language used in strings and enforce the correct title-case or sentence-case. If auto-detection isn’t desired, you can explicitly specify the target language. Beyond the default Title-case capitalization, MPS 2026.1 EAP provides three additional options:

Sentence-case – Follows IntelliJ Platform’s built-in rules.
Inherited – Uses the capitalization style of the nearest ancestor ICheckedNamePolicy.
No capitalization rules – Disables automatic correction.

Splitting Binary Operations Across Lines

Long lines containing binary operations can now be split into multiple lines directly in the editor. A dedicated intention action (Split/Join Binary Operation) lets you toggle between single-line and multi-line layouts for any given BinaryOperation. This makes complex expressions easier to read and maintain.

New Read-Only Inspector Editor Style

A new editor style called read-only-inspector has been introduced to improve workflow when working with inspector panels. When this style is applied to a cell in the main editor, the inspector becomes read-only for the inspected node whenever that cell is selected. Key properties of this style include:

Disabled by default.
Inheritable and overridable—works similarly to the existing read-only style.
No effect on main editor cells; it only influences the inspector.
The read-only behavior set by this style can be overridden in any deeper inspector cell tree.

Simplified Dependency Management in Build Language

MPS Build Language now automatically handles transitive dependencies. You no longer need to list every transitively reachable build script explicitly. For example, if BuildA depends on BuildB, and BuildB depends on BuildC, BuildA can access BuildC without a direct dependency declaration. The generator emits ${artifacts.BuildC} Ant properties for such cases, which can be supplied from an outer build tool like Gradle or Maven.

Get the EAP Build

Download the MPS 2026.1 EAP from the official JetBrains website and start exploring these enhancements. As this is an early preview, feedback and bug reports are invaluable for refining the final release.

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