MPS 2026.1 EAP: What’s New in the First Early Access Build?

Welcome to the MPS 2026.1 Early Access Program! This first build brings significant under-the-hood upgrades, new editor capabilities, and smarter language tooling. Below, we answer your most pressing questions about the highlights of this release.

What major platform updates does MPS 2026.1 EAP include?

MPS 2026.1 EAP completes the migration to the latest IntelliJ Platform 2026.1, along with JDK 25 and Kotlin 2.3 as the embedded runtime and language. This upgrade ensures better performance, compatibility with modern Java features, and access to the newest IDE infrastructure. Additionally, MPS now builds and ships its own kotlinx-metadata-klib and kotlin-metadata-jvm artifacts directly from the Kotlin repository at the matching 2.3.0 tag. This restores KLib-based Kotlin stubs support, which the last public kotlinx-metadata-klib:0.0.6 could no longer provide. Overall, these changes lay a solid foundation for future enhancements and ensure MPS stays in sync with the broader JetBrains ecosystem.

How does the new natural language support improve string validation?

MPS now leverages the IntelliJ Platform’s natural language support powered by Grazie. This means that when you define ICheckedNamePolicy instances (for intentions, actions, tools, etc.), MPS can check whether string values follow proper capitalization rules according to a specific natural language. You can install language support for select languages, and the IDE will automatically detect the language used in strings and verify correct capitalization. If you prefer, you can bypass detection and explicitly specify the desired language. This makes naming conventions more robust across multilingual projects.

What capitalization options are available for ICheckedNamePolicy?

In addition to the default Title-case capitalization rules, MPS offers three other options:

1. Sentence-case – follows the IntelliJ Platform’s rules for sentence capitalization.
2. Inherited – uses the capitalization rules of the closest ancestor ICheckedNamePolicy.
3. No capitalization rules – disables automatic capitalization checking.

These choices give you fine-grained control over how string names are validated, whether you enforce strict casing or allow freeform text. The support is especially useful for teams with mixed-language codebases or specific naming guidelines.

How can I split binary operations into multiple lines?

Long binary operations in the editor can now be easily split across multiple lines. A dedicated intention action lets you toggle between single‑line and multi‑line layouts for any BinaryOperation. This helps improve readability when dealing with complex expressions, allowing you to break them at logical points without manual reformatting. The feature is context‑sensitive and works directly in the editor, making refactoring quick and intuitive.

What is the new read‑only‑inspector style?

The read‑only‑inspector style is a new boolean property that enforces a read‑only state on all editor cells within the inspector. When you apply this style to a cell in the main editor, the inspector becomes read‑only for the inspected node as long as that cell is selected. Key properties: it is disabled by default, it is inheritable and overridable (like the standard read‑only style), it has no effect on main editor cells, and any read‑only style set by this mechanism can be overridden in deeper inspector cell trees. This gives you granular control over which parts of the inspector remain editable during design.

How do transitive dependencies work in Build Language now?

In MPS 2026.1 EAP, the Build Language no longer requires every transitively reachable build script to be explicitly listed in dependencies. If build script BuildA depends on BuildB, and BuildB depends on BuildC, then BuildA can now reach BuildC through BuildB without directly listing BuildC. The generator emits ${artifacts.BuildC} Ant properties for such transitive dependencies, and these properties can be supplied from outer build tools like Gradle or Maven. This reduces redundancy and simplifies build script maintenance, especially in large projects with deep dependency chains.

How can I download and participate in the EAP?

You can download the first MPS 2026.1 EAP build from the official JetBrains website. Simply visit the MPS download page and select the Early Access Program version. Once installed, you can start experimenting with all the new features—including platform upgrades, natural language validation, binary operation splitting, the read‑only‑inspector, and transitive dependency support. Your feedback is invaluable; report any issues via the issue tracker or share your thoughts in the community forums. Join the EAP today and help shape the next stable release of MPS!