JetBrains MPS Releases Bug-Fix Updates for Multiple Versions
New updates enhance projectional agent toolkit and testing capabilities.
1Multi-version bug-fix rollout
JetBrains has released simultaneous updates for four major MPS versions: 2026.1.1, 2025.3.2, 2025.2.4, and 2025.1.4. These maintenance releases address various issues across the platform. The updates are available for immediate download, with separate patch notes detailing fixes for each version. This coordinated release strategy ensures developers across different MPS adoption cycles receive critical updates.
2Projectional Agent Toolkit upgrades
The 2026.1.1 update brings significant improvements to the Projectional Agent Toolkit. Agents can now interact with individual nodes more effectively, manipulating attributes and creating node copies. Enhanced editor context access provides caret and selection information, while clearer diagnostics handle modal dialog conflicts. These changes collectively improve the agent-assisted development experience in MPS projects.
3Enhanced node manipulation capabilities
New features allow agents to directly work with NodeAttributes and PropertyAttributes, expanding their ability to modify project elements. The capability to create node copies introduces new workflow possibilities. Developers gain richer context awareness during agent operations, including precise selection tracking. These technical upgrades make agent behaviors more predictable and development processes more transparent.
4Improved testing integration
The release enhances agent guidance for editor tests and YouTrack issue creation. Test execution becomes more reliable with the updated toolkit. These improvements particularly benefit teams implementing test-driven development with MPS. The updates address common pain points in maintaining consistent testing environments across projectional development workflows.
5Modal dialog handling
Agents now receive clearer diagnostics when modal dialogs block tool execution. This improvement reduces unexpected behavior during complex editing sessions. Developers gain better visibility into operation-blocking scenarios, allowing for more robust error handling. The change particularly benefits workflows involving multiple simultaneous tool interactions.
6Skill update requirement
JetBrains emphasizes the need to update MPS skills in existing projects to fully utilize the new capabilities. This requirement ensures compatibility with the enhanced agent behaviors. Teams maintaining long-running MPS projects must account for this migration step. The documentation provides specific guidance on implementing these updates across different project configurations.
7Version-specific fixes
Each MPS version (2026.1.1, 2025.3.2, 2025.2.4, 2025.1.4) receives tailored bug fixes addressing version-specific issues. The updates maintain backward compatibility while resolving known problems. Developers can access complete fix lists for their specific version through the provided release notes. This approach allows teams to assess the impact on their particular codebase.
8Impact on projectional workflows
These updates collectively enhance the reliability and capability of agent-assisted projectional development. The improvements make complex editing operations more predictable and easier to manage. For teams using MPS for domain-specific language development, the toolkit upgrades offer tangible productivity benefits. The release demonstrates JetBrains' ongoing commitment to refining MPS's unique projectional editing paradigm.
Original article: The JetBrains Blog — JetBrains MPS Releases Bug-Fix Updates for Multiple Versions