ReSharper 2026.3 Adds Claude Agent, Codex, and .NET 11 Support
JetBrains integrates third-party AI agents and updates tooling for latest .NET framework releases.
1Expanded AI Agent Integration
ReSharper 2026.3 introduces Claude Agent and Codex alongside the existing Junie model within the AI Assistant tool window. Developers can now choose their preferred model to edit code, execute terminal commands, or explain complex solutions directly inside Visual Studio. This integration utilizes the Agent Client Protocol to connect external models seamlessly.
2Refactoring Capabilities for Agents
All three supported AI agents, including Junie, Claude, and Codex, can now leverage ReSharper’s native refactoring engine. Instead of performing manual file edits, agents can execute complex tasks like renaming symbols or moving types between namespaces. This functionality bridges the gap between generative AI suggestions and robust, automated code architectural changes.
3New Free Tier Access
JetBrains has launched Junie Lite, a free model tier accessible to any user with a registered JetBrains Account. This tier does not require a paid ReSharper license, lowering the barrier for entry. Other premium agents still require a JetBrains AI subscription, as the platform currently does not support personal API keys.
4Full .NET 11 and C# 15
This release provides day-one support for the newly launched .NET 11 and C# 15. Key language features include union types, closed class hierarchies, and labeled break statements. ReSharper includes specific inspections and quick-fixes to help developers migrate existing codebases to these modern syntax standards while maintaining full IDE feature compatibility.
5Memory Safety and Decompilation
ReSharper 2026.3 introduces support for the memory safety redesign preview, identifying unsafe expressions and missing modifiers. Additionally, the decompiler now correctly displays runtime-async methods as standard async methods. These improvements ensure that developers can accurately analyze and debug code that utilizes the latest runtime-level asynchronous execution patterns in .NET 11.
6Advanced Code Analysis Tools
New inspections in this version detect common errors such as character values used as array indices or culture-sensitive sorting issues. Parameter information now groups overloads with shared leading parameters, simplifying navigation for complex method calls. These enhancements aim to reduce runtime bugs and improve code readability for developers working on large projects.
7C++ and Testing Updates
C++ developers gain a class layout view to visualize memory arrangement and new format string checks for Unreal Engine logging macros. The test runner has been upgraded to support xUnit v3 4.0 and NUnit 5.0. Furthermore, Microsoft.Testing.Platform is now enabled by default, simplifying test discovery for frameworks like TUnit without manual configuration.
8Strategic Development Impact
By integrating third-party agents via the Agent Client Protocol, JetBrains is positioning ReSharper as a vendor-neutral hub for AI-assisted development. The combination of deep language support for C# 15 and expanded testing framework compatibility ensures that enterprise teams can adopt the latest Microsoft technologies while maintaining high-quality, automated development workflows.