IntelliJ IDEA 2026.3: A Watershed Release Turning the IDE into an Agent Platform

After upgrading to IntelliJ IDEA 2026.3, the author considers this version a watershed moment for the IDE. Historically, IDEA updates focused on language features, framework support, and performance fixes. Version 2026.3 visibly pivots: from the splash screen to the main UI, JetBrains places the Agent ahead of the editor, signaling a shift from a tool that helps you write code to a place where an Agent writes code for you.

Home, Worktree, and Air

The splash screen now shows a "powered with air" tagline. The familiar Welcome screen is replaced by a new Home view. The left side still lists recent projects and open/create actions, but you can now edit files, open a terminal, and perform Git operations without fully loading the project.

Git Worktree receives first-class support. Worktree allows multiple working directories from the same repository, each checking out a different branch. This fits AI Agent parallel work: several Agents in one directory read each other's half-finished changes and produce tangled diffs; with separate Worktrees, changes are naturally isolated, and a misbehaving Agent's Worktree can be discarded without affecting the main workspace. Air sessions can also run inside temporary Worktrees. Home and Worktree remain independent, so traditional single-branch projects work as before.

Inside a project, the center of the UI is now occupied by Air's task input box, flanked by the project tree and Maven toolbar. Air is positioned as an end-to-end Agent environment: it provides session entry points, supports multiple ACP-compatible Agents, allows custom API keys or existing model subscriptions, and grants Junie Lite free quota via JetBrains Account. Air aims to keep the entire Agent loop — code generation, terminal commands, isolated Worktree execution, diff comparison, and review — inside the main IDE window.

Focus on Running and Debugging

Beyond Agent marketing, the author highlights practical improvements for daily development:

ij-debugger skill : Agents can read run/debug configurations, set non-blocking logpoints, and collect diagnostic data. Crucially, logpoints and historical process output persist in the panel after the debug session ends, unlike the previous behavior where everything disappeared on stop.

Terminal overhaul : The built-in terminal now uses libghostty, delivering noticeably smoother rendering and lower input latency. Terminal tabs can be dragged into the main editor area and placed side-by-side with code files.

Remote development : System-level OpenSSH support is built in. Linux remote environments gain a lightweight transition phase that loads a basic interactive UI first while the full service starts in the background.

Other additions include Java and Kotlin extensions for Cursor and VS Code, early Java 28 EA syntax support, cross-database engine joint queries, and a batch of stability fixes (UI lag, abnormal idle CPU usage, memory not fully released after closing large projects). For Java developers, these stability gains outweigh a pop-up dialog.

Agent Perspective: JetBrains Already Behind

The author finds the central Air UI unappealing, not because they reject Agents, but because their Agent workflow already lives in a more comfortable environment: Orca. Orca presents a terminal-centric workspace — projects and task workspaces on the left, the current session and terminal output in the center, and a full file tree on the right. Agents run commands, execute automated tests, and inspect changed file context directly in the terminal. This standalone environment avoids the overhead of the full IDE runtime.

Disable Air, Let IDEA Do One Less Thing

Since the author doesn't need two Agent interfaces, the immediate step after upgrading is to turn Air off. In Preferences/Settings → Plugins → Installed, locate Air (bundled with 2026.3). No Uninstall option exists, but the dropdown offers Disable. After disabling and restarting, the plugin shows an Enable button and the master switch grays out. Air and the original AI Assistant are separate components: AI Assistant handles code completion and inline interactions, while Air is the full-task Agent shell. Disabling Air only removes the central Agent input and multi-Agent session management; the traditional coding environment remains unaffected.