[BUG] [JetBrains] Failed to connect to IntelliJ IDEA 2026.1 on Windows - SSE port not responding

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report (please file separate reports for different bugs)
• [x] I am using the latest version of Claude Code

What's Wrong?

The Claude Code plugin fails to connect to IntelliJ IDEA 2026.1.
Two error messages are displayed:

• "IntelliJ IDEA Disconnected"
• "Cannot launch Claude Code - please ensure Claude Code is installed

and the 'claude' command is in your system path"

Claude Code starts and works normally in the terminal but IDE
integration never connects. The /ide command returns
"Failed to connect to IntelliJ IDEA".

What Should Happen?

Claude Code should connect to IntelliJ IDEA and display
"Connected" status, enabling diff viewer, selection context
sharing, and diagnostic sharing features.

Error Messages/Logs

In Claude Code terminal:
> /ide
Failed to connect to IntelliJ IDEA.

IntelliJ idea.log confirms:
- Plugin loaded: Claude Code [Beta] (0.1.14-beta)
- CLAUDE_CODE_SSE_PORT correctly injected in terminal env
- idea64.exe listening on SSE port (confirmed via netstat)

However:
> curl -H "Accept: text/event-stream" http://localhost:[SSE_PORT]
→ empty response, no data returned

Steps to Reproduce

1. Install Claude Code CLI v2.1.126 on Windows 10
2. Install Claude Code [Beta] plugin 0.1.14-beta on IntelliJ IDEA 2026.1.1
3. Open IntelliJ IDEA and open a project
4. Open integrated terminal (PowerShell or CMD)
5. Run: claude
6. Observe "IntelliJ IDEA Disconnected" message
7. Run: /ide
8. Observe "Failed to connect to IntelliJ IDEA"

Additional diagnostic:

• CLAUDE_CODE_SSE_PORT is correctly set in terminal environment
• netstat confirms idea64.exe listens on that port
• curl on that port returns empty response

Claude Model

Other

Is this a regression?

No, this never worked

Last Working Version

N/A

Claude Code Version

2.1.126 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

IntelliJ IDEA terminal

Additional Information

• IntelliJ IDEA 2026.1.1 (build IU-261.23567.138) - very recent release
• Plugin version: 0.1.14-beta
• Single IntelliJ instance running (confirmed via tasklist)
• Claude executable path: C:\Users\[user]\.local\bin\claude.exe
• Tried setting absolute path in plugin settings → same result
• Tried forcing port manually: set CLAUDE_CODE_SSE_PORT=54009 && claude → same result
• Corporate environment (enterprise Windows)
• Amazon Q variables (FIG_TERM, PROCESS_LAUNCHED_BY_Q) appear in

some PowerShell terminals injected by IntelliJ itself,
but Amazon Q is not installed

• Hypothesis: incompatibility between IntelliJ 2026.1 and plugin 0.1.14-beta.

IntelliJ opens the SSE port but returns empty response to curl,
suggesting it does not respond to the protocol Claude Code expects.