[BUG] Claude Code UI broken in IntelliJ when using IntelliJ client with devcontainer back end.

Environment

• Platform (select one):
• [X] Anthropic API
• [ ] AWS Bedrock
• [ ] Google Vertex AI
• [ ] Other: <!-- specify -->
• Claude CLI version: 1.0.73 (Claude Code)
• Operating System: Debian GNU/Linux 12 (bookworm) client on macOS 15.6 (24G84) host
• Terminal: IntelliJ built in Terminal

Bug Description

When running Claude using the IntelliJ plugin in an IntelliJ client with a Devcontainer back end, the terminal display is messed up:

<img width="1670" height="383" alt="Image" src="https://github.com/user-attachments/assets/abffc383-72a9-422e-8629-dcc398eeb9a8" />

Though, if you run it directly using the claude command from an existing terminal tab, it is fine:

<img width="1664" height="291" alt="Image" src="https://github.com/user-attachments/assets/41273bd3-6672-49ca-8d55-7267ba92802a" />

Steps to Reproduce

1. Create and launch a IntelliJ devcontainer environment (docs)
2. Install Claude Code and the Claude Code plugin
3. Launch Claude Code via the plugin.

Expected Behavior

Claude Code launches in the terminal with fully functional UI

Actual Behavior

Claude Code launches in the terminal with broken UI

Additional Context

I think this maybe be related to this issue I had previously reported with the IntelliJ terminal in devcontainers. As it looks a bit similar.

This issue had gone away in the "Reworked 2025" terminal, so my suspicion is that when the Claude plugin launches claude in a terminal it may still be launching it in the "Classic" terminal (if so, possibly you don't have any control over this).

As an aside, whenever I launch the plugin I also get an error that Claude isn't installed, even though it is, and launches. I suspect this is because the check actually checks if it is installed on the host, whereas it's installed on the client. I found there was a setting in the plugin to disable this, though.