[BUG] VS Code extension ignores model configuration and defaults to Opus 4.1

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?

VS Code extension ignores model configuration and always uses Opus 4.1 instead of Opus 4.5.

I have configured "claude-opus-4-5-20251101" in:

• VS Code settings.json: "claudeCode.selectedModel": "claude-opus-4-5-20251101"
• .claude/settings.local.json: "model": "claude-opus-4-5-20251101"
• claude.json: "model": "claude-opus-4-5-20251101"

Opus 4.5 WORKS via CLI:
echo "test" | claude --model claude-opus-4-5-20251101 → Success!

But the VS Code extension always shows "Legacy: Opus 4.1" in the model selector.

I tried:

• Reinstalling the extension
• Restarting VS Code
• Setting environment variable ANTHROPIC_MODEL
• All configuration files are correct

I was using Opus 4.5 before and it suddenly stopped working.

Environment:

• Windows 11
• Claude Code CLI: 2.0.75
• VS Code extension: 2.0.46
• Max plan subscriber

What Should Happen?

The VS Code extension should use Opus 4.5 (claude-opus-4-5-20251101) when configured, just like the CLI does.

The model selector should show "Opus 4.5" instead of "Legacy: Opus 4.1" when Opus is selected.

Error Messages/Logs

Steps to Reproduce

1. Open VS Code with Claude Code extension installed
2. Go to Settings (Ctrl+,) and set "claudeCode.selectedModel" to "claude-opus-4-5-20251101"
3. Also add to .claude/settings.local.json: "model": "claude-opus-4-5-20251101"
4. Restart VS Code completely
5. Open a new Claude Code chat
6. Click on model selector or ask "What model are you using?"
7. Result: Shows "Legacy: Opus 4.1" (claude-opus-4-1-20250805) instead of Opus 4.5

To verify Opus 4.5 works via CLI:

1. Open terminal
2. Run: echo "test" | claude --model claude-opus-4-5-20251101
3. Result: Works correctly with Opus 4.5

The CLI respects the model parameter, but the VS Code extension ignores all configuration and defaults to Opus 4.1.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.0.75 (Claude Code)

Platform

Anthropic API

Operating System

Windows

Terminal/Shell

VS Code integrated terminal

Additional Information

_No response_