[FEATURE] vscode:// URI handler should support newWindow parameter to open in a new VS Code window

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

When using the vscode://anthropic.claude-code/open?prompt=... deep link, Claude Code opens in whichever VS Code window is currently focused. If you're mid-session in another window, this is disruptive — the prompt hijacks your current context.

Proposed Solution

Support a newWindow=true query parameter that opens a fresh VS Code window before starting the Claude Code session:

vscode://anthropic.claude-code/open?prompt=...&newWindow=true
This would mirror how the VS Code CLI handles code -n (new window).

Alternative Solutions

None currently — manually opening a new VS Code window before clicking the link works but defeats the one-click experience.

Priority

High - Significant impact on productivity

Feature Category

Developer tools/SDK

Use Case Example

I'm building a prototype gallery where each card has an "Edit in VS Code" button that deep-links into a Claude Code session scoped to that project's folder. Since team members may already have unrelated VS Code windows open, opening in a new window would keep sessions cleanly separated without interrupting existing work.

Additional Context

_No response_