Session started with a slash command (e.g. /model) hangs blank ~4-5 min in VS Code integrated terminal (Windows 11)

Description

When using the VS Code integrated terminal in a new claude session like this one, is I start this new session with a slash anything, the session will not show any progress and sits empty like Claude is doing nothing for the first 5 minutes. It will eventually start showing progress, but will sit empty for many minutes. If I start this session not using a slash command, with just a text prompt, there are no issues. This has been happening for a few months now. You can use this session as an example. I started a fresh claude session using the integrated VS Code integrated terminal with the slash model command and this session did not show any progress for about 4 minutes. No Claude progress, the model screen did not appear, nothing. It sat blank like Claude was doing nothing.

Steps to Reproduce

1. Open the VS Code integrated terminal on Windows 11.
2. Start a fresh Claude Code session whose first input is a slash command (e.g. /model).
3. Observe: the UI sits completely blank — no progress indicator, no model-selection screen, nothing — for ~4–5 minutes.
4. Eventually it renders and works normally.

Expected behavior

The slash command (e.g. /model) renders its UI immediately — the same way the session behaves when the first input is a plain text prompt.

Actual behavior

~4–5 minutes of a fully blank/idle screen before anything appears. Only occurs when the first action is a slash command; a plain text prompt as the first input has no delay.

Environment

• Claude Code version: 2.1.220
• OS: Windows 11 Enterprise 10.0.26200
• Terminal: VS Code integrated terminal (bash / Git Bash shell)
• Model: Opus 4.8 (1M context)
• Platform: Anthropic API

Additional context

• Reproducible for the past several months.
• Starting the session with a plain text prompt instead of a slash command: no delay, works normally.
• This session was a live example: started via /model and sat blank ~4 minutes before rendering.
• A local /feedback diagnostic bundle exists but is intentionally not attached (public repo); it can be provided via private support if needed.