[BUG] /mcp interactive dialog replaced by plain text output in VSCode extension since 2.1.205

Preflight Checklist

• [x] I have searched existing issues and this hasn't been reported yet
• [x] This is a single bug report
• [x] I am using the latest version of Claude Code

What's Wrong?

The /mcp command in the VSCode extension chat panel no longer opens the interactive management dialog. Instead, it displays a plain text summary:

8 MCP server(s): 4 connected, 0 not connected, 4 disabled.
Use /mcp in the terminal for details.

The VS Code documentation still describes the expected behavior:

Type /mcp in the chat panel. The MCP management dialog lets you enable or disable servers, reconnect to a server, and manage OAuth authentication.

Without the dialog, there is no way to enable/disable/reconnect MCP servers from the VSCode extension — users must switch to the terminal.

Steps to Reproduce

1. Open Claude Code in VS Code extension (chat panel, not terminal mode)
2. Type /mcp and submit

Expected Behavior

The interactive MCP management dialog opens, allowing enable/disable/reconnect of servers.

Actual Behavior

A one-line text summary is printed. No interactive dialog appears.

Bisect

| Version | Dialog? |
|---------|---------|
| 2.1.204 | ✅ Yes |
| 2.1.205 | ❌ No (text only) |
| 2.1.207 | ❌ No (text only) |

Other built-in slash commands (/help, /config) work normally on all versions tested.

Environment

| | |
|---|---|
| Claude Code extension | 2.1.207 |
| VS Code | 1.128.0 (fc3def6) |
| Electron | 42.5.0 |
| OS | macOS Darwin arm64 25.5.0 |

Workaround

Run claude mcp commands in the integrated terminal, or downgrade to 2.1.204.