bug: desktop slash menu lists /fast twice, once as "Custom command"

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?

In the Claude desktop app's Code tab, typing /fast shows two fast entries in the slash menu:

1. fast, the app's native command (tooltip "Turn fast mode…")
2. fast, with the subtitle Custom command

The second entry is not a user-defined command. No fast command or skill exists in ~/.claude/commands, ~/.claude/skills or any installed plugin. It is Claude Code's built-in /fast, which the session reports in its command list.

The desktop slash menu seems to handle a name collision between an app command and a CLI command by listing the CLI one a second time, labelled "Custom command" and routed to the CLI. It should hide it instead. The "Custom command" label is also misleading, since the user never created it.

What Should Happen?

/fast should appear once. When a Claude Code built-in has the same name as a native app command, the menu should show only the native entry. The "Custom command" subtitle should apply only to commands the user or a plugin defined.

Steps to Reproduce

1. Open the Claude desktop app, then the Code tab, and start or open a local session.
2. Type /fast in the prompt box.
3. Two fast entries appear; the second is labelled "Custom command".

Is this a regression?

I don't know

Claude Code Version

2.1.281 (bundled with Claude desktop 2.9939.2)

Platform

Anthropic API (Claude Max subscription)

Operating System

macOS 26.6.2

Terminal/Shell

Claude desktop app (Code tab)