[BUG] Web (desktop): / slash-command menu does not appear on first prompt of a cloud session

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?

On the desktop web client (claude.ai/code), pressing / in the prompt input on
the first turn of a fresh cloud session does not open the slash-command
autocomplete menu. We know skills/commands are loaded because invoking them by typing the
full name and hitting Enter works fine. Only the
typeahead UI fails to mount.

Environment

• Client: claude.ai/code (web)
• Browser / OS: Chrome 147.0.7727.138 (Official Build) (arm64) / MacOS 26.3.1 (a)
• Session type: cloud (CLAUDE_CODE_REMOTE_ENVIRONMENT_TYPE=cloud_default)
• Claude Code version (reported by container): 2.1.42
• Environment runner: release-b5ac58d65-ext
• Reproducibility: every fresh session

What Should Happen?

Expected: filtered dropdown of available commands appears, as it does in
the desktop CLI.

Actual: no dropdown. Subsequent characters are appended as plain text. The
prompt submits as prose unless I type the full command name from memory.

Additional observations

• Skills are confirmed loaded server-side: the agent reports them listed in

its system context from turn 0, and invoking by full name routes correctly
via the Skill tool.

• Workaround: type the full command name (no autocomplete) and submit, or send a dummy first prompt.

Error Messages/Logs

Steps to Reproduce

1. Open a new cloud session at claude.ai/code on a project that has skills

available (built-in /openspec-*, /review, etc.).

1. Before sending any prompt, click into the input box.
2. Type /.

Expected: filtered dropdown of available commands appears, as it does in
the desktop CLI.

Actual: no dropdown. Subsequent characters are appended as plain text. The
prompt submits as prose unless I type the full command name from memory.

Claude Model

None

Is this a regression?

I don't know

Last Working Version

_No response_

Claude Code Version

2.1.42

Platform

Anthropic API

Operating System

macOS

Terminal/Shell

Other

Additional Information

_No response_