[Bug] Pasted slash command with arguments is not recognised as a command in the desktop app (stays plain text)

Environment

• Claude Code 2.1.280, Claude desktop app 2.9939.4, macOS 27.0

Describe the bug

In the desktop app, pasting a slash command with arguments into the input box does not register it as a command — the text stays plain text and is sent to the model as an ordinary message.

The only way to get it recognised is manual: put the caret right after the /compact token, wait for the command dropdown to appear, and pick the entry from the dropdown. Then the pasted remainder becomes the command argument.

This matters for /compact <instructions> in particular, because the useful form of that command is long: the instructions describe what the summariser must keep verbatim. Handing a user a ready-to-paste line is the natural workflow, and it silently does the wrong thing — the "instructions" are sent as a chat message instead of steering compaction, and the user only finds out afterwards.

Reproduction

1. Copy a line such as /compact keep items 1-5 verbatim to the clipboard.
2. Paste it into the desktop app input box.
3. Observe: no command chip / no argument highlighting; submitting sends it as ordinary text.
4. Place the caret directly after /compact, select the command from the dropdown that appears, then submit → now it runs as a command with the rest as arguments.

Expected behavior

A pasted /command args should be recognised the same way a typed one is — or, at minimum, the input should show clearly that it is not a command before it is submitted.

Note

#60781 reported a related mobile-only case and was closed as not planned; that report states desktop paste executes immediately. On the current desktop app it does not, at least for a command with arguments.