[Desktop] Slash-command autocomplete no longer triggers mid-message since 1.40609.0 (terminal CLI unaffected)

Description

In the Claude Code desktop app (macOS), typing / in the middle of a message used to bring up the slash-command/skill autocomplete popup, the same way it does at the start of the input. Since the app auto-updated to 1.40609.0 (installed 2026-08-27 16:39 local time), the popup only appears when / is the first character of the message. Mid-message / is now treated as plain text with no autocomplete.

The terminal CLI is unaffected: on the same machine, CLI 2.1.252 still shows the command picker when / is typed mid-line.

Note this is a composer/autocomplete regression only — skill invocation itself still works. If the skill name is typed out fully mid-message (e.g. "roda /qa-gate e depois /gstack-ship"), the model still resolves and invokes the skills via the Skill tool, exactly as before. What was lost is the typing affordance.

Environment

• Desktop app: Claude.app 1.40609.0, auto-updated 2026-08-27 16:39 (bundle mtime) — regression noticed within days of this update
• CLI: 2.1.252 (not affected)
• OS: macOS (Darwin 25.5.0)
• No local config that could explain it: no keybindings.json, nothing relevant in settings.json, no changes to ~/.claude around that date

Steps to reproduce

1. Open the Claude Code desktop app on macOS (1.40609.0).
2. In the message composer, type some text, e.g. please run .
3. Type / followed by the beginning of an installed skill name, e.g. /qa.

Expected behavior

The slash-command autocomplete popup appears at the cursor and filters skills as you type (as it did before 2026-08-27, and as the terminal CLI still does mid-line).

Actual behavior

No popup; the /... text stays as plain text. The popup only triggers when / is the very first character of the input.

Additional context

• The desktop changelog for 1.40609.0 does not mention composer or slash-command changes, so if this was intentional it shipped undocumented.
• Related older feature requests (all closed "not planned"): #55173, #44488, #29752, #40413. This report differs from those: it describes behavior that was present in the desktop app and disappeared after the 1.40609.0 update, i.e. a regression rather than a feature request — and the CLI currently does support mid-line / autocomplete, so the two surfaces are now inconsistent.