[FEATURE] Slash-command autocomplete dropdown in claude.ai/code web UI (parity with the desktop app)

Preflight Checklist

• [x] I have searched existing requests and this feature hasn't been requested yet
• [x] This is a single feature request (not multiple features)

Problem Statement

On claude.ai/code in a web browser (any browser, desktop), typing / in the prompt input does not open a typeahead dropdown of available slash commands / skills. The text after / is submitted as prose unless I type the full command name from memory.

The Claude Code desktop app (Mac/Windows download) — whose UI is nearly identical to the web app — already shows this dropdown: as soon as / is typed, a filtered list of matching commands appears and can be selected.

The gap matters because:

• Skill/command discovery via typeahead is how users learn what is installed.
• With plugins and per-project skills, the set is unbounded — memorizing names doesn't scale.
• Typo-correcting a command silently submits prose to the model instead of invoking the skill, which wastes a turn and is easy to miss.

Proposed Solution

Bring the web app to parity with the desktop app: when the prompt input contains / at the start of the current token, render the same typeahead dropdown the desktop app shows, filtered by what follows /. Keyboard navigation (↑ / ↓ / Enter / Esc) and click-to-select should match the desktop app exactly.

The backend that produces the command list is presumably shared with the desktop app (same session, same skill registry). The ask is the front-end surface.

Alternative Solutions

• Type the full command name from memory. Works but doesn't scale past a handful of commands and offers no typo correction.
• Switch to the desktop app. Defeats the point of having a web client; web sessions are useful from machines where the desktop app isn't installed.
• Send /help as the first prompt to list commands, then copy a name. Slow and noisy.

Priority

Medium - Would be very helpful

Feature Category

Other

Use Case Example

1. Open a fresh cloud session at claude.ai/code in a browser on a project with several installed skills (built-in + plugins + project .claude/skills/).
2. Click into the prompt input and type /end intending to find /end-session.
3. Desktop app: dropdown filters to /end-session (and any other matches); arrow-down + Enter selects it.
4. Web app today: no dropdown; /end followed by space is submitted as prose, the model interprets the text rather than the skill runs.
5. With this feature, web and desktop behave the same — the user learns the surface by typing, not by reading docs.

Additional Context

Related existing issues:

• #57275 — open bug framed as "menu does not appear on first prompt of a cloud session" on the web client. The observed gap on subsequent turns is the same as on the first turn for users I've talked to, but #57275 is scoped narrower than this request.
• #56204 — closed (not planned) for the mobile surface specifically. This request is the desktop-browser case and does not re-argue the mobile one.
• #40342 — closed, syntax highlighting for slash commands in remote-control / web; complementary but different (display vs. discovery).

The desktop app and the web app render an almost-identical prompt input UI today, which makes the missing typeahead feel like a port that didn't quite ship rather than a deliberate platform difference.

https://claude.ai/code/session_016BFa3WSr2KtzRTXSirSawY