Remote Control: slash-command output invoked from mobile never appears in the local session

Running /context from the Claude Android app in a Remote Control session prints the result in the app, but nothing appears in the local terminal session — no output, and no indication that a command was run at all. Running the same command from the terminal shows it in both places.

The Remote Control docs state that "the conversation and the progress of subagents and dynamic workflows stay in sync across all connected devices, so you can send messages from your terminal, browser, and phone interchangeably." Command output invoked from the phone doesn't appear to be covered by that sync.

Environment: Claude Android app 1.260721.20, Galaxy S24 Ultra, Android 16 / One UI 8.5, driving a local claude CLI session on Debian 12 over Remote Control.

Repro:

1. Start a Remote Control session from the CLI, connect from the Android app.
2. Run /context from the app — output renders in the app.
3. Look at the terminal — nothing. No output, no marker that a command was run.
4. Run /context from the terminal — it renders on both surfaces.

This matters beyond /context: when working across both surfaces, the terminal stops being a complete record of the session. Anything run from the phone is invisible on the machine actually hosting it.

Related observation: there appear to be two rendering paths. Invoked from mobile, the output is markdown. Invoked from the terminal, it's the ANSI box-drawing layout, which then renders poorly on the phone.

Also related: #82854 reports /context not working at all from mobile. On 1.260721.20 it works for me, so that may be version-specific or already fixed — the defect I'm reporting is the missing output on the local side, not the command failing.

Related: #83425 (the session's statusLine is also not rendered in the remote UI).