Mod ui.render (AbovePrompt/Pane) not drawn in desktop/iOS views of a Remote Control session

Same on 2.1.289 (macOS), with two more data points.

A session started from the desktop app's Code tab draws mods fine there. Our open-asks band (an AbovePrompt with Text, Button and Input) renders in that Code tab, so the desktop surface works when the desktop hosts the session.

The same mod in a terminal session started with --remote-control draws only in the terminal. Open that session in the Code tab and nothing shows above the prompt. Its hooks still run there: the Stop hook keeps writing to $.store. Only the drawing never reaches the viewer.

I host most sessions in the terminal and read them in the desktop app all day, so for me mods are mostly invisible right now.

Separate thing, desktop-hosted session: a mod whose AbovePrompt mounts a Client module (a fork of mindful-claude) shows Client hooks/breathe.tsx: did not load within 10s (a content security policy may have refused its runtime...). Same mod, terminal host, draws fine. Want that in its own issue?

— printed by Claude Code, signed by me.

Same behaviour here on Linux, one version later.

Setup

• Host: Claude Code 2.1.289 on Debian 13, session served through claude remote-control
• Viewers: Claude desktop app 2.9939.4 on Linux (community package, not an official build) and the Claude mobile app
• Mod: a small plugin that draws an AbovePrompt band (Box + Text) and registers a slash command

What happens

• The mod loads in the Remote Control session: its slash command runs and its classic.UserPromptSubmit hook fires.
• The AbovePrompt band never appears in the desktop app or the mobile app.
• $.session.surfaces() called from inside that session returns an empty list while both apps are viewing it. So no client attaches as a render surface at all (session.attach never fires), rather than attaching and failing to draw.

Expected
The desktop app attaches as surface desktop and draws the band, as the render sites table says for AbovePrompt.

Updating the desktop app from a July build to 2.9939.4 made no difference.

Same here on newer builds — Claude Code CLI 2.1.291, Claude Desktop 2.19675.1 (bundled Claude Code 2.1.288), macOS. Our mod draws a button toolbar in the AbovePrompt band (logo + buttons that run a skill, send a prompt or fill the input), loaded via CLAUDE_CODE_PLUGIN_DIRS.

One data point that narrows it down: the same mod IS drawn in the Desktop app when the session is a local one created in the Desktop Code tab (bordered band, buttons as chips with hotkey badges). It is only missing when Desktop, claude.ai or mobile view a terminal-hosted session over Remote Control. So the Desktop renderer supports it; what is missing is forwarding ui.render to remote viewers and routing onPress / ui.press back to the host session.

The public mods types already seem to anticipate this: RenderSurface = 'terminal' | 'desktop' | 'mobile' | 'vscode', session.attach / session.detach for remote clients, and a viewport note about "a remote surface".