Use it

Code mode

Switch a room to Code and ask for an app. The room's model writes the files, runs them in a sandboxed preview and fixes its own errors.

Code mode turns a room into a small coding agent. Ask for an app, like “build a snake game”. The room’s model writes the files, runs the page in a sandboxed preview, reads its console errors and fixes them. Everyone in the room can watch and run the same preview.

It builds static web apps: HTML, CSS and JavaScript. There is no shell and no server code.

Build your first app

Start a model. In a room, pick a model and press Start the model. Code turns on once the model runs.
Press Code in the header.
Ask for something, for example build a snake game, and press Send. The first request creates a project named from your words.
Watch it work. The timeline shows each step, each tool call and a diff for every file. The preview opens on the right.
Ask for changes, like make the snake faster every 5 points. The agent remembers the conversation until you press New task. Files and previews stay.

Templates

Small models do much better changing an app that already runs. Press New, pick a template in the menu next to the name, and press Enter. The app runs straight away, and on the host the prompt box holds a first change to try.

Template	What it is
Game	Catch the falling stars on a canvas, with score and lives.
Dashboard	Stat cards, a bar chart and a table.
Form app	A sign-up form with checks and a saved list.
Landing page	A hero, three features and an email sign-up box.

Empty project (the default) starts with no files.

Previews

The app is served on a virtual port, :5173. Nothing opens a real port. When a file changes, the preview reloads by itself.

Reload loads the files again. Open shows the app full size in a new tab, still sandboxed.
The Console under the preview shows logs and errors. The agent reads them too. Send to agent asks it to fix the errors.
The app can’t reach the room’s page, your storage or the network (except two script CDNs and Google Fonts).
A <form> submit never fires in the sandbox. Ask for a button instead.
localStorage works, but is empty again after each reload.

How the sandbox works: Preview sandbox.

Files and approvals

A project lives on the room’s host device.

Saved in this browser (default): edits apply straight away. Auto-approve edits is on.
Folder on disk: the host picks one with Open folder… (Chrome and Edge on desktop). Each edit waits for Approve, Reject… or Allow edits for this task.

In a folder, files that could run commands (package.json, Makefile, shell scripts) always ask. The agent can’t see hidden or key files (.env, .git, *.pem) at all.

The host can also open any file in Files, edit it and save.

Who can use Code

Anyone in the room can send requests when Who sees the chat is set to everyone. Otherwise Code belongs to the host.

Requests run one at a time. Up to 6 wait, at most 2 per person.
The asker or the host can press Stop.
Only the host can open a folder from disk.

On a phone, Code has three tabs: Agent, Preview and Files.

Download

Press Download above the file list:

Project .zip: every file. Hidden and key files are left out.
One HTML file: the app in one file you can double-click. It stays sandboxed.

Other devices download the files of the preview on their screen. On a phone you get the share sheet.

Press Share in the preview bar. Every device gets a card with Download and Open full screen. Each device keeps the 3 latest shared versions.

Details

The agent: its tools, how a request runs, why it stops.
Preview sandbox: the virtual port, limits, the console, previews on other devices.
Security model: the full threat model.