box by Simular

box is a cloud Linux desktop for your AI. Add it to Claude, ChatGPT, Claude Code, Codex, Cursor or DeepSeek Harness as a remote MCP server and your AI can use a real computer: open a browser, click, type, read the screen and run commands.

Key facts

• Product: box, from Simular. Portal: https://box.simular.ai.
• Interface: one hosted MCP server, box (https://relay.simular.cloud/mcp). You sign in with your Simular account the first time your AI connects (OAuth); no key to paste. For apps that can't sign in, a personal key works as Authorization: Bearer cb_...: https://box.simular.ai/keys.
• The computer: one cloud Linux desktop per account. It sleeps when no one uses it and wakes when your AI connects.
• Cost: the box itself is free. Its model calls use your account's daily credits.

Getting started

Claude (claude.ai and the desktop app)

1. In Claude (claude.ai or the desktop app), open Settings → Connectors.
2. Click Add custom connector. Name it box and paste the URL below; leave the advanced settings empty.
3. Click Connect, sign in to box and approve. Then turn box on in a chat’s tools menu.

The URL: https://relay.simular.cloud/mcp

ChatGPT (chatgpt.com)

1. In ChatGPT, open Plugins (chatgpt.com/plugins), click Add and choose Add custom MCP server.
2. Name it box. Under Connection, paste the URL below as the Server URL, and choose OAuth as the authentication.
3. Confirm the warning (I understand and want to continue), click Create as a plugin, then install it. Sign in to box and approve when asked.
4. In a chat, type @ and pick box, then ask for a task.

The URL: https://relay.simular.cloud/mcp

Claude Code

claude mcp add --transport http box https://relay.simular.cloud/mcp

Then run /mcp in Claude Code, pick box and choose Authenticate.

Codex

# ~/.codex/config.toml
[mcp_servers.box]
url = "https://relay.simular.cloud/mcp"

# then sign in: codex mcp login box

Cursor

{
  "mcpServers": {
    "box": {
      "url": "https://relay.simular.cloud/mcp"
    }
  }
}

Cursor asks you to sign in to box the first time.

DeepSeek Harness (dsh)

dsh plugin add https://github.com/simular-ai/box-plugin/releases/download/dsh-v0.1.0/dsh-box.tgz
export BOX_TOKEN=cb_your_key

dsh can't sign in, so it uses a personal key: make one at https://box.simular.ai/keys and set it as BOX_TOKEN. Restart dsh. box's tools show up as mcp__box__*.

Or tell your coding agent Set up box from https://box.simular.ai/install and it does the rest. Then ask for a task, for example: Use box to open Chrome, search Google for "Simular", and summarize the top 3 results.

Docs

• Connect box over MCP: the full setup guide, per app, with troubleshooting.
• All docs pages, and every page in one file.