Get started with your box

Code in a box is your own Linux machine for coding agents (4 vCPU, 16 GB, 100 GB disk). Claude Code or Codex works in it on your repositories; you watch, steer and open the pull request. The disk persists, so repositories, worktrees and agent sessions are still there next time.

1. Sign in. Sign in with GitHub and install the compiler.dev App on your organization (the same App as for CI). Your organization needs prepaid credit; if it has none, the box card shows Add credit to start your box with a link to Billing.

2. Add a key. Open Workspaces (or Start coding in your box on the Overview) and create your box. Then paste your own key: an Anthropic key for Claude Code (from console.anthropic.com → API keys) or an OpenAI key for Codex (from platform.openai.com → API keys). Keys are stored encrypted, sent only to your box, and never shown again. Model usage is billed to you by Anthropic or OpenAI.

3. Start. The first boot takes about a minute; after that, Start resumes a stopped box in about 15 seconds. Sending a prompt to a stopped box starts it too.

4. Chat. Pick a repository and the agent, describe the change, and press Start chat. Each chat gets its own git worktree on branch ws/…. You see the agent's messages and commands live, then the tests it ran and the diff; send a follow-up for the next change, or open the pull request. Up to 3 agents can work on your box at once.

5. Open on another device. Open on another device makes a one-time link, valid for 5 minutes, that opens the same chats in another browser (your phone, say) for 12 hours without signing in there. Sign out other devices ends those sessions.

6. Stop. Press Stop when you're done, or just leave: the box stops by itself after 60 minutes with no agent working and nobody in an open chat. A tab you left open in the background, or haven't touched for 30 minutes, doesn't keep it awake. Stopping keeps the disk; deleting the box deletes the disk.

Fewer tokens. Agents in a box run their shell commands through RTK, which compacts the output of builds, tests and git before the model reads it (typically 60–90% less). Run rtk gain in the box to see what it saved. To bypass it for one command, start the command with RTK_DISABLED=1. To turn it off for the box, run rtk init -g --uninstall and rtk init -g --codex --uninstall; the agents then see raw output, and the box does not put it back until we ship a newer RTK version.

Costs: $0.0065 per running minute (about $0.39 an hour) plus $0.10 per GB-month for the disk ($10 a month for 100 GB, also while stopped), drawn from your organization's prepaid credit. The card shows this month's cost.
Limits: one box per person, up to 3 agents at once, and a daily spend limit per organization ($25 by default; ask us to raise it). New chats are refused when the disk is 95% full; archive finished chats to free space.
Fair use: crypto mining and outbound email (port 25) are blocked.