Cloudflare Computer

Cloudflare Computer is an early-preview sandbox for experiments and prototypes. It stores one workspace in each Fabric session Durable Object and runs commands through a just-bash Dynamic Worker. It is not a Linux container and should not be treated as production-ready until Cloudflare stabilizes Computer and Worker Loader.

Install the managed adapter:

fh add cloudflare-computer

Or configure the generated Cloudflare target directly:

export default {
  sandbox: {
    backend: "cloudflare",
    mode: "computer",
    loaderBinding: "LOADER",
    cwd: "/workspace",
  },
};

The Cloudflare build emits all required topology: a worker_loaders binding, the experimental compatibility flag, an entry-module WorkspaceServiceProxy export, and __getWorkspaceStub() on FabricHarnessSessionObject. At runtime Harness constructs the Computer Workspace with the Durable Object's SQLite storage, waitUntil, createGitClient(), and WorkerShellBackend loopback { binding: "FABRIC_HARNESS_SESSIONS", id }.

Because exec() works, the normal Harness tools apply unchanged: bash, grep, glob, read, write, and edit. The default working directory is /workspace. The native workspace is available through cloudflareComputerWorkspace(sessionSandbox) for typed git or direct filesystem operations.

Requirements and limits

• Install @cloudflare/computer, @platformatic/vfs, and @fabric-harness/cloudflare.
• Worker Loader is beta and requires the experimental compatibility flag.
• just-bash implements shell commands in JavaScript; native binaries and language toolchains require Cloudflare Sandbox.
• Computer state lives in the Fabric session Durable Object and follows its identity and isolation boundary.
• Cancellation rejects promptly, sends SIGKILL to the workspace run, consumes late settlement, and disposes the run handle.
• Existing @cloudflare/shell Workspace data is not migrated. Hydrate and verify a fresh Computer workspace before switching traffic.

The old shell-workspace mode and fh add cloudflare-shell command remain deprecated aliases for one release window. New code should use computer and cloudflare-computer.

See examples/with-cloudflare-shell-workspace for a runnable migration example. Its historical directory and package names are retained so existing workspace filters do not break.