Cloud Agents

Run agents in the cloud on Modal, Fly.io, or Vercel Sandbox — they keep running after you close your Mac

Overview

Cloud Agents run your coding agents in a remote sandbox instead of on your Mac. Launch one from Agent Home and Agentastic provisions a VM with your chosen provider, syncs your worktree up to it, and runs the agent there. Because the session lives in the cloud:

  • Agents keep running after you close your laptop.
  • The same agent stays reachable from any of your machines.
  • Sync Down from VM pulls the agent's changes back to your local worktree when you're ready.

Cloud worktrees share the same terminals, source control, and diff experience as local and remote workspaces, and show a cloud badge in the sidebar so you can tell them apart.

Supported Providers

Add one or more backends under Settings → Cloud. You can add several accounts of the same provider (for example a personal and a team Modal account).

ProviderBest forCredentials
ModalShort-lived tasksToken ID + Token Secret
Fly.ioLonger-lived, region-pinned machinesAPI Token
Vercel SandboxVercel Sandbox microVMsAccess Token + Team ID + Project ID

Adding a Provider

  1. Open Settings → Cloud.
  2. Click Add Provider and choose Modal, Fly.io, or Vercel Sandbox.
  3. Enter the credentials for that provider (see below). Agentastic validates them against the provider's API and stores them in your macOS Keychain — never in settings.json, so your settings stay safe to sync or share.
  4. Enable the provider.

Modal

Fly.io

  • API Token (fo1_…) from fly.io/user/personal_access_tokens
  • Optionally set an organization, an app-name prefix, and an IP allocation mode — IPv6 + dedicated IPv4 (most reliable for SSH from IPv4-only networks) or IPv6 only (avoids Fly's dedicated-IPv4 billing).

Vercel Sandbox

  • Access Token (vercel_…) from vercel.com/account/settings/tokens
  • Team ID (team_…) and Project ID (prj_…)
  • Optionally choose a runtime (node24, node22, or python3.13) and a vCPU count (1, 2, 4, or 8).

Launching a Cloud Agent

  1. Open Agent Home.
  2. Compose your prompt and pick your agent as usual.
  3. Set the run target to a Cloud provider instead of Local.
  4. Send. Agentastic provisions the VM, syncs your worktree up, and starts the agent in the cloud.

Syncing Changes Back

While a cloud agent runs, its edits live on the VM. When you're ready to bring them home, use Sync Down from VM to pull the agent's changes into your local worktree.

Lifecycle & Cost Controls

Each provider account has guards that keep VMs from running away. Configure them per provider in Settings → Cloud:

SettingDefaultPurpose
Auto-destroy on idleOnShut the VM down after an idle window
Idle timeout800 secondsHow long with no activity before idle shutdown
Hard timeout8 hoursMaximum VM lifetime regardless of activity

Sessions are persistent across app restarts: reopen Agentastic and your cloud workspaces restore, reconnecting to the still-running VM.

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