# 639 Shell > A cloud for AI agents (alpha): Linux machines that are ready in seconds, made and driven by > agents over SSH, MCP or an HTTPS API, with sandboxes and secrets (snapshots and forks in beta). Made by > 639cloud. Free test drive with no sign-up: ssh try@shell.639cloud.com github: 639 Shell is an alpha, and we're looking for testers: agents and the people they work for. Pricing: free for alpha testers while we're in alpha; pricing will be published before general availability, and testers hear first. Speed: our servers aren't the fastest cloud, and we don't claim to be; we're aiming for value. Measured 2026-11-13, size s1, from outside our data center, median (95th percentile): a new machine runs its first command in 1.52 s (2.47 s), a fork in 4.12 s (4.42 s), a sleeping machine wakes and runs one in 1.25 s (1.27 s), and a command on an awake machine takes 0.08 s (0.11 s). Method: https://shell.639cloud.com/docs/benchmarks.md ## Try it - Test drive (1 hour, no sign-up; an SSH key on your GitHub account): ssh try@shell.639cloud.com github: '' - What it is, in short: ssh try@shell.639cloud.com - Sign up (keeps the trial machine): ssh try@shell.639cloud.com signup - After sign-up: ssh shell.639cloud.com (the app), ssh mcp@shell.639cloud.com (MCP over SSH), or the HTTPS API and SDKs - Questions, or just hello: ssh try@shell.639cloud.com github: feedback '' (add an email for an answer); signed up, Help → Chat in the app, with the people who build 639 Shell ## Docs - [Getting started](https://shell.639cloud.com/docs/getting-started.md) - [Machines](https://shell.639cloud.com/docs/machines.md) - [Sandboxes](https://shell.639cloud.com/docs/sandboxes.md) - [Shells and files](https://shell.639cloud.com/docs/shells-and-files.md) - [Networking](https://shell.639cloud.com/docs/networking.md) - [AI agents (MCP)](https://shell.639cloud.com/docs/agents-mcp.md) - [HTTPS API and SDKs](https://shell.639cloud.com/docs/api-and-sdks.md) - [Rules for agents](https://shell.639cloud.com/docs/rules-for-agents.md) - [Orgs and teams](https://shell.639cloud.com/docs/orgs-and-teams.md) - [Notifications](https://shell.639cloud.com/docs/notifications.md) - [Events and webhooks](https://shell.639cloud.com/docs/events-and-webhooks.md) - [Platforms](https://shell.639cloud.com/docs/platforms.md) - [Benchmarks](https://shell.639cloud.com/docs/benchmarks.md) ## Guides - [A home base for agent systems](https://shell.639cloud.com/guides/home-base-for-agent-systems.md): Linux machines for teams building large agent systems: workspaces agents keep between runs, rules they must follow, limits, events and an API for platforms. - [An MCP server for Linux machines](https://shell.639cloud.com/guides/mcp-server-for-linux-machines.md): Give Claude Code, Codex, Cursor or any MCP agent its own Linux machines: create them, run commands, move files and delete them, over SSH or HTTPS. - [Sandboxes for AI agents](https://shell.639cloud.com/guides/sandboxes-for-ai-agents.md): Run code an AI agent wrote, or code from the internet, on a throwaway Linux machine with no public address that deletes itself on time. ## Optional - [Every page in one file](https://shell.639cloud.com/llms-full.txt)