Sessions
A session is a git branch and a sandbox where the agent works.
A session is one unit of agent work. Machine cuts a git branch and provisions a sandbox for it. The session id, the branch name, and the sandbox id are the same value.
Status
A session reaches one of 4 states in practice.
| Status | Meaning |
|---|---|
provisioning | Machine cuts the branch and requests the sandbox. |
running | The sandbox is live and reachable. |
stopped | The session is paused, by you or by idle auto-stop. |
failed | Provisioning failed. |
The database defines 3 more values (queued, branching, completed).
Machine does not write them for a session today.
Stop, resume, and idle auto-stop
You can stop a session yourself. Resume brings back the same sandbox with the same filesystem and runtime identity. Only the running processes and memory reset. The OpenCode conversation remains attached to the session.
Machine also stops an idle session for you:
- After 15 minutes idle, for a normal session.
- After 5 minutes idle, for a session a trigger started.
An open dashboard tab does not keep a session alive. A busy agent turn blocks the stop. The maintenance sweep runs every 5 minutes. A normal automatic Stop therefore occurs approximately 15 to 20 minutes after the terminal turn.
Self-host operators can set KORTIX_SANDBOX_AUTOSTOP_MINUTES to change the
normal idle grace. This setting does not change active-turn protection.
What stop and delete keep
Deletion is permanent
Deleting a session destroys its sandbox for good, and purges its saved conversation history and saved attachments. Machine keeps the session record and the git branch, so you can still recover pushed work. Anything not pushed is gone.
| What | After stop | After delete |
|---|---|---|
| Files on the sandbox's disk | Kept | Gone |
| The agent's browser sign-ins | Kept | Gone |
| Running processes and memory | Reset | Gone |
| Saved conversation history and attachments | Kept, readable at once | Purged |
| Commits pushed to the session branch | Kept | Kept |
For your code, git is the durable record: work the agent commits and pushes survives a delete, and a merged change request makes it part of the project.
Saved conversation history
While a sandbox runs, Machine saves a copy of the session's conversation on the server: at the end of every agent turn, and once more when the session stops. When you open a stopped or waking session, the conversation appears right away from that saved copy. Opening it still wakes the sandbox.
- A small banner, not a loading screen. While the sandbox wakes, a status banner above the conversation shows the boot steps (Reserving your computer, Loading your workspace, Waking the agent, Connecting). You can scroll and read the whole time. If nothing will wake the sandbox on its own, the banner reads Computer stopped and offers Restart. A brand-new session has no saved conversation yet, so its first start still shows the full loading screen.
- You can send while it wakes. The composer stays live and says "Waking this session up… messages you send will be queued and go out automatically." Queued messages go to the agent as soon as the sandbox answers.
- Files still show. Images, show cards (including CSV and spreadsheet previews), and files you uploaded are saved with the conversation, so they render while the sandbox is off. HTML previews still need the running sandbox.
The saved copy is the conversation only. It does not save your code; that still lives on the sandbox's disk until the agent commits and pushes it.
Self-host operators can turn saving off with TRANSCRIPT_HISTORY_ENABLED=false
on the API service. It defaults to true. With it off, Machine stops saving new
history, and history it already saved is still served.
The agent's browser stays signed in
The browser the agent drives saves its cookies and local storage on the sandbox's own disk, and restores them the next time it launches. A site the agent signed in to stays signed in after the session stops and resumes, so you do not have to sign it in again on every run. Deleting the session removes the saved sign-ins along with the sandbox.
Runtime
Every session uses OpenCode REST. Machine stores the selected OpenCode agent and model when the session starts. Restart and resume keep the same session runtime.
Sharing a preview
You can share a session's live preview with a public link, in view-only or interactive mode.
Providers
Machine runs sessions on Daytona, Platinum, or E2B Cloud. A project follows the platform default, or requests a provider switch through the SDK — see SDK reference. A switch to a different provider is durable: the current provider keeps serving while the target warms, then activates. Every provider runs the same sandbox image.
For the full status enum, injected environment variables, and daemon endpoints, see Runtime. For how a session picks its agent, see Agents. For sessions a schedule or webhook starts, see Triggers. To land session work on the default branch, see Change requests.