Machine does work inside a session: a branch and a sandbox for one unit of work. A session ends when its change request (CR) merges back to the default branch. This page walks through the loop, then shows the three ways a session can start.

What happens when a session starts

Machine creates the session row and cuts a branch from the default branch. The branch name is the session id.
Machine resolves a sandbox image: the default image, or your own .kortix/Dockerfile if the manifest declares one.
The sandbox boots. Its daemon, kortix-agent, clones the repo to /workspace. It starts OpenCode REST. Session status becomes running.
The agent works. It reads secrets as environment variables, then commits and pushes to the session branch.
The agent opens a change request. You review it and merge it — the only way work reaches the default branch.

Git is the durable record for your code

Stopping a session pauses the sandbox but keeps its files, and the conversation stays readable from a saved copy while the sandbox is off. Deleting a session destroys the sandbox and its saved conversation for good. Only work committed and pushed to the branch survives a delete, and only a merged change request makes it permanent. See what stop and delete keep.

Three ways work runs

A session starts one of three ways.

Mode	How it works
On-demand	You ask in chat and get the result now.
Human-assisted	The agent works and checks in with you for the calls that matter.
Automated	A trigger — a schedule or webhook — starts the session end to end.