session.fork()

Example

const branched = await session.fork();
const fromMessage = await session.fork("message-id");

Two fork modes

Without messageId

Copy the full current history into a new session.

With messageId

Copy history up to that message and use it as the branching point.

Good use cases

• keep the main thread unchanged
• test different prompt directions on side branches
• rerun from a specific point

If you often need multiple experiments from the same context, fork() is much more convenient than manually duplicating history.