Sandboxes · 4 November 2026

A fork waits for room, as a create does

When no server has room for a copy, fork now retries with the same idempotency key for up to two minutes, as create, wake and restart do, in every SDK and in withruntime sandboxes fork. A fork refused for room pauses nothing and charges nothing. Set the wait as for a create (waitForCapacityMs in JavaScript, wait_for_capacity in Python and Ruby, WaitForCapacity in Go, waitForCapacity in Java); 0 fails immediately, and the CLI's --no-wait fails immediately. A fork of one copy now needs only the room a create of the same size needs; before, it needed four times its memory free on one server. A fork of many copies is still held to a quarter of each server's free memory past its first copy there, and is refused with details.fits when fewer copies fit. A fork that has already failed returns retryable: false, because its idempotency key returns the same error.