Sandboxes
Snapshottable, forkable execution environments for agent harnesses.
A sandbox is the isolated environment an agent harness runs in — with extremely fast
start, snapshot, and fork so that experiments are branchable. A snapshot is a derived
cache, never the source of truth: every snapshot carries provenance back to a
reproducibly-built genesis base, so a sandbox is reproducible by construction.
Sandboxes are the nodes of the fork tree; see
tree-native observability for how their telemetry is keyed.