drun

Deterministic, ephemeral runtimes for coding agents.

Give your agent a git-like sandbox it can branch, roll back, and discard — without ever touching your host.

Every session spins up a disposable workspace and vanishes when it's done — nothing persists on your machine unless you explicitly export it.

Available for macOS and Linux distros.

What it guardrails

• Ephemeral workspace Checkpoint, fork, and roll back like git — explore trajectories in parallel and discard dead ends without disrupting the host.
• Network Only allowlisted domains are reachable. Everything else is denied by default.
• Commands Forbidden commands are rejected before they ever run.
• Filesystem Access is restricted to the session workspace and explicitly mounted paths.
• Resources Hard caps on memory and execution time — enforced by the runtime, not by policy the agent could talk its way around.

drun — deterministic run. Every guardrail here is a limit that can't be breached by design, not a suggestion.