cocoon sandbox

MicroVM sandboxes for AI agents, built on cocoon. Warm claims are sub-millisecond; a pool miss clones from a golden snapshot in tens of milliseconds; cold boot is ~200ms on bare metal.

SDK (Go)                sandboxd (per node)              guest microVM
sandbox.New() ── HTTP ─► claim: warm pool / golden clone  CH (egress) | FC (none)
sb.Exec/Files/… ─ HTTP upgrade ─► byte relay ── vsock ──► silkd :2048
                        memberlist mesh: warm-count gossip,
                        MOVED-style redirect to the owning node

Two network lanes, derived from the claim: net=none → Firecracker, no NIC, vsock-only (hardened default); net=egress → Cloud Hypervisor with a bridge/CNI NIC. Backends are never user-selected.

Guides

• Deploying sandboxd — single node, configuration reference, images, running as a service
• Clusters — joining a mesh, querying members, how redirect placement works, relocating handles
• sandboxd HTTP API — claim/release/relay endpoints and wire types
• Go SDK — connecting (single node and clusters), every option, the full sandbox surface, error handling
• silkd — the in-guest daemon: protocol, verb reference, lanes and limits
• Performance — measured latencies and the environments they were measured in

Repository

Source, issue tracker and design docs: github.com/cocoonstack/sandbox. Deep-dive design documents live in cocoon-specs/design (sandbox-fast-boot.md, sandbox-control-plane.md, sandbox-silkd.md).