Kern ships a 1.52MB container runtime that starts in 3.5ms and serves agents over MCP.

Apache-2.0, rootless, single static binary, no daemon, claiming about 3.5ms container start against Docker's roughly 297ms and zero resident memory when idle (GitHub). It reads OCI images and docker-compose files but deliberately skips Docker's API, overlay networks and Swarm, and ships Python and Node bindings plus an MCP server so agents can drive it directly. The stated primary use case is untrusted and AI-generated code, which is exactly the workload the paid sandbox vendors price per hour.