kosa8

kosa8 is a container and sandbox platform for AI agents, published at kosa8.com. Each agent runs in its own sealed machine that can be saved, copied, forked and rewound, and it installs with a one-line shell command. It runs on Apple-silicon Macs and x86-64 Linux, and on Windows 11 through WSL2 (preview).

What It Is

kosa8 treats a whole machine as the unit of work: a real VM with its own kernel and disk, rather than a container sharing a host kernel. Users start a coding agent such as Claude Code, Codex or Gemini with a command like kosa8 agent run claude. The agent sees only the workspace folder it is given. The network is closed except for an allow-list, and API keys are brokered so the sandbox holds a placeholder instead of the real key. It also works with the Docker CLI and Compose through a Docker-compatible API.

Checkpoint, Rewind and Fork

Checkpoints capture the entire machine, including memory and running processes. Rewinding resumes processes from the saved instant rather than restarting. The site's own examples show a checkpoint in about 697 ms and a rewind in about 485 ms. A running machine can be forked into several parallel branches, and the explore command runs variants and reports which branch won.

Governance and Evidence

For regulated teams, kosa8 documents hash-chained action records marked as human or agent, signed approvals by one or two named approvers, signed organisation policies, CUI labels, FIPS 140-3 builds, offline licences and air-gapped operation. Evidence can be exported as signed packages that a third party can verify. A lab mode detonates malware samples in a sealed VM with a simulated internet and produces signed reports.

Local Models

kosa8 can pull a model from Hugging Face and serve it locally through OpenAI-compatible and Anthropic-compatible endpoints. Vendor-stated benchmark figures include a 178 ms container start and an 897 ms sandbox restore. The site says shared host folders read at about a third of native speed.