tai42-sandbox-docker

Docker sandbox provider for the TAI ecosystem — per-session containers on a REMOTE Docker engine over the Docker Engine API.

Each session runs as its own hardened container on a remote engine reached over mTLS. The app container spawns no local process, holds no host Docker socket, and mounts no host path; real work is driven through the engine's exec API against an idle session container.

Enable it

sandbox_module: tai42_sandbox_docker

Configuration

The SANDBOX_DOCKER_ env group. SANDBOX_DOCKER_HOST is required (a unix:///var/run/... socket path or a tcp://host:port) and is the only variable that enters the recycle-pinned app env; the mTLS client certificates are read from the canonical /certs/client mount. Resource-cap fallbacks (SANDBOX_DOCKER_DEFAULT_CPU / SANDBOX_DOCKER_DEFAULT_MEMORY_MB), the image SANDBOX_DOCKER_PULL_POLICY, and the shared TTL / reap / exec-timeout knobs round out the group.

Security model

• Remote engine over mTLS — no host Docker socket, no privilege in the app container.
• Per-session containers hardened with no-new-privileges, all capabilities dropped, never privileged, and no host bind mount.
• Single-workspace-mount isolation invariant: a session mounts ONLY its own workspace volume and can never read the engine's mTLS client identity.
• Network tiers none / internal / egress map onto the engine's network mode; egress default is OPEN, so tool-result data is exfiltratable under open egress (the egress firewall is provisioned at the tai-distribution layer).

Durability model

An ephemeral session's workspace is an anonymous volume reaped with the session; a persistent session binds a durable named tai-sbx-<workspace_key> volume that survives the session and its reap, removed only by an explicit unforced teardown. The durable store is provisioned at the tai-distribution layer.

See docs/index.mdx and the tai-docs operate page for the full settings table and deployment topology.

The current release line tracks the 7.x contract (tai42-contract>=7,<8).