docker-sandbox
Skill9 starsChanged 4 months agoMITView on GitHub
Docker usage in readme2demo — the base image, hardened sandbox lifecycle, the Docker-socket opt-in, and diagnosing container/daemon failures. Use when touching sandbox.py, images/base/Dockerfile, render.py, verify.py, or when a run fails with a docker/daemon/permission/disk error.
5 other projects use a version of this.
Adopted by
Most recently taken up by
- weininghui/skillstheir own version, first seen Oct 30, 2026
- jnotsknab/mux-swarmtheir own version, first seen Oct 11, 2026
- joelhooks/joelclawtheir own version, first seen Oct 8, 2026
- ariana-dot-dev/cloud-sandbox-vm-skillstheir own version, first seen Jun 13, 2026
- albertdobmeyer/openskill-forgetheir own version, first seen Apr 2, 2026
Other versions5 projects use a version of this.
Word for word · 0
None found.
Edited · 0
None found.
Wrote their own version · 5
- joelhooks/joelclaw★ 65same name
- jnotsknab/mux-swarm★ 9same name
- ariana-dot-dev/cloud-sandbox-vm-skills★ 2same name
- albertdobmeyer/openskill-forge★ 1same name
- weininghui/skills★ 1same name
How matches are found. Word for word: the exact same text. Edited: shares passages with this file (“99% same” means 99% of its five-word phrases also appear here; 10% or more counts). Their own version: similar meaning, or, weakest, the same name. We can’t tell which project had it first. Projects are counted among the 200 most-starred candidates, and mentions are links to the repository we found, up to 50 per site, so both counts are a floor.
In this repository9 other files it gives its agents.
- CLAUDE.mdCLAUDE.md
- docs/llms.txtllms.txt
- add-engineSkill
- add-failure-classSkill
- debug-runSkill
- git-github-operatorSkill
- python-standardsSkill
- sandbox-toolchainsSkill
- vhs-videoSkill
The file
We split this skill into the rules it gives an agent
2 rules. 0 are common, 1 is distinctive, and 1 is very specific to this project.
0
Common
Most of the 4 edited versions we read keep these.
1
Distinctive
This author's own choices. Worth a look.
1
Very specific
Tied to their project's names, files or tools. Probably skip.
- Common
- Distinctive
- Very specific
- Very specific: line 31
Every container: --cap-drop ALL, --security-opt no-new-privileges, --memory/--cpus/--pids-limit, non-root user demo (uid 1000), wall-clock …
- Distinctive: line 55
verify passes but render image errors → stale base image.
“Common” is measured: kept by at least 6 in 10 of the 4 edited versions of this file we could read. “Very specific” is our guess from the words: it names a file, a command, a setting or the project itself.
Files
Docker & the sandbox
The container IS the security boundary. READMEs are untrusted code; the agent
runs INSIDE the container so --dangerously-skip-permissions is safe.
The base image (images/base/Dockerfile)
- Built FROM
ghcr.io/charmbracelet/vhs:latestso ONE image serves the agent run, the verify replay, AND the video render (vhs + ttyd + ffmpeg from the base; git/Go/Python/Node + Claude Code added on top). This is why the video can execute real toolchain steps on camera. ENTRYPOINT []+CMD ["bash"]: the VHS image shipsENTRYPOINT ["vhs"]; reset it sosandbox.pycan run arbitrary commands. The renderer re-invokes vhs via--entrypoint vhs.- Go comes from the official tarball at build time (distro packages lag and strand agents on "go >= 1.2x required"). Rebuild periodically to stay current.
- The Claude Code npm pin is COUPLED to the stream-json parser
(
engines/claude_code.py) — bump them together. - Rebuild after ANY Dockerfile change:
docker build --no-cache -t readme2demo/base:latest images/base/. The render stage preflights the image (render.check_render_image) and errors clearly if it's stale (missing vhs/ffmpeg/git).
Hardening (sandbox.py — never weaken without discussion)
Every container: --cap-drop ALL, --security-opt no-new-privileges,
--memory/--cpus/--pids-limit, non-root user demo (uid 1000), wall-clock
timeout, destroyed after the stage. Run dirs are mounted with ABSOLUTE paths
(docker -v treats relative as a volume name).
Docker-socket opt-in (--allow-docker-socket)
For tools that manage containers themselves (toolhive thv run,
testcontainers, compose repos). Mounts /var/run/docker.sock into agent +
verify + render. The non-root user needs --group-add $(socket gid) —
sandbox.docker_socket_gid probes it (stat -c %g) or every socket call is
EACCES and the tool reports "no container runtime available" despite the mount.
Pierces isolation: trusted repos only; the CLI prints the warning in red.
Diagnosing docker failures
input/output error/containerd meta.db→ Docker VM disk full (VHS writes a PNG per frame).docker system prune -af --volumes; restart Docker Desktop; raise the VM disk. The render mitigations (24fps, mp4-only, short ffmpeg gif preview) exist because full-length GIFs once filled the disk.- exit 125 from
docker run→ bad flags / relative mount path — check the Sandbox args. - "no container runtime available" WITH
--allow-docker-socket→ group-add gid problem (above). - verify passes but render image errors → stale base image; rebuild.
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Your trail
Files you open will collect here, so you can find them again.
Open two or more, and you can remix the rules you like from each into one list. Kept in this browser only.
Now do this for your own.
Bring your CLAUDE.md, AGENTS.md or skills. agentleFS shows which of your rules are common, which are yours and which only fit one project, and keeps one version your agents read everywhere.