Wiggle

A working copy of the sandbox that Claude (claude.ai) runs code in.

When Claude executes a command, reads a file, converts a document, or takes a screenshot, it is not running on a web server. It is running inside a small virtual machine, one per conversation. This repository is that machine: the same files, tools, packages, and instructions, packaged so you can run it yourself on Docker, e2b, Modal, or any Linux host.

Codename wiggle is what Anthropic calls this VM internally.

Quick start

docker build -t wiggle .
docker run -it wiggle bash

# inside:
soffice --version            # LibreOffice 24.2
python3 -c "import pandas"   # full data science stack
ls /mnt/skills               # the 40 playbooks Claude follows

Want the exact bytes instead of a rebuild? The GitHub release carries the full filesystem of a live session (8.9 GB, sanitized):

cat wiggle-part-aa wiggle-part-ab > wiggle.tar.zst
zstd -d -c wiggle.tar.zst | docker import - wiggle:live

See ROOTFS.md for the full download and verification steps.

How it works

• Claude decides to run something and sends the command over a private channel to a supervisor process inside the VM.
• The supervisor starts the command with a fixed environment (see meta/env-contract.md) and streams the output back.
• The command runs as root with no seccomp and no user sandbox. Inside this VM, root is normal. The isolation that matters is the VM boundary itself.
• User files arrive as mounted folders under /mnt/user-data. In production those are remote storage; here they are plain directories.

Machine spec to match if you care about parity: 1 vCPU, 3.9 GiB RAM, no swap. Details in meta/box-spec.md.

What is inside

The skills are the interesting part. They are plain Markdown instruction files that Claude reads before doing certain jobs: how to fill a PDF form, how to run deep research (including the sub-agent prompts), how to drive the desktop with computer use, how to build a skill. Public ones cover office documents and file reading; example ones cover deep-research, morning briefings, painting, MCP server building, and more. Browse them under mnt-skills/.

Two custom Anthropic binaries are included: extract-text (turns uploaded documents into text, Rust) and the mount daemon interface (rclone-filestore, Go, documented in meta/filestore-api.md).

What is not included

Four things live outside the filesystem, so no dump could contain them:

• The supervisor binary itself (runs from RAM, never from disk).
• The model, which is remote by definition.
• Anthropic's egress firewall and its CA roots.
• The remote storage service behind /mnt/user-data, whose contract is documented in meta/filestore-api.md.

For e2b users: e2b's own daemon takes the supervisor's role, which is why this image drops straight into an e2b template.

Using it with your own agent

Any agent that can shell into a container can use this box exactly the way Claude does: read the relevant /mnt/skills/*/SKILL.md, then run the tools it names. Inject the environment from meta/env-contract.md and the behavior matches production, quirks included.

Known quirks (present in the original, kept on purpose)

• pandoc x.md -o x.pdf fails until you add fonts-lmodern or use the Chromium fallback. The real sandbox has the same hole.
• pip install is blocked by PEP 668. Use uv. The offline wheel cache is included.
• ImageMagick has no SVG coder and ignores -quality for webp. Use Pillow or sharp.
• Tool exit codes lie often. Verify outputs (test -s out && file out) instead of trusting success.
• extract-text segfaults under x86 emulation on ARM Macs. It is fine on native x86-64 hosts.

Repository layout

• Dockerfile the recovered build recipe (verified to build green)
• _context/ build inputs: pinned manifests and the Anthropic binaries
• mnt-skills/ the 40 skills, copied into the image at /mnt/skills
• meta/ dpkg-manifest, uv-manifest, env-contract, filestore-api, box-spec
• ROOTFS.md how to get the exact live filesystem dump
• LICENSE and NOTICE

License

The build recipe, scripts, and documentation in this repo are MIT (LICENSE).

Everything Anthropic-made is theirs, not MIT:

• The 40 skill files in mnt-skills/ and the Anthropic binaries each carry Anthropic's own license (NOTICE and each LICENSE.txt), which does not clearly allow redistribution. They are here as captured research artifacts.
• If you would rather not ship them, delete mnt-skills/ and remove the one COPY mnt-skills/ line from the Dockerfile. The box still builds and runs; any user can re-obtain the skills by asking Claude to show them.

Not affiliated with Anthropic.