Cloud sandbox reference
Pre-installed languages, tools, and limits of the VM templates behind cloud environments.
Cloud sandboxes run as isolated Firecracker microVMs on Clusterbase-managed
infrastructure. Each one boots from the VM template named by the environment's
template_id, and everything listed here
is on the image already — the agent can use it without an installation step.
These specifications apply to cloud environments, the only environment type
in v1.
Templates
| Template | Operating system | vCPU | Memory | Disk | Use it for |
|---|---|---|---|---|---|
development | Debian 13 (trixie) | 4 | 4 GB | 14 GB | Shared Agent image for Work, Build, and managed agents. |
browser | Ubuntu 24.04 LTS | 4 | 4 GB | 15 GB | Browser automation with Chrome and agent-browser. |
desktop | Ubuntu 24.04 LTS | 4 | 4 GB | 10 GB | A graphical Xfce desktop with a visible browser. |
GET /v1/environment-templates returns the same list. Saved environments accept
all three; an on-demand run uses development.
Work uses the same image with its existing 2-vCPU, 1-GB runtime allocation.
Programming languages
| Language | Version | Package manager | Templates |
|---|---|---|---|
| Python | Distribution python3 | pip, uv 0.11.21 | All (uv is not on desktop) |
| Node.js | 24.16.0 (22.17.1 on desktop) | npm | All |
| Bun | 1.3.14 | bun | development, desktop |
| Go | 1.26.4 | go modules | development |
| Rust | 1.96.0 (rustup) | cargo | development |
| C/C++ | GCC (build-essential) | make; cmake and pkg-config on development | development, desktop |
On development and browser, pip install and pip uninstall
are routed through uv pip. Call python3 -m pip to reach pip directly.
Java, Ruby, PHP, and Deno are not installed. The images are Debian and Ubuntu,
so apt-get install adds them for the life of the sandbox.
Pre-installed libraries
The shared development Agent image carries the libraries its bundled skills depend on:
- Python:
anthropic,mcp,numpy,pandas,openpyxl,lxml,defusedxml,pypdf,pdfplumber,pdf2image,reportlab,Pillow,imageio,imageio-ffmpeg,pytesseract,PyYAML,markitdown[pptx] - Node.js:
docx,pptxgenjs,sharp,react,react-dom,react-icons
The Agent image also carries esbuild. desktop carries esbuild and typescript.
Databases
No database server or client is installed on any template. Install one with
apt-get when a session needs it, or connect to a
managed database over the network.
Utilities
System tools
git— Version controlcurl,wget— HTTP clientsunzip— Archive extractionripgrep(rg) — Fast file searchfile— File type detection (development,desktop; notbrowser)vim— Text editor (not ondesktop)net-tools,lsof— Network and process inspection (lsofis not ondesktop)
Development tools
make,gcc,g++— Build toolchaincmake,pkg-config,protobuf-compiler—developmentonlynginx—developmentgh2.99.0 — GitHub CLI,developmentonlyccp— Clusterbase CLI, on every template exceptbrowserforge— Forge CLI,developmentonly
Image tools
development and desktop (not browser) carry basic image
inspection and conversion tools:
- ImageMagick (
magick) — image inspection and conversion webp(cwebp) — WebP encoding
Document processing
Installed on the shared Agent image:
- LibreOffice — Office document conversion
pandoc— Document conversion- Poppler utilities (
pdftotext,pdftoppm) — PDF processing tesseract— Optical character recognition
Browser automation
agent-browser0.31.1 with Chrome for Testing —browser- A visible browser on an Xfce desktop (1440×900), with
xdotool,xclip, andscrot—desktop
jq, ffmpeg, tmux, and docker are not installed.
Sandbox specifications
| Property | Value |
|---|---|
| Isolation | Firecracker microVM |
| Architecture | x86_64 (amd64) |
| Init system | systemd |
| User | root |
| Working directory | /workspace — git repos clone to /workspace/<name>; library-files, scratch, inputs and uploads are reserved |
| App checkout | /workspace/app — the pinned source of a Cluster App session |
| Synced folder | /workspace/library-files — the session's Storage folder, when one is mounted; chat attachments land at attachments/<id>/<name> |
| Deliverables | /workspace/library-files/outputs — files written here sync back to Storage |
| Scratch | /workspace/scratch — working files that are not synced |
| Deployment inputs | /workspace/inputs/<file-id>/<name> — written once at launch, not synced |
| VM uploads | /workspace/uploads/<name> — files sent with the VM upload API; not synced |
| Skills | /mnt/skills — the full repo on development and desktop, absent on browser |
| Compute and disk | Fixed by the template — see Templates |
| DNS | 8.8.8.8, 8.8.4.4 |
| Network | unrestricted — see Networking |
Idle behavior
A development sandbox pauses after 15 minutes without tool calls or traffic to
its preview port. A desktop sandbox pauses after 15 minutes with no connected
viewer, control lease, or computer-use activity — see
Sandboxes. Pausing snapshots memory to disk and frees the
VM; the next tool call or connection resumes the same VM with its files,
uncommitted git work, and processes intact.
Compute is not billed while paused. A detached background process does not count
as activity.
Networking
Outbound traffic to the public internet is unrestricted. Private address ranges
(10.0.0.0/8, 172.16.0.0/12, 192.168.0.0/16, 100.64.0.0/10) and the cloud
metadata endpoint are blocked from inside the sandbox.
Inbound, only ports a template declares are published, each at an
https://sbx-…. hostname; every other port and the VM's own address stay
private. development publishes port 8000 as a public preview. The desktop
ports require a short-lived access token.