Cloud sandbox reference

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

GET /v1/environment-templates returns the same list. Saved environments accept all four; an on-demand run accepts development and workspace.

Programming languages

On development, workspace, 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 workspace template 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

development installs no pip Python libraries, but does carry Pillow via the system python3-pil package, and only esbuild globally from npm. desktop adds 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 control
• curl, wget — HTTP clients
• unzip — Archive extraction
• ripgrep (rg) — Fast file search
• file — File type detection (development, workspace, desktop; not browser)
• vim — Text editor (not on desktop)
• net-tools, lsof — Network and process inspection (lsof is not on desktop)

Development tools

• make, gcc, g++ — Build toolchain
• cmake, pkg-config, protobuf-compiler — development only
• nginx — development and workspace
• gh 2.99.0 — GitHub CLI, development only
• ccp — Clusterbase CLI, on every template except browser
• forge — Forge CLI, development only

Image tools

development, workspace, 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 workspace:

• LibreOffice — Office document conversion
• pandoc — Document conversion
• Poppler utilities (pdftotext, pdftoppm) — PDF processing
• tesseract — Optical character recognition

Browser automation

• agent-browser 0.31.1 with Chrome for Testing — browser
• A visible browser on an Xfce desktop (1440×900), with xdotool, xclip, and scrot — desktop

jq, ffmpeg, tmux, and docker are not installed.

Sandbox specifications

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.