sbx-templates

Custom sandbox templates for Docker AI Sandboxes (sbx). Built on top of docker/sandbox-templates:claude-code-minimal.

See USAGE.md for install, one-time host setup, creating/re-attaching sandboxes, credential storage, and git signing.

Architecture

A shared base image contains common tooling, with thin per-language layers on top:

docker/sandbox-templates:claude-code-minimal
  +-- base
        +-- bun       (Bun + TypeScript LSP)
        +-- rust      (Rust + rust-analyzer)
        +-- golang    (Go + gopls)
        +-- python    (Python/uv + Pyright)

What's in the base image

Developer tools

Tool	Description
Bun	JavaScript runtime (also provides npm/npx for LSP servers)
Python	Default Python runtime (managed by uv, with python/python3 on PATH)
GitHub CLI	GitHub from the command line
1Password CLI	Secrets management
delta	Syntax-highlighted git diffs
yq	YAML processor (jq for YAML)
ripgrep	Fast recursive search
fd	Fast file finder
bat	cat with syntax highlighting
eza	Modern ls replacement
fzf	Fuzzy finder
tmux	Terminal multiplexer
zsh + oh-my-zsh	Shell with plugins (git, gh, docker, tmux, fzf)
beads (bd)	Issue/task tracker for coding agents
prek	Fast Rust reimplementation of pre-commit

Security

Tool	Description
Socket Firewall	Supply chain protection for package installs

Language images

Image	Runtime	LSP	sfw alias
bun	Bun	typescript-language-server	bun, bunx
rust	rustup + stable toolchain, wild linker, cargo-binstall, cargo-cache	rust-analyzer	cargo
golang	Go (system-wide)	gopls	—
python	uv + default Python	Pyright	pip, uv

Local build

# Build base first
docker build -t sbx-templates:base base/

# Build language images
docker build -t sbx-templates:bun bun/
docker build -t sbx-templates:rust rust/
docker build -t sbx-templates:golang golang/
docker build -t sbx-templates:python python/

CI

Images are built and pushed to GHCR on every push to main:

1. Build base image
2. Parallel-build all language images on top of the base (by digest)
3. Sign all images with cosign (keyless via GitHub OIDC)

Supply chain verification

Binary dependencies are verified during the build:

Dependency	Verification method
bun, yq, delta, sfw, beads, prek	SHA256 checksums (hardcoded, auto-updated by Renovate)
apt packages	GPG-signed repos (GitHub CLI, 1Password)

Output images are signed in CI with cosign (keyless via GitHub OIDC).

Dependency management

Renovate tracks and auto-updates:

• Upstream base image digest (docker/sandbox-templates:claude-code-minimal)
• Tool versions (bun, delta, yq, sfw, mold, beads, prek)
• GitHub Actions versions

Checksums for bun, yq, delta, sfw, beads, and prek are automatically recomputed via postUpgradeTasks when their versions are bumped.