Creating sbx templates

A template is an image, and it decides what is installed. What a sandbox is permitted to do belongs in a kit — reach for creating-sbx-kits instead when the answer is a spec field.

Build a template when something must be baked in: a compiler toolchain, a large dependency tree, a config that has to exist before the agent starts.

Pick a base

docker/sandbox-templates:<variant>, all Ubuntu, all running as a non-root agent user with sudo:

claude-code, claude-code-minimal (no Node, Python, Go or Java), codex, copilot, cursor-agent, docker-agent, droid, gemini, kiro, opencode, shell (no agent at all).