Agent skills

Sandbar ships three agent skills from its repository: sandbar and sandbar-cli in skills/, and add-provider in .agents/skills/. A skill is a SKILL.md file that an agent loads when a task needs it, so the guidance stays out of your prompt until it is useful.

Skill	Teaches an agent to
sandbar	Write application code with sandbar-sdk and a provider adapter: connect, create and clean up sandboxes, run commands, move files, and handle uncertain outcomes without repeating work.
sandbar-cli	Create, use and remove sandboxes from the shell with the sandbar command, read its JSON output and exit codes, and clean up after failures.
add-provider	Write a provider adapter with @sandbar-sdk/adapter: verify the account, map the shared setup options, implement create and destroy, test with adapterSuite, then package and document it. See Write an adapter.

Install

Install with the skills installer, which supports Claude Code, Codex, Cursor and other agents:

npx skills add pandemicsyn/sandbar --skill sandbar -g
npx skills add pandemicsyn/sandbar --skill sandbar-cli -g
npx skills add pandemicsyn/sandbar --skill add-provider

-g installs the skill for your user. Leave it out to install into the current project instead, so everyone working in the repository gets it; that suits add-provider, which belongs in the adapter’s repository.

The CLI also carries its own copy of sandbar-cli, matching its version. sandbar skill install writes it to ~/.agents/skills (and ~/.claude/skills when Claude Code is set up), and sandbar skill install --project writes it into the current folder. sandbar skill prints it.

For an agent without a skill system, copy the SKILL.md contents into its project or user instructions.

What the skills do not do

The skills never hold credentials. The SDK skill reads keys from environment variables; the CLI skill uses your existing sandbar.json profiles and tells the agent to leave configuration to you. Both tell the agent that live sandboxes cost money, to clean up what it creates, and never to retry an operation whose outcome is unknown.

For one-off tasks you can still paste the SDK prompt or the provider integration prompt instead.