docker/sbx-kit-junie-mixin repository overview

⁠junie-mixin

JetBrains' Junie⁠ as a kind: mixin kit: an overlay you layer onto a shell workload, rather than a sandbox image of its own. The workload form is ../junie⁠.

⁠Compose it

sbx create --kit docker.io/dockerdev/sbx-kit-shell --kit ./junie-mixin
sbx exec <sandbox> -- sh -lc 'junie'

junie lands at /home/agent/.local/bin/junie, with a shim on PATH at /usr/local/bin/junie.

Composing this kit and ../junie is refused: both provide junie, and one capability name has one owner.

⁠What it carries

A pinned stable-channel Junie install, the six model-provider credentials Junie can route through (anthropic, google, junie, openai, openrouter, xai, all optional) and the runtime egress policy they need.

The pin is two args, because JetBrains ships two version numbers: version (build arg JUNIE_MARKETING_VERSION, e.g. 26.9.21) is the release the binary reports and what provides: ["junie@<version>"] publishes, and build (build arg JUNIE_VERSION, e.g. 3294.5) is the JetBrains build number, which is the only thing install.sh's own documented override accepts. The overlay asserts junie --version contains both, so they cannot drift apart. Both must stay equal to the workload's, since the two shapes provide one name. See ../junie/README.md⁠ for how to bump them.

⁠Prefer a login shell

JUNIE_SKIP_UPDATE_CHECK=1 rides in /etc/profile.d/junie-env.sh because a mixin's image config never becomes the composed image's. That variable is what seals the shim's auto-update poll, and the egress policy deliberately omits the hosts the poll would reach — so from a non-login shell the check fails against a blocked host rather than being skipped. Use sh -lc.

⁠What it leaves to the base

• The launch command. The mixin sets no ENTRYPOINT.
• No session verbs. agent-sessions@1 drives the workload's entrypoint, which under a mixin is the base's shell. The workload form declares --task there; here you pass it yourself.
• The context-file profile. agent-context@1's filename is workload-only, so this kit contributes a body and the base decides which file the agent reads.