monoceros add-feature

Adds a devcontainer feature to a workbench’s config. The feature is baked into the container on the next monoceros apply.

monoceros add-feature <name> <feature> [-- <opt>=<value> ...] [--yes]

<feature> is either a Monoceros catalog short name (claude, atlassian/twg, …) or a full OCI ref (ghcr.io/devcontainers/features/docker-in-docker:2). A short name brings its catalog-defined default options; anything after -- overrides them as key=value pairs.

Examples

# Catalog short name, with its defaults
monoceros add-feature acme claude

# Override a feature option
monoceros add-feature acme node -- version=20

# A full OCI feature ref
monoceros add-feature acme ghcr.io/devcontainers/features/docker-in-docker:2

Behavior

• Idempotent. Re-adding the same ref with the same options is a no-op. Adding the same ref with different options is an error - remove it first, or edit the yml.
• No confirmation prompt. The edit is written straight to the yml as soon as you run the command.
• Edits the yml only. Run monoceros apply to rebuild the container with the new feature.
• A plugin-hosting feature brings a commented example. claude is written with a commented plugins: block underneath its options, so the shape is in the file when you want it. Uncomment it, put your own marketplace in, apply. See Claude Code.

See also

• Feature catalog - what you can add.
• monoceros list-components - browse the catalog and its options from your terminal.
• monoceros remove-feature - the inverse.