agent-seed

Builds the plugin seed directory baked into container images. A devcontainer or CI runner using it starts with the catalog and its plugins already present, cloning nothing at runtime and needing no git credentials.

Behaviour worth knowing

• The seed is never written to, and auto-updates are disabled for seed marketplaces
• Seed entries overwrite matching user configuration on every startup
• Opting out of a seed plugin means /plugin disable; removing a seed marketplace fails
• Paths resolve by probing at runtime, so the seed works when mounted elsewhere
• Several seeds layer with a colon separator, first match winning, which gives you a company base plus a department overlay

Managed settings are defaults, not policy

managed-settings.json lands in /etc/claude-code/, the highest-precedence location. But the Dockerfile lives in a repository, and anyone with write access can delete the COPY line.

Use this for consistent defaults. Anything that genuinely must not be bypassed goes through server-managed settings or MDM.

The sign-in trap

Mounting a volume at ~/.claude does not keep engineers signed in, because ~/.claude.json sits outside that directory and holds the OAuth account, personal MCP servers, and per-project trust. Set CLAUDE_CONFIG_DIR to the same path. The reference devcontainer/devcontainer.json does this; copy it rather than writing your own.