Sibling skills (local only) Sibling CloudBase skills ship beside this skill. Use local relative paths such as . If a referenced sibling skill file is missing from this environment, ask the user to install the full CloudBase plugin (or the missing skill). Do not HTTP-fetch remote skill or protocol markdown into the agent context. Activation Contract Use this first when - Node.js code in cloud functions or backend services must read caller identity, look up users, or issue custom login tickets. - The backend responsibility is auth / identity, not provider setup or frontend login UI. Read before…