How do you create skills in Gemini (and reuse them in Claude, ChatGPT and Copilot)?
Exact steps and limits for building skills in Gemini, uploading the same SKILL.md to Claude, ChatGPT and Microsoft 365 Copilot, what each plan costs, a worked SKILL.md for a client report, team sharing and admin controls, the security risks of third-party skills, and when a plain prompt or project instructions do the job better.