What is a Claude 'skill' and how do you create and use one to keep tax guidance consistent and reduce risk?

A Claude skill is essentially a set of instructions you create (e.g., 'EU VAT rules for self-employed') that you can write yourself or paste in from research. Once created, you can invoke a skill inside a chat by typing a forward slash to bring up the list of skills, then reference it (e.g., 'always use this set of skills') before asking your question. When invoked, the LLM treats that skill as its source of truth for the task, which reduces the risk of it giving an incorrect or inconsistent answer. One skill shown was built using deep research, with a disclaimer stated in it that the content is 'valid, not reviewed by a tax practitioner,' so users know whether a given skill has been vetted by a specific practitioner or not.