Access rights concern personal data, not every document

A subject access request covers personal data about the requester, not every document that mentions a topic.

It is often used as a general disclosure tool and it is narrower than that. It also has limits where other people's personal data is entangled, or where legal privilege applies. Understanding the actual scope prevents both over-disclosure, which harms third parties, and reflexive refusal, which is unlawful.

More on UK GDPR