Descriptions of tables is insufficient (we had it) - you also need descriptions of the systems writing to the tables.
My favorite example was a report that was only accurate if generated on a Tuesday or Thursday due to when the ETL pipeline ran. A small config change on the opposite side of a code base completely altered the semantics of the data!
If you're interested please drop an email. I've only worked deeply with pipelines extracting data from documents and I'd be interested in hearing what the challenges with databases are.
My favorite example was a report that was only accurate if generated on a Tuesday or Thursday due to when the ETL pipeline ran. A small config change on the opposite side of a code base completely altered the semantics of the data!