Plenary and To a T

Plenary adjective - Not lacking any part or member that properly belongs to it.

To a T and plenary are semantically related. In some cases you can use "To a T" instead an adjective "Plenary".

To a T adverb - In every detail.

Plenary and to a T are semantically related. Sometimes you can use "Plenary" instead an adjective phrase "To a T".