Yes, Design is a mechanism
de•sign ( P ) Pronunciation Key (d-zn)
v. de•signed, de•sign•ing, de•signs
1. To conceive or fashion in the mind; invent: design a good excuse for not attending the conference.
2. To formulate a plan for; devise: designed a marketing strategy for the new product.
3. To plan out in systematic, usually graphic form: design a building; design a computer program.
4. To create or contrive for a particular purpose or effect: a game designed to appeal to all ages.
5. To have as a goal or purpose; intend.
6. To create or execute in an artistic or highly skilled manner.
So, a plan is the mechanism for building a house?
It is a mechanism.
Ever hear of the "House that Jack built"? The story I remember is that Jack didn't have a plan and the resulting house exemplified that fact. His mechanism for building a house was "willy-nilly".
Edison had a mechanism for his designs- "99% persperation, 1% inspiration".
Which was different than Tesla, who had a better mechanism for his- actual research and development.
Therefore it would appear even the mechanism of design has different mechanisms.
And again- without direct observation or designer input the ONLY possible way to make a reasonable inference about the mechanism used is by studying the design. Therefore knowing the mechanism is not a pre-requisite for inferring design. It is, however, a driving force to understand the design- find a specific design mechanism. Then test it. It may turn out to be the mechanism. You never know until you try.