In "Program Primer v1.0 A Manual for Architects," program is defined as being the formal written instructions from the client to the architect. However, unwritten and alternate requirements are also a part of the program. The article claims that the most important author of these alternate requirements is the architect.
The article introduces performative requirements in addition to the proscriptive requirements of the traditional definition of program. Ultimately, it is the architect's responsibility to actively redefine the program by considering performative requirements, as well as other issues that are relevant to the project.
The performative requirements imposed by the architect represents an extremely important part of the architects job. Many people could take a list of programmatic requirements, organize them, and erect a building to suit those needs. It is the experience and skill of the architect that allows him/her to identify and resolve all those additional issues that the project requires.
Undoubtedly, different architects will make different interventions and decisions on what is relevant. This is because each architect works with a different set of experiences and values that filters what he/she perceives as required by the project.
This idea to me is very closely approaching the idea of the diagram, an intrinsic base of knowledge carried within the architecture, the blueprints of how it works. Earliest forms of architecture were mediators between people and the environment, responding by necessity to the pressures of the outside world. An example of this are the many forms of passive heating and cooling that have been around for centuries. Similarly, contextual analysis can seen as reading or deciphering the diagram of forces (physical, social, environmental, etc...) that exist within the environment.
It is this analysis that begins to shape the performative requirements of a project. Without acknowledging and engaging in a dialogue with these external pressures, it is impossible for a building to be truly successful.