I am playing with similar ideas.

I am inspired by this to make a harness that intentionally does sparse checkouts, so the agents only can see so much context.

I am also playing with the idea of layering additional data structures on top of the "code" that cover different aspects. For example, a tree structure of performance requirements that has durable symbolic references to entities in the code that are especially relevant. Another tree can cover aspects of security, another legal compliance, another UI guidelines.