How granular is the control over the internal process?

In my experiments I've had some success modeling the work to be done as a DAG of typed artifacts with a combination of code + LLM doing decomposition, transforms, synthesis, and fitness checking to generate the output. It took me a lot of tries to arrive at that formula and it would be cool to have something more general. I also run part of it against local compute because it would be far beyond my budget to do it all on Opus, so something for that would be nice too.