Spec driven development (SDD) is a promising way to have agents organize work when doing agentic software development. The idea is to split the work into recognizable parts such as specification, planning, task creation and implementation. Then there are agents with specialized instructions performing each of these functions in sequence and building upon the work of the previous agent. The specific parts available depend on the specific implementation of SDD.

Following this sort of process seems to generate fairly reasonable outcomes fairly reliably. However, this process also generates quite a bit of documentation and plans that, strictly speaking, are not required for the code to function in addition to generating the code itself and performing tasks such as testing and debugging. This begs the question of the costs associated with the generation of all these artifacts.

In this talk I will present a way to estimate the energy, water and carbon costs of agentic development and present the results of estimating the costs of an example project developed using agents and SSD.