How to handle drifting Spec in SDD
Let’s talk about "spec", as we can see in "Spec Driven Development" (SDD).
Since SDD gained traction, one of the main complaint about this is that once the development is done, the "Spec" drifts inevitably as the code evolves.
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My opinion is that SDD or any agentic loop you execute on your project works, it does, but a simple Plan mode (or grill-me) + execution loop will give a very good result, especially if you have built your Project Harness.
SDD frameworks, opensource or custom, will just give "structure" and better reproducibility to this process.
In this article I argue that 2 levels requirement specifications (ReqSpec)are the sweet spor for non-drifting spec. And I explain the difference with the Spec in SDD that I will call ChangeSpec.
Posted Jul 30, 2026, 2:08 PM UTC