Should SDD include a discovery and validation loop?

[pandeyshivendra]

I tried SDD yesterday and found the workflow a bit linear:

spec → plan → tasks → code

In practice, some assumptions in the spec can only be validated by inspecting the existing system and challenging the design against how it actually behaves.

I wonder if the workflow could be more iterative:

discover → spec → challenge → plan → implement → verify → update spec ↻

Or perhaps the workflow should vary depending on the type of system being built.

Curious if others have had a similar experience or if there’s already a recommended approach for this.