I had a lot of issues with spec-driven approaches, agents are too readily producing fluff, large projects have so many specs agents start making mistakes maintaining them. There's a constant consistency tax.
In the end every spec is just a bunch of facts, so I decided to leave that and throw away everything else while making it friendlier for agentic use.
Introducing facts - skills and CLI for agents to use facts-driven development. https://github.com/av/facts
I would be happy to see some prove that this works. A project that started and went go. How a friendlier specification looks like and why agents understand it better.