Very similar, in particular the first phase is lot of markdown and no code too, but spec-kit is clearly more matrue and wide in features and support, while my scaffold is newborn and supports just Claude Code.

I feel that my scaffold is more adherent to old-style waterfall, for example it begins with the definition of the stakeholders, and take advantage of the less adopted practice to maintain assumptions and constraints, not just user stories and requirements.

A big difference is that I have introduced decisions, that are not just design decision, but also coding decisions: after the initial requirement elicitation phase whenever the agent needs to decide on approach or estabilish a pattern, that is crystallised in a decision artifact, and they are indexed in a way that future coding sessions will automatically inject the relevant decisions in their context. Another difference is that when using the scaffold you can tell high level goals, and if the project is complex enough the design will propose a split in multiple components. Every component can be seen as a separtate codebase, with different stack and procedures. In this way you obtain a mono-repo, but with a shared requirement/design that helps a lot in the change management, because sometime changes will affect several components, and without the shared requirements and design it will be pretty hard to automate.