Spec Kit vs BMAD vs OpenSpec: Choosing an SDD Framework in 2026

If the AI writes the code, the spec is the artifact. That's the entire thesis. Everything else is tooling. TL;DR Pick based on your codebase: Existing codebase, adding features → OpenSpec New project from scratch → Spec Kit Compliance, audit trails, regulated → BMAD Unsure? → OpenSpec. It tends to minimize adoption friction compared to the others, works on both greenfield and brownfield, and won't lock you in. If that's all you needed, stop here. The rest is the reasoning. Disclosure I haven't r