Comparing SDD Frameworks: spec-kit vs OpenSpec vs get-shit-done

Notes on the differences between three Spec Driven Development frameworks — GitHub's spec-kit, Fission-AI's OpenSpec, and gsd-build's get-shit-done.

Published: Monday, May 18, 2026 Last modified: Monday, May 18, 2026

I did try https://kiro.dev/ and https://antigravity.google/ but they were so slow as to be unusable.

Notes on three Spec Driven Development (SDD) frameworks I’ve been comparing:

It retrospect I wish I generated unique ANTHROPIC_API_KEY keys for these experiments to get a better understanding of the costs.

spec-kit

Using https://github.com/kaihendry/ai-check-guardrails

Not a perfect experience with Claude code, nonetheless I thought it did well:

OpenSpec

https://github.com/kaihendry/asaguard

get-shit-done

https://github.com/kaihendry/ai-siem-endpoint

Takeaways

My “own way” of using beads and vibing doesn’t seem eclipsed in my mind by SDD. The frameworks may help clarify some large features, but normally I’ve already broken them down already in my mind.

I don’t feel any of these frameworks captured the initial prompting very well and it feels wrong to manually edit their outputs.