https://github.com/github/spec-kit: Toolkit to help you get started with Spec-Driven Development
https://github.com/Fission-AI/OpenSpec: Spec-driven development (SDD) for AI coding assistants.
https://github.com/bmad-code-org/BMAD-METHOD: Breakthrough Method for Agile Ai Driven Development
https://www.builder.io/blog/codex-vs-claude-code
Something Big Is Happening, Feb 2026: https://x.com/mattshumer_/status/2021256989876109403
Harness engineering: leveraging Codex in an agent-first world, Feb 2026: https://openai.com/index/harness-engineering/
claude-code-best-practice: https://github.com/shanraisshan/claude-code-best-practice
https://platform.claude.com/docs/en/build-with-claude/prompt-engineering/claude-prompting-best-practices