​​​​​​​​​​​​​​​ GitHub Spec Kit is an open-source toolkit that introduces a spec-driven development (SDD) methodology for working with AI coding agents like GitHub Copilot, Claude Code, and Gemini CLI . Rather than “vibe coding” features directly with AI, Spec Kit structures development into three phases: creating a detailed specification (the “what” and “why”), generating a technical implementation plan (the “how”), and breaking down the plan into actionable tasks . The toolkit consists of a Py