GitHub Spec Kit is GitHub’s open-source toolkit for spec-driven development (SDD). Released September 2025, it structures how AI coding agents understand and execute your requirements.
Core Philosophy
Treat coding agents like literal-minded pair programmers, not search engines. Specifications become the source of truth; code is the generated output that serves the specification.
Installation
uv tool install specify-cli --from git+https://github.com/github/spec-kit.gitWorkflow Commands
| Command | Purpose |
|---|---|
/speckit.constitution | Project principles, guardrails, immutable rules |
/speckit.specify | What you’re building, user stories, acceptance criteria |
/speckit.plan | Tech stack, architecture, how to build it |
/speckit.tasks | Breakdown into implementable chunks |
/speckit.implement | Execute tasks according to plan |
Optional: /speckit.clarify (resolve ambiguity), /speckit.analyze (consistency check), /speckit.checklist (validate requirements)
Supported Agents
17+ agents including: Claude Code, GitHub Copilot, Cursor, Gemini CLI, Windsurf, Qwen, and others.
Alternatives
- Kiro (AWS): Simpler three-document structure (product.md, structure.md, tech.md). More IDE-integrated.
- Tessl: Spec-as-source approach where specs are the maintained artifact. Still in private beta.
See Martin Fowler’s comparison for deeper analysis.
Criticism
- Creates “a sea of markdown documents” that can be tedious to review
- Feels like waterfall with extra steps for small tasks
- Agents still miss context, ignore instructions, or over-interpret
- Not great for brownfield codebases or exploratory work
Related
- The methodology behind Spec Kit
- My workflow combining Spec Kit with Ralph Wiggum loop
- AI limitations for creative work