Spec Kit is a toolkit for [Spec-Driven Development](concepts/sdd.md) (SDD), a methodology that puts specifications at the center of AI-assisted software development. Instead of jumping straight to code, you describe _what_ to build, refine it through structured phases, and let your AI coding agent implement it.
Define what to build before building it. Rich templates, quality checklists, and cross-artifact analysis come out of the box. Each phase produces a Markdown artifact that feeds the next — giving your AI coding agent structured context instead of ad-hoc prompts.
<span class="pillar-stat">30+ integrations</span> — Copilot, Gemini, Codex, Windsurf, Zed, Claude, Forge, Kiro, and more. Switch freely between agents with a single command. No lock-in.
Run `specify init` with your agent of choice and Spec Kit sets up the right command files, context rules, and directory structures automatically. If your agent isn't listed, the `generic` integration is an escape hatch for any tool.
<span class="pillar-stat">105 community extensions</span> (60+ authors), <span class="pillar-stat">22 presets</span>, and growing. Tune the core process with presets, extend it with extensions, orchestrate it with workflows, or replace it entirely. Build and publish your own.
<a href="community/presets.md" class="pillar-link">Browse community presets →</a>
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### Integrate into your organization
Works offline, behind firewalls, and on **Windows, macOS, and Linux**. Host your own extension and preset catalogs so your organization controls what gets installed.
Community extensions like CI Guard and Architecture Guard add compliance gates and governance that fit the way your team already works.
**200+ contributors** power the Spec Kit ecosystem — from core integrations to entirely new development processes. Anyone can create and publish an extension, preset, or workflow.