Spec Kit
Free💫 Toolkit to help you get started with Spec-Driven Development
FreeFree tier
About Spec Kit
Spec Kit is an extensible, intent-driven harness that guides coding agents across the software development lifecycle (SDLC) through structured phases: Spec → Plan → Tasks → Implement. It includes rich templates, quality checklists, and cross-artifact analysis to move beyond ad-hoc prompts. With 35 integrations for agents like Copilot, Gemini, and Codex, and 138 community extensions, users can tailor the process for Spec-Driven Development (SDD), product management, migration, fiction writing, and more. Works offline, on Windows, macOS, and Linux, and supports air-gapped enterprise environments with custom catalogs.
Key Features
Core SDD process: Spec → Plan → Tasks → Implement
Rich templates, quality checklists, and cross-artifact analysis
35 integrations with coding agents (Copilot, Gemini, Codex, Zed, Claude, Forge, Kiro, etc.)
138 community extensions from 70+ authors
25 presets for tuning the core process
Extensible with presets, extensions, workflows, and bundles
Works offline, behind firewalls, on Windows, macOS, Linux
Enterprise/air-gapped support with custom catalogs
240+ contributors and 121K+ GitHub stars
No lock-in: switch agents with a single command
Pros & Cons
Pros
- Open source under MIT license
- Large community ecosystem with 240+ contributors and 138 extensions
- Works with many coding agents (no vendor lock-in)
- Extensible via presets, extensions, workflows, and bundles
- Operates offline and in air-gapped environments
- Supports enterprise catalogs for curated integrations
Cons
- Requires understanding of Spec-Driven Development philosophy
- Learning curve for non-software processes
- Primarily produces Markdown artifacts (text-based)
Best For
Spec-Driven Development (SDD) for software projectsAutomated SDLC workflow from specification to implementationProduct management with Product Forge preset.NET Framework migration with FX→.NET presetFiction book writing with Fiction Book Writing presetMulti-agent orchestration with quality assurance gates (MAQA)Compliance and governance with CI Guard and Architecture Guard extensionsAny business process modeling using custom presets and workflows
FAQ
What is Spec Kit?
Spec Kit is an extensible, intent-driven harness that pushes any coding agent beyond code, guiding it across the SDLC or any business process. It uses structured phases (Spec → Plan → Tasks → Implement) to keep intent at the center.
How do I install Spec Kit?
Install using the uv tool: 'uv tool install specify-cli' then 'specify init my-project --integration copilot'.
What integrations are supported?
Spec Kit supports 35 integrations including GitHub Copilot, Gemini, Codex, Kilo Code, Zed, Claude, Forge, Kiro, and more. A generic integration is also available for any tool.
Can it work offline or behind a firewall?
Yes, Spec Kit works offline, behind firewalls, and on Windows, macOS, and Linux. It supports air-gapped enterprise environments with custom catalogs.
Is Spec Kit open source?
Yes, Spec Kit is open source under the MIT license and has over 240 contributors.