🌱 Spec Kit
Build high-quality software faster.
An open source toolkit that allows you to focus on product scenarios and predictable outcomes instead of vibe coding every piece from scratch.
---
## Table of Contents
- [🤔 What is Spec-Driven Development?](#-what-is-spec-driven-development)
- [⚡ Get Started](#-get-started)
- [📽️ Video Overview](#️-video-overview)
- [🌍 Community](#-community)
- [🤖 Supported AI Coding Agent Integrations](#-supported-ai-coding-agent-integrations)
- [🔧 Specify CLI Reference](#-specify-cli-reference)
- [🧩 Making Spec Kit Your Own: Extensions & Presets](#-making-spec-kit-your-own-extensions--presets)
- [📦 Bundles: Role-Based Setups](#-bundles-role-based-setups)
- [📚 Core Philosophy](#-core-philosophy)
- [🌟 Development Phases](#-development-phases)
- [🎯 Experimental Goals](#-experimental-goals)
- [🔧 Prerequisites](#-prerequisites)
- [📖 Learn More](#-learn-more)
- [💬 Support](#-support)
- [🙏 Acknowledgements](#-acknowledgements)
- [📄 License](#-license)
## 🤔 What is Spec-Driven Development?
Spec-Driven Development **flips the script** on traditional software development. For decades, code has been king — specifications were just scaffolding we built and discarded once the "real work" of coding began. Spec-Driven Development changes this: **specifications become executable**, directly generating working implementations rather than just guiding them.
## ⚡ Get Started
### 1. Install Specify CLI
Requires **[uv](https://docs.astral.sh/uv/)** ([install uv](./docs/install/uv.md)). Replace `vX.Y.Z` with the latest release tag from [Releases](https://github.com/github/spec-kit/releases) — keep the leading `v` (for example, `v0.12.11`, not `0.12.11`):
```bash
uv tool install specify-cli --from git+https://github.com/github/spec-kit.git@vX.Y.Z
```
Prefer installing from PyPI? The `specify-cli` package is also published there:
```bash
uv tool install specify-cli
```
See the [Installation Guide](./docs/installation.md) for alternative methods, verification, upgrade, and troubleshooting.
### 2. Initialize a project
```bash
specify init my-project --integration copilot
cd my-project
```
To check for updates or upgrade the installed CLI, use the self-management commands. See the [Upgrade Guide](./docs/upgrade.md) for detailed scenarios and customization options.
```bash
# Check whether a newer release is available (read-only — does not modify anything)
specify self check
# Preview what would run, without actually upgrading
specify self upgrade --dry-run
# Upgrade in place to the latest stable release (auto-detects uv tool vs pipx install)
specify self upgrade
# Or pin a specific release tag (replace vX.Y.Z[suffix] with your desired release tag)
specify self upgrade --tag vX.Y.Z[suffix]
```
Bare `specify self upgrade` executes immediately, matching the no-prompt behavior of commands like `pip install -U` and `npm update`. For `uv tool` installs, it runs `uv tool install specify-cli --force --from ` under the hood so pinned release tags work, including dev, alpha/beta/rc, or build metadata suffixes. `uvx` (ephemeral) runs and source checkouts are detected and produce path-specific guidance instead of running an installer. Set `SPECIFY_UPGRADE_TIMEOUT_SECS` to cap how long the installer subprocess may run (default: no timeout — interrupt with `Ctrl+C` if needed).
### 3. Establish project principles
Launch your coding agent in the project directory. Most agents expose spec-kit as `/speckit.*` slash commands; Codex CLI in skills mode uses `$speckit-*` instead; GitHub Copilot CLI uses `/agents` to select the agent or address it directly in a prompt.
Use the **`/speckit.constitution`** command to create your project's governing principles and development guidelines that will guide all subsequent development.
```bash
/speckit.constitution Create principles focused on code quality, testing standards, user experience consistency, and performance requirements
```
### 4. Create the spec
Use the **`/speckit.specify`** command to describe what you want to build. Focus on the **what** and **why**, not the tech stack.
```bash
/speckit.specify Build an application that can help me organize my photos in separate photo albums. Albums are grouped by date and can be re-organized by dragging and dropping on the main page. Albums are never in other nested albums. Within each album, photos are previewed in a tile-like interface.
```
### 5. Create a technical implementation plan
Use the **`/speckit.plan`** command to provide your tech stack and architecture choices.
```bash
/speckit.plan The application uses Vite with minimal number of libraries. Use vanilla HTML, CSS, and JavaScript as much as possible. Images are not uploaded anywhere and metadata is stored in a local SQLite database.
```
### 6. Break down into tasks
Use **`/speckit.tasks`** to create an actionable task list from your implementation plan.
```bash
/speckit.tasks
```
### 7. Execute implementation
Use **`/speckit.implement`** to execute all tasks and build your feature according to the plan.
```bash
/speckit.implement
```
For detailed step-by-step instructions, see our [comprehensive guide](./spec-driven.md).
## 📽️ Video Overview
Want to see Spec Kit in action? Watch our [video overview](https://www.youtube.com/watch?v=a9eR1xsfvHg&pp=0gcJCckJAYcqIYzv)!
[](https://www.youtube.com/watch?v=a9eR1xsfvHg&pp=0gcJCckJAYcqIYzv)
## 🌍 Community
Explore community-contributed resources on the [Spec Kit docs site](https://github.github.io/spec-kit/):
- [Extensions](https://github.github.io/spec-kit/community/extensions.html) — commands, hooks, and capabilities
- [Presets](https://github.github.io/spec-kit/community/presets.html) — template and terminology overrides
- [Bundles](https://github.github.io/spec-kit/community/bundles.html) — role and team stacks composed from existing components
- [Walkthroughs](https://github.github.io/spec-kit/community/walkthroughs.html) — end-to-end SDD scenarios
- [Friends](https://github.github.io/spec-kit/community/friends.html) — projects that extend or build on Spec Kit
> [!NOTE]
> Community contributions are independently created and maintained by their respective authors. Review source code before installation and use at your own discretion.
Want to contribute? See the [Extension Publishing Guide](extensions/EXTENSION-PUBLISHING-GUIDE.md), the [Presets Publishing Guide](presets/PUBLISHING.md), or the [Community Bundles guide](docs/community/bundles.md).
## 🤖 Supported AI Coding Agent Integrations
Spec Kit works with 30+ AI coding agents — both CLI tools and IDE-based assistants. See the full list with notes and usage details in the [Supported AI Coding Agent Integrations](https://github.github.io/spec-kit/reference/integrations.html) guide.
Run `specify integration list` to see all available integrations in your installed version.
## Available Slash Commands
After running `specify init`, your AI coding agent will have access to these slash commands for structured development. For integrations that support skills mode, passing `--integration --integration-options="--skills"` installs agent skills instead of slash-command prompt files.
### Core Commands
Essential commands for the Spec-Driven Development workflow:
| Command | Agent Skill | Description |
| ------------------------ | ---------------------- | -------------------------------------------------------------------------- |
| `/speckit.constitution` | `speckit-constitution` | Create or update project governing principles and development guidelines |
| `/speckit.specify` | `speckit-specify` | Define what you want to build (requirements and user stories) |
| `/speckit.plan` | `speckit-plan` | Create technical implementation plans with your chosen tech stack |
| `/speckit.tasks` | `speckit-tasks` | Generate actionable task lists for implementation |
| `/speckit.taskstoissues` | `speckit-taskstoissues`| Convert generated task lists into GitHub issues for tracking and execution |
| `/speckit.implement` | `speckit-implement` | Execute all tasks to build the feature according to the plan |
| `/speckit.converge` | `speckit-converge` | Assess the codebase against spec/plan/tasks and append remaining work as new tasks |
### Optional Commands
Additional commands for enhanced quality and validation:
| Command | Agent Skill | Description |
| -------------------- | ---------------------- | ------------------------------------------------------------------------------------------------------------------------------------ |
| `/speckit.clarify` | `speckit-clarify` | Clarify underspecified areas (recommended before `/speckit.plan`; formerly `/quizme`) |
| `/speckit.analyze` | `speckit-analyze` | Cross-artifact consistency & coverage analysis (run after `/speckit.tasks`, before `/speckit.implement`) |
| `/speckit.checklist` | `speckit-checklist` | Generate custom quality checklists that validate requirements completeness, clarity, and consistency (like "unit tests for English") |
## 🔧 Specify CLI Reference
For full command details, options, and examples, see the [CLI Reference](https://github.github.io/spec-kit/reference/overview.html).
## 🧩 Making Spec Kit Your Own: Extensions & Presets
Spec Kit can be tailored to your needs through two complementary systems — **extensions** and **presets** — plus project-local overrides for one-off adjustments:
| Priority | Component Type | Location |
| -------: | ------------------------------------------------- | -------------------------------- |
| ⬆ 1 | Project-Local Overrides | `.specify/templates/overrides/` |
| 2 | Presets — Customize core & extensions | `.specify/presets/templates/` |
| 3 | Extensions — Add new capabilities | `.specify/extensions/templates/` |
| ⬇ 4 | Spec Kit Core — Built-in SDD commands & templates | `.specify/templates/` |
- **Templates** are resolved at **runtime** — Spec Kit walks the stack top-down and uses the first match.
- Project-local overrides (`.specify/templates/overrides/`) let you make one-off adjustments for a single project without creating a full preset.
- **Extension/preset commands** are applied at **install time** — when you run `specify extension add` or `specify preset add`, command files are written into agent directories (e.g., `.claude/commands/`).
- If multiple presets or extensions provide the same command, the highest-priority version wins. On removal, the next-highest-priority version is restored automatically.
- If no overrides or customizations exist, Spec Kit uses its core defaults.
### Extensions — Add New Capabilities
Use **extensions** when you need functionality that goes beyond Spec Kit's core. Extensions introduce new commands and templates — for example, adding domain-specific workflows that are not covered by the built-in SDD commands, integrating with external tools, or adding entirely new development phases. They expand *what Spec Kit can do*.
```bash
# Search available extensions
specify extension search
# Install an extension
specify extension add
```
For example, extensions could add Jira integration, post-implementation code review, V-Model test traceability, or project health diagnostics.
See the [Extensions reference](https://github.github.io/spec-kit/reference/extensions.html) for the full command guide. Browse the [community extensions](https://github.github.io/spec-kit/community/extensions.html) for what's available.
### Presets — Customize Existing Workflows
Use **presets** when you want to change *how* Spec Kit works without adding new capabilities. Presets override the templates and commands that ship with the core *and* with installed extensions — for example, enforcing a compliance-oriented spec format, using domain-specific terminology, or applying organizational standards to plans and tasks. They customize the artifacts and instructions that Spec Kit and its extensions produce.
```bash
# Search available presets
specify preset search
# Install a preset
specify preset add
```
For example, presets could restructure spec templates to require regulatory traceability, adapt the workflow to fit the methodology you use (e.g., Agile, Kanban, Waterfall, jobs-to-be-done, or domain-driven design), add mandatory security review gates to plans, enforce test-first task ordering, or localize the entire workflow to a different language. The [pirate-speak demo](https://github.com/mnriem/spec-kit-pirate-speak-preset-demo) shows just how deep the customization can go. Multiple presets can be stacked with priority ordering.
See the [Presets reference](https://github.github.io/spec-kit/reference/presets.html) for the full command guide, including resolution order and priority stacking.
## 📦 Bundles: Role-Based Setups
Extensions and presets are individual building blocks. A **bundle** packages a
curated set of them — extensions, presets, steps, and workflows — into a single,
versioned, role-oriented setup so a whole team persona (product manager, business
analyst, security researcher, developer, …) can be provisioned with one command.
A bundle is described by a hand-written `bundle.yml` manifest. It pins each
component to a version and, optionally, targets a specific integration; a bundle
with no `integration` is **agnostic** and inherits whatever integration the
project already uses.
```bash
# Discover bundles in the active catalog stack
specify bundle search []
# Inspect the exact component set a bundle will add (equals what install does)
specify bundle info
# Install a bundle's full component set in one operation
specify bundle install
# See what's installed, then update or remove non-destructively
specify bundle list
specify bundle update # or --all
specify bundle remove # removes only this bundle's components
```
Bundles resolve from a **priority-ordered catalog stack** (project > user >
built-in). Each source carries an install policy: `install-allowed` sources can
be installed from, while `discovery-only` sources are visible in `search`/`info`
but refuse installation. Manage the stack with `specify bundle catalog list|add|remove`.
Authors validate and package bundles locally. Distribution is hosting the built
artifact and adding a catalog source; community bundle submissions use the
[Bundle Submission](https://github.com/github/spec-kit/issues/new?template=bundle_submission.yml)
issue template so required component catalogs and install evidence can be reviewed:
```bash
specify bundle validate --path ./my-bundle # structural + reference checks
specify bundle build --path ./my-bundle # produce a versioned .zip artifact
```
Four ready-to-read example manifests live under
[`examples/bundles/`](examples/bundles/) (product manager, business analyst,
security researcher, developer).
Key guarantees: `info` shows exactly what `install` adds (transparency);
installs are idempotent and confined to the project root; `remove` never touches
components another installed bundle still needs; and all consume/author commands
work **offline** against local or pinned sources.
### When to Use Which
| Goal | Use |
| --- | --- |
| Add a brand-new command or workflow | Extension |
| Customize the format of specs, plans, or tasks | Preset |
| Integrate an external tool or service | Extension |
| Enforce organizational or regulatory standards | Preset |
| Ship reusable domain-specific templates | Either — presets for template overrides, extensions for templates bundled with new commands |
| Provision a complete role-based setup in one command | Bundle |
## 📚 Core Philosophy
Spec-Driven Development is a structured process that emphasizes:
- **Intent-driven development** where specifications define the "*what*" before the "*how*"
- **Rich specification creation** using guardrails and organizational principles
- **Multi-step refinement** rather than one-shot code generation from prompts
- **Heavy reliance** on advanced AI model capabilities for specification interpretation
## 🌟 Development Phases
| Phase | Focus | Key Activities |
| ---------------------------------------- | ------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| **0-to-1 Development** ("Greenfield") | Generate from scratch | - Start with high-level requirements
- Generate specifications
- Plan implementation steps
- Build production-ready applications
|
| **Creative Exploration** | Parallel implementations | - Explore diverse solutions
- Support multiple technology stacks & architectures
- Experiment with UX patterns
|
| **Iterative Enhancement** ("Brownfield") | Brownfield modernization | - Add features iteratively
- Modernize legacy systems
- Adapt processes
|
For existing projects, keep Spec Kit tooling updates separate from feature
artifact evolution: refresh managed project files when upgrading, and update
`specs/` artifacts when intended behavior changes. The
[Evolving Specs guide](./docs/guides/evolving-specs.md) describes the
recommended brownfield loop.
## 🎯 Experimental Goals
Our research and experimentation focus on:
### Technology independence
- Create applications using diverse technology stacks
- Validate the hypothesis that Spec-Driven Development is a process not tied to specific technologies, programming languages, or frameworks
### Enterprise constraints
- Demonstrate mission-critical application development
- Incorporate organizational constraints (cloud providers, tech stacks, engineering practices)
- Support enterprise design systems and compliance requirements
### User-centric development
- Build applications for different user cohorts and preferences
- Support various development approaches (from vibe-coding to AI-native development)
### Creative & iterative processes
- Validate the concept of parallel implementation exploration
- Provide robust iterative feature development workflows
- Extend processes to handle upgrades and modernization tasks
## 🔧 Prerequisites
- **Linux/macOS/Windows**
- [Supported](#-supported-ai-coding-agent-integrations) AI coding agent.
- [uv](https://docs.astral.sh/uv/) for package management (recommended) or [pipx](https://pipx.pypa.io/) for persistent installation
- [Python 3.11+](https://www.python.org/downloads/)
- [Git](https://git-scm.com/downloads)
If you encounter issues with an agent, please open an issue so we can refine the integration.
## 📖 Learn More
- **[Complete Spec-Driven Development Methodology](./spec-driven.md)** - Deep dive into the full process
- **[Quick Start Guide](https://github.github.io/spec-kit/quickstart.html)** - Step-by-step implementation walkthrough
---
## 💬 Support
For support, please open a [GitHub issue](https://github.com/github/spec-kit/issues/new). We welcome bug reports, feature requests, and questions about using Spec-Driven Development.
## 🙏 Acknowledgements
This project is heavily influenced by and based on the work and research of [John Lam](https://github.com/jflam).
## 📄 License
This project is licensed under the terms of the MIT open source license. Please refer to the [LICENSE](./LICENSE) file for the full terms.