An open source toolkit for building high-quality software with any AI coding agent — a ready-to-use spec-driven process (or bring your own), endlessly extensible, community-driven, and built for your whole organization.
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Note
One year of Spec Kit — and 1.0.0
One year after the first commit, Spec Kit has reached 1.0.0 — not because the work is finished or its shape is frozen, but because the project has grown into something coherent, useful, and shaped by far more people than those who started it.
The lead maintainer's personal anniversary post, Spec Kit Turns One — and Ships 1.0.0, defines what 1.0.0 actually means for the project: it is now just a number. As agents make adapting to change dramatically cheaper, the value moves from stability to adaptability.
To everyone who has used Spec Kit, challenged its assumptions, reported a problem, contributed code or documentation, created an extension or preset, shared an idea, or helped someone else get started: thank you. This milestone belongs to the community that carried the project through its first year and continues to shape where it goes next.
- 🤔 What is Spec-Driven Development?
- 🐞 Bug Fixing with Spec Kit
- 💡 Assessing Ideas with Spec Kit
- ⚡ Get Started
- 📽️ Video Overview
- 🌍 Community
- 🤖 Supported AI Coding Agent Integrations
- 🔧 Specify CLI Reference
- 🧩 Making Spec Kit Your Own: Extensions & Presets
- 📦 Bundles: Role-Based Setups
- 📚 Core Philosophy
- 🌟 Development Phases
- 🎯 Experimental Goals
- 🔧 Prerequisites
- 📖 Learn More
- 💬 Support
- 🙏 Acknowledgements
- 📄 License
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.
Replace vX.Y.Z with the latest release tag, keeping the leading v.
uv tool install specify-cli --from git+https://github.com/github/spec-kit.git@vX.Y.Z
specify init my-project --integration copilot
cd my-projectLaunch your coding agent in the project directory, then:
- Establish your project principles once (
/speckit-constitution). This is a one-time step per project. - Specify what you want to build (
/speckit-specify). - Plan how you will build it (
/speckit-plan). - Break down the plan into actionable tasks (
/speckit-tasks). - Implement the tasks (
/speckit-implement). - Converge the implementation against the spec, plan, and tasks (
/speckit-converge).
Note
Repeat steps 4 and 5 until /speckit-converge reports Converged.
Bug fixes are risky when an agent jumps straight from a report to a patch without validating the diagnosis or confirming that the fix resolves the original symptom. The bundled, opt-in bug extension provides a repeatable assess → fix → test workflow that keeps each fix scoped, evidence-based, and documented from root cause through verification.
Replace vX.Y.Z with the latest release tag, keeping the leading v.
uv tool install specify-cli --from git+https://github.com/github/spec-kit.git@vX.Y.Z
specify init my-project --integration copilot
cd my-project
specify extension add bugLaunch your coding agent in the project directory, then:
- Assess the bug (
/speckit-bug-assess "<bug report>" slug=login-crash). - Fix the assessed cause (
/speckit-bug-fix slug=login-crash). - Test the fix (
/speckit-bug-test slug=login-crash).
Good ideas deserve evidence before commitment, whether or not they become software. The bundled, opt-in assess extension turns a raw idea into a documented go / needs-clarification / kill decision through an independent intake → research → define → shape → decide workflow.
Replace vX.Y.Z with the latest release tag, keeping the leading v.
uv tool install specify-cli --from git+https://github.com/github/spec-kit.git@vX.Y.Z
specify init my-project --integration copilot
cd my-project
specify extension add assessLaunch your coding agent in the project directory, then:
- Intake the idea (
/speckit-assess-intake "<idea>" slug=offline-mode). - Research supporting and opposing evidence (
/speckit-assess-research slug=offline-mode). - Define the problem, goals, and success metrics (
/speckit-assess-define slug=offline-mode). - Shape possible solutions and their trade-offs (
/speckit-assess-shape slug=offline-mode). - Decide whether to proceed, clarify, or stop (
/speckit-assess-decide slug=offline-mode).
Note
Idea assessment is standalone. If you choose to build an idea with a go decision, you can hand it off to /speckit-specify.
Requires uv (install uv). Replace vX.Y.Z with the latest release tag from Releases — keep the leading v (for example, v0.12.11, not 0.12.11):
uv tool install specify-cli --from git+https://github.com/github/spec-kit.git@vX.Y.ZPrefer installing from PyPI? The specify-cli package is also published there:
uv tool install specify-cliSee the Installation Guide for alternative methods, verification, upgrade, and troubleshooting.
specify init my-project --integration copilot
cd my-projectFor CI or AI agent harnesses (no keyboard, or a PTY that cannot send arrow keys), pass --non-interactive so init never hangs on a picker. Combine with --force when initializing into a non-empty directory:
specify init my-project --non-interactive --ignore-agent-tools
specify init --here --force --non-interactive --integration claudeTo check for updates or upgrade the installed CLI, use the self-management commands. See the Upgrade Guide for detailed scenarios and customization options.
# 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 <git ref> 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).
Launch your coding agent in the project directory. Most agents expose spec-kit as /speckit.* slash commands; Codex CLI and Command Code in skills mode use $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.
/speckit.constitution Create principles focused on code quality, testing standards, user experience consistency, and performance requirementsUse the /speckit.specify command to describe what you want to build. Focus on the what and why, not the tech stack.
/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.Use the /speckit.plan command to provide your tech stack and architecture choices.
/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.Use /speckit.tasks to create an actionable task list from your implementation plan.
/speckit.tasksUse /speckit.implement to execute all tasks and build your feature according to the plan.
/speckit.implementFor detailed step-by-step instructions, see our comprehensive guide.
Want to see Spec Kit in action? Watch our video overview!
Explore community-contributed resources on the Spec Kit docs site:
- Extensions — commands, hooks, and capabilities
- Presets — template and terminology overrides
- Bundles — role and team stacks composed from existing components
- Walkthroughs — end-to-end SDD scenarios
- Friends — 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, the Presets Publishing Guide, or the Community Bundles guide.
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 guide.
Run specify integration list to see all available integrations in your installed version.
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 <agent> --integration-options="--skills" installs agent skills instead of slash-command prompt files.
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 |
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") |
For full command details, options, and examples, see the CLI Reference.
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 addorspecify 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.
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.
# Search available extensions
specify extension search
# Install an extension
specify extension add <extension-name>For example, extensions could add Jira integration, post-implementation code review, V-Model test traceability, or project health diagnostics.
See the Extensions reference for the full command guide. Browse the community extensions for what's available.
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.
# Search available presets
specify preset search
# Install a preset
specify preset add <preset-name>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 shows just how deep the customization can go. Multiple presets can be stacked with priority ordering.
See the Presets reference for the full command guide, including resolution order and priority stacking.
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.
# Discover bundles in the active catalog stack
specify bundle search [<query>]
# Inspect the exact component set a bundle will add (equals what install does)
specify bundle info <bundle-id>
# Install a bundle's full component set in one operation
specify bundle install <bundle-id>
# See what's installed, then update or remove non-destructively
specify bundle list
specify bundle update <bundle-id> # or --all
specify bundle remove <bundle-id> # removes only this bundle's componentsBundles 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 issue template so required component catalogs and install evidence can be reviewed:
specify bundle validate --path ./my-bundle # structural + reference checks
specify bundle build --path ./my-bundle # produce a versioned .zip artifactFour ready-to-read example bundle manifests live under
examples/bundles/ (product manager, business analyst,
security researcher, developer). These are bundle packaging examples, not
filled generated feature specs; for end-to-end community examples, see the
community walkthroughs.
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.
| 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 |
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
| Phase | Focus | Key Activities |
|---|---|---|
| 0-to-1 Development ("Greenfield") | Generate from scratch |
|
| Creative Exploration | Parallel implementations |
|
| Iterative Enhancement ("Brownfield") | Brownfield modernization |
|
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 describes the
recommended brownfield loop.
Our research and experimentation focus on:
- 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
- Demonstrate mission-critical application development
- Incorporate organizational constraints (cloud providers, tech stacks, engineering practices)
- Support enterprise design systems and compliance requirements
- Build applications for different user cohorts and preferences
- Support various development approaches (from vibe-coding to AI-native development)
- Validate the concept of parallel implementation exploration
- Provide robust iterative feature development workflows
- Extend processes to handle upgrades and modernization tasks
- Linux/macOS/Windows
- Supported AI coding agent.
- uv for package management (recommended) or pipx for persistent installation
- Python 3.11+
- Git
If you encounter issues with an agent, please open an issue so we can refine the integration.
- Complete Spec-Driven Development Methodology - Deep dive into the full process
- Quick Start Guide - Step-by-step implementation walkthrough
For support, please open a GitHub issue. We welcome bug reports, feature requests, and questions about using Spec-Driven Development.
This project is heavily influenced by and based on the work and research of John Lam.
This project is licensed under the terms of the MIT open source license. Please refer to the LICENSE file for the full terms.