🌱 Spec Kit

Build with a spec, fix a bug, or assess an idea — with your coding agent.

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Spec Kit is an open source toolkit that gives AI coding agents structured processes, reusable templates, and documented outcomes. Start with a ready-made process, customize it, or bring your own.

Choose your process

What you need	Process	Outcome
Build a feature or application	Spec-Driven Development	A specification carried through planning, implementation, and convergence
Diagnose and repair broken behavior	Bug fixing	An assessed cause, scoped fix, and recorded verification
Decide whether an idea deserves investment	Idea assessment	An evidence-backed go, clarify, or stop decision
Adopt or create a different process	Your own process	A process adapted or assembled from reusable primitives

These are independent entry points, not mandatory phases. SDD ships in core; bug fixing and assessment are bundled extensions you install when needed, and the primitives below let you adopt or create other processes.

Capabilities

Spec Kit combines ready-to-use processes with composable mechanisms:

Capability	Spec Kit mechanism
Connect to or switch between coding agents	Integration
Add a command, quality gate, or complete process	Extension
Connect a process to an external tool or service	Extension
React to coding-agent lifecycle events	Extension runtime event
Run extension commands before or after Spec Kit commands	Extension hook
Adapt templates, commands, terminology, or methodology	Preset
Enforce organizational or regulatory standards	Preset
Override a template for one project	Project-local override
Automate prompts, commands, gates, and shell tasks	Workflow
Modify an installed workflow without forking it	Workflow overlay
Add reusable executable behavior to workflows	Workflow step
Install a curated setup for a role or team	Bundle
Discover community components	Catalog
Host a private catalog of approved components	Catalog
Access private catalogs and component downloads	Authentication
Work offline or behind a firewall	Local sources and self-hosted catalogs
Inspect which layer supplies a command, template, or script	Artifact inventory

Search the active catalogs with commands such as specify extension search, specify preset search, specify workflow search, and specify bundle search. Spec Kit includes community catalogs, and organizations can add their own curated sources. Catalog listings are not audits or endorsements, so review community source code before installing or running it.

Get started

You need Python 3.11+, uv, and a supported AI coding agent on Linux, macOS, or Windows.

Run these commands in your terminal to install Spec Kit and create a project. This example uses GitHub Copilot.

uv tool install specify-cli
specify init my-project --integration copilot
cd my-project

After installing the Specify CLI and creating your project, launch your coding agent in the project directory, then choose a process below.

For other setups:

• Installation for pinned releases, other installers, CI, and troubleshooting.
• Existing projects to start with code you already have.
• Other agents for integration keys and invocation syntax.
• Upgrade to update an existing installation.

Spec-Driven Development

Define what to build and why, then turn the specification into a plan, tasks, and working code.

The minimal flow is shown below. Create a constitution once per project and repeat the remaining steps for each feature. Run these skills in your agent's chat, not your terminal, one at a time, reviewing each result before continuing.

This example uses GitHub Copilot's default skills syntax. For another agent, use its equivalent invocation syntax.

/speckit-constitution Create principles focused on code quality, testing, and maintainability.
/speckit-specify Build a photo organizer with albums grouped by date and a tile preview of each album.
/speckit-plan Use Vite with vanilla JavaScript. Keep images local and store metadata in SQLite.
/speckit-tasks
/speckit-implement
/speckit-converge

Repeat implement and converge until convergence reports Converged. For clarification, checklists, and consistency analysis, see the SDD walkthrough.

SDD walkthrough · Command reference

Bug fixing

Assess the cause, fix the bug, and verify the original symptom is resolved. No SDD feature workflow is required first.

Install the bug-fixing extension in your terminal, from the project directory:

specify extension add bug

Run these skills in your agent's chat, not your terminal, one at a time, reviewing each result before continuing.

This example uses GitHub Copilot's default skills syntax. For another agent, use its equivalent invocation syntax.

/speckit-bug-assess "Submitting an empty password crashes the login form." slug=login-crash
/speckit-bug-fix slug=login-crash
/speckit-bug-test slug=login-crash

Review the reports in .specify/bugs/login-crash/. The final verdict is verified, partial, or failed; only verified confirms a successful fix.

Bug-fixing walkthrough · Command reference

Idea assessment

Gather evidence to decide whether an idea is worth pursuing. No source code or SDD feature workflow is required.

Install the assessment extension in your terminal, from the project directory:

specify extension add assess

Run these skills in your agent's chat, not your terminal, one at a time, reviewing each result before continuing.

This example uses GitHub Copilot's default skills syntax. For another agent, use its equivalent invocation syntax.

/speckit-assess-intake "Let users work offline and sync when they reconnect." slug=offline-mode
/speckit-assess-research slug=offline-mode
/speckit-assess-define slug=offline-mode
/speckit-assess-shape slug=offline-mode
/speckit-assess-decide slug=offline-mode

Review the artifacts in .specify/assessments/offline-mode/ and the final decision: go, needs-clarification, or kill. Resolve unknowns by editing the existing Markdown artifacts, directly or with your agent, rather than rerunning whole stages. If you choose to build a software idea with a go decision, establish a project constitution if needed, then pass the handoff summary from decision.md to /speckit-specify. Stopping with a documented reason is also a useful outcome.

Assessment walkthrough · Command reference

Customize or bring your own process

Customize Spec-Driven Development, bug fixing, or idea assessment to fit your team's standards. Or bring your own process without adopting any of them. Combine the capabilities above to match your goal:

• Adapt an existing process with a preset, such as requiring regulatory traceability in plans. Use a project-local override for a one-off template change.
• Bring your own process by adding its commands through an extension and exposing them to your coding agent through an integration.
• Automate commands and checks in a workflow. Use overlays to adapt an installed workflow without forking it, or add custom workflow steps when the built-in types are not enough.
• Share a reusable setup by packaging its extensions, presets, workflows, and workflow steps in a bundle.

Start with the smallest change that meets your needs; you do not have to replace the whole process.

Customization guide · Community components and walkthroughs

Documentation

• CLI reference and process commands
• SDD philosophy, full methodology, and evolving existing specs
• Project history
• How Spec Kit uses Spec Kit

In the news

• Open Source Friday: Spec Kit Part 2 (October 16, 2026) — Manfred Riem and Nicole Haugen discuss Spec Kit 1.0 and the expanded toolkit.
• Open Source Friday with Spec Kit (May 8, 2026) — An introduction and SDD demonstration with Manfred Riem.

Star history

Thanks to everyone who helps Spec Kit shine.

Support and contributing

Report a bug or request a feature · Contributing guide · Code of conduct

Spec Kit is MIT licensed.