Spec Kit is an open source toolkit that gives AI coding agents structured processes, reusable templates, and documented outcomes. Start with one of the three processes below, customize it, or bring your own.
| 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 |
These are independent entry points, not three mandatory phases. SDD ships in core; bug fixing and assessment are bundled extensions you install when needed.
You need Python 3.11+, uv, and a supported AI coding agent on Linux, macOS, or Windows. For CLI setup only, run this in your terminal to install Spec Kit and create a project:
uv tool install specify-cli
specify init my-project --integration copilot
cd my-projectThe examples use GitHub Copilot's default skills mode. Replace copilot with
your integration key
to use another supported agent.
Already have code? Follow the existing-project guide. For pinned releases, other installers, CI, or troubleshooting, see Installation. To update an existing installation, see Upgrade.
Now launch your coding agent in the project directory and choose a process
below. Invoke each /speckit-* skill in your agent's chat, one at a time,
and review the result before continuing. These are agent skills, not terminal
commands. Other agents and modes may use
different invocation syntax.
Define what and why before deciding how to build it. SDD turns your requirements into a specification, a technical plan, and actionable tasks, then guides implementation against those artifacts.
Constitution once per project; specify → plan → tasks → implement → converge per feature.
Invoke these skills in your agent's chat:
/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 → converge until convergence reports Converged. Add clarification, checklists, and consistency analysis when you need extra quality gates.
SDD walkthrough · Command reference
Keep diagnosis, repair, and verification separate so the agent fixes the assessed cause and checks the original symptom. No SDD feature workflow is required first.
CLI setup (terminal): install the opt-in extension from the project directory:
specify extension add bugThen invoke the assess → fix → test skills in your agent's chat:
/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
The reports live in .specify/bugs/login-crash/. Review the final verdict:
verified, partial, or failed. Missing verification is not a successful fix.
Bug-fixing walkthrough · Command reference
Gather evidence before committing to an idea, whether or not it becomes software. This standalone process works even in a project with no source code.
CLI setup (terminal): install the opt-in extension from the project directory:
specify extension add assessThen invoke the intake → research → define → shape → decide skills in your agent's chat:
/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
The artifacts live in .specify/assessments/offline-mode/, ending in a
go / needs-clarification / kill decision. Resolve unknowns by refining the
existing Markdown artifacts directly or with the agent, rather than regenerating
whole stages. A go decision can be handed to /speckit-specify if you choose
to build it; stopping with a documented reason is also a useful result.
Assessment walkthrough · Command reference
Extensions add capabilities, presets adapt existing behavior, workflows automate steps, and bundles package a role-based setup. Use project-local overrides for one-off template changes.
Customization guide · Community extensions, presets, bundles, and walkthroughs
- CLI reference and process commands
- SDD philosophy, full methodology, and evolving existing specs
- Video overview and project history
- How Spec Kit uses Spec Kit
Thanks to everyone who helps Spec Kit shine.
Report a bug or request a feature · Contributing guide · Code of conduct
Spec Kit is MIT licensed.