Frequently asked questions
The questions every team asks before adopting spec-driven development — answered plainly.
How is spec-driven development different from agile?
Agile governs how work is scheduled and delivered — sprints, standups, retros. Spec-driven development governs how work is defined before it is built. They compose well: a spec can serve as the definition of done for a sprint's worth of stories, and the review gate fits naturally into sprint review.
Is a spec just a design doc by another name?
Not quite. A design doc describes how something will be built. A spec describes what must be built and how success will be verified — and it directly drives the plan and the task breakdown. In the spec lifecycle, the design lives inside the plan stage (S2), derived from the spec rather than preceding it.
How long does writing a spec take?
A feature spec typically takes a few hours to a day to draft, plus one review cycle to approve. That investment is recovered many times over in avoided rework — catching a misunderstood requirement at spec review costs minutes; catching it in QA costs days. See the methodology for the full rationale.
Do small changes need specs too?
No. Spec-driven development is deliberate overhead, and for trivial changes the spec would exceed the work itself. Use judgment: the bugfix template covers the middle ground — a lightweight spec for changes where the diagnosis and the regression risk matter.
How do specs work with AI coding agents?
AI agents are excellent implementers of precise contracts and poor guessers of intent. A spec converts fuzzy requirements into a machine-checkable build contract — exactly the input agents perform best on. The practical rule: hand the agent the spec, not a prompt.
What happens when the spec turns out to be wrong mid-build?
Work stops. The spec is amended through its revision block, the plan is re-checked against the change, and building resumes. The document always leads — it is updated deliberately, never silently outrun.
Who owns a spec?
Every spec has exactly one owner, named in its revision block. Anyone can propose changes; the owner approves them. Unowned specs rot — open questions linger and revisions go unrecorded.
Is Anthropic Spec Kit affiliated with Anthropic?
No. This is an independent project focused on specification craft in the age of AI-assisted development. It is not affiliated with, sponsored by, or endorsed by Anthropic.