Specdd

specdd — Spec-Driven Development

What this skill does

User requests for features are incomplete by design — the user gives you the top-of-mind 30%, not the full spec. Coding from that ships things that compile but miss the actual intent, skip the boring-but-critical states (loading, empty, error, edge), and feel unpolished.

specdd inverts that: you produce a spec the user agrees with before writing code. The spec captures intent, the user, the UX, edge cases, and non-functional requirements. The user keeps creative control; you stop guessing.

Not waterfall. The spec is small, agent-readable, revisable. Goal is alignment, not bureaucracy.

When to use

Use it for any feature, screen, flow, component, API, change, or capability — even a one-line request.

Skip for: one-liners (rename, typo), pure Q&A or research, bugs with clear repro, or continuing in-progress work that already has a spec.

If unsure, use it. Under-use is the more common mistake.

Scale ceremony to scope

Scope	Signal	Artifacts
Quick	Single component, <30 min, no new surface area	Inline mini-spec (5–8 bullets) in chat. No files.
Feature	New UI / flow, 1–4 hours	spec.md + plan.md inline or as files. Skip tasks.
Project	Multi-day, multiple files/services	spec.md + plan.md + tasks.md as files in specs/<feature-name>/.

User can override: "just a quick one" or "do this properly".

The workflow

1. TRIAGE     →  scope, scale, skip-or-not
2. INTERVIEW  →  fill gaps the user didn't think to mention
3. SPEC       →  what & why (user-facing, no tech)
4. PLAN       →  how (tech approach, files, decisions)
5. TASKS      →  ordered, testable work units (Project scope only)
6. BUILD & VERIFY → implement against spec; run production-grade checklist before "done"

You don't ask permission to follow this workflow — it's the default. You DO surface the spec and plan for confirmation before building.

Phase 1 — Triage

1. Skip check: one-liner, question, research? → abandon skill.
2. Scope: Quick / Feature / Project.
3. Existing spec? Read specs/ first if it exists.
4. Surface: chat-only or filesystem-capable? Affects whether spec lives in chat or in a file.

State triage briefly: "Treating this as a Feature — drafting a spec, then we'll build."

Phase 2 — Interview

Heart of the skill. Ask the few right questions to fill gaps — not a 20-question form.

Rules:

• 3–5 questions per round max. Prefer 1–2.
• Use tappable options when available — much easier than typing.
• Don't ask what you can reasonably infer or read from the codebase.
• State assumptions inline: "Assuming X — flag if wrong."
• For Quick scope, skip the interview; just state assumptions.

Cover the gaps the user didn't already address, in priority order:

1. WHO — user, technical level, device/context
2. WHAT — core story ("As a X, I want Y, so that Z")
3. WHY — the underlying problem (often reveals a better solution)
4. DONE — acceptance criteria, smallest version that ships
5. EDGE — empty / error / loading / offline / unauthorized / slow-network
6. OUT — what is explicitly NOT in scope
7. NON-FUNCTIONAL — perf, a11y, security/privacy, observability, i18n

See references/interview-playbook.md for question templates by request type.

Phase 3 — Spec

Use references/spec-template.md. The spec is user-facing and tech-free — no frameworks, libraries, file names, or function names. If you're writing useState or POST /api/, you're in the Plan.

Show spec to user. Wait for explicit "looks good" / "ship it". Revisions are normal — expect 1–3 rounds for non-trivial features.

Phase 4 — Plan

Use references/plan-template.md. Covers stack choices, file-level breakdown, key decisions with one-line rationale, alternatives considered, risks. Under 2 minutes to read. If longer, split the feature.

Phase 5 — Tasks (Project scope only)

Use references/tasks-template.md. Each task: independently completable in one agent turn, has an observable "done" signal, has explicit dependencies.

For Quick or Feature scope, the agent's todo list is enough — skip the file.

Phase 6 — Build & verify

Implement against the spec. While building:

• If the spec is wrong or incomplete, stop and revise the spec, don't silently deviate.
• Don't add scope the spec didn't ask for. ("I also added X" is a smell.)

Before declaring done, run the checklist in references/production-checklist.md — empty/error/loading states, a11y, keyboard, mobile, edge inputs, observability. Report what you verified and what you didn't: "Verified items 1–15, skipped i18n (single-locale), didn't test screen-reader behavior end-to-end."

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Common-sense gates

Push back before building, not after. UX defaults this skill assumes:

• Names a solution, not a problem. Ask what they're trying to do. ("Add a modal" may mean "let users edit X without losing context".)
• Custom version of a solved problem. Surface the standard pattern. ("Custom date picker? Native handles a11y, locales, keyboard for free.")
• Scope creep in one sentence. If a single sentence implies three features, name them; ask which is the MVP.
• Conflicting requirements. "Fast AND comprehensive AND simple" — surface the trade-off, let the user pick.
• Destructive actions without safeguards. Delete / overwrite / bulk-edit / send need confirmation patterns. Don't ship without one.
• Auth/permission gaps. If a feature touches user data, ask who can see/edit/delete it.

Five-states rule. Every screen / component / feature has these. If the spec doesn't address all five, it's incomplete:

1. Loading — what shows while data fetches
2. Empty — what shows with no data (the first thing new users see — must have a primary action)
3. Error — what shows on failure (with a recovery path; "Something went wrong" alone is not acceptable)
4. Partial — what shows when some-but-not-all data arrived
5. Ideal — the loaded / happy state everyone draws first

Other defaults baked in. State them when relevant; the user can override:

• Feedback within 100ms of any action; skeleton (not spinner) for loads >300ms
• Optimistic updates with rollback (defer optimism for server-assigned IDs)
• Confirmation scales with destruction: undo toast → modal → type-the-name
• Errors are actionable (what happened, why if knowable, what to do now)
• Keyboard reachable; visible focus; Esc closes; Enter submits
• Mobile usable at 360px; touch targets ≥44×44px
• Forms validate on blur, errors inline at the field, submit shows progress
• Respect prefers-reduced-motion; animations short (150–250ms) and ease-out

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Anti-patterns

• Spec theatre. Producing a long spec to look thorough. Specs scale with scope.
• Firehose interview. A 12-question form makes users bounce. Ask 2–3, infer the rest, surface assumptions.
• Pre-coding the spec. "Use React Query with optimistic updates" is plan, not spec.
• Silent drift. When implementation reveals a flaw, update the spec — don't quietly diverge.
• Skipping verify. The difference between "done" and "delightful" is the checklist.

Worked examples

• references/examples/example-quick-feature.md — Quick scope, inline only
• references/examples/example-feature-spec.md — Feature scope with spec + plan
• references/examples/example-project.md — Project scope with files

Read the relevant example if unsure what the output should look like at a given scope.