Spec-Driven Development as a single Agent Skill. Drop it in, type naturally, ship features that don't embarrass you in two weeks.

specdd turns vague, top-of-mind feature requests into production-grade specs before code is written — without a CLI, without four config files, without ceremony you don't need. One skill, any modern AI coding agent: Claude (Code, Desktop, Web), Codex, Copilot, Cursor, Windsurf, Gemini CLI, anything else that reads SKILL.md or AGENTS.md-style instructions.

You: "build me a settings page where users can change their email"

specdd:
  → triages the scope (Feature)
  → asks the 2-3 questions you didn't think to address (verification email?
    active sessions? what's the success state?)
  → produces a tech-free spec + a 2-minute technical plan
  → only after you say "ship it" → writes code
  → runs the production-grade checklist before declaring done

No npx, no uv tool install, no specify init. Just a folder.

Why specdd exists

Two patterns broke the same way:

Vibe-coding — describe a feature in one line, get code that compiles and looks right but misses the empty state, the error state, the keyboard handling, the "what happens when the user double-clicks the button" — discovered in production.

Heavy spec frameworks like github/spec-kit — fix the rigor problem but introduce a CLI, four mandatory artifacts, and ceremony that's overkill for solo and one-off work.

specdd splits the difference. Spec-driven development that scales down to a 15-minute task and scales up to a multi-day project — same workflow, different ceremony.

What you get

• One opinionated workflow — triage → interview → spec → plan → (tasks) → build & verify
• Question-asking by default — interviews you for the gaps your one-liner left, instead of guessing
• Tech-free specs — what & why for the user, separated from how for the agent
• Production-grade checklist before "done" — empty/error/loading states, a11y, keyboard, mobile, observability
• UX defaults baked in — five-states rule, confirmation patterns, optimistic updates, accessible focus management
• Scales to scope — Quick (5-line inline mini-spec), Feature (spec + plan inline), Project (spec + plan + tasks as files)
• Surface-agnostic — same skill in Claude Code, Claude.ai, Codex CLI, Cursor, Copilot, Windsurf

Install

Claude Code (recommended)

/plugin marketplace add unboundinnov/specdd
/plugin install specdd@specdd

That's it. The skill activates automatically when you ask for any feature work.

Claude Code (manual, no plugin system)

git clone --depth=1 https://github.com/unboundinnov/specdd /tmp/specdd-src
cp -r /tmp/specdd-src/plugins/specdd/skills/specdd ~/.claude/skills/
rm -rf /tmp/specdd-src

Or scope to a single project: copy into .claude/skills/ inside the project instead.

Claude.ai (Pro / Team / Enterprise / Max)

1. Download specdd.zip from Releases (or zip plugins/specdd/skills/specdd/).
2. Claude.ai → Settings → Capabilities → Skills → Upload skill.
3. Upload the zip.

Codex CLI

mkdir -p ~/.codex/skills
git clone --depth=1 https://github.com/unboundinnov/specdd /tmp/specdd-src
cp -r /tmp/specdd-src/plugins/specdd/skills/specdd ~/.codex/skills/
rm -rf /tmp/specdd-src

Cursor / Copilot / Windsurf / Aider / others

These agents don't natively load SKILL.md yet. Copy the content of SKILL.md into the agent's instructions file:

• Cursor: .cursor/rules/specdd.mdc (or legacy .cursorrules)
• GitHub Copilot: .github/copilot-instructions.md
• Windsurf: .windsurfrules
• Aider: CONVENTIONS.md referenced from .aider.conf.yml

Reference files in references/ can be copied alongside or inlined.

How it works

SKILL.md is the entry point; templates, checklists, and examples are in references/.

specdd vs spec-kit

What specdd inherits from SDD literature (and spec-kit): the spec → plan → tasks workflow shape, the spec.md / plan.md / tasks.md filenames, the "tech-free spec" framing. These are general SDD concepts (Spec Driven Development pre-dates spec-kit), and keeping the filenames means specs migrate cleanly if you ever adopt spec-kit later.

What's specdd's own: the triage step (scale to scope), the interview phase with tappable options, the build & verify phase with the production-grade checklist, UX-first opinionation with the five-states rule, the common-sense gates. No CLI, no slash commands, no constitution.

Examples

See references/examples/:

• example-quick-feature.md — Quick scope (~15 min of work)
• example-feature-spec.md — Feature scope (~3 hours of work)
• example-project.md — Project scope (multi-day)

Contributing

Issues and PRs welcome. Particularly interested in:

• Request-type interview playbooks (the more specific, the better)
• Surface-specific install instructions for new agents
• Worked examples from real projects

Open an issue first for substantial changes; keep PRs focused; match the existing tone.

License

MIT. See LICENSE.

Credits

Inspired by, and respectfully different from, github/spec-kit, BMAD, and Kiro. Built on the Agent Skills format by Anthropic.

If specdd helps you ship better, a ⭐ helps people find it.