spec-driven-development

An agent skill by addyosmani, from addyosmani/agent-skills. Tags: design, developer-tools, documents.

What it does

Creates specs before coding. Use when starting a new project, feature, or significant change and no specification exists yet. Use when drafting a PRD or requirements document with objectives and scope, or when requirements are unclear, ambiguous, or only exist as a vague idea. Use when a single requirement spans several independently testable capabilities and needs decomposing into a capability map of modules before specifying.

Install

With the skills CLI, which installs into Claude Code, Codex, Cursor and other agents:

npx skills add addyosmani/agent-skills --skill spec-driven-development

Or copy the skill folder into Claude Code's skills directory by hand (~/.claude/skills for every project, or .claude/skills inside one):

git clone --depth 1 https://github.com/addyosmani/agent-skills
cp -r agent-skills/skills/spec-driven-development ~/.claude/skills/spec-driven-development

Safety box score

Grade A, minimal risk: 4 of 100 risk points, rated 2026-10-20. The grade rates what the skill and its scripts can reach on the machine of whoever installs it, across eight categories from shell execution to secrets access. How the score works.

This skill is a documentation-first workflow for writing specs, plans, and task lists before implementation. It stays local to the repository and does not itself run code, access the network, or require elevated privileges, but it does create and update project files and enforces human approval gates before continuing.

Category levels, from 0 (none) to 3 (high)
Category	Level	Why
Code & shell execution	0 (none)	No shell commands, scripts, or code execution are defined; the skill is limited to drafting markdown artifacts.
Network access	0 (none)	The file contains no download, upload, or remote communication steps; external references are textual only.
Filesystem reach	1 (low)	It writes within the repository, including saving specs and later `tasks/plan.md` / `tasks/todo.md` and module specs such as `SPEC-identity.md`.
Secrets & credentials	0 (none)	It explicitly says `Never: Commit secrets`, and it does not ask for tokens, passwords, or other credentials.
Privilege & persistence	0 (none)	There is no sudo, service installation, shell startup editing, or system configuration change required.
Instruction hijack surface	0 (none)	The workflow adds approval gates and tells the agent to stop after writing the spec; it does not instruct bypassing confirmations, hiding content, or following untrusted instructions.
Irreversible actions	0 (none)	It does not send messages, deploy, publish, pay, book, or delete anything; it only prepares artifacts for later human review.
Transparency	0 (none)	Everything is readable markdown; there are no binaries, encoded payloads, or generated installers.

Before installing

Read `SKILL.md` and confirm you want a workflow that writes specs and task files into the repo.
Check whether your project already uses a spec system such as OpenSpec so you do not create duplicate artifacts.
Expect a multi-turn process: this skill stops after the spec and waits for human approval before planning or coding.
If you need one-shot implementation, do not use this skill; it is intentionally gated.

Rated 2026-10-20 by an automated review of 1 file from the skill's repository.

Source

Repository: addyosmani/agent-skills (all skills from this repository)
Path: skills/spec-driven-development/SKILL.md
Branch: main
Updated: 2026-09-19

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