Spec-driven development
Write the specification first, then let the implementation be judged against it rather than against taste.
Installation
$ npx skills add addyosmani/agent-skillsThe CLI's unit is the repository, so this installs everything in addyosmani/agent-skills, not spec-driven-development alone. It writes into whichever agent directories it finds — Claude Code, Codex, Cursor, Copilot, Windsurf, Zed.
Summary
Write the specification first, then let the implementation be judged against it rather than against taste.
- Reach for it when work that will be reviewed by someone who was not in the room when it was scoped.
- Sits in Plan & specify — turning an intention into something an agent can execute without inventing the requirements as it goes.
- Stack-agnostic — nothing in it assumes a particular language or framework.
- Published by Addy Osmani. Well regarded, but not the vendor of the thing it covers.
- Installing pulls the whole addyosmani/agent-skills repository: this catalogue lists 19 other entries from it, and the repo may hold more.
Where it sits in delivery
Plan & specifyTurning an intention into something an agent can execute without inventing the requirements as it goes.Everything in Plan →
The skill itself
The full text lives with its publisher and changes when they change it. Read it there rather than here — a mirrored copy of somebody else's procedure goes stale silently, and this page would have no way of telling you.
Related
More in Plan & specify
- Define goalShapes intent into a measurable objective with explicit evidence and bounded scope, rather than a description of activity.
openai/skills - Ask questions if underspecifiedMakes the agent stop and ask instead of filling a gap in the requirements with a plausible guess.
trailofbits/skills - BrainstormingPulls a vague idea apart into options and trade-offs before anything is committed to a plan.
obra/superpowers - Writing plansThe plan format the rest of the superpowers library executes against — ordered, checkable steps rather than prose.
obra/superpowers - Constraint-driven developmentStates the constraints — budget, latency, compatibility, blast radius — as inputs rather than discovering them in review.
addyosmani/agent-skills - Context engineeringDeliberately curating what the agent sees and when — the single biggest lever on output quality.
addyosmani/agent-skills