Use when starting a new project, feature, or significant change and no specification exists yet. Use when requirements are unclear, ambiguous, or only exist as a vague idea.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# Spec-Driven Development
## Overview
Write a structured specification before writing any code. The spec is the shared source of truth between you and the human engineer — it defines what we're building, why, and how we'll know it's done. Code without a spec is guessing.
## When to Use
- Starting a new project or feature
- Requirements are ambiguous or incomplete
- The change touches multiple files or modules
- You're about to make an architectural decision
- The task would take more than 30 minutes to implement
**When NOT to use:** Single-line fixes, typo corrections, or changes where requirements are unambiguous and self-contained.
## The Gated Workflow
Spec-driven development has four phases. Do not advance to the next phase until the current one is validated.
```
SPECIFY ──→ PLAN ──→ TASKS ──→ IMPLEMENT
│ │ │ │
▼ ▼ ▼ ▼
Human Human Human Human
reviews reviews reviews reviews
```
### Phase 1: Specify
Start with a high-level vision. Ask the human clarifying questions until requirements are concrete.
…
The line at the top of this page pins the label git:20260215.74445ea, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
GET https://markdownregistry.com/api/v1/artifacts/art_6c4p6xtpnngp2m5b
GET https://markdownregistry.com/api/v1/resolve?ref=lll0k0lad/agent-skills/spec-driven-development
GET https://markdownregistry.com/api/v1/blob/915f6c9c3e931f92b64a961c5d82b64680b5f579d6d318666141930e2b08d95a
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
lll0k0lad/agent-skills · skills/api-and-interface-design/SKILL.md · Use when designing APIs, module boundaries, or any public interface. Use when creating REST or GraphQL endpoints…
lll0k0lad/agent-skills · skills/browser-testing-with-devtools/SKILL.md · Use when building or debugging anything that runs in a browser. Use when you need to inspect the DOM, capture console…
lll0k0lad/agent-skills · skills/ci-cd-and-automation/SKILL.md · Use when setting up or modifying build and deployment pipelines. Use when you need to automate quality gates, configure…
lll0k0lad/agent-skills · skills/code-review-and-quality/SKILL.md · Use before merging any change. Use when reviewing code written by yourself, another agent, or a human. Use when you…
lll0k0lad/agent-skills · skills/context-engineering/SKILL.md · Use when starting a new session, when agent output quality degrades, when switching between tasks, or when you need to…
lll0k0lad/agent-skills · skills/debugging-and-error-recovery/SKILL.md · Use when tests fail, builds break, behavior doesn't match expectations, or you encounter any unexpected error. Use when…
lll0k0lad/agent-skills · skills/documentation-and-adrs/SKILL.md · Use when making architectural decisions, changing public APIs, shipping features, or when you need to record context…
lll0k0lad/agent-skills · skills/frontend-ui-engineering/SKILL.md · Use when building or modifying user-facing interfaces. Use when creating components, implementing layouts, managing…
lll0k0lad/agent-skills · skills/git-workflow-and-versioning/SKILL.md · Use when making any code change. Use when committing, branching, resolving conflicts, or when you need to organize work…
lll0k0lad/agent-skills · skills/idea-refine/SKILL.md · Refine ideas through structured divergent and convergent thinking. Use "idea-refine" or "ideate" to trigger.
addyosmani/agent-skills · skills/spec-driven-development/SKILL.md · Creates specs before coding. Use when starting a new project, feature, or significant change and no specification…
a5c-ai/babysitter · library/methodologies/pilot-shell/skills/spec-driven-development/SKILL.md · Specification creation and management for the Pilot Shell methodology. Covers semantic search, clarifying questions…
sandbaseai/sandbase-skills · marketing/spec-driven-development/SKILL.md · Plan, implement, or review spec driven development work in an existing codebase with compatibility, security, and…
shashankswe2020-ux/whoop-mcp · .github/skills/spec-driven-development/SKILL.md · Creates specs before coding. Use when starting a new project, feature, or significant change and no specification…
magnus919/agent-skills · spec-driven-development/SKILL.md · Design and run a Spec-Driven Development (SDD) pipeline for AI software factories — where structured specifications are…
nota-america/forgecat-agent-profiles · profiles/addyosmani/agent-skills/for-forgecat/platforms/cursor/.cursor/skills/spec-driven-development/SKILL.md · Creates specs before coding. Use when starting a new project, feature, or significant change and no specification…
nota-america/forgecat-agent-profiles · profiles/addyosmani/agent-skills/for-forgecat/skills/spec-driven-development/SKILL.md · Creates specs before coding. Use when starting a new project, feature, or significant change and no specification…
nota-america/forgecat-agent-profiles · profiles/addyosmani/agent-skills/for-codex/.agents/skills/spec-driven-development/SKILL.md · Creates specs before coding. Use when starting a new project, feature, or significant change and no specification…
