# Openspec

> OpenSpec — lightweight fluid spec framework for AI-assisted development. USE FOR: "openspec", "opsx", "/opsx:propose", "propose feature", "spec before coding", "iterative spec", "brownfield spec", "AI spec framework", "change proposal", "design before implement", "fluid specs", "spec folder", "openspec init". Lighter alternative to spec-kit: no rigid phases, works on existing projects.

- Skill: `mahmoud20138/openspec` (Agent Skill)
- Install (CLI): `npx skillmds@latest add mahmoud20138/openspec`
- Raw SKILL.md: https://api.skillmd.com/api/skills/mahmoud20138/openspec/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: mahmoud20138 (https://skillmd.com/u/mahmoud20138)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/mahmoud20138/openspec

---


# OpenSpec — Fluid Spec-Driven Development

> "Fluid not rigid. Iterative not waterfall. Built for brownfield."
> Lighter alternative to Spec Kit — no phase gates, works on existing projects.

## vs Spec Kit

| | OpenSpec | Spec Kit |
|--|---------|---------|
| Style | Fluid, iterative | Structured, gated phases |
| Best for | Brownfield + greenfield | Greenfield projects |
| Phase gates | No | Yes (must complete each phase) |
| Commands | 3 core + 8 extended | 8 ordered commands |
| Install | npm global | uv/uvx |
| Models | Opus 4.5+ recommended | Any |

## Installation
```bash
npm install -g @fission-ai/openspec@latest
cd your-project
openspec init

# Opt out of telemetry
export OPENSPEC_TELEMETRY=0
```

## Core 3-Command Workflow
```
1. /opsx:propose "feature name"  → generates change folder
2. /opsx:apply                   → AI implements tasks
3. /opsx:archive                 → moves to archive
```

## Change Folder Structure
```
.openspec/changes/<feature-name>/
├── proposal.md     ← rationale and scope
├── specs/          ← requirements and scenarios
├── design.md       ← technical approach
└── tasks.md        ← implementation checklist
```

## All Commands

| Command | Purpose |
|---------|---------|
| `/opsx:propose "idea"` | Create new change folder with proposal + specs + design + tasks |
| `/opsx:apply` | Implement tasks from current change |
| `/opsx:archive` | Archive completed change |
| `/opsx:new` | Start fresh change |
| `/opsx:continue` | Resume in-progress change |
| `/opsx:ff` | Fast-forward (skip to implementation) |
| `/opsx:verify` | Validate implementation against spec |
| `/opsx:sync` | Synchronize agent instructions |
| `/opsx:bulk-archive` | Archive multiple completed changes |
| `/opsx:onboard` | Team onboarding setup |

## CLI Commands
```bash
openspec init              # initialize in project
openspec config profile    # select workflow type
openspec update            # refresh agent instructions + slash commands
```

## Key Principles
- **No phase gates** — update any artifact at any time
- **Brownfield first** — works on existing codebases
- **Context management** — clear context before implementation phases
- **Best with Opus 4.5+** — high-reasoning models get best results
- **20+ AI tools** — Claude Code, Cursor, Copilot, Windsurf, etc.