# OpenSpec

> Open-source specification framework for guiding and verifying coding agents

OpenSpec adds a Git-tracked Markdown specification layer to codebases so coding agents understand intent, requirements, and constraints before generating code. It structures changes into proposals, designs, and spec deltas, merging updates back into living documentation once features ship. This helps teams align AI agents across sessions and shift focus from heavy code diff reviews to plan reviews.

Website: https://ycombinator.com/launches/Pdc-openspec-the-spec-framework-for-coding-agents

## What it is for

- Define technical requirements and constraints before triggering AI code generation
- Maintain living architecture documentation that evolves alongside code changes
- Verify coding agent output against defined feature specs and edge cases
- Persist agent context and plans across separate chat sessions via Git

## Features

- Spec library stored directly in Git as Markdown files
- Changes system tracking proposals, design docs, implementation tasks, and spec deltas
- Automatic merging of spec deltas into system documentation upon feature completion
- Integrations with 20+ AI coding tools including Claude Code, Cursor, Copilot, and Windsurf
- Slash commands and agent skills to draft and iterate on specifications

## Pricing

Open source. Free open-source framework; commercial team workspaces in development

## Details

- Type: Web app
- Category: [Development](https://xiry.app/topics/development.md)
- Topic: [AI Coding Tools](https://xiry.app/topics/development/ai-coding-tools.md)
- Open source: yes
- Platforms: Command line, other
- For: Software engineers and development teams using AI coding assistants
- Tags: coding agents, specifications, developer tools, documentation, open source

## Why it was saved

- [@ycombinator, 6 March 2026](https://x.com/ycombinator/status/2030067562642616622): Solves agent intent-guessing by specifying intent upfront; agents verify work against the spec; works across 20+ coding agents (Claude Code, Cursor, Codex, GitHub Copilot, OpenCode, Windsurf, Gemini CLI, Antigravity, Cline, RDDUJC).

## Related

- [Inspo](https://xiry.app/resources/inspo): Design inspiration MCP server and archive for AI coding agents. (Web app, Free)
- [agent-skills](https://xiry.app/resources/agent-skills): Curated skills and performance rules for AI coding agents by Vercel. (GitHub repo, Open source)
- [AI App Builders & Coding Assistants Roster](https://xiry.app/resources/ai-app-builders-and-coding-assistants-roster): Curated roster of 20 AI app builders and coding assistants. (List)
- [animation-reverse-engineering](https://xiry.app/resources/animation-reverse-engineering): Claude Code skill to turn animation videos into production Framer Motion code. (GitHub repo, Free)
- [Hallmark](https://xiry.app/resources/hallmark): Design skill preventing LLMs from generating generic, AI-looking web interfaces (GitHub repo, Open source)
- [MCP in Cursor Guide](https://xiry.app/resources/mcp-in-cursor-guide): Walkthrough for setting up Model Context Protocol servers inside Cursor (Framework, Free)

Updated 10 October 2026. Page: https://xiry.app/resources/openspec

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