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Development · Web app

OpenSpec

Open-source specification framework for guiding and verifying coding agents

From the Xiry library · Updated 10 October 2026

Visit ycombinator.com ↗

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.

What it's 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
Topic
AI Coding Tools
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: 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).

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