whereismyai
Ruler
Ruler is an open-source CLI that keeps one set of instructions for AI coding agents and writes it to each agent's config, from Copilot to Claude Code.
Ruler solves the problem of maintaining separate instruction files for each AI coding assistant. Teams keep their rules as Markdown files in a .ruler directory, and Ruler distributes them to the right configuration files for GitHub Copilot, Claude Code, Cursor, Windsurf, Cline, Amp, Aider, Gemini CLI, Junie, OpenCode, RooCode, Zed, Kiro and other agents. Nested .ruler directories give different parts of a project their own context-specific rules, and a ruler.toml file controls which agents are updated and where their files go. Ruler also distributes MCP server settings, can manage skills and subagents for agents that support them, and adds generated files to .gitignore. It installs with npm, is created by Eleanor Berger, and is open source.
Ruler at a glance
- Best for: Software engineer
- Runs on: CLI, open source
- Pricing: Free and open source
- Released: May 2025
- Category: AI coding tool
- Website: github.com/intellectronica/ruler
Key features
- Single .ruler directory of Markdown rules
- Writes config files for 20+ coding agents
- Nested rules for parts of a project
- ruler.toml to target agents and paths
- MCP server settings distribution
- Automatic .gitignore entries
- Simple init and apply commands
Use it for
- Keep Claude Code, Cursor and Copilot rules in sync
- Give a monorepo package its own agent rules
- Share MCP server settings across agents
Companions
Tools that articles about Ruler recommend using with it, each with its job.
- Claude Code — Built to work with Claude Code.
- Context7 — Provides up-to-date documentation for AI agents and code editors.
- Playwright MCP — Enables LLMs to interact with web pages using structured accessibility snapshots.
- GitHub MCP Server — Reads pull requests, issues and code search on GitHub.
- Superpowers — Brainstorm, plan and execute skills for bigger tasks.
- gstack — Skill bundle for planning, review and shipping.
Alternatives to Ruler
- Ruleherd — Audits existing agent instruction files for contradictions and drift without new formats.
- CLI Manager — Manage multiple AI coding agents and watch visible sessions from a single interface.
- GitHub Copilot — Built into GitHub, with Claude and Codex agents on the same plan
- Cline — Open source, any model, with approval on every step
- OpenAgentsControl — Generates code matching your patterns and requires approval before execution.
- OpenCode — Works with 75+ model providers, local models, and existing subscriptions
- Gauge CLI — Runs real coding agents locally to find where they get stuck in your product.
- Coucou — It provides open-source, real-time agent monitoring and approvals directly from the screen notch.
- jevgrep — Reduces coding agent costs by providing targeted, relevant repository context.
- GitHub Copilot CLI — Integrates directly into your terminal for local, natural language AI coding assistance.
- Ponytail — Cuts unneeded code and dependencies by enforcing a minimal-code ladder.
- CodeGraph — It eliminates file crawling, reducing AI agent tool calls by 88% and cutting costs.
All Ruler alternatives