Ruler
A tool that stores AI coding-assistant instructions in one place and automatically distributes them to the configuration files each supported agent expects.
Ruler centralizes instructions for AI coding assistants so a team does not have to maintain a separate configuration file for every tool. Instructions are written once as Markdown files in a central directory, including nested directories for context specific to a subproject, and Ruler then applies them to the configuration files that agents such as GitHub Copilot, Claude Code, and others expect.
Beyond plain instructions, it can propagate Model Context Protocol server settings to each agent's own configuration format, lets a project fine-tune which agents are affected and where their output goes through a configuration file, and keeps the generated, agent-specific files out of version control automatically. A simple CLI initializes and applies the configuration.
It is written in TypeScript, published on npm, and currently in a beta research preview.