I use Cursor and Claude Code, sometimes Codex, and I'm about to try OpenCode. Each tool has its own rules format, and I've been maintaining them separately. Ruler generates each tool's native config from a single source. Worth setting up.

Tool agnosticism with common rules

I'm trying to keep up. There are too many tools. I don't want to migrate things around. We're using this at work too, since different devs use different tools. Here's how I set up Ruler to consolidate my Cursor and Claude rules together.

I had this rule in Cursor:

# Monorepo rules

This git repo is a monorepo. It contains multiple sub-projects.
Do not look for context or cross-reference calls between sub-projects.
Each directory within apps/ and games/ is a sub-project. They shouldn't
share code.

Claude Code has CLAUDE.md files scattered through the tree:

File	Contents
CLAUDE.md (root)	Branching: never commit to main, always PR
apps/games/sillyapp/CLAUDE.md	iOS build and test commands, simulator lifecycle
apps/blog/.../posts/CLAUDE.md	Blog writing voice, formatting rules, structure
apps/games/kid-bot-battle-sim/features/CLAUDE.md	Interface details for that feature set

Ruler Setup

npm install -g @intellectronica/ruler

Initialize at the repo root:

ruler init

This creates a .ruler/ directory and a ruler.toml config. Drop your instructions as Markdown files inside .ruler/, then:

ruler apply

What happens when you run it

Claude Code gets CLAUDE.md. Everything else (Cursor, OpenCode, Codex, Copilot, 30+ others) gets AGENTS.md. Generated files go into .gitignore automatically, so only the .ruler/ source is committed.

Ruler supports nested directories. A .ruler/ at the repo root applies globally. A .ruler/ inside a sub-project applies when an agent is working there. That matches how Claude Code already loads CLAUDE.md files walking up the directory tree.

graph TD
    A[".ruler/ at repo root\nbranching, monorepo"] --> B[Claude Code]
    A --> C[Everyone Else\nCursor, OpenCode, Codex...]
    E[".ruler/ in sillyapp/\nbuild, test"] --> B
    E --> C
    F[".ruler/ in posts/\nblog style"] --> B
    F --> C
    B --> G[CLAUDE.md]
    C --> H[AGENTS.md]

You can symlink ~/.ruler to your dir too if you want global Claude rules.

Note: Consider just using AGENTS.md

Most tools read AGENTS.md: Cursor, OpenCode, Codex, others. If all you have is rules, it's not a bad idea to skip all of this and just use that format. I think it might win. That doesn't help with Skills, though.

Skills

Rules are basically just fancy prompt context that are always loaded. Skills are just fancy prompt context loaded on-demand, maybe with some extra files sometimes. Different tools implement them in different ways:

• Claude Code: .claude/skills/
• Cursor: .cursor/skills/
• Other tools follow the same pattern under their own config directories

Ruler figures it out and distributes them for you. Could this all just be a bash script? Yes. Does it do a bunch of stuff I don't understand too? Also, probably, yes.

Enabled by default. Pass --no-skills to skip it:

ruler apply           # distributes rules + skills
ruler apply --no-skills  # rules only

---

Consolidating rules: Migration steps

The ruler.toml at the root lists the agents to target:

default_agents = ["claude", "cursor"]

Content moves from existing config files into .ruler/ source files:

.ruler/
  branching.md        # from root CLAUDE.md
  monorepo.md         # from .cursor/rules/monorepo.md (Claude never saw this)
apps/games/sillyapp/
  .ruler/
    build.md          # from sillyapp/CLAUDE.md
apps/blog/blog/markdown/posts/
  .ruler/
    style.md          # from posts/CLAUDE.md
apps/games/kid-bot-battle-sim/features/
  .ruler/
    interfaces.md     # from features/CLAUDE.md

Root .ruler/branching.md (was only in Claude Code):

# Branching

Never commit directly to `main`. Always create a branch and open a PR
against main for review.

Root .ruler/monorepo.md (was only in Cursor):

# Monorepo

This repo contains multiple independent sub-projects under `apps/` and
`games/`. Do not cross-reference or import code between sub-projects.
Each directory in those folders is its own isolated project.

The project-specific files (sillyapp build commands, blog style guide) move into .ruler/ inside their directories unchanged. Content stays the same, location shifts.

Note: the existing hand-written CLAUDE.md files get replaced by generated versions after ruler apply. Edit the .ruler/ source, not the output.