Centralize AI Assistant Instructions with Ruler: The Ultimate Developer Workflow Solution

The AI Collaboration Challenge in Modern Development

As software teams increasingly adopt AI coding assistants, a new challenge emerges: managing consistent instructions across multiple tools. Each AI agent—GitHub Copilot, Claude, Cursor, Aider, and others—requires its own configuration files with unique formats and locations. This fragmentation creates significant hurdles:

  1. Instruction inconsistency across different AI tools
  2. Duplicated effort when updating guidelines
  3. Version control headaches with scattered configuration files
  4. Onboarding friction for new team members

These challenges grow exponentially as teams scale and adopt more AI tools. Ruler provides an elegant solution—a centralized system for managing all AI assistant instructions from a single source.

What is Ruler? The Centralized AI Orchestrator

Ruler is an open-source Node.js tool that solves configuration fragmentation through:

  • Unified rule management: Stores all AI instructions in Markdown files within a .ruler/ directory
  • Automatic distribution: Generates agent-specific configuration files from central rules
  • Targeted configuration: Enables precise control over which agents receive updates
  • Git integration: Automatically manages .gitignore to exclude generated files

Developed by Intellectronica, Ruler streamlines your AI ecosystem while maintaining each tool’s unique configuration requirements.

Core Functionality Explained

Centralized Rule Management

Ruler creates a dedicated .ruler/ directory as your instruction hub:

.ruler/
├── coding_standards.md
├── api_conventions.md
├── security_guidelines.md
├── ruler.toml
└── mcp.json

Markdown files are automatically concatenated in alphabetical order during processing, with clear source tracking:

--- Source: security_guidelines.md ---
# Security Protocols
- Validate all user inputs
- Use parameterized SQL queries

--- Source: python_conventions.md ---
# Python Standards
- Follow PEP 8 guidelines
- Use type hints consistently

Intelligent Rule Distribution

Ruler translates central rules into agent-specific formats:

  1. Scans .ruler/ for Markdown files
  2. Combines content while preserving original structure
  3. Generates target files like .github/copilot-instructions.md or CLAUDE.md
  4. Updates configuration files with proper syntax for each AI agent

Granular Agent Control

Configure precisely which agents receive updates through ruler.toml:

[agents]
copilot = { enabled = true, output_path = ".github/custom_copilot.md" }
claude = { enabled = true }
aider = { enabled = false }  # Disabled for this project

Model Context Protocol (MCP) Integration

Ruler manages shared context servers through mcp.json:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": ["@modelcontextprotocol/server-filesystem", "/project"]
    }
  }
}

This configuration propagates to all supported agents, ensuring consistent contextual understanding across your AI ecosystem.

Supported AI Agents

Ruler currently supports these AI development tools:

AI Agent Rules Location MCP Configuration
GitHub Copilot .github/copilot-instructions.md .vscode/mcp.json
Claude CLAUDE.md claude_desktop_config.json
Cursor .cursor/rules/ruler_cursor_instructions.mdc .cursor/mcp.json
Aider ruler_aider_instructions.md .mcp.json
Gemini CLI GEMINI.md .gemini/settings.json
Firebase Studio .idx/airules.md –
10+ other tools [See documentation] [See documentation]

Getting Started Guide

Installation Requirements

  • Node.js 18.x or higher
  • npm (comes with Node.js)

Setup Process

Global installation (recommended):

npm install -g @intellectronica/ruler

Project initialization:

cd your-project
ruler init

This creates the directory structure:

.ruler/
├── instructions.md
├── ruler.toml
└── mcp.json

Creating Effective Rules

Organize guidelines into focused Markdown files:

# API Development Standards

## Design Principles
- RESTful resource modeling
- Version in URL path (v1/, v2/)
- JSON for all request/responses

## Error Handling
- Standard HTTP status codes
- Consistent error response format:
  { "error": { "code": "E123", "message": "Description" } }

Best practice tips:

  1. Create separate files for different concern areas
  2. Use clear section headers
  3. Provide specific examples where helpful
  4. Update files when project standards evolve

Core Commands Deep Dive

The apply Command

The primary command processes rules into agent configurations:

ruler apply [options]

Key options:

--agents copilot,claude    # Target specific agents
--config custom.toml        # Use alternate configuration
--no-mcp                   # Skip MCP propagation
--verbose                  # Detailed output

Execution workflow:

  1. Locates nearest .ruler/ directory
  2. Combines all Markdown files
  3. Generates target agent files
  4. Updates MCP configurations
  5. Modifies .gitignore if enabled

The revert Command

Safely undo changes with:

ruler revert [options]

Practical applications:

  • Remove Ruler configurations during tool evaluation
  • Clean up when switching project branches
  • Reset to pre-Ruler state during troubleshooting

Configuration Mastery

Understanding ruler.toml

The primary configuration file supports:

# Default agents to configure
default_agents = ["copilot", "claude"]

# MCP settings
[mcp]
enabled = true
merge_strategy = "merge"  # Alternative: "overwrite"

# Gitignore management
[gitignore]
enabled = true

# Agent-specific settings
[agents.copilot]
enabled = true
output_path = ".github/team_copilot_rules.md"

[agents.aider]
enabled = false

Configuration Precedence

Ruler applies settings in this order:

  1. Command-line arguments (highest priority)
  2. Settings in ruler.toml
  3. Built-in default values

Real-World Implementation Scenarios

Rapid Project Setup

Accelerate new projects with consistent standards:

# Initialize Ruler
ruler init

# Add team standards
echo "# Code Review Standards\n- All tests must pass\n- 80% coverage minimum" > .ruler/review.md

# Apply configurations
ruler apply

Team Standardization Workflow

Maintain consistency across contributors:

  1. Commit .ruler/ directory to version control
  2. Team members sync repository changes
  3. Run ruler apply to update local configurations
  4. AI assistants immediately follow latest guidelines

CI/CD Integration

Ensure configuration consistency with GitHub Actions:

name: Verify Ruler Config
on: [pull_request]

jobs:
  ruler-check:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-node@v4
        with:
          node-version: '18'
      - run: npm install -g @intellectronica/ruler
      - run: ruler apply --no-gitignore
      - run: |
          if [ -n "$(git status --porcelain)" ]; then
            echo "Ruler configuration outdated!"
            exit 1
          fi

Troubleshooting Guide

Common Issues and Solutions

Installation problems:

# Permission errors (Unix systems)
sudo npm install -g @intellectronica/ruler

# Alternative without installation
npx @intellectronica/ruler apply

Configuration not applying:

  1. Verify agent enabled in ruler.toml
  2. Confirm agent not excluded by –agents flag
  3. Check output_path setting matches agent requirements

Debugging Techniques

Use verbose mode for detailed diagnostics:

ruler apply --verbose

Output includes:

  • Configuration loading details
  • File processing steps
  • Agent-specific operations
  • Error messages with context

Advanced Implementation Patterns

Project-Specific Context Injection

Enhance AI understanding with project knowledge:

# Project Architecture

## Core Components
- API Gateway: Node.js + Express
- Data Service: Python + FastAPI
- Cache Layer: Redis

## Data Flow
1. User request → API Gateway
2. Gateway → Authentication Service
3. → Data Service → PostgreSQL

Environment-Specific Configurations

Maintain different standards across environments:

.ruler/
├── production/
│   ├── security.md
│   └── deployment.md
├── staging/
│   └── security.md
└── apply-environment.sh

Switching script:

#!/bin/bash
ENV=$1
rm -rf .ruler/rules
cp -R .ruler/$ENV/* .ruler/rules/
ruler apply

Frequently Asked Questions

Q: How do I handle agent-specific instructions?
A: Use Markdown sections dedicated to particular agents:

## For GitHub Copilot
- Prefer async/await over callbacks

## For Claude
- Avoid Python 3.10+ features

Q: Can I use Ruler in monorepos?
A: Yes! Create separate .ruler/ directories in each subproject and run ruler apply in each package.

Q: How does Ruler handle existing configurations?
A: Creates .bak backups before modifying files. Use ruler revert to restore originals.

Q: Is Ruler suitable for enterprise environments?
A: Absolutely. The centralized approach scales effectively with:

  • Clear configuration versioning
  • Team access management through source control
  • CI/CD pipeline integration
  • Audit trails through git history

Project Roadmap and Contribution

Ruler welcomes community involvement:

  • Source: https://github.com/intellectronica/ruler
  • Issue Tracking: https://github.com/intellectronica/ruler/issues
  • Contribution Guide:

    git clone https://github.com/intellectronica/ruler.git
cd ruler
npm install
npm run build
npm test

Current development priorities:

  1. Expanding supported agent ecosystem
  2. Enhancing configuration validation
  3. Improving cross-platform compatibility
  4. Developing VS Code extension

Conclusion: Unified AI Governance

Centralized AI instruction management enhances team collaboration – Source: Pexels

Ruler transforms AI assistant management from a fragmented chore into a streamlined workflow. By implementing Ruler, development teams gain:

  1. Consistent standards enforcement across all AI tools
  2. Significant time savings on configuration management
  3. Seamless onboarding for new team members
  4. Version-controlled evolution of development guidelines
  5. Flexible adaptation to changing project requirements

As AI becomes increasingly embedded in development workflows, tools like Ruler provide the necessary infrastructure for sustainable, scalable AI adoption.

Get started today:

npm install -g @intellectronica/ruler
ruler init

Explore the project:

  • https://github.com/intellectronica/ruler
  • https://www.npmjs.com/package/@intellectronica/ruler
  • https://github.com/intellectronica/ruler/discussions