Ruler: Centralise Your AI Coding Assistant Instructions

GitHub: intellectronica/ruler NPM: @intellectronica/ruler Animation by Isaac Flath of Elite AI-Assisted Coding ➡︎

---

> Beta Research Preview
>
> - Please test this version carefully in your environment
> - Report issues at https://github.com/intellectronica/ruler/issues

Why Ruler?

Managing instructions across multiple AI coding tools becomes complex as your team grows. Different agents (GitHub Copilot, Claude, Cursor, Aider, etc.) require their own configuration files, leading to:

- Inconsistent guidance across AI tools
- Duplicated effort maintaining multiple config files
- Context drift as project requirements evolve
- Onboarding friction for new AI tools
- Complex project structures requiring context-specific instructions for different components

Ruler solves this by providing a single source of truth for all your AI agent instructions, automatically distributing them to the right configuration files. With support for nested rule loading, Ruler can handle complex project structures with context-specific instructions for different components.

Core Features

- Centralised Rule Management: Store all AI instructions in a dedicated .ruler/ directory using Markdown files
- Nested Rule Loading: Support complex project structures with multiple .ruler/ directories for context-specific instructions
- Automatic Distribution: Ruler applies these rules to configuration files of supported AI agents
- Targeted Agent Configuration: Fine-tune which agents are affected and their specific output paths via ruler.toml
- MCP Server Propagation: Manage and distribute Model Context Protocol (MCP) server settings
- .gitignore Automation: Keeps generated agent config files out of version control automatically
- Simple CLI: Easy-to-use commands for initialising and applying configurations

Supported AI Agents

| Agent | Rules File(s) | MCP Configuration / Notes | Skills Support / Location |
| ---------------------- | ---------------------------------------------- | ------------------------------------------------ | ------------------------- |
| AGENTS.md | AGENTS.md | (pseudo-agent ensuring root AGENTS.md exists) | - |
| GitHub Copilot | AGENTS.md | .vscode/mcp.json | .claude/skills/ |
| Claude Code | CLAUDE.md | .mcp.json | .claude/skills/ |
| OpenAI Codex CLI | AGENTS.md | .codex/config.toml | .codex/skills/ |
| Pi Coding Agent | AGENTS.md | - | .pi/skills/ |
| Jules | AGENTS.md | - | - |
| Cursor | AGENTS.md | .cursor/mcp.json | .cursor/skills/ |
| Windsurf | AGENTS.md | .windsurf/mcp_config.json | - |
| Cline | .clinerules | - | - |
| Crush | CRUSH.md | .crush.json | - |
| Amp | AGENTS.md | - | .agents/skills/ |
| Antigravity | .agent/rules/ruler.md | - | .agent/skills/ |
| Amazon Q CLI | .amazonq/rules/ruler_q_rules.md | .amazonq/mcp.json | - |
| Aider | AGENTS.md, .aider.conf.yml | .mcp.json | - |
| Firebase Studio | .idx/airules.md | .idx/mcp.json | - |
| Open Hands | .openhands/microagents/repo.md | config.toml | - |
| Gemini CLI | AGENTS.md | .gemini/settings.json | .gemini/skills/ |
| Junie | .junie/guidelines.md | - | - |
| AugmentCode | .augment/rules/ruler_augment_instructions.md | - | - |
| Kilo Code | AGENTS.md | .kilocode/mcp.json | .claude/skills/ |
| OpenCode | AGENTS.md | opencode.json | .opencode/skill/ |
| Goose | .goosehints | - | .agents/skills/ |
| Qwen Code | AGENTS.md | .qwen/settings.json | - |
| RooCode | AGENTS.md | .roo/mcp.json | .roo/skills/ |
| Zed | AGENTS.md | .zed/settings.json (project root, never $HOME) | - |
| Trae AI | .trae/rules/project_rules.md | - | - |
| Warp | WARP.md | - | - |
| Kiro | .kiro/steering/ruler_kiro_instructions.md | .kiro/settings/mcp.json | - |
| Firebender | firebender.json | firebender.json (rules and MCP in same file) | - |
| Factory Droid | AGENTS.md | .factory/mcp.json | .factory/skills/ |
| Mistral Vibe | AGENTS.md | .vibe/config.toml | .vibe/skills/ |
| JetBrains AI Assistant | .aiassistant/rules/AGENTS.md | - | - |

Getting Started

$3

Requires Node.js ^20.19.0 || ^22.12.0 || >=23.

Global Installation (Recommended for CLI use):

``bash
npm install -g @intellectronica/ruler
`

Using npx (for one-off commands):

`bash
npx @intellectronica/ruler apply
`

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1. Navigate to your project's root directory
2. Run ruler init
3. This creates:

- .ruler/ directory
- .ruler/AGENTS.md: The primary starter Markdown file for your rules
- .ruler/ruler.toml: The main configuration file for Ruler (now contains sample MCP server sections; legacy .ruler/mcp.json no longer scaffolded)
- (Optional legacy fallback) If you previously used .ruler/instructions.md, it is still respected when AGENTS.md is absent. (The prior runtime warning was removed.)

Additionally, you can create a global configuration to use when no local .ruler/ directory is found:

`bash
ruler init --global
`

The global configuration will be created to $XDG_CONFIG_HOME/ruler (default: ~/.config/ruler).

Core Concepts

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This is your central hub for all AI agent instructions:

- Primary File Order & Precedence:
1. A repository root AGENTS.md (outside .ruler/) if present (highest precedence, prepended)
2. .ruler/AGENTS.md (new default starter file)
3. Legacy .ruler/instructions.md (only if .ruler/AGENTS.md absent; no longer emits a deprecation warning)
4. Remaining discovered .md files under .ruler/ (and subdirectories) in sorted order
- Rule Files (*.md): Discovered recursively from .ruler/ or $XDG_CONFIG_HOME/ruler and concatenated in the order above
- Concatenation Marker: Each file's content is prepended with for traceability
- ruler.toml: Master configuration for Ruler's behavior, agent selection, output paths, and MCP server settings
- mcp.json: (Legacy, deprecated) Shared MCP server settings - no longer scaffolded but still supported for backward compatibility

This ordering lets you keep a short, high-impact root AGENTS.md (e.g. executive project summary) while housing detailed guidance inside .ruler/.

$3

Ruler now supports nested rule loading with the --nested flag, enabling context-specific instructions for different parts of your project:

`
project/
├── .ruler/ # Global project rules
│ ├── AGENTS.md
│ └── coding_style.md
├── src/
│ └── .ruler/ # Component-specific rules
│ └── api_guidelines.md
├── tests/
│ └── .ruler/ # Test-specific rules
│ └── testing_conventions.md
└── docs/
└── .ruler/ # Documentation rules
└── writing_style.md
`

How it works:

- Discover all .ruler/ directories in the project hierarchy
- Load and concatenate rules from each directory in order
- Decide whether nested mode is enabled using the following precedence:
1. ruler apply --nested (or --no-nested) takes top priority
2. nested = true in ruler.toml
3. Default to disabled when neither option is provided
- When a run is nested, downstream configs are forced to keep nested = true. If a child config attempts to disable it, Ruler keeps nested processing active and emits a warning in the logs.
- Nested processing carries forward each directory's own MCP bundle and configuration settings so that generated files remain scoped to their source directories while being normalized back to the project root.

> [!CAUTION]
> Nested mode is experimental and may change in future releases. The CLI logs this warning the first time a nested run is detected so you know the behavior may evolve.

Perfect for:

- Monorepos with multiple services
- Projects with distinct components (frontend/backend)
- Teams needing different instructions for different areas
- Complex codebases with varying standards

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Granularity: Break down complex instructions into focused .md files:

- coding_style.md
- api_conventions.md
- project_architecture.md
- security_guidelines.md

Example rule file (.ruler/python_guidelines.md):

`markdown


Python Project Guidelines

General Style

- Follow PEP 8 for all Python code
- Use type hints for all function signatures and complex variables
- Keep functions short and focused on a single task

Error Handling

- Use specific exception types rather than generic Exception
- Log errors effectively with context

Security

- Always validate and sanitize user input
- Be mindful of potential injection vulnerabilities
`

Usage: The apply Command

$3

`bash
ruler apply [options]
`

The apply command looks for .ruler/ in the current directory tree, reading the first match. If no such directory is found, it will look for a global configuration in $XDG_CONFIG_HOME/ruler.

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| Option | Description |
| ------------------------------ | ---------------------------------------------------------------------- |
| --project-root | Project root path (default: current directory). |
| --agents | Comma-separated agent names to target (see supported list below). |
| --config | Custom ruler.toml path. |
| --mcp / --with-mcp | Enable applying MCP server configurations (default: true). |
| --no-mcp | Disable applying MCP server configurations. |
| --mcp-overwrite | Overwrite native MCP config instead of merging. |
| --gitignore | Enable automatic .gitignore updates (default: true). |
| --no-gitignore | Disable automatic .gitignore updates. |
| --nested | Enable nested rule loading (default: inherit from config or disabled). |
| --no-nested | Disable nested rule loading even if nested = true in config. |
| --backup | Toggle creation of .bak backup files (default: enabled). |
| --skills | Enable skills support (experimental, default: enabled). |
| --no-skills | Disable skills support. |
| --dry-run | Preview changes without writing files. |
| --local-only | Skip $XDG_CONFIG_HOME when looking for configuration. |
| --verbose / -v | Display detailed output during execution. |

$3

Apply rules to all configured agents:

`bash
ruler apply
`

Apply rules only to GitHub Copilot and Claude:

`bash
ruler apply --agents copilot,claude
`

Apply rules only to Firebase Studio:

`bash
ruler apply --agents firebase
`

Apply rules only to Warp:

`bash
ruler apply --agents warp
`

Apply rules only to Trae AI:

`bash
ruler apply --agents trae
`

Apply rules only to RooCode:

`bash
ruler apply --agents roo
`

Use a specific configuration file:

`bash
ruler apply --config ./team-configs/ruler.frontend.toml
`

Apply rules with verbose output:

`bash
ruler apply --verbose
`

Apply rules but skip MCP and .gitignore updates:

`bash
ruler apply --no-mcp --no-gitignore
`

Usage: The revert Command

The revert command safely undoes all changes made by ruler apply, restoring your project to its pre-ruler state. It intelligently restores files from backups (.bak files) when available, or removes generated files that didn't exist before.

$3

When experimenting with different rule configurations or switching between projects, you may want to:

- Clean slate: Remove all ruler-generated files to start fresh
- Restore originals: Revert modified files back to their original state
- Selective cleanup: Remove configurations for specific agents only
- Safe experimentation: Try ruler without fear of permanent changes

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`bash
ruler revert [options]
`

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| Option | Description |
| ------------------------------ | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| --project-root | Path to your project's root (default: current directory) |
| --agents | Comma-separated list of agent names to revert (agentsmd, aider, amazonqcli, amp, antigravity, augmentcode, claude, cline, codex, copilot, crush, cursor, factory, firebase, firebender, gemini-cli, goose, jules, junie, kilocode, kiro, mistral, opencode, openhands, pi, qwen, roo, trae, warp, windsurf, zed) |
| --config | Path to a custom ruler.toml configuration file |
| --keep-backups | Keep backup files (.bak) after restoration (default: false) |
| --dry-run | Preview changes without actually reverting files |
| --verbose / -v | Display detailed output during execution |
| --local-only | Only search for local .ruler directories, ignore global config |

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Revert all ruler changes:

`bash
ruler revert
`

Preview what would be reverted (dry-run):

`bash
ruler revert --dry-run
`

Revert only specific agents:

`bash
ruler revert --agents claude,copilot
`

Revert with detailed output:

`bash
ruler revert --verbose
`

Keep backup files after reverting:

`bash
ruler revert --keep-backups
`

Configuration (ruler.toml) in Detail

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Defaults to .ruler/ruler.toml in the project root. Override with --config CLI option.

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`toml


Default agents to run when --agents is not specified

Uses case-insensitive substring matching

default_agents = ["copilot", "claude", "aider"]

--- Global MCP Server Configuration ---

[mcp]

Enable/disable MCP propagation globally (default: true)

enabled = true

Global merge strategy: 'merge' or 'overwrite' (default: 'merge')

merge_strategy = "merge"

--- MCP Server Definitions ---

[mcp_servers.filesystem]
command = "npx"
args = ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/project"]

[mcp_servers.git]
command = "npx"
args = ["-y", "@modelcontextprotocol/server-git", "--repository", "."]

[mcp_servers.remote_api]
url = "https://api.example.com"

[mcp_servers.remote_api.headers]
Authorization = "Bearer your-token"

--- Global .gitignore Configuration ---

[gitignore]

Enable/disable automatic .gitignore updates (default: true)

enabled = true

--- Agent-Specific Configurations ---

[agents.copilot]
enabled = true

[agents.claude]
enabled = true
output_path = "CLAUDE.md"

[agents.aider]
enabled = true
output_path_instructions = "AGENTS.md"
output_path_config = ".aider.conf.yml"

OpenAI Codex CLI agent and MCP config

[agents.codex]
enabled = true
output_path = "AGENTS.md"
output_path_config = ".codex/config.toml"

Agent-specific MCP configuration for Codex CLI

[agents.codex.mcp]
enabled = true
merge_strategy = "merge"

[agents.firebase]
enabled = true
output_path = ".idx/airules.md"

[agents.gemini-cli]
enabled = true

[agents.jules]
enabled = true

[agents.junie]
enabled = true
output_path = ".junie/guidelines.md"

Agent-specific MCP configuration

[agents.cursor.mcp]
enabled = true
merge_strategy = "merge"

Disable specific agents

[agents.windsurf]
enabled = false

[agents.kilocode]
enabled = true
output_path = "AGENTS.md"

[agents.warp]
enabled = true
output_path = "WARP.md"
`

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1. CLI flags (e.g., --agents, --no-mcp, --mcp-overwrite, --no-gitignore)
2. Settings in ruler.toml (default_agents, specific agent settings, global sections)
3. Ruler's built-in defaults (all agents enabled, standard output paths, MCP enabled with 'merge')

MCP (Model Context Protocol) Server Configuration

MCP provides broader context to AI models through server configurations. Ruler can manage and distribute these settings across compatible agents.

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You can now define MCP servers directly in ruler.toml using the [mcp_servers.] syntax:

`toml


Global MCP behavior

[mcp]
enabled = true
merge_strategy = "merge" # or "overwrite"

Local (stdio) server

[mcp_servers.filesystem]
command = "npx"
args = ["-y", "@modelcontextprotocol/server-filesystem", "/path/to/project"]

[mcp_servers.filesystem.env]
API_KEY = "your-api-key"

Remote server

[mcp_servers.search]
url = "https://mcp.example.com"

[mcp_servers.search.headers]
Authorization = "Bearer your-token"
"X-API-Version" = "v1"
`

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For backward compatibility, you can still use the JSON format; a warning is issued encouraging migration to TOML. The file is no longer created during ruler init.

`json
{
"mcpServers": {
"filesystem": {
"command": "npx",
"args": [
"-y",
"@modelcontextprotocol/server-filesystem",
"/path/to/project"
]
},
"git": {
"command": "npx",
"args": ["-y", "@modelcontextprotocol/server-git", "--repository", "."]
}
}
}
`

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When both TOML and JSON configurations are present:

1. TOML servers take precedence over JSON servers with the same name
2. Servers are merged from both sources (unless using overwrite strategy)
3. Deprecation warning is shown encouraging migration to TOML (warning shown once per run)

$3

Local/stdio servers require a command field:

`toml
[mcp_servers.local_server]
command = "node"
args = ["server.js"]

[mcp_servers.local_server.env]
DEBUG = "1"
`

Remote servers require a url field (headers optional; bearer Authorization token auto-extracted for OpenHands when possible):

`toml
[mcp_servers.remote_server]
url = "https://api.example.com"

[mcp_servers.remote_server.headers]
Authorization = "Bearer token"
`

Ruler uses this configuration with the merge (default) or overwrite strategy, controlled by ruler.toml or CLI flags.

Home Directory Safety: Ruler never writes MCP configuration files outside your project root. Any historical references to user home directories (e.g. ~/.codeium/windsurf/mcp_config.json or ~/.zed/settings.json) have been removed; only project-local paths are targeted.

Note for OpenAI Codex CLI: To apply the local Codex CLI MCP configuration, set the CODEX_HOME environment variable to your project’s .codex directory:

`bash
export CODEX_HOME="$(pwd)/.codex"
`

Skills Support (Experimental)

⚠️ Experimental Feature: Skills support is currently experimental. Skills are only propagated to agents with native skills support; other agents are skipped with a warning.

Ruler can manage and propagate skills to supported AI agents. Skills are stored in .ruler/skills/ and are automatically distributed to compatible agents when you run ruler apply.

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Skills are specialized knowledge packages that extend AI agent capabilities with domain-specific expertise, workflows, or tool integrations. Ruler discovers skills in your .ruler/skills/ directory and propagates them to compatible agents:

- Agents with native skills support: Skills are copied directly to each agent's native skills directory:
- Claude Code: .claude/skills/
- GitHub Copilot: .claude/skills/ (shared with Claude Code)
- Kilo Code: .claude/skills/ (shared with Claude Code)
- OpenAI Codex CLI: .codex/skills/
- OpenCode: .opencode/skill/
- Pi Coding Agent: .pi/skills/
- Goose: .agents/skills/
- Amp: .agents/skills/ (shared with Goose)
- Antigravity: .agent/skills/
- Factory Droid: .factory/skills/
- Mistral Vibe: .vibe/skills/
- Roo Code: .roo/skills/
- Gemini CLI: .gemini/skills/
- Cursor: .cursor/skills/

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Skills can be organized flat or nested:

`
.ruler/skills/
├── my-skill/
│ ├── SKILL.md # Required: skill instructions/knowledge
│ ├── helper.py # Optional: additional resources (scripts)
│ └── reference.md # Optional: additional resources (docs)
└── another-skill/
└── SKILL.md
`

Each skill must contain:

- SKILL.md - Primary skill file with instructions or knowledge base

Skills can optionally include additional resources like:

- Markdown files with supplementary documentation
- Python, JavaScript, or other scripts
- Configuration files or data

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Skills support is enabled by default but can be controlled via:

CLI flags:

`bash


Enable skills (default)

ruler apply --skills

Disable skills

ruler apply --no-skills
`

Configuration in ruler.toml:

`toml
[skills]
enabled = true # or false to disable
`

$3

If you run Ruler for agents that do not support native skills, Ruler logs a warning and skips skills propagation for those agents.

$3

When skills support is enabled and gitignore integration is active, Ruler automatically adds:

- .claude/skills/ (for Claude Code, GitHub Copilot, and Kilo Code)
- .codex/skills/ (for OpenAI Codex CLI)
- .opencode/skill/ (for OpenCode)
- .pi/skills/ (for Pi Coding Agent)
- .agents/skills/ (for Goose and Amp)
- .agent/skills/ (for Antigravity)
- .factory/skills/ (for Factory Droid)
- .vibe/skills/ (for Mistral Vibe)
- .roo/skills/ (for Roo Code)
- .gemini/skills/ (for Gemini CLI)
- .cursor/skills/ (for Cursor)

to your .gitignore file within the managed Ruler block.

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- For agents with native skills support (Claude Code, GitHub Copilot, Kilo Code, OpenAI Codex CLI, OpenCode, Pi Coding Agent, Goose, Amp, Antigravity, Factory Droid, Mistral Vibe, Roo Code, Gemini CLI, Cursor): No additional requirements.

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Ruler validates discovered skills and issues warnings for:

- Missing required file (SKILL.md)
- Invalid directory structures (directories without SKILL.md and no sub-skills)

Warnings don't prevent propagation but help identify potential issues.

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Test skills propagation without making changes:

`bash
ruler apply --dry-run
`

This shows which skills would be copied.

$3

`bash


1. Add a skill to your project

mkdir -p .ruler/skills/my-skill
cat > .ruler/skills/my-skill/SKILL.md << 'EOF'

My Custom Skill

This skill provides specialized knowledge for...

Usage

When working on this project, always follow these guidelines:
- Use TypeScript for all new code
- Write tests for all features
- Follow the existing code style
EOF

2. Apply to all agents (skills enabled by default)

ruler apply

3. Skills are now available to compatible agents:

- Claude Code, GitHub Copilot & Kilo Code: .claude/skills/my-skill/

- OpenAI Codex CLI: .codex/skills/my-skill/

- OpenCode: .opencode/skill/my-skill/

- Pi Coding Agent: .pi/skills/my-skill/

- Goose & Amp: .agents/skills/my-skill/

- Antigravity: .agent/skills/my-skill/

- Factory Droid: .factory/skills/my-skill/

- Mistral Vibe: .vibe/skills/my-skill/

- Roo Code: .roo/skills/my-skill/

- Gemini CLI: .gemini/skills/my-skill/

- Cursor: .cursor/skills/my-skill/

`

.gitignore Integration

Ruler automatically manages your .gitignore file to keep generated agent configuration files out of version control.

$3

- Creates or updates .gitignore in your project root
- Adds paths to a managed block marked with # START Ruler Generated Files and # END Ruler Generated Files
- Preserves existing content outside this block
- Sorts paths alphabetically and uses relative POSIX-style paths

$3

`gitignore


Your existing rules

node_modules/
*.log

START Ruler Generated Files

.aider.conf.yml
.clinerules
AGENTS.md
CLAUDE.md

END Ruler Generated Files

dist/
`

$3

- CLI flags: --gitignore or --no-gitignore
- Configuration: [gitignore].enabled in ruler.toml
- Default: enabled

Practical Usage Scenarios

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`bash


Initialize Ruler in your project

cd your-project
ruler init

Edit the generated files

- Add your coding guidelines to .ruler/AGENTS.md (or keep adding additional .md files)

- Customize .ruler/ruler.toml if needed

Apply rules to all AI agents

ruler apply
`

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For large projects with multiple components or services, enable nested rule loading so each directory keeps its own rules and MCP bundle:

`bash


Set up nested .ruler directories

mkdir -p src/.ruler tests/.ruler docs/.ruler

Add component-specific instructions

echo "# API Design Guidelines" > src/.ruler/api_rules.md
echo "# Testing Best Practices" > tests/.ruler/test_rules.md
echo "# Documentation Standards" > docs/.ruler/docs_rules.md
`

`toml


.ruler/ruler.toml


nested = true
`

`bash


The CLI inherits nested mode from ruler.toml

ruler apply --verbose

Override from the CLI at any time

ruler apply --no-nested
`

This creates context-specific instructions for different parts of your project while maintaining global rules in the root .ruler/ directory. Nested runs automatically keep every nested config enabled even if a child tries to disable it.

> [!NOTE]
> The CLI prints "Nested mode is experimental and may change in future releases." the first time nested processing runs. Expect refinements in future versions.

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1. Create .ruler/coding_standards.md, .ruler/api_usage.md
2. Commit the .ruler directory to your repository
3. Team members pull changes and run ruler apply to update their local AI agent configurations

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1. Detail your project's architecture in .ruler/project_overview.md
2. Describe primary data structures in .ruler/data_models.md
3. Run ruler apply to help AI tools provide more relevant suggestions

$3

`json
{
"scripts": {
"ruler:apply": "ruler apply",
"dev": "npm run ruler:apply && your_dev_command",
"precommit": "npm run ruler:apply"
}
}
`

$3

`yaml


.github/workflows/ruler-check.yml

name: Check Ruler Configuration
on:
pull_request:
paths: ['.ruler/**']

jobs:
check-ruler:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
- uses: actions/setup-node@v4
with:
node-version: '20'
cache: 'npm'

- name: Install Ruler
run: npm install -g @intellectronica/ruler

- name: Apply Ruler configuration
run: ruler apply --no-gitignore

- name: Check for uncommitted changes
run: |
if [[ -n $(git status --porcelain) ]]; then
echo "::error::Ruler configuration is out of sync!"
echo "Please run 'ruler apply' locally and commit the changes."
exit 1
fi
`

Troubleshooting

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"Cannot find module" errors:

- Ensure Ruler is installed globally: npm install -g @intellectronica/ruler
- Or use npx @intellectronica/ruler

Permission denied errors:

- On Unix systems, you may need sudo for global installation

Agent files not updating:

- Check if the agent is enabled in ruler.toml
- Verify agent isn't excluded by --agents flag
- Use --verbose to see detailed execution logs

Configuration validation errors:

- Ruler now validates ruler.toml format and will show specific error details
- Check that all configuration values match the expected types and formats

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Use --verbose flag to see detailed execution logs:

`bash
ruler apply --verbose
`

This shows:

- Configuration loading details
- Agent selection logic
- File processing information
- MCP configuration steps

FAQ

Q: Can I use different rules for different agents?
A: Currently, all agents receive the same concatenated rules. For agent-specific instructions, include sections in your rule files like "## GitHub Copilot Specific" or "## Aider Configuration".

Q: How do I set up different instructions for different parts of my project?
A: Enable nested mode either by setting nested = true in ruler.toml or by passing ruler apply --nested. The CLI inherits the config setting by default, but --no-nested always wins if you need to opt out for a run. Nested mode keeps loading rules (and MCP settings) from every .ruler/ directory in the hierarchy, forces child configs to remain nested, and logs "Nested mode is experimental and may change in future releases." if any nested processing occurs.

Q: How do I temporarily disable Ruler for an agent?
A: Set enabled = false in ruler.toml under [agents.agentname], or use --agents flag to specify only the agents you want.

Q: What happens to my existing agent configuration files?
A: Ruler creates backups with .bak extension before overwriting any existing files.

Q: Can I run Ruler in CI/CD pipelines?
A: Yes! Use ruler apply --no-gitignore in CI to avoid modifying .gitignore. See the GitHub Actions example above.

Q: How do I migrate from older versions using instructions.md?
A: Simply rename .ruler/instructions.md to .ruler/AGENTS.md (recommended). If you keep the legacy file and omit AGENTS.md, Ruler will still use it (without emitting the old deprecation warning). Having both causes AGENTS.md to take precedence; the legacy file is still concatenated afterward.

Q: How does OpenHands MCP propagation classify servers?
A: Local stdio servers become stdio_servers. Remote URLs containing /sse are classified as sse_servers; others become shttp_servers. Bearer tokens in an Authorization header are extracted into api_key where possible.

Q: Where is Zed configuration written now?
A: Ruler writes a settings.json in the project root (not the user home dir) and transforms MCP server definitions to Zed's context_servers format including source: "custom".

Q: What changed about MCP initialization?
A: ruler init now only adds example MCP server sections to ruler.toml instead of creating .ruler/mcp.json. The JSON file is still consumed if present, but TOML servers win on name conflicts.

Q: Is Kiro supported?
A: Yes. Kiro receives concatenated rules at .kiro/steering/ruler_kiro_instructions.md.

Development

$3

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

$3

`bash


Run all tests

npm test

Run tests with coverage

npm run test:coverage

Run tests in watch mode

npm run test:watch
`

$3

`bash


Run linting

npm run lint

Run formatting

npm run format
``

Contributing

Contributions are welcome! Please:

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Ensure all tests pass
6. Submit a pull request

For bugs and feature requests, please open an issue.

License

MIT

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© Eleanor Berger
ai.intellectronica.net