Custom Modes

Roo Code allows you to create custom modes to tailor Roo's behavior to specific tasks or workflows. Custom modes can be either global (available across all projects) or project-specific (defined within a single project). Each mode—including custom ones—features Sticky Models, automatically remembering and selecting the last model you used with it. This lets you assign different preferred models to different tasks without reconfiguration, as Roo switches between models when you change modes.

Mode-Specific Instruction File Locations

You can provide instructions for custom modes using dedicated files or directories within your workspace. This allows for better organization and version control compared to only using the JSON customInstructions property.

Preferred Method: Directory (.roo/rules-{mode-slug}/)

.
├── .roo/
│   └── rules-docs-writer/  # Example for mode slug "docs-writer"
│       ├── 01-style-guide.md
│       └── 02-formatting.txt
└── ... (other project files)

Fallback Method: Single File (.roorules-{mode-slug})

.
├── .roorules-docs-writer  # Example for mode slug "docs-writer"
└── ... (other project files)

The directory method takes precedence if it exists and contains files. See Mode-Specific Instructions via Files/Directories for details.

Why Use Custom Modes?

• Specialization: Create modes optimized for specific tasks, like "Documentation Writer," "Test Engineer," or "Refactoring Expert"

• Safety: Restrict a mode's access to sensitive files or commands. For example, a "Review Mode" could be limited to read-only operations

• Experimentation: Safely experiment with different prompts and configurations without affecting other modes

• Team Collaboration: Share custom modes with your team to standardize workflows

  

  Roo Code's interface for creating and managing custom modes.

What's Included in a Custom Mode?

Custom modes allow you to define:

• A unique name and slug: For easy identification
• A role definition: Placed at the beginning of the system prompt, this defines Roo's core expertise and personality for the mode. This placement is crucial as it shapes Roo's fundamental understanding and approach to tasks
• Custom instructions: Added near the end of the system prompt, these provide specific guidelines that modify or refine Roo's behavior for the mode. You can define these using the customInstructions JSON property, and/or by adding instruction files to a dedicated directory (see below). The preferred method for file-based instructions is now using a .roo/rules-{mode-slug}/ directory, which allows for better organization and takes precedence over the older .roorules-{mode-slug} file method. This structured placement allows for more nuanced control over Roo's responses.
• Allowed tools: Which Roo Code tools the mode can use (e.g., read files, write files, execute commands)
• File restrictions: (Optional) Limit file access to specific file types or patterns (e.g., only allow editing .md files)

Custom Mode Configuration (JSON Format)

Both global and project-specific configurations use the same JSON format. Each configuration file contains a customModes array of mode definitions:

{
  "customModes": [
    {
      "slug": "mode-name",
      "name": "Mode Display Name",
      "roleDefinition": "Mode's role and capabilities",
      "groups": ["read", "edit"],
      "customInstructions": "Additional guidelines"
    }
  ]
}

Required Properties

slug

• A unique identifier for the mode
• Use lowercase letters, numbers, and hyphens
• Keep it short and descriptive
• Example: "docs-writer", "test-engineer"

name

• The display name shown in the UI
• Can include spaces and proper capitalization
• Example: "Documentation Writer", "Test Engineer"

roleDefinition

• Detailed description of the mode's role and capabilities
• Defines Roo's expertise and personality for this mode
• Example: "You are a technical writer specializing in clear documentation"

groups

• Array of allowed tool groups
• Available groups: "read", "edit", "browser", "command", "mcp"
• Can include file restrictions for the "edit" group

File Restrictions Format

["edit", {
  "fileRegex": "\\.md$",
  "description": "Markdown files only"
}]

Understanding File Restrictions

The fileRegex property uses regular expressions to control which files a mode can edit:

• \\.md$ - Match files ending in ".md"
• \\.(test|spec)\\.(js|ts)$ - Match test files (e.g., "component.test.js")
• \\.(js|ts)$ - Match JavaScript and TypeScript files

Common regex patterns:

• \\. - Match a literal dot
• (a|b) - Match either "a" or "b"
• $ - Match the end of the filename

Learn more about regular expressions

Optional Properties

customInstructions

• Additional behavioral guidelines for the mode
• Example: "Focus on explaining concepts and providing examples"

Mode-Specific Instructions via Files/Directories

In addition to the customInstructions property in JSON, you can provide mode-specific instructions via files in your workspace. This is particularly useful for:

• Organizing lengthy or complex instructions into multiple, manageable files.
• Managing instructions easily with version control.
• Allowing non-technical team members to modify instructions without editing JSON.

There are two ways Roo Code loads these instructions, with a clear preference for the newer directory-based method:

1. Preferred Method: Directory-Based Instructions (.roo/rules-{mode-slug}/)

• Structure: Create a directory named .roo/rules-{mode-slug}/ in your workspace root. Replace {mode-slug} with your mode's slug (e.g., .roo/rules-docs-writer/).
• Content: Place one or more files (e.g., .md, .txt) containing your instructions inside this directory. You can organize instructions further using subdirectories; Roo Code reads files recursively, appending their content to the system prompt in alphabetical order based on filename.
• Loading: All instruction files found within this directory structure will be loaded and applied to the specified mode.

2. Fallback (Backward Compatibility): File-Based Instructions (.roorules-{mode-slug})

• Structure: If the .roo/rules-{mode-slug}/ directory does not exist or is empty, Roo Code will look for a single file named .roorules-{mode-slug} in your workspace root (e.g., .roorules-docs-writer).
• Loading: If found, the content of this single file will be loaded as instructions for the mode.

Precedence:

• The directory-based method (.roo/rules-{mode-slug}/) takes precedence. If this directory exists and contains files, any corresponding root-level .roorules-{mode-slug} file will be ignored for that mode.
• This ensures that projects migrated to the new directory structure behave predictably, while older projects using the single-file method remain compatible.

Combining with JSON customInstructions:

• Instructions loaded from either the directory or the fallback file are combined with the customInstructions property defined in the mode's JSON configuration.
• Typically, the content from the files/directories is appended after the content from the JSON customInstructions property.

Configuration Precedence

Mode configurations are applied in this order:

1. Project-level mode configurations (from .roomodes)
2. Global mode configurations (from custom_modes.json)
3. Default mode configurations

This means that project-specific configurations will override global configurations, which in turn override default configurations. You can override any default mode (like "code", "debug", etc.) by including a mode with the same slug in either your global or project-specific configuration.

• Note on Instruction Files: Within the loading of mode-specific instructions from the filesystem, the directory .roo/rules-{mode-slug}/ takes precedence over the single file .roorules-{mode-slug} found in the workspace root.

Creating Custom Modes

You have three options for creating custom modes:

1. Ask Roo! (Recommended)

You can quickly create a basic custom mode by asking Roo Code to do it for you. For example:

Create a new mode called "Documentation Writer". It should only be able to read files and write Markdown files.

Roo Code will guide you through the process. However, for fine-tuning modes or making specific adjustments, you'll want to use the Prompts tab or manual configuration methods described below.

2. Using the Prompts Tab

1. Open Prompts Tab: Click the icon in the Roo Code top menu bar

2. Create New Mode: Click the button to the right of the Modes heading

3. Fill in Fields:

   

   The custom mode creation interface showing fields for name, slug, save location, role definition, available tools, and custom instructions.

   • Name: Enter a display name for the mode
   • Slug: Enter a lowercase identifier (letters, numbers, and hyphens only)
   • Save Location: Choose Global (via custom_modes.json, available across all workspaces) or Project-specific (via .roomodes file in project root)
   • Role Definition: Define Roo's expertise and personality for this mode (appears at the start of the system prompt)
   • Available Tools: Select which tools this mode can use
   • Custom Instructions: (Optional) Add behavioral guidelines specific to this mode (appears at the end of the system prompt)

4. Create Mode: Click the "Create Mode" button to save your new mode

Note: File type restrictions can only be added through manual configuration.

3. Manual Configuration

You can configure custom modes by editing JSON files through the Prompts tab:

Both global and project-specific configurations can be edited through the Prompts tab:

1. Open Prompts Tab: Click the icon in the Roo Code top menu bar
2. Access Settings Menu: Click the button to the right of the Modes heading
3. Choose Configuration:
   • Select "Edit Global Modes" to edit custom_modes.json (available across all workspaces)
   • Select "Edit Project Modes" to edit .roomodes file (in project root)
4. Edit Configuration: Modify the JSON file that opens
5. Save Changes: Roo Code will automatically detect the changes

Example Configurations

Each example shows different aspects of mode configuration:

Basic Documentation Writer

{
  "customModes": [{
    "slug": "docs-writer",
    "name": "Documentation Writer",
    "roleDefinition": "You are a technical writer specializing in clear documentation",
    "groups": [
      "read",
      ["edit", { "fileRegex": "\\.md$", "description": "Markdown files only" }]
    ],
    "customInstructions": "Focus on clear explanations and examples"
  }]
}

Test Engineer with File Restrictions

{
  "customModes": [{
    "slug": "test-engineer",
    "name": "Test Engineer",
    "roleDefinition": "You are a test engineer focused on code quality",
    "groups": [
      "read",
      ["edit", { "fileRegex": "\\.(test|spec)\\.(js|ts)$", "description": "Test files only" }]
    ]
  }]
}

Overriding Default Modes

You can override Roo Code's built-in modes (like "code", "debug", "ask") with customized versions that better suit your workflow. This is done by creating a custom mode with the same slug as a default mode.

Overriding Modes Globally

To customize a default mode across all your projects:

1. Open Prompts Tab: Click the icon in the Roo Code top menu bar
2. Access Settings Menu: Click the button to the right of the Modes heading
3. Edit Global Modes: Select "Edit Global Modes" to edit custom_modes.json
4. Add Your Override: Create an entry with the same slug as the built-in mode you want to override

{
  "customModes": [{
    "slug": "code",
    "name": "Code",
    "roleDefinition": "You are a software engineer with global-specific constraints",
    "groups": [
      "read",
      ["edit", { "fileRegex": "\\.(js|ts)$", "description": "JS/TS files only" }]
    ],
    "customInstructions": "Focus on project-specific JS/TS development"
  }]
}

This example replaces the default "Code" mode with a custom version that can only edit JavaScript and TypeScript files.

Project-Specific Mode Override

To override a default mode for just one project:

1. Open Prompts Tab: Click the icon in the Roo Code top menu bar
2. Access Settings Menu: Click the button to the right of the Modes heading
3. Edit Project Modes: Select "Edit Project Modes" to edit the .roomodes file
4. Add Your Override: Create an entry with the same slug as the built-in mode you want to override

{
  "customModes": [{
    "slug": "code",
    "name": "Code (Project-Specific)",
    "roleDefinition": "You are a software engineer with project-specific constraints",
    "groups": [
      "read",
      ["edit", { "fileRegex": "\\.(js|ts)$", "description": "JS/TS files only" }]
    ],
    "customInstructions": "Focus on project-specific JS/TS development"
  }]
}

Project-specific overrides take precedence over global overrides, which in turn override the built-in defaults.

Common Use Cases for Overriding Default Modes

Common reasons to override built-in modes include:

• Restricting file access: Limit a mode to specific file types for safety (e.g., restricting "Code" mode to only edit non-production files)
• Specializing behavior: Customize a mode's expertise for your tech stack (e.g., making "Debug" mode focus on your framework)
• Adding custom instructions: Integrate project standards or team guidelines directly into modes
• Changing available tools: Remove certain tools from modes to prevent unwanted operations

tip

When overriding default modes, test your configuration carefully. Small changes to core modes can significantly impact functionality. Consider creating a backup of your original configuration before making substantial changes.

By following these instructions, you can create and manage custom modes to enhance your workflow with Roo Code.

Understanding Regex in Custom Modes

Regex patterns in custom modes let you precisely control which files Roo can edit:

Basic Syntax

When you specify fileRegex in a custom mode, you're creating a pattern that file paths must match:

["edit", { "fileRegex": "\\.md$", "description": "Markdown files only" }]

Important Rules

• Double Backslashes: In JSON, backslashes must be escaped with another backslash. So \.md$ becomes \\.md$
• Path Matching: Patterns match against the full file path, not just the filename
• Case Sensitivity: Regex patterns are case-sensitive by default

Common Pattern Examples

Pattern	Matches	Doesn't Match
\\.md$	readme.md, docs/guide.md	script.js, readme.md.bak
^src/.*	src/app.js, src/components/button.tsx	lib/utils.js, test/src/mock.js
\\.(css|scss)$	styles.css, theme.scss	styles.less, styles.css.map
docs/.*\\.md$	docs/guide.md, docs/api/reference.md	guide.md, src/docs/notes.md
^(?!.*(test|spec)).*\\.js$	app.js, utils.js	app.test.js, utils.spec.js

Pattern Building Blocks

• \\. - Match a literal dot (period)
• $ - Match the end of the string
• ^ - Match the beginning of the string
• .* - Match any character (except newline) zero or more times
• (a|b) - Match either "a" or "b"
• (?!...) - Negative lookahead (exclude matches)

Testing Your Patterns

Before applying a regex pattern to a custom mode:

1. Test it on sample file paths to ensure it matches what you expect
2. Remember that in JSON, each backslash needs to be doubled (\d becomes \\d)
3. Start with simpler patterns and build complexity gradually

tip

Let Roo Build Your Regex Patterns

Instead of writing complex regex patterns manually, you can ask Roo to create them for you! Simply describe which files you want to include or exclude:

Create a regex pattern that matches JavaScript files but excludes test files

Roo will generate the appropriate pattern with proper escaping for JSON configuration.

Community Gallery

Ready to explore more? Check out the Custom Modes Gallery to discover and share custom modes created by the community!