Permissions Configuration

Configure tool permissions and security settings in Crush

By default, Crush asks for permission before running tool calls. You can configure which tools are allowed to run without prompting, or disable tools entirely for security.

Permission Prompts

When Crush wants to use a tool, it will prompt you for permission:

Crush wants to run: bash
Command: npm install lodash

Allow? [y/n/always]

You can:

• y - Allow this specific tool call
• n - Deny this tool call
• always - Always allow this tool without prompting

Allowing Tools

To allow specific tools without permission prompts, add them to allowed_tools:

{
  "$schema": "https://charm.land/crush.json",
  "permissions": {
    "allowed_tools": [
      "view",
      "ls",
      "grep",
      "edit"
    ]
  }
}

Use allowed_tools with care. Allowing tools like bash without prompts can be dangerous.

Read-Only Tools

Safe read-only tools you might want to allow:

{
  "permissions": {
    "allowed_tools": [
      "view",
      "ls",
      "grep",
      "glob",
      "sourcegraph"
    ]
  }
}

These tools only read files and don’t make changes to your system.

Safe Edit Tools

If you trust Crush to make edits:

{
  "permissions": {
    "allowed_tools": [
      "view",
      "ls",
      "grep",
      "edit",
      "write",
      "multiedit"
    ]
  }
}

Including MCP Tools

Allow specific MCP tools by their prefixed name:

{
  "permissions": {
    "allowed_tools": [
      "view",
      "grep",
      "mcp_context7_get-library-doc"
    ]
  }
}

MCP tool names follow the pattern: mcp_{server-name}_{tool-name}

YOLO Mode

For maximum productivity (and minimum safety), use the --yolo flag to skip all permission prompts:

crush --yolo

Be very, very careful with YOLO mode.

In YOLO mode:

• Crush can run any tool without asking
• No confirmation for destructive operations
• No safety net for mistakes

Only use in trusted environments with version control.

When to Use YOLO Mode

✅ Safe scenarios:

• Working in a throwaway development environment
• Everything is in version control
• Testing or experimentation
• You’re watching what Crush does

❌ Unsafe scenarios:

• Production systems
• Unversioned code
• Shared environments
• When you’re not paying attention

Disabling Built-In Tools

Completely disable tools by adding them to disabled_tools:

{
  "$schema": "https://charm.land/crush.json",
  "options": {
    "disabled_tools": [
      "bash",
      "sourcegraph"
    ]
  }
}

Disabled tools are completely hidden from the agent. Crush won’t even know they exist.

Available Tools to Disable

Built-in tools you can disable:

• agent - Launch sub-agents
• bash - Execute shell commands
• job_output - Get background job output
• job_kill - Kill background jobs
• download - Download files from URLs
• edit - Edit files
• multiedit - Edit multiple files
• lsp_diagnostics - Get LSP diagnostics
• lsp_references - Find LSP references
• lsp_restart - Restart LSP servers
• fetch - Fetch web content
• agentic_fetch - Agentic web browsing
• glob - Find files by pattern
• grep - Search file contents
• ls - List directory contents
• sourcegraph - Search with Sourcegraph
• todos - Manage todo items
• view - Read files
• write - Write files
• list_mcp_resources - List MCP resources
• read_mcp_resource - Read MCP resources

Disabling Dangerous Tools

For maximum safety, disable potentially dangerous tools:

{
  "options": {
    "disabled_tools": [
      "bash",
      "job_output",
      "job_kill",
      "download"
    ]
  }
}

Read-Only Mode

To make Crush read-only, disable all write tools:

{
  "options": {
    "disabled_tools": [
      "bash",
      "edit",
      "multiedit",
      "write",
      "download",
      "job_output",
      "job_kill"
    ]
  }
}

Crush can still:

• Read files (view)
• Search files (grep, glob)
• List directories (ls)
• Use LSP for code intelligence
• Answer questions about your code

Disabling MCP Tools

Disable specific tools from MCP servers:

{
  "mcp": {
    "github": {
      "type": "http",
      "url": "https://api.githubcopilot.com/mcp/",
      "disabled_tools": [
        "create_issue",
        "create_pull_request",
        "delete_repository"
      ]
    }
  }
}

See the MCP Configuration page for more details.

Security Best Practices

1. Start Restrictive

Begin with minimal permissions and add tools as needed:

{
  "permissions": {
    "allowed_tools": [
      "view",
      "ls",
      "grep"
    ]
  }
}

2. Use Version Control

Always use version control (Git) so you can review and revert changes:

git status
git diff
git checkout -- file.js  # Revert unwanted changes

3. Review Changes

Before committing, review what Crush changed:

git diff
crush diff  # If Crush provides a diff command

4. Project-Specific Permissions

Use project-specific .crush.json for sensitive projects:

{
  "$schema": "https://charm.land/crush.json",
  "permissions": {
    "allowed_tools": ["view", "grep", "ls"]
  },
  "options": {
    "disabled_tools": ["bash", "download"]
  }
}

5. Audit Logs

Enable debug logging to audit what Crush does:

{
  "options": {
    "debug": true
  }
}

Logs are saved to ./.crush/logs/crush.log.

Permission Levels

Here are recommended permission levels for different scenarios:

Level 1: Maximum Security (Read-Only)

{
  "permissions": {
    "allowed_tools": ["view", "ls", "grep", "glob"]
  },
  "options": {
    "disabled_tools": ["bash", "edit", "write", "multiedit", "download"]
  }
}

Use for: Production analysis, sensitive codebases

Level 2: Moderate Security (Safe Edits)

{
  "permissions": {
    "allowed_tools": ["view", "ls", "grep", "glob", "edit", "write"]
  },
  "options": {
    "disabled_tools": ["bash", "download"]
  }
}

Use for: Development with version control

Level 3: Balanced (Most Tools)

{
  "permissions": {
    "allowed_tools": [
      "view", "ls", "grep", "glob",
      "edit", "write", "multiedit"
    ]
  }
}

Use for: Active development, trusted environments

Level 4: YOLO (Maximum Productivity)

crush --yolo

Use for: Throwaway projects, experimentation

Never use YOLO mode on production systems or code without version control.

Next Steps

Tools Overview

Learn about all available tools

MCP Configuration

Configure MCP server permissions