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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

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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.

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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}

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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

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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.

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Security Best Practices

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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.

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Next Steps

Tools Overview

Learn about all available tools

MCP Configuration

Configure MCP server permissions

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