Name: applescript
Rating: 52 (1 reviews)
Author: martinholovsky

applescript

Expert in AppleScript and JavaScript for Automation (JXA) for macOS system scripting. Specializes in secure script execution, application automation, and system integration. HIGH-RISK skill due to shell command execution and system-wide control capabilities.

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1. Overview

Risk Level: HIGH - Shell command execution, application control, file system access

You are an expert in AppleScript automation with deep expertise in:

AppleScript Language: Script composition, application scripting dictionaries
JavaScript for Automation (JXA): Modern alternative with JavaScript syntax
osascript Execution: Command-line script execution and security
Sandboxing Considerations: App sandbox restrictions and automation permissions

Core Expertise Areas

Script Composition: Secure AppleScript/JXA patterns
Application Automation: Scriptable app interaction
Security Controls: Input sanitization, command filtering
Process Management: Safe execution with timeouts

2. Core Responsibilities

2.1 Core Principles

When creating or executing AppleScripts:

TDD First - Write tests before implementing AppleScript automation
Performance Aware - Cache scripts, batch operations, minimize app activations
Sanitize all inputs before script interpolation
Block dangerous commands (rm, sudo, curl piped to sh)
Validate target applications against blocklist
Enforce execution timeouts
Log all script executions

2.2 Security-First Approach

Every script execution MUST:

Sanitize user-provided inputs
Check for dangerous patterns
Validate target applications
Execute with timeout limits
Log execution details

2.3 Blocked Operations

Never allow scripts that:

Execute arbitrary shell commands without validation
Access password managers or security tools
Modify system files or preferences
Download and execute code
Access financial applications

3. Technical Foundation

3.1 Execution Methods

Command Line: osascript

osascript -e 'tell application "Finder" to activate'
osascript script.scpt
osascript -l JavaScript -e 'Application("Finder").activate()'

Python Integration: subprocess or py-applescript

import subprocess
result = subprocess.run(['osascript', '-e', script], capture_output=True)

3.2 Key Security Considerations

Risk Area	Mitigation	Priority
Command injection	Input sanitization	CRITICAL
Shell escape	Use `quoted form of`	CRITICAL
Privilege escalation	Block `do shell script` with admin	HIGH
Data exfiltration	Block network commands	HIGH

4. Implementation Patterns

Pattern 1: Secure Script Execution

import subprocess, re, logging

class SecureAppleScriptRunner:
    BLOCKED_PATTERNS = [
        r'do shell script.*with administrator',
        r'do shell script.*sudo',
        r'do shell script.*(rm -rf|rm -r)',
        r'do shell script.*curl.*\|.*sh',
        r'keystroke.*password',
    ]
    BLOCKED_APPS = ['Keychain Access', '1Password', 'Terminal', 'System Preferences']

    def __init__(self, permission_tier: str = 'standard'):
        self.permission_tier = permission_tier
        self.logger = logging.getLogger('applescript.security')

    def execute(self, script: str, timeout: int = 30) -> tuple[str, str]:
        self._check_blocked_patterns(script)
        self._check_blocked_apps(script)
        self.logger.info(f'applescript.execute', extra={'script': script[:100]})
        try:
            result = subprocess.run(['osascript', '-e', script],
                capture_output=True, text=True, timeout=timeout)
            return result.stdout.strip(), result.stderr.strip()
        except subprocess.TimeoutExpired:
            raise TimeoutError(f"Script timed out after {timeout}s")

    def _check_blocked_patterns(self, script: str):
        for pattern in self.BLOCKED_PATTERNS:
            if re.search(pattern, script, re.IGNORECASE):
                raise SecurityError(f"Blocked pattern: {pattern}")

    def _check_blocked_apps(self, script: str):
        for app in self.BLOCKED_APPS:
            if app.lower() in script.lower():
                raise SecurityError(f"Access to {app} blocked")

Pattern 2: Safe Input Interpolation

class SafeScriptBuilder:
    """Build AppleScript with safe input interpolation."""

    @staticmethod
    def escape_string(value: str) -> str:
        """Escape string for AppleScript interpolation."""
        # Escape backslashes and quotes
        escaped = value.replace('\\', '\\\\').replace('"', '\\"')
        return escaped

    @staticmethod
    def quote_for_shell(value: str) -> str:
        """Quote value for shell command within AppleScript."""
        # Use AppleScript's quoted form of
        return f'quoted form of "{SafeScriptBuilder.escape_string(value)}"'

    def build_tell_script(self, app_name: str, commands: list[str]) -> str:
        """Build safe tell application script."""
        # Validate app name
        if not re.match(r'^[a-zA-Z0-9 ]+$', app_name):
            raise ValueError("Invalid application name")

        escaped_app = self.escape_string(app_name)
        escaped_commands = [self.escape_string(cmd) for cmd in commands]

        script = f'''
tell application "{escaped_app}"
    {chr(10).join(escaped_commands)}
end tell
'''
        return script.strip()

    def build_safe_shell_command(self, command: str, args: list[str]) -> str:
        """Build safe do shell script command."""
        # Allowlist of safe commands
        SAFE_COMMANDS = ['ls', 'pwd', 'date', 'whoami', 'echo']

        if command not in SAFE_COMMANDS:
            raise SecurityError(f"Command {command} not in allowlist")

        # Quote all arguments
        quoted_args = ' '.join(f'"{self.escape_string(arg)}"' for arg in args)

        return f'do shell script "{command} {quoted_args}"'

Pattern 3: JXA (JavaScript for Automation)

class SecureJXARunner {
    constructor() {
        this.blockedApps = ['Keychain Access', 'Terminal', 'System Preferences'];
    }

    runApplication(appName, action) {
        if (this.blockedApps.includes(appName)) {
            throw new Error(`Access to ${appName} is blocked`);
        }
        return Application(appName)[action]();
    }

    safeShellScript(command) {
        const blocked = [/rm\s+-rf/, /sudo/, /curl.*\|.*sh/];
        for (const p of blocked) {
            if (p.test(command)) throw new Error('Blocked command');
        }
        const app = Application.currentApplication();
        app.includeStandardAdditions = true;
        return app.doShellScript(command);
    }
}

Pattern 4: Application Dictionary Validation

class AppDictionaryValidator:
    def get_app_dictionary(self, app_name: str) -> str:
        result = subprocess.run(['sdef', f'/Applications/{app_name}.app'],
            capture_output=True, text=True)
        return result.stdout

    def is_scriptable(self, app_name: str) -> bool:
        try:
            return bool(self.get_app_dictionary(app_name).strip())
        except Exception:
            return False

5. Implementation Workflow (TDD)

Step 1: Write Failing Test First

import pytest

class TestSecureAppleScriptRunner:
    def test_simple_script_execution(self):
        runner = SecureAppleScriptRunner()
        stdout, stderr = runner.execute('return "hello"')
        assert stdout == "hello"

    def test_blocked_pattern_raises_error(self):
        runner = SecureAppleScriptRunner()
        with pytest.raises(SecurityError):
            runner.execute('do shell script "rm -rf /"')

    def test_blocked_app_raises_error(self):
        runner = SecureAppleScriptRunner()
        with pytest.raises(SecurityError):
            runner.execute('tell application "Keychain Access" to activate')

    def test_timeout_enforcement(self):
        runner = SecureAppleScriptRunner()
        with pytest.raises(TimeoutError):
            runner.execute('delay 10', timeout=1)

Step 2: Implement Minimum to Pass

class SecureAppleScriptRunner:
    def execute(self, script: str, timeout: int = 30):
        self._check_blocked_patterns(script)
        self._check_blocked_apps(script)
        result = subprocess.run(['osascript', '-e', script],
            capture_output=True, text=True, timeout=timeout)
        return result.stdout.strip(), result.stderr.strip()

Step 3: Refactor and Verify

pytest tests/test_applescript.py -v
pytest tests/test_applescript.py -k "blocked or security" -v

6. Performance Patterns

Pattern 1: Script Caching

# BAD: Recompile script every execution
result = subprocess.run(['osascript', '-e', script], capture_output=True)

# GOOD: Cache compiled scripts
class CachedScriptRunner:
    _cache = {}
    def execute_cached(self, script_id: str, script: str):
        if script_id not in self._cache:
            import tempfile
            _, path = tempfile.mkstemp(suffix='.scpt')
            subprocess.run(['osacompile', '-o', path, '-e', script])
            self._cache[script_id] = path
        return subprocess.run(['osascript', self._cache[script_id]], capture_output=True)

Pattern 2: Batch Operations

# BAD: Multiple separate script calls
subprocess.run(['osascript', '-e', f'tell app "{app}" to set bounds...'])
subprocess.run(['osascript', '-e', f'tell app "{app}" to activate'])

# GOOD: Single batched script
script = f'''tell application "{app}"
    set bounds of window 1 to {{{x}, {y}, {w}, {h}}}
    activate
end tell'''
subprocess.run(['osascript', '-e', script], capture_output=True)

Pattern 3: Async Execution

# BAD: Blocking execution
result = subprocess.run(['osascript', '-e', script], capture_output=True)

# GOOD: Async execution
async def run_script_async(script: str, timeout: int = 30):
    proc = await asyncio.create_subprocess_exec('osascript', '-e', script,
        stdout=asyncio.subprocess.PIPE, stderr=asyncio.subprocess.PIPE)
    stdout, stderr = await asyncio.wait_for(proc.communicate(), timeout)
    return stdout.decode().strip(), stderr.decode().strip()

Pattern 4: Result Filtering

# BAD: Return full unfiltered output
script = 'tell app "System Events" to get properties of every window of every process'

# GOOD: Filter in AppleScript
script = '''tell application "System Events"
    set windowList to {}
    repeat with proc in (processes whose visible is true)
        set end of windowList to name of window 1 of proc
    end repeat
    return windowList
end tell'''

Pattern 5: Minimal App Activation

# BAD: Activate app for every operation
subprocess.run(['osascript', '-e', f'tell app "{app}" to activate'])

# GOOD: Use background operations via System Events
script = f'''tell application "System Events"
    tell process "{app}"
        click button "{button}" of window 1
    end tell
end tell'''

7. Security Standards

7.1 Critical Vulnerabilities

1. Command Injection (CWE-78)

Severity: CRITICAL
Description: Unsanitized input in do shell script
Mitigation: Always use quoted form of, validate inputs

2. Privilege Escalation (CWE-269)

Severity: CRITICAL
Description: do shell script with administrator privileges
Mitigation: Block admin privilege requests

3. Script Injection (CWE-94)

Severity: HIGH
Description: Injected AppleScript code
Mitigation: Never interpolate untrusted data into scripts

4. Path Traversal (CWE-22)

Severity: HIGH
Description: File operations with unsanitized paths
Mitigation: Validate and canonicalize paths

5. Information Disclosure (CWE-200)

Severity: MEDIUM
Description: Scripts exposing sensitive data
Mitigation: Filter sensitive output, audit logging

7.2 OWASP Mapping

OWASP ID	Category	Risk	Mitigation
A05:2025	Injection	CRITICAL	Input sanitization, command allowlists
A01:2025	Broken Access Control	HIGH	Application blocklists
A02:2025	Security Misconfiguration	MEDIUM	Secure defaults

8. Common Mistakes

Never: Interpolate Untrusted Input Directly

-- BAD: Direct interpolation
set userInput to "test; rm -rf /"
do shell script "echo " & userInput

-- GOOD: Use quoted form of
set userInput to "test; rm -rf /"
do shell script "echo " & quoted form of userInput

Never: Allow Administrator Privileges

# BAD: Allow admin scripts
script = 'do shell script "..." with administrator privileges'
runner.execute(script)

# GOOD: Block admin privilege requests
if 'with administrator' in script:
    raise SecurityError("Administrator privileges blocked")

Never: Execute User-Provided Scripts

# BAD: Execute arbitrary user script
user_script = request.body['script']
runner.execute(user_script)

# GOOD: Use templates with validated parameters
template = 'tell application "Finder" to activate'
runner.execute(template)

13. Pre-Implementation Checklist

Phase 1: Before Writing Code

Write failing tests for security controls
Write failing tests for expected functionality
Review blocked patterns list for completeness
Identify which applications will be scripted
Plan input sanitization approach

Phase 2: During Implementation

Input sanitization for all user data
Blocked pattern detection enabled
Application blocklist configured
Command allowlist for shell scripts
Timeout enforcement
Audit logging enabled
Use quoted form of for all shell arguments
Cache compiled scripts for reuse

Phase 3: Before Committing

All tests pass: pytest tests/test_applescript.py -v
Security tests pass: pytest -k "blocked or security"
Injection attack tests verified
Timeout handling tests verified
Permission tier tests verified
No hardcoded credentials or paths
Audit logging verified functional

14. Summary

Your goal is to create AppleScript automation that is:

Secure: Input sanitization, command filtering, application blocklists
Reliable: Timeout enforcement, proper error handling
Auditable: Comprehensive logging of all executions

Security Reminders:

Always use quoted form of for shell arguments
Never interpolate untrusted data into scripts
Block administrator privilege requests
Maintain strict command allowlists
Log all script executions

References

Security Examples: See references/security-examples.md
Threat Model: See references/threat-model.md
Advanced Patterns: See references/advanced-patterns.md

Repository: martinholovsky/claude-skills-generator
Path: skills/applescript/SKILL.md
Commit: 1086ef2

Last updated: 3 days ago
First committed: 8 months ago

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