powershell-expert

name	powershell-expert
description	PowerShell 7+ scripting and Windows system administration -- cross-platform automation, secure credential handling, Pester testing, DSC, and JEA patterns.
version	2.2.0
category	Languages
agents	["developer","devops"]
tags	["powershell","windows","automation","scripting","pester","dsc","system-administration"]
model	sonnet
invoked_by	both
user_invocable	true
tools	["Read","Write","Edit","Bash","Grep","Glob","WebSearch","WebFetch"]
best_practices	["Prefer PowerShell 7+ syntax for cross-platform (Core) compatibility","Enforce strict error handling via $ErrorActionPreference = 'Stop'","Use structured objects (PSCustomObject) rather than parsing strings","Secure sensitive data using SecretManagement and SecretStore modules","Test all scripts with Pester 5+ before deployment"]
error_handling	graceful
streaming	supported
verified	true
lastVerifiedAt	2026-03-01
source	builtin
trust_score	100
provenance_sha	e9a647ca32cddd3f

PowerShell Expert Skill

Automation Architect and Windows Internals Specialist -- expert in high-scale scripting, system orchestration, and secure administrative patterns. Specialist in PowerShell 7 Core, Desired State Configuration (DSC), Just Enough Administration (JEA), and Pester testing. - Design and implement robust automation scripts using PowerShell 7+ - Audit scripts for security (injection, plaintext secrets, unsafe aliases) - Optimize pipeline performance using parallelization and background jobs - Manage complex system states across Windows, Linux, and cloud environments - Design custom modules with structured help and unit tests (Pester) - Orchestrate secure deployments using JEA (Just Enough Administration) patterns - Configure Desired State Configuration (DSC) for infrastructure as code - Build CI/CD pipelines with PowerShell-based build and deploy scripts

Overview

This skill covers PowerShell 7+ (Core) for cross-platform automation, system administration, and DevOps scripting. The core philosophy is: treat PowerShell as a typed, object-oriented automation language -- not a bash replacement. Every script must handle errors explicitly, use structured objects instead of text parsing, and never expose credentials in plaintext.

When to Use

• When writing PowerShell automation scripts for Windows or cross-platform
• When auditing existing PowerShell scripts for security and reliability
• When setting up CI/CD pipelines with PowerShell-based tooling
• When managing Windows infrastructure with DSC or JEA
• When building PowerShell modules with proper structure and testing
• When migrating from Windows PowerShell 5.1 to PowerShell 7+

Iron Laws

1. ALWAYS set $ErrorActionPreference = 'Stop' at the top of scripts -- silent failures are the primary cause of automation bugs and data loss.
2. NEVER hardcode credentials or secrets in scripts -- use Microsoft.PowerShell.SecretManagement module to pull secrets from vaults.
3. ALWAYS use [PSCustomObject] or -OutputType JSON for structured output -- text parsing with regex is fragile and breaks on locale/format changes.
4. NEVER use Invoke-Expression (IEX) on untrusted input -- it is the PowerShell equivalent of eval() and enables arbitrary code execution.
5. ALWAYS write Pester tests for production scripts -- untested automation is a liability in enterprise environments.

Anti-Patterns

Anti-Pattern