AvoidDefaultValueForMandatoryParameter.md

description	Avoid Default Value For Mandatory Parameter
ms.date	07/21/2026
ms.topic	reference
title	AvoidDefaultValueForMandatoryParameter

AvoidDefaultValueForMandatoryParameter

Severity Level: Warning

Default state: Always enabled

Description

This rule detects when mandatory parameters have default values assigned. Mandatory parameters shouldn't have default values because they can't be used. When a parameter is marked as mandatory, PowerShell always prompts the user for a value if one isn't supplied when calling the function. Any default value assigned to a mandatory parameter is unreachable and serves no purpose.

Example

Noncompliant

function Test
{

    [CmdletBinding()]
    Param
    (
        [Parameter(Mandatory=$true)]
        $Parameter1 = 'default Value'
    )
}

Compliant

function Test
{
    [CmdletBinding()]
    Param
    (
        [Parameter(Mandatory=$true)]
        $Parameter1
    )
}

Configure rule

This rule is always enabled and isn't configurable. Use one of the following methods to avoid using this rule:

• Create a custom rule configuration file to include only the rules you want or exclude the rules you don't want.
• Add the appropriate rule suppression attributes to your code to suppress the rule for specific code blocks. For more information, see the Suppressing rules section of Using PSScriptAnalyzer.