Test-MgGraphConnection

Connect to Microsoft Graph using application (client credential) authentication. Returns $true on success, $false on failure.

note

The function name is Test-MgGraphConnection. The legacy alias CheckMGGraphConnection remains available for backward compatibility.

The function ensures that the Microsoft.Graph module is available (optionally auto-installs it), then performs a client credentials flow to obtain an access token and calls Connect-MgGraph -AccessToken. It returns $true/$false. Logging uses Write-Log when available; if Nebula.Log is missing, the module exposes a compatible Write-Log/Log-Message that delegates to Write-NALog.

Syntax

Test-MgGraphConnection -TenantId <Guid> -ClientId <Guid> -ClientSecret <String>
                       [-AutoInstall] [-LogLocation <String>] [-ShowInformations]

Parameters

Parameter	Description	Required	Default
TenantId	Azure AD tenant ID (GUID).	Yes	-
ClientId	App registration (client) ID.	Yes	-
ClientSecret	Client secret associated with the app registration.	Yes	-
AutoInstall	Install Microsoft.Graph if missing.	No	$false
LogLocation	Full path of the log file. Used by Write-Log if available.	No	-
ShowInformations	When $true, writes verbose connection details (client secrets are masked).	No	$false

important

• Auto-install is supported: add -AutoInstall if Microsoft.Graph might be missing.
• ShowInformations masks secrets but still prints identifiers; enable only for troubleshooting and protect the log file.

Examples

• Basic connection (Boolean return)

$secret = Get-Content "$env:APPDATA\nebula\.graph_secret.txt" -Raw

$connected = Test-MgGraphConnection `
  -TenantId "00000000-0000-0000-0000-000000000000" `
  -ClientId "11111111-1111-1111-1111-111111111111" `
  -ClientSecret $secret `
  -LogLocation "$env:APPDATA\nebula\logs\graph-connect.log"

if (-not $connected) { throw "Unable to connect to Microsoft Graph." }

• Auto-install if needed

$connected = CheckMGGraphConnection `
  -TenantId $tenantId `
  -ClientId $clientId `
  -ClientSecret $clientSecret `
  -AutoInstall

if (-not $connected) { throw "Unable to connect to Microsoft Graph." }

• Enable verbose diagnostics

$connected = Test-MgGraphConnection `
  -TenantId $tenantId `
  -ClientId $clientId `
  -ClientSecret $clientSecret `
  -LogLocation "C:\Logs\graph-debug.log" `
  -ShowInformations $true

if (-not $connected) { throw "Unable to connect to Microsoft Graph." }

note

• When Nebula.Log is installed, its Write-Log handles log output; otherwise Nebula.Automations provides a compatible Write-Log/Log-Message that delegates to Write-NALog.
• Secrets are masked when verbose logging is enabled.

Questions and answers

Does Test-MgGraphConnection auto-install Microsoft.Graph?

Only when you specify -AutoInstall. Otherwise the module must already be installed.

What does Test-MgGraphConnection log?

If Nebula.Log is available, it uses Write-Log and honors -LogLocation. Otherwise it exposes a compatible Write-Log (Write-NALog).

How are secrets masked?

With -ShowInformations it masks secrets in logs but still prints identifiers; enable it only for troubleshooting and protect the log file.