diff --git a/Private/Get-CustomApp.ps1 b/Private/Get-CustomApp.ps1
index 28ca71e..d528c3e 100644
--- a/Private/Get-CustomApp.ps1
+++ b/Private/Get-CustomApp.ps1
@@ -1,6 +1,10 @@
 function Get-CustomApp {
     param (
-        [string]$Id
+        [string]$Id,
+
+        # Detection callers pass this so a scheduled check never makes a
+        # network call; it reads whatever copy is already on disk.
+        [switch]$NoRefresh
     )
 
     # --- 1. CLOUD SOURCE ---
@@ -22,7 +26,7 @@ function Get-CustomApp {
 
         # Logic: Only download if the cache doesn't exist OR it's older than 60 minutes.
         # This prevents spamming GitHub every time you run a command.
-        $NeedUpdate = $true
+        $NeedUpdate = -not $NoRefresh
         if (Test-Path $CachePath) {
             $LastWrite = (Get-Item $CachePath).LastWriteTime
             if ((Get-Date) -lt $LastWrite.AddMinutes(60)) { $NeedUpdate = $false }
diff --git a/Private/Get-ManifestIndex.ps1 b/Private/Get-ManifestIndex.ps1
index 99089ec..5a747fc 100644
--- a/Private/Get-ManifestIndex.ps1
+++ b/Private/Get-ManifestIndex.ps1
@@ -10,6 +10,7 @@ function Get-ManifestIndex {
     [CmdletBinding()]
     param(
         [int]$CacheHours = 12,
+        [switch]$NoRefresh,
         [switch]$Force
     )
 
@@ -19,7 +20,9 @@ function Get-ManifestIndex {
     try {
         if (-not (Test-Path $CacheDir)) { New-Item -ItemType Directory -Path $CacheDir -Force -ErrorAction Stop | Out-Null }
 
-        $NeedUpdate = $true
+        # Detection runs on a schedule on every endpoint, so it must never make
+        # a network call. -NoRefresh reads whatever is already cached.
+        $NeedUpdate = -not $NoRefresh
         if (-not $Force -and (Test-Path $CachePath)) {
             $Age = (Get-Date) - (Get-Item $CachePath).LastWriteTime
             if ($Age.TotalHours -lt $CacheHours) { $NeedUpdate = $false }
@@ -59,10 +62,11 @@ function Get-IndexedManifest {
     [CmdletBinding()]
     param(
         [Parameter(Mandatory=$true)][string]$Id,
-        [Parameter(Mandatory=$true)][string]$SysArch
+        [Parameter(Mandatory=$true)][string]$SysArch,
+        [switch]$NoRefresh
     )
 
-    $Index = Get-ManifestIndex
+    $Index = Get-ManifestIndex -NoRefresh:$NoRefresh
     if (-not $Index -or -not $Index.Packages) { return $null }
 
     $Entry = $Index.Packages.$Id
diff --git a/Public/Test-TecharyApp.ps1 b/Public/Test-TecharyApp.ps1
index 82ebb9e..8f81a88 100644
--- a/Public/Test-TecharyApp.ps1
+++ b/Public/Test-TecharyApp.ps1
@@ -1,42 +1,150 @@
 function Test-TecharyApp {
+    <#
+    .SYNOPSIS
+        Reports whether an application is installed.
+
+    .DESCRIPTION
+        Detection order, most precise first:
+
+          1. ProductCode from the manifest index or cache. winget records the
+             ARP subkey name here (for example "7-Zip", or an MSI product GUID),
+             so this is a direct key lookup and is definitive.
+          2. Exact DisplayName, from the custom catalogue or from -Name itself.
+          3. Substring DisplayName match, which is what this function used to do
+             exclusively. Retained so existing callers do not start returning
+             false, but reported as imprecise because it produces false
+             positives: "Teams" matches "Microsoft Teams Meeting Add-in for
+             Microsoft Office" on a machine with no Teams desktop app.
+          4. MSIX package name.
+
+        Makes no network calls. The manifest index and custom catalogue are
+        read from their existing on-disk caches only, because this runs on a
+        schedule on every endpoint.
+
+    .PARAMETER Name
+        A winget package ID ("7zip.7zip"), a custom catalogue ID ("MyDPD"),
+        or a display name.
+
+    .PARAMETER Detailed
+        Return an object describing what matched instead of a boolean.
+    #>
     [CmdletBinding()]
     param (
         [Parameter(Mandatory=$true)]
-        [string]$Name # App ID (e.g. "MyDPD") or Display Name
+        [string]$Name,
+
+        [switch]$Detailed
     )
 
-    # 1. RESOLVE ID -> DISPLAY NAME
-    # Check if this ID exists in your Custom Catalog with a specific DisplayName mapping
-    $CustomApp = Get-CustomApp -Id $Name
-    if ($CustomApp -and $CustomApp.DisplayName) {
-        $Name = $CustomApp.DisplayName
+    $Hives = @(
+        "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall",
+        "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall",
+        "HKCU:\Software\Microsoft\Windows\CurrentVersion\Uninstall"
+    )
+
+    function New-Result {
+        param($Installed, $MatchedBy, $DisplayName, $Version, $Key)
+        [PSCustomObject]@{
+            Name             = $Name
+            Installed        = [bool]$Installed
+            MatchedBy        = $MatchedBy
+            DisplayName      = $DisplayName
+            InstalledVersion = $Version
+            RegistryKey      = $Key
+        }
     }
 
-    # 2. SEARCH REGISTRY (Classic Apps)
-    $Paths = @(
-        "HKLM:\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*",
-        "HKLM:\SOFTWARE\WOW6432Node\Microsoft\Windows\CurrentVersion\Uninstall\*",
-        "HKCU:\Software\Microsoft\Windows\CurrentVersion\Uninstall\*"
-    )
+    if ($env:PROCESSOR_ARCHITECTURE -eq "ARM64") { $SysArch = "arm64" }
+    elseif ([Environment]::Is64BitOperatingSystem) { $SysArch = "x64" }
+    else { $SysArch = "x86" }
+
+    # --- 1. PRODUCT CODE (definitive) ---------------------------------
+    $ProductCode = $null
+    try {
+        $Indexed = Get-IndexedManifest -Id $Name -SysArch $SysArch -NoRefresh
+        if ($Indexed) { $ProductCode = $Indexed.ProductCode }
+    } catch {}
+
+    if (-not $ProductCode) {
+        $CachedManifest = Join-Path $env:ProgramData ("TecharyGet\ManifestCache\" + ($Name -replace '[\\/:*?"<>|]', '_') + ".json")
+        if (Test-Path $CachedManifest) {
+            try { $ProductCode = (Get-Content $CachedManifest -Raw | ConvertFrom-Json).ProductCode } catch {}
+        }
+    }
+
+    if ($ProductCode) {
+        foreach ($Hive in $Hives) {
+            $Key = Join-Path $Hive $ProductCode
+            if (Test-Path $Key) {
+                $Item = Get-ItemProperty -Path $Key -ErrorAction SilentlyContinue
+                Write-Verbose "Matched on ProductCode '$ProductCode' at $Key"
+                $R = New-Result $true 'ProductCode' $Item.DisplayName $Item.DisplayVersion $Key
+                if ($Detailed) { return $R } else { return $true }
+            }
+        }
+    }
+
+    # --- 2. EXACT DISPLAY NAME ----------------------------------------
+    # A custom catalogue entry carries the real ARP DisplayName for its ID.
+    $Candidates = New-Object System.Collections.Generic.List[string]
+    $Candidates.Add($Name)
+    try {
+        $CustomApp = Get-CustomApp -Id $Name -NoRefresh
+        if ($CustomApp -and $CustomApp.DisplayName) { $Candidates.Add($CustomApp.DisplayName) }
+    } catch {}
+
+    $AllArp = foreach ($Hive in $Hives) {
+        Get-ItemProperty -Path (Join-Path $Hive '*') -ErrorAction SilentlyContinue
+    }
 
-    foreach ($Path in $Paths) {
-        $Match = Get-ItemProperty $Path -ErrorAction SilentlyContinue | 
-                 Where-Object { $_.DisplayName -like "*$Name*" } | 
-                 Select-Object -First 1
-        
-        if ($Match) {
-            Write-Verbose "Found Registry Match: $($Match.DisplayName)"
-            return $true
+    foreach ($Candidate in $Candidates) {
+        $Exact = $AllArp | Where-Object { $_.DisplayName -eq $Candidate } | Select-Object -First 1
+        if ($Exact) {
+            Write-Verbose "Matched exactly on DisplayName '$Candidate'"
+            $R = New-Result $true 'ExactName' $Exact.DisplayName $Exact.DisplayVersion $Exact.PSPath
+            if ($Detailed) { return $R } else { return $true }
         }
     }
 
-    # 3. SEARCH MSIX (Modern Apps)
-    $Msix = Get-AppxPackage -Name "*$Name*" -ErrorAction SilentlyContinue | Select-Object -First 1
-    if ($Msix) {
-        Write-Verbose "Found MSIX: $($Msix.Name)"
-        return $true
+    # --- 3. SUBSTRING (imprecise, kept for compatibility) -------------
+    foreach ($Candidate in $Candidates) {
+        # Escaped: an unescaped name containing [ or ] is a wildcard pattern,
+        # which previously made the comparison silently match nothing.
+        $Pattern = "*" + [System.Management.Automation.WildcardPattern]::Escape($Candidate) + "*"
+        $Loose = $AllArp | Where-Object { $_.DisplayName -like $Pattern } | Select-Object -First 1
+        if ($Loose) {
+            Write-Verbose "Matched '$Candidate' only as a substring of '$($Loose.DisplayName)'. This is imprecise; add the package to the manifest index for an exact ProductCode match."
+            $R = New-Result $true 'Substring' $Loose.DisplayName $Loose.DisplayVersion $Loose.PSPath
+            if ($Detailed) { return $R } else { return $true }
+        }
+    }
+
+    # --- 4. MSIX ------------------------------------------------------
+    # SYSTEM sees almost no packages of its own, so enumerate for all users
+    # when we are able to.
+    $IsElevated = $false
+    try {
+        $Identity = [Security.Principal.WindowsIdentity]::GetCurrent()
+        $IsElevated = (New-Object Security.Principal.WindowsPrincipal($Identity)).IsInRole(
+            [Security.Principal.WindowsBuiltInRole]::Administrator)
+    } catch {}
+
+    foreach ($Candidate in $Candidates) {
+        $Pattern = "*" + [System.Management.Automation.WildcardPattern]::Escape($Candidate) + "*"
+        $Msix = $null
+        try {
+            if ($IsElevated) { $Msix = Get-AppxPackage -AllUsers -Name $Pattern -ErrorAction SilentlyContinue | Select-Object -First 1 }
+            if (-not $Msix)  { $Msix = Get-AppxPackage -Name $Pattern -ErrorAction SilentlyContinue | Select-Object -First 1 }
+        } catch {}
+
+        if ($Msix) {
+            Write-Verbose "Matched MSIX package '$($Msix.Name)'"
+            $R = New-Result $true 'Msix' $Msix.Name $Msix.Version $Msix.PackageFullName
+            if ($Detailed) { return $R } else { return $true }
+        }
     }
 
-    # 4. NOT FOUND
-    return $false
-}
\ No newline at end of file
+    # --- 5. NOT FOUND -------------------------------------------------
+    $R = New-Result $false 'None' $null $null $null
+    if ($Detailed) { return $R } else { return $false }
+}