feat(winmd-api-search): add WinMD cache generator script and related files

- Add PowerShell 7 ForEach-Object -Parallel pattern for single terminal execution
- Document that spawning multiple terminals is NOT trackable by the agent
- Add PR quality requirements (no stub code, proper titles, full descriptions)
- Add quality gate checks for worktree validation
- Document the correct copilot CLI invocation pattern

.github/skills/winmd-api-search/SKILL.md

@@ -0,0 +1,156 @@
+---
+name: winmd-api-search
+description: 'Find and explore Windows desktop APIs. Use when building features that need platform capabilities — camera, file access, notifications, UI controls, AI/ML, sensors, networking, etc. Discovers the right API for a task and retrieves full type details (methods, properties, events, enumeration values).'
+---
+
+# WinMD API Search
+
+This skill helps you find the right Windows API for any capability and get its full details. It searches a local cache of all WinMD metadata from:
+
+- **Windows Platform SDK** — all `Windows.*` WinRT APIs (always available, no restore needed)
+- **WinAppSDK / WinUI** — bundled as a baseline in the cache generator (always available, no restore needed)
+- **NuGet packages** — any additional packages in restored projects that contain `.winmd` files
+- **Project-output WinMD** — class libraries (C++/WinRT, C#) that produce `.winmd` as build output
+
+Even on a fresh clone with no restore or build, you still get full Platform SDK + WinAppSDK coverage.
+
+## When to Use
+
+- User wants to build a feature and you need to find which API provides that capability
+- User asks "how do I do X?" where X involves a platform feature (camera, files, notifications, sensors, AI, etc.)
+- You need the exact methods, properties, events, or enumeration values of a type before writing code
+- You're unsure which control, class, or interface to use for a UI or system task
+
+## How to Use
+
+Pick the path that matches the situation:
+
+---
+
+### Discover — "I don't know which API to use"
+
+The user describes a capability in their own words. You need to find the right API.
+
+**1. Translate user language → search keywords**
+
+Map the user's daily language to programming terms. Try multiple variations:
+
+| User says | Search keywords to try (in order) |
+|-----------|-----------------------------------|
+| "take a picture" | `camera`, `capture`, `photo`, `MediaCapture` |
+| "load from disk" | `file open`, `picker`, `FileOpen`, `StorageFile` |
+| "describe what's in it" | `image description`, `Vision`, `Recognition` |
+| "show a popup" | `dialog`, `flyout`, `popup`, `ContentDialog` |
+| "drag and drop" | `drag`, `drop`, `DragDrop` |
+| "save settings" | `settings`, `ApplicationData`, `LocalSettings` |
+
+Start with simple everyday words. If results are weak or irrelevant, try the more technical variation.
+
+**2. Run searches**
+
+```powershell
+.\.github\skills\winmd-api-search\scripts\Invoke-WinMdQuery.ps1 -Action search -Query "<keyword>"
+```
+
+This returns ranked namespaces with top matching types and the **JSON file path**.
+
+**3. Read the JSON to choose the right API**
+
+Use `read_file` on the file path(s) from the top results. The JSON has all types in that namespace — full members, signatures, parameters, return types, enumeration values.
+
+Read and decide which types and members fit the user's requirement.
+
+**4. Use the API knowledge to answer or write code**
+
+---
+
+### Lookup — "I know the API, show me the details"
+
+You already know (or suspect) the type or namespace name. Go direct:
+
+```powershell
+# Get all members of a known type
+.\.github\skills\winmd-api-search\scripts\Invoke-WinMdQuery.ps1 -Action members -TypeName "Microsoft.UI.Xaml.Controls.NavigationView"
+
+# Get enum values
+.\.github\skills\winmd-api-search\scripts\Invoke-WinMdQuery.ps1 -Action enums -TypeName "Microsoft.UI.Xaml.Visibility"
+
+# List all types in a namespace
+.\.github\skills\winmd-api-search\scripts\Invoke-WinMdQuery.ps1 -Action types -Namespace "Microsoft.UI.Xaml.Controls"
+
+# Browse namespaces
+.\.github\skills\winmd-api-search\scripts\Invoke-WinMdQuery.ps1 -Action namespaces -Filter "Microsoft.UI"
+```
+
+If you need full detail beyond what `-Action members` shows, use `-Action search` to get the JSON file path, then `read_file` the JSON directly.
+
+---
+
+### Other Commands
+
+```powershell
+# List cached projects
+.\.github\skills\winmd-api-search\scripts\Invoke-WinMdQuery.ps1 -Action projects
+
+# Show stats
+.\.github\skills\winmd-api-search\scripts\Invoke-WinMdQuery.ps1 -Action stats
+```
+
+> If only one project is cached, `-Project` is auto-selected.
+> If multiple projects exist, add `-Project <name>`.
+
+## Search Scoring
+
+The search ranks type names against your query:
+
+| Score | Match type | Example |
+|-------|-----------|---------|
+| 100 | Exact name | `Button` → `Button` |
+| 80 | Starts with | `Navigation` → `NavigationView` |
+| 60 | Contains | `Dialog` → `ContentDialog` |
+| 50 | PascalCase initials | `ASB` → `AutoSuggestBox` |
+| 40 | Multi-keyword AND | `navigation item` → `NavigationViewItem` |
+| 20 | Fuzzy character match | `NavVw` → `NavigationView` |
+
+Results are grouped by namespace. Higher-scored namespaces appear first.
+
+## Cache Setup
+
+If the cache doesn't exist, generate it:
+
+```powershell
+# Single project
+.\.\.github\skills\winmd-api-search\scripts\Update-WinMdCache.ps1 -ProjectDir <project-folder>
+
+# All projects in the repo
+.\.\.github\skills\winmd-api-search\scripts\Update-WinMdCache.ps1
+```
+
+Requires:
+- **.NET SDK 8.0 or later** — auto-detects the highest installed SDK (>= 8). Install from [dotnet.microsoft.com](https://dotnet.microsoft.com/download) if not available.
+
+No project restore or build is needed for baseline coverage (Platform SDK + WinAppSDK). For additional NuGet packages, the project needs `dotnet restore` (which generates `project.assets.json`) or a `packages.config` file.
+
+Cache is stored at `Generated Files\winmd-cache\`, deduplicated per-package+version.
+
+### What gets indexed
+
+| Source | When available |
+|--------|----------------|
+| Windows Platform SDK | Always (reads from local SDK install) |
+| WinAppSDK (latest) | Always (bundled as baseline in cache generator) |
+| Project NuGet packages | After `dotnet restore` or with `packages.config` |
+| Project-output `.winmd` | After project build (class libraries that produce WinMD) |
+
+> **Note:** This cache directory should be in `.gitignore` — it's generated, not source.
+
+## Troubleshooting
+
+| Issue | Fix |
+|-------|-----|
+| "Cache not found" | Run `Update-WinMdCache.ps1` |
+| "Multiple projects cached" | Add `-Project <name>` |
+| "Namespace not found" | Use `-Action namespaces` to list available ones |
+| "Type not found" | Use fully qualified name (e.g., `Microsoft.UI.Xaml.Controls.Button`) |
+| Stale after NuGet update | Re-run `Update-WinMdCache.ps1` |
+| Cache in git history | Add `Generated Files/` to `.gitignore` |

.github/skills/winmd-api-search/scripts/Invoke-WinMdQuery.ps1

@@ -0,0 +1,455 @@
+<#
+.SYNOPSIS
+    Query WinMD API metadata from cached JSON files.
+
+.DESCRIPTION
+    Reads pre-built JSON cache of WinMD types, members, and namespaces.
+    The cache is organized per-package (deduplicated) with project manifests
+    that map each project to its referenced packages.
+
+    Supports listing namespaces, types, members, searching, enum value lookup,
+    and listing cached projects/packages.
+
+.PARAMETER Action
+    The query action to perform:
+    - projects    : List cached projects
+    - packages    : List packages for a project
+    - stats       : Show aggregate statistics for a project
+    - namespaces  : List all namespaces (optional -Filter prefix)
+    - types       : List types in a namespace (-Namespace required)
+    - members     : List members of a type (-TypeName required)
+    - search      : Search types and members (-Query required)
+    - enums       : List enum values (-TypeName required)
+
+.PARAMETER Project
+    Project name to query. Auto-selected if only one project is cached.
+    Use -Action projects to list available projects.
+
+.PARAMETER Namespace
+    Namespace to query types from (used with -Action types).
+
+.PARAMETER TypeName
+    Full type name e.g. "Microsoft.UI.Xaml.Controls.Button" (used with -Action members, enums).
+
+.PARAMETER Query
+    Search query string (used with -Action search).
+
+.PARAMETER Filter
+    Optional prefix filter for namespaces (used with -Action namespaces).
+
+.PARAMETER CacheDir
+    Path to the winmd-cache directory. Defaults to "Generated Files\winmd-cache"
+    relative to the workspace root.
+
+.PARAMETER MaxResults
+    Maximum number of results to return for search. Defaults to 30.
+
+.EXAMPLE
+    .\Invoke-WinMdQuery.ps1 -Action projects
+    .\Invoke-WinMdQuery.ps1 -Action packages -Project BlankWInUI
+    .\Invoke-WinMdQuery.ps1 -Action stats -Project BlankWInUI
+    .\Invoke-WinMdQuery.ps1 -Action namespaces -Filter "Microsoft.UI"
+    .\Invoke-WinMdQuery.ps1 -Action types -Namespace "Microsoft.UI.Xaml.Controls"
+    .\Invoke-WinMdQuery.ps1 -Action members -TypeName "Microsoft.UI.Xaml.Controls.Button"
+    .\Invoke-WinMdQuery.ps1 -Action search -Query "NavigationView"
+    .\Invoke-WinMdQuery.ps1 -Action enums -TypeName "Microsoft.UI.Xaml.Visibility"
+#>
+[CmdletBinding()]
+param(
+    [Parameter(Mandatory)]
+    [ValidateSet('projects', 'packages', 'stats', 'namespaces', 'types', 'members', 'search', 'enums')]
+    [string]$Action,
+
+    [string]$Project,
+    [string]$Namespace,
+    [string]$TypeName,
+    [string]$Query,
+    [string]$Filter,
+    [string]$CacheDir,
+    [int]$MaxResults = 30
+)
+
+# ─── Resolve cache directory ─────────────────────────────────────────────────
+
+if (-not $CacheDir) {
+    # Convention: skill lives at .github/skills/winmd-api-search/scripts/
+    # so workspace root is 4 levels up from $PSScriptRoot.
+    $scriptDir = $PSScriptRoot
+    $root = (Resolve-Path (Join-Path $scriptDir '..\..\..\..')).Path
+    $CacheDir = Join-Path $root 'Generated Files\winmd-cache'
+}
+
+if (-not (Test-Path $CacheDir)) {
+    Write-Error "Cache not found at: $CacheDir`nRun: .\Update-WinMdCache.ps1 (from .github\skills\winmd-api-search\scripts\)"
+    exit 1
+}
+
+# ─── Project resolution helpers ──────────────────────────────────────────────
+
+function Get-CachedProjects {
+    $projectsDir = Join-Path $CacheDir 'projects'
+    if (-not (Test-Path $projectsDir)) { return @() }
+    Get-ChildItem $projectsDir -Filter '*.json' | ForEach-Object { $_.BaseName }
+}
+
+function Resolve-ProjectManifest {
+    param([string]$Name)
+
+    $projectsDir = Join-Path $CacheDir 'projects'
+    if (-not (Test-Path $projectsDir)) {
+        Write-Error "No projects cached. Run Update-WinMdCache.ps1 first."
+        exit 1
+    }
+
+    if ($Name) {
+        $path = Join-Path $projectsDir "$Name.json"
+        if (-not (Test-Path $path)) {
+            $available = (Get-CachedProjects) -join ', '
+            Write-Error "Project '$Name' not found. Available: $available"
+            exit 1
+        }
+        return Get-Content $path | ConvertFrom-Json
+    }
+
+    # Auto-select if only one project
+    $manifests = Get-ChildItem $projectsDir -Filter '*.json' -ErrorAction SilentlyContinue
+    if ($manifests.Count -eq 0) {
+        Write-Error "No projects cached. Run Update-WinMdCache.ps1 first."
+        exit 1
+    }
+    if ($manifests.Count -eq 1) {
+        return Get-Content $manifests[0].FullName | ConvertFrom-Json
+    }
+
+    $available = ($manifests | ForEach-Object { $_.BaseName }) -join ', '
+    Write-Error "Multiple projects cached — use -Project to specify. Available: $available"
+    exit 1
+}
+
+function Get-PackageCacheDirs {
+    param($Manifest)
+    $dirs = @()
+    foreach ($pkg in $Manifest.packages) {
+        $dir = Join-Path $CacheDir 'packages' $pkg.id $pkg.version
+        if (Test-Path $dir) {
+            $dirs += $dir
+        }
+    }
+    return $dirs
+}
+
+# ─── Action: projects ────────────────────────────────────────────────────────
+
+function Show-Projects {
+    $projects = Get-CachedProjects
+    if ($projects.Count -eq 0) {
+        Write-Output "No projects cached."
+        return
+    }
+    Write-Output "Cached projects ($($projects.Count)):"
+    foreach ($p in $projects) {
+        $manifest = Get-Content (Join-Path $CacheDir 'projects' "$p.json") | ConvertFrom-Json
+        $pkgCount = $manifest.packages.Count
+        Write-Output "  $p ($pkgCount package(s))"
+    }
+}
+
+# ─── Action: packages ────────────────────────────────────────────────────────
+
+function Show-Packages {
+    $manifest = Resolve-ProjectManifest -Name $Project
+    Write-Output "Packages for project '$($manifest.projectName)' ($($manifest.packages.Count)):"
+    foreach ($pkg in $manifest.packages) {
+        $metaPath = Join-Path $CacheDir 'packages' $pkg.id $pkg.version 'meta.json'
+        if (Test-Path $metaPath) {
+            $meta = Get-Content $metaPath | ConvertFrom-Json
+            Write-Output "  $($pkg.id)@$($pkg.version) — $($meta.totalTypes) types, $($meta.totalMembers) members"
+        } else {
+            Write-Output "  $($pkg.id)@$($pkg.version) — (cache missing)"
+        }
+    }
+}
+
+# ─── Action: stats ───────────────────────────────────────────────────────────
+
+function Show-Stats {
+    $manifest = Resolve-ProjectManifest -Name $Project
+    $totalTypes = 0
+    $totalMembers = 0
+    $totalNamespaces = 0
+    $totalWinMd = 0
+
+    foreach ($pkg in $manifest.packages) {
+        $metaPath = Join-Path $CacheDir 'packages' $pkg.id $pkg.version 'meta.json'
+        if (Test-Path $metaPath) {
+            $meta = Get-Content $metaPath | ConvertFrom-Json
+            $totalTypes += $meta.totalTypes
+            $totalMembers += $meta.totalMembers
+            $totalNamespaces += $meta.totalNamespaces
+            $totalWinMd += $meta.winMdFiles.Count
+        }
+    }
+
+    Write-Output "WinMD Index Statistics — $($manifest.projectName)"
+    Write-Output "======================================"
+    Write-Output "  Packages:   $($manifest.packages.Count)"
+    Write-Output "  Namespaces: $totalNamespaces (may overlap across packages)"
+    Write-Output "  Types:      $totalTypes"
+    Write-Output "  Members:    $totalMembers"
+    Write-Output "  WinMD files: $totalWinMd"
+}
+
+# ─── Action: namespaces ──────────────────────────────────────────────────────
+
+function Get-Namespaces {
+    param([string]$Prefix)
+    $manifest = Resolve-ProjectManifest -Name $Project
+    $dirs = Get-PackageCacheDirs -Manifest $manifest
+    $allNs = @()
+
+    foreach ($dir in $dirs) {
+        $nsFile = Join-Path $dir 'namespaces.json'
+        if (Test-Path $nsFile) {
+            $allNs += (Get-Content $nsFile | ConvertFrom-Json)
+        }
+    }
+
+    $allNs = $allNs | Sort-Object -Unique
+    if ($Prefix) {
+        $allNs = $allNs | Where-Object { $_ -like "$Prefix*" }
+    }
+    $allNs | ForEach-Object { Write-Output $_ }
+}
+
+# ─── Action: types ───────────────────────────────────────────────────────────
+
+function Get-TypesInNamespace {
+    param([string]$Ns)
+    if (-not $Ns) {
+        Write-Error "-Namespace is required for 'types' action."
+        exit 1
+    }
+
+    $manifest = Resolve-ProjectManifest -Name $Project
+    $dirs = Get-PackageCacheDirs -Manifest $manifest
+    $safeFile = $Ns.Replace('.', '_') + '.json'
+    $found = $false
+    $seen = @{}
+
+    foreach ($dir in $dirs) {
+        $filePath = Join-Path $dir "types\$safeFile"
+        if (-not (Test-Path $filePath)) { continue }
+        $found = $true
+        $types = Get-Content $filePath | ConvertFrom-Json
+        foreach ($t in $types) {
+            if ($seen.ContainsKey($t.fullName)) { continue }
+            $seen[$t.fullName] = $true
+            Write-Output "$($t.kind) $($t.fullName)$(if ($t.baseType) { " : $($t.baseType)" } else { '' })"
+        }
+    }
+
+    if (-not $found) {
+        Write-Error "Namespace not found: $Ns"
+        exit 1
+    }
+}
+
+# ─── Action: members ─────────────────────────────────────────────────────────
+
+function Get-MembersOfType {
+    param([string]$FullName)
+    if (-not $FullName) {
+        Write-Error "-TypeName is required for 'members' action."
+        exit 1
+    }
+
+    $ns = $FullName.Substring(0, $FullName.LastIndexOf('.'))
+    $safeFile = $ns.Replace('.', '_') + '.json'
+
+    $manifest = Resolve-ProjectManifest -Name $Project
+    $dirs = Get-PackageCacheDirs -Manifest $manifest
+
+    foreach ($dir in $dirs) {
+        $filePath = Join-Path $dir "types\$safeFile"
+        if (-not (Test-Path $filePath)) { continue }
+
+        $types = Get-Content $filePath | ConvertFrom-Json
+        $type = $types | Where-Object { $_.fullName -eq $FullName }
+        if (-not $type) { continue }
+
+        Write-Output "$($type.kind) $($type.fullName)"
+        if ($type.baseType) { Write-Output "  Extends: $($type.baseType)" }
+        Write-Output ""
+        foreach ($m in $type.members) {
+            Write-Output "  [$($m.kind)] $($m.signature)"
+        }
+        return
+    }
+
+    Write-Error "Type not found: $FullName"
+    exit 1
+}
+
+# ─── Action: search ──────────────────────────────────────────────────────────
+# Ranks namespaces by best type-name match score.
+# Outputs: ranked namespaces with top matching types and the JSON file path.
+# The LLM can then read_file the JSON to inspect all members intelligently.
+
+function Search-WinMd {
+    param([string]$SearchQuery, [int]$Max)
+    if (-not $SearchQuery) {
+        Write-Error "-Query is required for 'search' action."
+        exit 1
+    }
+
+    $manifest = Resolve-ProjectManifest -Name $Project
+    $dirs = Get-PackageCacheDirs -Manifest $manifest
+
+    # Collect: namespace → { bestScore, matchingTypes[], filePath }
+    $nsResults = @{}
+
+    foreach ($dir in $dirs) {
+        $nsFile = Join-Path $dir 'namespaces.json'
+        if (-not (Test-Path $nsFile)) { continue }
+        $nsList = Get-Content $nsFile | ConvertFrom-Json
+
+        foreach ($n in $nsList) {
+            $safeFile = $n.Replace('.', '_') + '.json'
+            $filePath = Join-Path $dir "types\$safeFile"
+            if (-not (Test-Path $filePath)) { continue }
+
+            $types = Get-Content $filePath | ConvertFrom-Json
+            foreach ($t in $types) {
+                $score = Get-MatchScore -Name $t.name -FullName $t.fullName -Query $SearchQuery
+                if ($score -le 0) { continue }
+
+                if (-not $nsResults.ContainsKey($n)) {
+                    $nsResults[$n] = @{ BestScore = 0; Types = @(); FilePath = $filePath }
+                }
+                $entry = $nsResults[$n]
+                if ($score -gt $entry.BestScore) { $entry.BestScore = $score }
+                $entry.Types += "$($t.kind) $($t.fullName) [$score]"
+            }
+        }
+    }
+
+    if ($nsResults.Count -eq 0) {
+        Write-Output "No results found for: $SearchQuery"
+        return
+    }
+
+    $ranked = $nsResults.GetEnumerator() |
+        Sort-Object { $_.Value.BestScore } -Descending |
+        Select-Object -First $Max
+
+    foreach ($r in $ranked) {
+        $ns = $r.Key
+        $info = $r.Value
+        Write-Output "[$($info.BestScore)] $ns"
+        Write-Output "    File: $($info.FilePath)"
+        # Show top 5 matching types in this namespace
+        $info.Types | Select-Object -First 5 | ForEach-Object { Write-Output "    $_" }
+        Write-Output ""
+    }
+}
+
+# ─── Search scoring ──────────────────────────────────────────────────────────
+# Simple ranked scoring on type names. Higher = better.
+#   100 = exact name    80 = starts-with    60 = substring
+#    50 = PascalCase     40 = multi-keyword   20 = fuzzy subsequence
+
+function Get-MatchScore {
+    param([string]$Name, [string]$FullName, [string]$Query)
+
+    $q = $Query.Trim()
+    if (-not $q) { return 0 }
+
+    if ($Name -eq $q) { return 100 }
+    if ($Name -like "$q*") { return 80 }
+    if ($Name -like "*$q*" -or $FullName -like "*$q*") { return 60 }
+
+    $initials = ($Name.ToCharArray() | Where-Object { [char]::IsUpper($_) }) -join ''
+    if ($initials.Length -ge 2 -and $initials -like "*$q*") { return 50 }
+
+    $words = $q -split '\s+' | Where-Object { $_.Length -gt 0 }
+    if ($words.Count -gt 1) {
+        $allFound = $true
+        foreach ($w in $words) {
+            if ($Name -notlike "*$w*" -and $FullName -notlike "*$w*") {
+                $allFound = $false
+                break
+            }
+        }
+        if ($allFound) { return 40 }
+    }
+
+    if (Test-FuzzySubsequence -Text $Name -Pattern $q) { return 20 }
+
+    return 0
+}
+
+function Test-FuzzySubsequence {
+    param([string]$Text, [string]$Pattern)
+    $ti = 0
+    $tLower = $Text.ToLowerInvariant()
+    $pLower = $Pattern.ToLowerInvariant()
+    foreach ($ch in $pLower.ToCharArray()) {
+        $idx = $tLower.IndexOf($ch, $ti)
+        if ($idx -lt 0) { return $false }
+        $ti = $idx + 1
+    }
+    return $true
+}
+
+# ─── Action: enums ───────────────────────────────────────────────────────────
+
+function Get-EnumValues {
+    param([string]$FullName)
+    if (-not $FullName) {
+        Write-Error "-TypeName is required for 'enums' action."
+        exit 1
+    }
+
+    $ns = $FullName.Substring(0, $FullName.LastIndexOf('.'))
+    $safeFile = $ns.Replace('.', '_') + '.json'
+
+    $manifest = Resolve-ProjectManifest -Name $Project
+    $dirs = Get-PackageCacheDirs -Manifest $manifest
+
+    foreach ($dir in $dirs) {
+        $filePath = Join-Path $dir "types\$safeFile"
+        if (-not (Test-Path $filePath)) { continue }
+
+        $types = Get-Content $filePath | ConvertFrom-Json
+        $type = $types | Where-Object { $_.fullName -eq $FullName }
+        if (-not $type) { continue }
+
+        if ($type.kind -ne 'Enum') {
+            Write-Error "$FullName is not an Enum (kind: $($type.kind))"
+            exit 1
+        }
+        Write-Output "Enum $($type.fullName)"
+        if ($type.enumValues) {
+            $type.enumValues | ForEach-Object { Write-Output "  $_" }
+        } else {
+            Write-Output "  (no values)"
+        }
+        return
+    }
+
+    Write-Error "Type not found: $FullName"
+    exit 1
+}
+
+# ─── Dispatch ─────────────────────────────────────────────────────────────────
+
+switch ($Action) {
+    'projects'   { Show-Projects }
+    'packages'   { Show-Packages }
+    'stats'      { Show-Stats }
+    'namespaces' { Get-Namespaces -Prefix $Filter }
+    'types'      { Get-TypesInNamespace -Ns $Namespace }
+    'members'    { Get-MembersOfType -FullName $TypeName }
+    'search'     { Search-WinMd -SearchQuery $Query -Max $MaxResults }
+    'enums'      { Get-EnumValues -FullName $TypeName }
+}

.github/skills/winmd-api-search/scripts/Update-WinMdCache.ps1

@@ -0,0 +1,113 @@
+<#
+.SYNOPSIS
+    Generate or refresh the WinMD cache for the Agent Skill.
+
+.DESCRIPTION
+    Builds and runs the standalone cache generator to export cached JSON files
+    from all WinMD metadata found in project NuGet packages and Windows SDK.
+
+    The cache is per-package+version: if two projects reference the same
+    package at the same version, the WinMD data is parsed once and shared.
+
+    Supports single project or recursive scan of an entire repo.
+
+.PARAMETER ProjectDir
+    Path to a project directory (contains .csproj/.vcxproj), or a project file itself.
+    Defaults to scanning the workspace root.
+
+.PARAMETER Scan
+    Recursively discover all .csproj/.vcxproj files under ProjectDir.
+
+.PARAMETER OutputDir
+    Path to the cache output directory. Defaults to "Generated Files\winmd-cache".
+
+.EXAMPLE
+    .\Update-WinMdCache.ps1
+    .\Update-WinMdCache.ps1 -ProjectDir BlankWInUI
+    .\Update-WinMdCache.ps1 -Scan -ProjectDir .
+    .\Update-WinMdCache.ps1 -ProjectDir "src\MyApp\MyApp.csproj"
+#>
+[CmdletBinding()]
+param(
+    [string]$ProjectDir,
+    [switch]$Scan,
+    [string]$OutputDir = 'Generated Files\winmd-cache'
+)
+
+$ErrorActionPreference = 'Stop'
+
+# Convention: skill lives at .github/skills/winmd-api-search/scripts/
+# so workspace root is 4 levels up from $PSScriptRoot.
+$root = (Resolve-Path (Join-Path $PSScriptRoot '..\..\..\..')).Path
+$generatorProj = Join-Path $PSScriptRoot 'cache-generator' 'CacheGenerator.csproj'
+
+# Default: if no ProjectDir, scan the workspace root
+if (-not $ProjectDir) {
+    $ProjectDir = $root
+    $Scan = $true
+}
+
+Push-Location $root
+
+try {
+    # Detect installed .NET SDK — require >= 8.0
+    $dotnetSdks = dotnet --list-sdks 2>$null
+    $bestMajor = $dotnetSdks |
+        ForEach-Object { if ($_ -match '^(\d+)\.') { [int]$Matches[1] } } |
+        Where-Object { $_ -ge 8 } |
+        Sort-Object -Descending |
+        Select-Object -First 1
+
+    if (-not $bestMajor) {
+        Write-Error "No .NET SDK >= 8.0 found. Install from https://dotnet.microsoft.com/download"
+        exit 1
+    }
+
+    $targetFramework = "net$bestMajor.0"
+    Write-Host "Using .NET SDK: $targetFramework" -ForegroundColor Cyan
+
+    Write-Host "Building cache generator..." -ForegroundColor Cyan
+    dotnet restore $generatorProj -p:TargetFramework=$targetFramework --nologo -v q
+    dotnet build $generatorProj -c Release --nologo -v q -p:TargetFramework=$targetFramework --no-restore
+    if ($LASTEXITCODE -ne 0) {
+        Write-Error "Build failed"
+        exit 1
+    }
+
+    # Run the built executable directly (avoids dotnet run target framework mismatch issues)
+    $generatorDir = Join-Path $PSScriptRoot 'cache-generator'
+    $exePath = Join-Path $generatorDir "bin\Release\$targetFramework\CacheGenerator.exe"
+    if (-not (Test-Path $exePath)) {
+        # Fallback: try dll with dotnet
+        $dllPath = Join-Path $generatorDir "bin\Release\$targetFramework\CacheGenerator.dll"
+        if (Test-Path $dllPath) {
+            $exePath = $null
+        } else {
+            Write-Error "Built executable not found at: $exePath"
+            exit 1
+        }
+    }
+
+    $runArgs = @()
+    if ($Scan) {
+        $runArgs += '--scan'
+    }
+
+    $runArgs += $ProjectDir
+    $runArgs += $OutputDir
+
+    Write-Host "Exporting WinMD cache..." -ForegroundColor Cyan
+    if ($exePath) {
+        & $exePath @runArgs
+    } else {
+        dotnet $dllPath @runArgs
+    }
+    if ($LASTEXITCODE -ne 0) {
+        Write-Error "Cache export failed"
+        exit 1
+    }
+
+    Write-Host "Cache updated at: $OutputDir" -ForegroundColor Green
+} finally {
+    Pop-Location
+}

.github/skills/winmd-api-search/scripts/cache-generator/CacheGenerator.csproj

@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <!-- Default fallback; Update-WinMdCache.ps1 overrides via -p:TargetFramework=net{X}.0 -->
+    <TargetFramework Condition="'$(TargetFramework)' == ''">net8.0</TargetFramework>
+    <Nullable>enable</Nullable>
+    <ImplicitUsings>enable</ImplicitUsings>
+  </PropertyGroup>
+  <!-- System.Reflection.Metadata is inbox in net9.0+, only needed for net8.0 -->
+  <ItemGroup Condition="'$(TargetFramework)' == 'net8.0'">
+    <PackageReference Include="System.Reflection.Metadata" Version="9.*" />
+  </ItemGroup>
+
+  <!--
+    Baseline WinAppSDK packages: downloaded during restore so the cache generator
+    can always index WinAppSDK APIs, even if the target project hasn't been restored.
+    ExcludeAssets="all" means they're downloaded but don't affect this tool's build.
+  -->
+  <ItemGroup>
+    <PackageReference Include="Microsoft.WindowsAppSDK" Version="*" ExcludeAssets="all" />
+  </ItemGroup>
+</Project>

.github/skills/winmd-api-search/scripts/cache-generator/Directory.Build.props

@@ -0,0 +1,3 @@
+<Project>
+  <!-- Isolate this standalone tool from the repo-level build configuration -->
+</Project>

.github/skills/winmd-api-search/scripts/cache-generator/Directory.Build.targets

@@ -0,0 +1,3 @@
+<Project>
+  <!-- Isolate this standalone tool from the repo-level build targets -->
+</Project>

.github/skills/winmd-api-search/scripts/cache-generator/Directory.Packages.props

@@ -0,0 +1,3 @@
+<Project>
+  <!-- Isolate this standalone tool from the repo-level Central Package Management -->
+</Project>