Added export and import of plugin archives (#885)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Tools/PluginSystem/PluginArchive.cs

@@ -0,0 +1,80 @@
+using System.IO.Compression;
+
+namespace AIStudio.Tools.PluginSystem;
+
+public static class PluginArchive
+{
+    /// <summary>
+    /// The file extension of plugin archives.
+    /// </summary>
+    /// <remarks>
+    /// Keep in sync with SHARE_FILE_EXTENSION in runtime/src/share_sheet.rs: the runtime only hands
+    /// archives with this extension to the native share sheet.
+    /// </remarks>
+    public const string PLUGIN_FILE_EXTENSION = ".mwplugin";
+
+
+    // Compatibility shim for Windows-created ZIPs with backslashes in entry names (dotnet/runtime#27620);
+    // remove after dotnet/runtime#27620 and #41914 are fixed.
+    // See documentation/compatibility-shims/2026-07-plugin-archive-zip-backslashes.md.
+    public static void Extract(string sourceArchiveFileName, string destinationDirectory)
+    {
+        using var archive = ZipFile.OpenRead(sourceArchiveFileName);
+        Directory.CreateDirectory(destinationDirectory);
+
+        var destinationDirectoryFullPath = Path.GetFullPath(destinationDirectory);
+        if (!destinationDirectoryFullPath.EndsWith(Path.DirectorySeparatorChar))
+            destinationDirectoryFullPath += Path.DirectorySeparatorChar;
+
+        foreach (var entry in archive.Entries)
+        {
+            var normalizedEntryName = NormalizeEntryName(entry.FullName);
+            var destinationPath = GetEntryDestinationPath(destinationDirectoryFullPath, normalizedEntryName);
+
+            if (normalizedEntryName.EndsWith('/'))
+            {
+                if (entry.Length != 0)
+                    throw new InvalidDataException($"The plugin archive contains a directory entry with data: '{entry.FullName}'.");
+
+                Directory.CreateDirectory(destinationPath);
+                continue;
+            }
+
+            Directory.CreateDirectory(Path.GetDirectoryName(destinationPath)!);
+            entry.ExtractToFile(destinationPath);
+        }
+    }
+
+    private static string NormalizeEntryName(string entryName)
+    {
+        var normalizedEntryName = entryName.Replace('\\', '/');
+        if (string.IsNullOrWhiteSpace(normalizedEntryName))
+            throw new InvalidDataException("The plugin archive contains an empty entry name.");
+
+        if (normalizedEntryName.Contains('\0'))
+            throw new InvalidDataException($"The plugin archive contains an invalid entry name: '{entryName}'.");
+
+        if (normalizedEntryName.StartsWith('/'))
+            throw new InvalidDataException($"The plugin archive contains a rooted entry name: '{entryName}'.");
+
+        if (normalizedEntryName is [_, ':', ..])
+            throw new InvalidDataException($"The plugin archive contains a drive-qualified entry name: '{entryName}'.");
+
+        var pathSegments = normalizedEntryName.Split('/', StringSplitOptions.RemoveEmptyEntries);
+        if (pathSegments.Length == 0 || pathSegments.Any(segment => segment is "." or ".."))
+            throw new InvalidDataException($"The plugin archive contains an unsafe entry name: '{entryName}'.");
+
+        return normalizedEntryName;
+    }
+
+    private static string GetEntryDestinationPath(string destinationDirectoryFullPath, string normalizedEntryName)
+    {
+        var pathSegments = normalizedEntryName.Split('/', StringSplitOptions.RemoveEmptyEntries);
+        var relativePath = Path.Combine(pathSegments);
+        var destinationPath = Path.GetFullPath(Path.Combine(destinationDirectoryFullPath, relativePath));
+        if (!destinationPath.StartsWith(destinationDirectoryFullPath, StringComparison.Ordinal))
+            throw new InvalidDataException($"The plugin archive contains an entry outside the destination directory: '{normalizedEntryName}'.");
+
+        return destinationPath;
+    }
+}

app/MindWork AI Studio/Tools/PluginSystem/PluginConfiguration.cs

@@ -179,6 +179,12 @@ public sealed class PluginConfiguration(bool isInternal, LuaState state, PluginT
         // Config: allow the user to add providers?
         ManagedConfiguration.TryProcessConfiguration(x => x.App, x => x.AllowUserToAddProvider, this.Id, settingsTable, dryRun);
 
+        // Config: allow the user to import plugin archives?
+        ManagedConfiguration.TryProcessConfiguration(x => x.App, x => x.AllowUserToImportPlugins, this.Id, settingsTable, dryRun);
+
+        // Config: allow the user to share or export plugins?
+        ManagedConfiguration.TryProcessConfiguration(x => x.App, x => x.AllowUserToSharePlugins, this.Id, settingsTable, dryRun);
+
         // Config: show administration settings?
         ManagedConfiguration.TryProcessConfiguration(x => x.App, x => x.ShowAdminSettings, this.Id, settingsTable, dryRun);
         

app/MindWork AI Studio/Tools/PluginSystem/PluginFactory.Download.cs

@@ -1,4 +1,3 @@
-using System.IO.Compression;
 using System.Net.Http.Headers;
 
 namespace AIStudio.Tools.PluginSystem;
@@ -130,69 +129,11 @@ public static partial class PluginFactory
         return wasSuccessful;
     }
 
-    // Compatibility shim for Windows-created ZIPs with backslashes in entry names (dotnet/runtime#27620).
-    // See documentation/compatibility-shims/2026-07-enterprise-config-zip-backslashes.md.
     private static void ExtractConfigPluginArchive(string sourceArchiveFileName, string destinationDirectory)
     {
-        using var archive = ZipFile.OpenRead(sourceArchiveFileName);
-        Directory.CreateDirectory(destinationDirectory);
-
-        var destinationDirectoryFullPath = Path.GetFullPath(destinationDirectory);
-        if (!destinationDirectoryFullPath.EndsWith(Path.DirectorySeparatorChar))
-            destinationDirectoryFullPath += Path.DirectorySeparatorChar;
-
-        foreach (var entry in archive.Entries)
-        {
-            var normalizedEntryName = NormalizeConfigPluginZipEntryName(entry.FullName);
-            var destinationPath = GetConfigPluginZipEntryDestinationPath(destinationDirectoryFullPath, normalizedEntryName);
-
-            if (normalizedEntryName.EndsWith('/'))
-            {
-                if (entry.Length != 0)
-                    throw new InvalidDataException($"The enterprise configuration plugin archive contains a directory entry with data: '{entry.FullName}'.");
-
-                Directory.CreateDirectory(destinationPath);
-                continue;
-            }
-
-            Directory.CreateDirectory(Path.GetDirectoryName(destinationPath)!);
-            entry.ExtractToFile(destinationPath);
-        }
+        PluginArchive.Extract(sourceArchiveFileName, destinationDirectory);
 
         if (!Directory.EnumerateFiles(destinationDirectory, "plugin.lua", SearchOption.AllDirectories).Any())
             throw new InvalidDataException("The enterprise configuration plugin archive does not contain a plugin.lua file.");
     }
-
-    private static string NormalizeConfigPluginZipEntryName(string entryName)
-    {
-        var normalizedEntryName = entryName.Replace('\\', '/');
-        if (string.IsNullOrWhiteSpace(normalizedEntryName))
-            throw new InvalidDataException("The enterprise configuration plugin archive contains an empty entry name.");
-
-        if (normalizedEntryName.Contains('\0'))
-            throw new InvalidDataException($"The enterprise configuration plugin archive contains an invalid entry name: '{entryName}'.");
-
-        if (normalizedEntryName.StartsWith('/'))
-            throw new InvalidDataException($"The enterprise configuration plugin archive contains a rooted entry name: '{entryName}'.");
-
-        if (normalizedEntryName is [_, ':', ..])
-            throw new InvalidDataException($"The enterprise configuration plugin archive contains a drive-qualified entry name: '{entryName}'.");
-
-        var pathSegments = normalizedEntryName.Split('/', StringSplitOptions.RemoveEmptyEntries);
-        if (pathSegments.Length == 0 || pathSegments.Any(segment => segment is "." or ".."))
-            throw new InvalidDataException($"The enterprise configuration plugin archive contains an unsafe entry name: '{entryName}'.");
-
-        return normalizedEntryName;
-    }
-
-    private static string GetConfigPluginZipEntryDestinationPath(string destinationDirectoryFullPath, string normalizedEntryName)
-    {
-        var pathSegments = normalizedEntryName.Split('/', StringSplitOptions.RemoveEmptyEntries);
-        var relativePath = Path.Combine(pathSegments);
-        var destinationPath = Path.GetFullPath(Path.Combine(destinationDirectoryFullPath, relativePath));
-        if (!destinationPath.StartsWith(destinationDirectoryFullPath, StringComparison.Ordinal))
-            throw new InvalidDataException($"The enterprise configuration plugin archive contains an entry outside the destination directory: '{normalizedEntryName}'.");
-
-        return destinationPath;
-    }
-}
+}

app/MindWork AI Studio/Tools/PluginSystem/PluginFactory.Loading.cs

@@ -265,6 +265,14 @@ public static partial class PluginFactory
         if(ManagedConfiguration.IsConfigurationLeftOver(x => x.App, x => x.AllowUserToAddProvider, AVAILABLE_PLUGINS))
             wasConfigurationChanged = true;
 
+        // Check for the plugin import permission:
+        if(ManagedConfiguration.IsConfigurationLeftOver(x => x.App, x => x.AllowUserToImportPlugins, AVAILABLE_PLUGINS))
+            wasConfigurationChanged = true;
+
+        // Check for the plugin sharing permission:
+        if(ManagedConfiguration.IsConfigurationLeftOver(x => x.App, x => x.AllowUserToSharePlugins, AVAILABLE_PLUGINS))
+            wasConfigurationChanged = true;
+
         // Check for admin settings visibility:
         if(ManagedConfiguration.IsConfigurationLeftOver(x => x.App, x => x.ShowAdminSettings, AVAILABLE_PLUGINS))
             wasConfigurationChanged = true;
@@ -377,16 +385,24 @@ public static partial class PluginFactory
         }
     }
 
-    public static async Task<PluginBase> Load(string? pluginPath, string code, CancellationToken cancellationToken = default)
+    /// <param name="pluginPath">The directory the plugin is located in, or null when the code has no directory yet.</param>
+    /// <param name="code">The Lua code of the plugin's main file.</param>
+    /// <param name="cancellationToken">Cancellation token for running the Lua code.</param>
+    /// <param name="allowedBaseDirectory">
+    /// The directory the plugin path must be nested in. Without it, the installed plugins directory
+    /// is used. Validating a plugin before its installation needs this, because the plugin lives in
+    /// a staging directory at that point and could not load any of its own Lua modules otherwise.
+    /// </param>
+    public static async Task<PluginBase> Load(string? pluginPath, string code, CancellationToken cancellationToken = default, string? allowedBaseDirectory = null)
     {
         if(ForbiddenPlugins.Check(code) is { IsForbidden: true } forbiddenState)
             return new NoPlugin($"This plugin is forbidden: {forbiddenState.Message}");
-        
+
         var state = LuaState.Create();
         if (!string.IsNullOrWhiteSpace(pluginPath))
         {
             // Add the module loader so that the plugin can load other Lua modules:
-            state.ModuleLoader = new PluginLoader(pluginPath);
+            state.ModuleLoader = new PluginLoader(pluginPath, allowedBaseDirectory);
         }
 
         // Add some useful libraries:

app/MindWork AI Studio/Tools/PluginSystem/PluginLoader.cs

@@ -14,10 +14,17 @@ namespace AIStudio.Tools.PluginSystem;
 /// Loading other modules outside the plugin directory is not allowed.
 /// </remarks>
 /// <param name="pluginDirectory">The directory where the plugin is located.</param>
-public sealed class PluginLoader(string pluginDirectory) : ILuaModuleLoader
+/// <param name="allowedBaseDirectory">
+/// The directory the plugin directory must be nested in. Without it, the installed plugins directory
+/// is used. Validating a plugin before its installation needs this, because the plugin is not
+/// installed yet and lives in a staging directory outside the installed plugins directory.
+/// </param>
+public sealed class PluginLoader(string pluginDirectory, string? allowedBaseDirectory = null) : ILuaModuleLoader
 {
     private static readonly string PLUGIN_BASE_PATH = Path.Join(SettingsManager.DataDirectory, "plugins");
 
+    private readonly string baseDirectory = string.IsNullOrWhiteSpace(allowedBaseDirectory) ? PLUGIN_BASE_PATH : allowedBaseDirectory;
+
     #region Implementation of ILuaModuleLoader
 
     /// <inheritdoc />
@@ -26,11 +33,11 @@ public sealed class PluginLoader(string pluginDirectory) : ILuaModuleLoader
         // Ensure that the user doesn't try to escape the plugin directory:
         if (moduleName.Contains("..") || pluginDirectory.Contains(".."))
             return false;
-        
-        // Ensure that the plugin directory is nested in the plugin base path:
-        if (!pluginDirectory.StartsWith(PLUGIN_BASE_PATH, StringComparison.OrdinalIgnoreCase))
+
+        // Ensure that the plugin directory is nested in the allowed base directory:
+        if (!pluginDirectory.StartsWith(this.baseDirectory, StringComparison.OrdinalIgnoreCase))
             return false;
-        
+
         var path = Path.Join(pluginDirectory, $"{moduleName}.lua");
         return File.Exists(path);
     }
@@ -40,7 +47,7 @@ public sealed class PluginLoader(string pluginDirectory) : ILuaModuleLoader
     {
         var path = Path.Join(pluginDirectory, $"{moduleName}.lua");
         var code = await File.ReadAllTextAsync(path, Encoding.UTF8, cancellationToken);
-		
+
         return new(moduleName, code);
     }
 

app/MindWork AI Studio/Tools/Rust/FileTypes.cs

@@ -1,4 +1,5 @@
 using AIStudio.Tools.PluginSystem;
+
 // ReSharper disable MemberCanBePrivate.Global
 
 namespace AIStudio.Tools.Rust;
@@ -81,6 +82,7 @@ public static class FileTypes
     // Other standalone types
     public static readonly FileTypeFilter CERTIFICATE_BUNDLE = FileTypeFilter.Leaf(TB("Certificate bundle"), "pem", "crt", "cer");
     public static readonly FileTypeFilter EXECUTABLES = FileTypeFilter.Leaf(TB("Executable"), "exe", "app", "bin", "appimage");
+    public static readonly FileTypeFilter PLUGIN_ARCHIVE = FileTypeFilter.Leaf(TB("Plugin archive"), PluginArchive.PLUGIN_FILE_EXTENSION.TrimStart('.'), "zip");
     
     public static FileTypeFilter? AsOneFileType(params FileTypeFilter[]? types)
     {

app/MindWork AI Studio/Tools/Services/AssistantPluginCheckResult.cs

@@ -0,0 +1,3 @@
+namespace AIStudio.Tools.Services;
+
+public sealed record AssistantPluginCheckResult(bool Success, Guid PluginId, string PluginName, string Issue);

app/MindWork AI Studio/Tools/Services/AssistantPluginDeleteResult.cs

@@ -0,0 +1,3 @@
+namespace AIStudio.Tools.Services;
+
+public sealed record AssistantPluginDeleteResult(bool Success, Guid PluginId, string PluginName, string PluginDirectory, string Issue);

app/MindWork AI Studio/Tools/Services/AssistantPluginInstallResult.cs

@@ -0,0 +1,3 @@
+namespace AIStudio.Tools.Services;
+
+public sealed record AssistantPluginInstallResult(bool Success, Guid PluginId, string PluginName, string PluginDirectory, bool ReplacedExisting, string Issue, bool Cancelled = false);

app/MindWork AI Studio/Tools/Services/AssistantPluginInstallService.cs

@@ -4,17 +4,10 @@ using AIStudio.Tools.AssistantSessions;
 using AIStudio.Tools.Media;
 using AIStudio.Tools.PluginSystem;
 using AIStudio.Tools.PluginSystem.Assistants;
+using AIStudio.Tools.Rust;
 
 namespace AIStudio.Tools.Services;
 
-public sealed record AssistantPluginInstallResult(bool Success, Guid PluginId, string PluginName, string PluginDirectory, bool ReplacedExisting, string Issue);
-
-public sealed record AssistantPluginCheckResult(bool Success, Guid PluginId, string PluginName, string Issue);
-
-public sealed record AssistantPluginDeleteResult(bool Success, Guid PluginId, string PluginName, string PluginDirectory, string Issue);
-
-public sealed record AssistantPluginUpdateResult(bool Success, Guid PluginId, string PluginName, string PluginDirectory, string Issue);
-
 public sealed class AssistantPluginInstallService
 {
     private static string TB(string fallbackEN) => I18N.I.T(fallbackEN, typeof(AssistantPluginInstallService).Namespace, nameof(AssistantPluginInstallService));
@@ -22,6 +15,7 @@ public sealed class AssistantPluginInstallService
     private const string PLUGIN_FILE_NAME = "plugin.lua";
     private const string ASSISTANT_BUILDER_DIRECTORY_PREFIX = "assistant-builder";
     private const string DELETE_BACKUP_DIRECTORY = ".plugin-delete-backups";
+    private const string INSTALL_BACKUP_DIRECTORY = ".plugin-install-backups";
     private const int DIRECTORY_PREFIX_MAX_LEN = 80;
     
     private readonly ILogger<AssistantPluginInstallService> logger;
@@ -31,6 +25,8 @@ public sealed class AssistantPluginInstallService
     private readonly SemaphoreSlim installSemaphore = new(1, 1);
     
     private static AssistantPluginInstallResult Error(string issue) => new(false, Guid.Empty, string.Empty, string.Empty, false, issue);
+
+    private static AssistantPluginInstallResult CancelledByUser() => new(false, Guid.Empty, string.Empty, string.Empty, false, string.Empty, true);
     
     private static AssistantPluginCheckResult CheckError(string issue) => new(false, Guid.Empty, string.Empty, issue);
     
@@ -38,11 +34,7 @@ public sealed class AssistantPluginInstallService
 
     private static AssistantPluginUpdateResult UpdateError(IPluginMetadata plugin, string pluginDirectory, string issue) => new(false, plugin.Id, plugin.Name, pluginDirectory, issue);
 
-    public AssistantPluginInstallService(
-        ILogger<AssistantPluginInstallService> logger,
-        SettingsManager settingsManager,
-        AssistantSessionService assistantSessionService,
-        MediaTranscriptionService mediaTranscriptionService)
+    public AssistantPluginInstallService(ILogger<AssistantPluginInstallService> logger, SettingsManager settingsManager, AssistantSessionService assistantSessionService, MediaTranscriptionService mediaTranscriptionService)
     {
         this.logger = logger;
         this.settingsManager = settingsManager;
@@ -127,76 +119,104 @@ public sealed class AssistantPluginInstallService
             return Error(rootIssue);
 
         await this.installSemaphore.WaitAsync(token);
-        AssistantPluginValidationResult validation;
         try
         {
-            validation = await this.ValidateIntoStagingAsync(lua, token);
+            var validation = await this.ValidateIntoStagingAsync(lua, token);
             if (!validation.Success || validation.AssistantPlugin is null)
                 return Error(validation.Issue);
 
-            Directory.CreateDirectory(assistantPluginsRoot);
+            return await this.InstallStagedAssistantAsync(assistantPluginsRoot, validation, token);
+        }
+        finally
+        {
+            this.installSemaphore.Release();
+        }
+    }
 
-            var stagingDirectory = validation.StagingDirectory;
-            var assistantPlugin = validation.AssistantPlugin;
-            string? backupDirectory = null;
-            string? finalDirectory = null;
-            var replacedExisting = false;
+    /// <summary>
+    /// Installs an assistant plugin archive that contains exactly one <c>plugin.lua</c> file.
+    /// Companion files are validated from and moved with the same staging directory.
+    /// </summary>
+    /// <param name="archivePath">The local <c>.mwplugin</c> or <c>.zip</c> archive path.</param>
+    /// <param name="confirmAsync">
+    /// Asks the user whether the validated archive may be installed. It is called after all checks
+    /// passed and before anything gets written. Returning false aborts the installation.
+    /// </param>
+    /// <param name="token">Cancellation token for extraction, validation, file IO, and plugin reload.</param>
+    /// <returns>Installation result that contains success state, installed plugin metadata, and a user-facing issue when installation failed.</returns>
+    public async Task<AssistantPluginInstallResult> InstallArchiveAsync(string archivePath, Func<PluginImportPreview, Task<bool>> confirmAsync, CancellationToken token)
+    {
+        if (!this.settingsManager.ConfigurationData.App.AllowUserToImportPlugins)
+            return Error(TB("Your organization has disabled importing plugins."));
 
+        if (!FileTypes.IsAllowedPath(archivePath, FileTypes.PLUGIN_ARCHIVE))
+            return Error(TB("Please select a plugin archive with the extension .mwplugin or .zip."));
+
+        if (!File.Exists(archivePath))
+            return Error(TB("The selected plugin archive does not exist."));
+
+        if (!TryGetAssistantPluginsRoot(out var assistantPluginsRoot, out var rootIssue))
+            return Error(rootIssue);
+
+        if (!PluginFactory.IsInitialized)
+            return Error(TB("The plugin system is not initialized yet."));
+
+        await this.installSemaphore.WaitAsync(token);
+        var stagingDirectory = Path.Join(Path.GetTempPath(), $"assistant-plugin-import.staging-{Guid.NewGuid():N}");
+        try
+        {
             try
             {
-                finalDirectory = DetermineFinalDirectory(assistantPluginsRoot, assistantPlugin);
-                if (!IsPathInsideDirectory(assistantPluginsRoot, finalDirectory))
-                    return Error(TB("The resolved plugin directory is outside the assistant plugin directory."));
+                token.ThrowIfCancellationRequested();
+                PluginArchive.Extract(archivePath, stagingDirectory);
 
-                if (Directory.Exists(finalDirectory))
-                {
-                    replacedExisting = true;
-                    backupDirectory = Path.Join(assistantPluginsRoot, $".{Path.GetFileName(finalDirectory)}.backup-{Guid.NewGuid():N}");
-                    Directory.Move(finalDirectory, backupDirectory);
-                }
+                var pluginFiles = Directory.EnumerateFiles(stagingDirectory, PLUGIN_FILE_NAME, SearchOption.AllDirectories).ToArray();
+                if (pluginFiles.Length != 1)
+                    return Error(TB("The plugin archive must contain exactly one plugin.lua file."));
 
-                Directory.Move(stagingDirectory, finalDirectory);
-                if (!string.IsNullOrWhiteSpace(backupDirectory) && Directory.Exists(backupDirectory))
-                {
-                    try
-                    {
-                        Directory.Delete(backupDirectory, true);
-                    }
-                    catch (Exception e)
-                    {
-                        this.logger.LogError(e, $"Failed to delete assistant plugin backup directory '{backupDirectory}'.");
-                    }
-                }
+                var pluginFile = pluginFiles[0];
+                var pluginDirectory = Path.GetDirectoryName(pluginFile)!;
+                var pluginCode = await File.ReadAllTextAsync(pluginFile, Encoding.UTF8, token);
+                var validation = await ValidateAssistantPluginCodeAsync(
+                    pluginDirectory,
+                    pluginCode.Trim(),
+                    TB("Currently, only assistant plugins can be imported."),
+                    TB("The imported assistant plugin is invalid. Issue: {0}"),
+                    TB("The imported assistant plugin uses the ID of another installed plugin."),
+                    token);
 
-                await PluginFactory.LoadAll(token);
-                this.logger.LogInformation($"Installed assistant plugin '{assistantPlugin.Name}' ({assistantPlugin.Id}) to '{finalDirectory}'.");
-                return new(true, assistantPlugin.Id, assistantPlugin.Name, finalDirectory, replacedExisting, string.Empty);
+                if (!validation.Success || validation.AssistantPlugin is null)
+                    return Error(validation.Issue);
+
+                // A plugin the user imports by hand never comes from a config server. We reject such
+                // archives because AI Studio trusts this self-declared flag: an imported plugin
+                // claiming it would be neither replaceable nor deletable through the user interface:
+                if (validation.AssistantPlugin.IsManagedByConfigServer)
+                    return Error(TB("This plugin archive declares itself as managed by a config server. Only the IT department of your organization might deploy such plugins."));
+
+                // The archive would replace an existing plugin: reject it when that plugin belongs
+                // to the IT department. We check this before asking the user, so that the
+                // confirmation never offers something we would refuse afterwards anyway:
+                var replacementIssue = GetAssistantReplacementIssue(validation.AssistantPlugin.Id);
+                if (!string.IsNullOrEmpty(replacementIssue))
+                    return Error(replacementIssue);
+
+                // Everything is validated, but nothing was written yet. This is the point where the
+                // user decides, because the plugin code comes from an untrusted source:
+                if (!await confirmAsync(CreateImportPreview(validation.AssistantPlugin)))
+                    return CancelledByUser();
+
+                return await this.InstallStagedAssistantAsync(assistantPluginsRoot, validation with { StagingDirectory = pluginDirectory }, token);
             }
-            catch (Exception e)
+            catch (Exception e) when (e is not OperationCanceledException)
             {
-                this.logger.LogError(e, "Failed to install assistant plugin.");
-
-                if (!string.IsNullOrWhiteSpace(backupDirectory) && Directory.Exists(backupDirectory) && !string.IsNullOrWhiteSpace(finalDirectory) && !Directory.Exists(finalDirectory))
-                {
-                    try
-                    {
-                        Directory.Move(backupDirectory, finalDirectory);
-                    }
-                    catch (Exception restoreException)
-                    {
-                        this.logger.LogError(restoreException, "Failed to restore the previous assistant plugin after a failed installation.");
-                    }
-                }
-
+                this.logger.LogError(e, "Failed to extract or validate assistant plugin archive '{ArchivePath}'.", archivePath);
                 return Error(string.Format(TB("Unexpected error: {0}"), e.Message));
             }
-            finally
-            {
-                this.TryDeleteStagingDirectory(stagingDirectory);
-            }
         }
         finally
         {
+            this.TryDeleteStagingDirectory(stagingDirectory);
             this.installSemaphore.Release();
         }
     }
@@ -289,9 +309,10 @@ public sealed class AssistantPluginInstallService
             Directory.Move(pluginDirectory, backupDirectory);
 
             wasEnabled = this.settingsManager.ConfigurationData.EnabledPlugins.Remove(plugin.Id);
-            removedAudits = this.settingsManager.ConfigurationData.AssistantPluginAudits
-                .Where(audit => audit.PluginId == plugin.Id)
-                .ToList();
+            removedAudits =
+            [
+                .. this.settingsManager.ConfigurationData.AssistantPluginAudits.Where(audit => audit.PluginId == plugin.Id)
+            ];
 
             if (removedAudits.Count > 0)
                 this.settingsManager.ConfigurationData.AssistantPluginAudits.RemoveAll(audit => audit.PluginId == plugin.Id);
@@ -412,6 +433,79 @@ public sealed class AssistantPluginInstallService
         }
     }
 
+    private async Task<AssistantPluginInstallResult> InstallStagedAssistantAsync(string assistantPluginsRoot, AssistantPluginValidationResult validation, CancellationToken token)
+    {
+        var stagingDirectory = validation.StagingDirectory;
+        var assistantPlugin = validation.AssistantPlugin!;
+        string? backupDirectory = null;
+        string? finalDirectory = null;
+        var replacedExisting = false;
+        var movedIntoPlace = false;
+
+        try
+        {
+            Directory.CreateDirectory(assistantPluginsRoot);
+            finalDirectory = DetermineFinalDirectory(assistantPluginsRoot, assistantPlugin);
+            if (!IsPathInsideDirectory(assistantPluginsRoot, finalDirectory))
+                return Error(TB("The resolved plugin directory is outside the assistant plugin directory."));
+
+            var replacementIssue = GetAssistantReplacementIssue(assistantPlugin.Id);
+            if (!string.IsNullOrWhiteSpace(replacementIssue))
+                return Error(replacementIssue);
+
+            if (Directory.Exists(finalDirectory))
+            {
+                replacedExisting = true;
+
+                // The backup goes to a directory outside the plugin root, so the plugin loader
+                // cannot discover it during the reload below. Otherwise, the previous version
+                // would be loaded a second time, next to the version we are installing:
+                backupDirectory = CreateInstallBackupDirectory(assistantPlugin);
+                Directory.CreateDirectory(Path.GetDirectoryName(backupDirectory)!);
+                Directory.Move(finalDirectory, backupDirectory);
+            }
+
+            Directory.Move(stagingDirectory, finalDirectory);
+            movedIntoPlace = true;
+            await PluginFactory.LoadAll(token);
+
+            if (!string.IsNullOrWhiteSpace(backupDirectory))
+                TryDeleteDirectory(backupDirectory, "assistant plugin backup", this.logger);
+
+            this.logger.LogInformation("Installed assistant plugin '{PluginName}' ({PluginId}) to '{PluginDirectory}'.", assistantPlugin.Name, assistantPlugin.Id, finalDirectory);
+            return new(true, assistantPlugin.Id, assistantPlugin.Name, finalDirectory, replacedExisting, string.Empty);
+        }
+        catch (Exception e)
+        {
+            this.logger.LogError(e, "Failed to install assistant plugin.");
+
+            // Only remove the target directory when this installation actually moved the plugin
+            // there. Otherwise, when moving the previous plugin into the backup directory failed,
+            // we would delete the still intact previous plugin:
+            if (movedIntoPlace && !string.IsNullOrWhiteSpace(finalDirectory) && Directory.Exists(finalDirectory))
+                TryDeleteDirectory(finalDirectory, "failed assistant plugin installation", this.logger);
+
+            if (!string.IsNullOrWhiteSpace(backupDirectory) && Directory.Exists(backupDirectory) && !string.IsNullOrWhiteSpace(finalDirectory) && !Directory.Exists(finalDirectory))
+            {
+                try
+                {
+                    Directory.Move(backupDirectory, finalDirectory);
+                    await PluginFactory.LoadAll(CancellationToken.None);
+                }
+                catch (Exception restoreException)
+                {
+                    this.logger.LogError(restoreException, "Failed to restore the previous assistant plugin after a failed installation.");
+                }
+            }
+
+            return Error(string.Format(TB("Unexpected error: {0}"), e.Message));
+        }
+        finally
+        {
+            this.TryDeleteStagingDirectory(stagingDirectory);
+        }
+    }
+
     private async Task<AssistantPluginValidationResult> ValidateIntoStagingAsync(string lua, CancellationToken token)
     {
         if (string.IsNullOrWhiteSpace(lua))
@@ -429,12 +523,12 @@ public sealed class AssistantPluginInstallService
             var stagedPluginFile = Path.Join(stagingDirectory, PLUGIN_FILE_NAME);
             await File.WriteAllTextAsync(stagedPluginFile, pluginCode, Encoding.UTF8, token);
 
-            var validation = await this.ValidateAssistantPluginCodeAsync(
+            var validation = await ValidateAssistantPluginCodeAsync(
                 stagingDirectory,
                 pluginCode,
                 TB("The generated plugin is not an assistant plugin. Issue: {0}"),
                 TB("The generated assistant plugin is invalid. Issue: {0}"),
-                TB("The generated assistant plugin uses the ID of an internal AI Studio plugin."),
+                TB("The generated assistant plugin uses the ID of another installed plugin."),
                 token);
 
             if (!validation.Success || validation.AssistantPlugin is null)
@@ -460,12 +554,12 @@ public sealed class AssistantPluginInstallService
 
         try
         {
-            return await this.ValidateAssistantPluginCodeAsync(
+            return await ValidateAssistantPluginCodeAsync(
                 pluginDirectory,
                 lua.Trim(),
                 TB("The edited plugin is not an assistant plugin. Issue: {0}"),
                 TB("The edited assistant plugin is invalid. Issue: {0}"),
-                TB("The edited assistant plugin uses the ID of an internal AI Studio plugin."),
+                TB("The edited assistant plugin uses the ID of another installed plugin."),
                 token);
         }
         catch (Exception e)
@@ -475,23 +569,25 @@ public sealed class AssistantPluginInstallService
         }
     }
 
-    private async Task<AssistantPluginValidationResult> ValidateAssistantPluginCodeAsync(
-        string pluginDirectory,
-        string pluginCode,
-        string notAssistantIssue,
-        string invalidAssistantIssue,
-        string internalPluginIdIssue,
-        CancellationToken token)
+    private static async Task<AssistantPluginValidationResult> ValidateAssistantPluginCodeAsync(string pluginDirectory, string pluginCode,
+        string notAssistantIssue, string invalidAssistantIssue, string conflictingPluginIdIssue, CancellationToken token)
     {
-        var plugin = await PluginFactory.Load(pluginDirectory, pluginCode, token);
+        // The plugin is not installed yet: it sits in a staging directory outside the installed
+        // plugins directory. We allow that directory as the module base, so the plugin can load its
+        // own Lua modules, e.g., an icon.lua, while we validate it:
+        var plugin = await PluginFactory.Load(pluginDirectory, pluginCode, token, pluginDirectory);
         if (plugin is not PluginAssistants assistantPlugin)
             return AssistantPluginValidationResult.Failure(string.Format(notAssistantIssue, string.Join("; ", plugin.Issues)));
 
         if (!assistantPlugin.IsValid)
             return AssistantPluginValidationResult.Failure(string.Format(invalidAssistantIssue, string.Join("; ", assistantPlugin.Issues)));
 
-        if (PluginFactory.AvailablePlugins.Any(availablePlugin => availablePlugin.Type is PluginType.ASSISTANT && availablePlugin.Id == assistantPlugin.Id && availablePlugin.IsInternal))
-            return AssistantPluginValidationResult.Failure(internalPluginIdIssue);
+        // Plugin IDs must be unique across all plugin types: several lookups resolve a plugin by its
+        // ID alone, e.g., the base language plugin in PluginFactory.Starting. An assistant plugin
+        // carrying the ID of a language or configuration plugin would break those lookups. Reusing
+        // the ID of another local assistant plugin stays allowed: that is how updating one works.
+        if (PluginFactory.AvailablePlugins.Any(availablePlugin => availablePlugin.Id == assistantPlugin.Id && (availablePlugin.IsInternal || availablePlugin.Type is not PluginType.ASSISTANT)))
+            return AssistantPluginValidationResult.Failure(conflictingPluginIdIssue);
 
         return new(true, string.Empty, assistantPlugin, string.Empty);
     }
@@ -547,22 +643,63 @@ public sealed class AssistantPluginInstallService
             : TB("The assistant plugin directory does not exist.");
     }
 
-    private void TryDeleteStagingDirectory(string stagingDirectory)
-    {
-        TryDeleteDirectory(stagingDirectory, "assistant plugin staging", this.logger);
-    }
-    
+    private void TryDeleteStagingDirectory(string stagingDirectory) => TryDeleteDirectory(stagingDirectory, "assistant plugin staging", this.logger);
+
     private static string DetermineFinalDirectory(string assistantPluginsRoot, PluginAssistants assistantPlugin)
     {
-        var existingPlugin = PluginFactory.AvailablePlugins
-            .OfType<IAvailablePlugin>()
-            .FirstOrDefault(plugin => plugin.Type is PluginType.ASSISTANT && plugin.Id == assistantPlugin.Id && !plugin.IsInternal);
-
+        var existingPlugin = FindReplaceableAssistantPlugin(assistantPlugin.Id);
         return existingPlugin is not null
             ? existingPlugin.LocalPath
             : Path.Join(assistantPluginsRoot, CreatePluginDirectoryName(assistantPlugin));
     }
 
+    /// <summary>
+    /// Finds the local assistant plugin that an installation with the given ID would replace.
+    /// </summary>
+    /// <param name="pluginId">The ID of the assistant plugin about to be installed.</param>
+    /// <returns>The plugin that would be replaced, or null when the installation adds a new plugin.</returns>
+    private static IAvailablePlugin? FindReplaceableAssistantPlugin(Guid pluginId) => PluginFactory.AvailablePlugins
+        .OfType<IAvailablePlugin>()
+        .FirstOrDefault(plugin => plugin.Type is PluginType.ASSISTANT && plugin.Id == pluginId && !plugin.IsInternal);
+
+    /// <summary>
+    /// Collects the metadata an archive declares about itself, together with the information about
+    /// the installed plugin it would replace.
+    /// </summary>
+    /// <param name="assistantPlugin">The validated assistant plugin from the archive.</param>
+    /// <returns>The preview shown to the user before the installation starts.</returns>
+    private static PluginImportPreview CreateImportPreview(PluginAssistants assistantPlugin) => new(assistantPlugin, FindReplaceableAssistantPlugin(assistantPlugin.Id));
+
+    /// <summary>
+    /// Checks whether an installation may replace the assistant plugin that currently uses the given ID.
+    /// Plugins deployed by a Config Server belong to the organization's IT, so neither an import nor
+    /// the Assistant Builder may overwrite them.
+    /// </summary>
+    /// <param name="pluginId">The ID of the assistant plugin about to be installed.</param>
+    /// <returns>A user-facing issue when the existing plugin must not be replaced, an empty string otherwise.</returns>
+    private static string GetAssistantReplacementIssue(Guid pluginId)
+    {
+        var existingPlugin = FindReplaceableAssistantPlugin(pluginId);
+        if (existingPlugin is null)
+            return string.Empty;
+
+        if (existingPlugin.IsManagedByConfigServer)
+            return TB("Config server managed assistant plugins cannot be replaced.");
+
+        if (string.IsNullOrWhiteSpace(existingPlugin.LocalPath))
+            return string.Empty;
+
+        // The metadata above and the running plugin read the same Lua field. We check both, though,
+        // just like the deletion path does:
+        var runningPlugin = PluginFactory.RunningPlugins
+            .OfType<PluginAssistants>()
+            .FirstOrDefault(candidate => candidate.Id == pluginId && IsSameDirectory(candidate.PluginPath, existingPlugin.LocalPath));
+
+        return runningPlugin?.IsManagedByConfigServer is true
+            ? TB("Config server managed assistant plugins cannot be replaced.")
+            : string.Empty;
+    }
+
     private static string CreatePluginDirectoryName(PluginAssistants assistantPlugin)
     {
         var safeName = CreateSafeDirectoryNamePart(assistantPlugin.Name);
@@ -628,6 +765,12 @@ public sealed class AssistantPluginInstallService
         return Path.Join(backupRoot, $"assistant-{plugin.Id:N}-{Guid.NewGuid():N}");
     }
 
+    private static string CreateInstallBackupDirectory(IPluginMetadata plugin)
+    {
+        var backupRoot = Path.Join(SettingsManager.DataDirectory, INSTALL_BACKUP_DIRECTORY);
+        return Path.Join(backupRoot, $"assistant-{plugin.Id:N}-{Guid.NewGuid():N}");
+    }
+
     private async Task TryRestoreDeletedAssistantPluginAsync(IAvailablePlugin plugin, string pluginDirectory, string backupDirectory, bool wasEnabled, List<PluginAssistantAudit> removedAudits, CancellationToken token)
     {
         try

app/MindWork AI Studio/Tools/Services/AssistantPluginUpdateResult.cs

@@ -0,0 +1,3 @@
+namespace AIStudio.Tools.Services;
+
+public sealed record AssistantPluginUpdateResult(bool Success, Guid PluginId, string PluginName, string PluginDirectory, string Issue);

app/MindWork AI Studio/Tools/Services/NativeShareService.cs

@@ -0,0 +1,6 @@
+namespace AIStudio.Tools.Services;
+
+public sealed class NativeShareService(RustService rustService)
+{
+    public Task<bool> Share(string filePath) => rustService.ShareFile(filePath);
+}

app/MindWork AI Studio/Tools/Services/PluginImportPreview.cs

@@ -0,0 +1,17 @@
+using AIStudio.Tools.PluginSystem;
+
+namespace AIStudio.Tools.Services;
+
+/// <summary>
+/// What the user gets to see before a plugin archive is installed. It is not bound to a specific
+/// plugin type, so it also serves upcoming import paths for other plugin types.
+/// </summary>
+/// <param name="Plugin">The plugin from the archive, with the metadata it declares about itself.</param>
+/// <param name="ExistingPlugin">The installed plugin that gets replaced or null when the archive adds a new plugin.</param>
+public sealed record PluginImportPreview(IPluginMetadata Plugin, IAvailablePlugin? ExistingPlugin)
+{
+    /// <summary>
+    /// True when an installed plugin with the same ID gets replaced.
+    /// </summary>
+    public bool ReplacesExisting => this.ExistingPlugin is not null;
+}

app/MindWork AI Studio/Tools/Services/PluginShareResult.cs

@@ -0,0 +1,3 @@
+namespace AIStudio.Tools.Services;
+
+public sealed record PluginShareResult(bool Success, string PluginName, string ArchivePath, string Issue, bool Cancelled = false);

app/MindWork AI Studio/Tools/Services/PluginShareService.cs

@@ -0,0 +1,242 @@
+using System.IO.Compression;
+using AIStudio.Settings;
+using AIStudio.Tools.PluginSystem;
+using AIStudio.Tools.Rust;
+
+namespace AIStudio.Tools.Services;
+
+public sealed class PluginShareService(NativeShareService nativeShareService, RustService rustService, SettingsManager settingsManager, ILogger<PluginShareService> logger)
+{
+    private static PluginShareResult ShareError(IAvailablePlugin plugin, string issue) => new(false, plugin.Name, string.Empty, issue);
+    
+    private static string TB(string fallbackEN) => I18N.I.T(fallbackEN, typeof(PluginShareService).Namespace, nameof(PluginShareService));
+
+    private const string PLUGIN_FILE_NAME = "plugin.lua";
+
+    /// <remarks>
+    /// Keep in sync with SHARE_DIRECTORY_NAME in runtime/src/share_sheet.rs: the runtime only hands
+    /// archives from a directory with this name to the native share sheet.
+    /// </remarks>
+    private const string TEMPORARY_ARCHIVE_DIRECTORY = "mindwork-ai-studio-plugin-shares";
+
+    private const int TEMPORARY_ARCHIVE_RETENTION_HOURS = 24;
+    private const int FILE_NAME_PREFIX_MAX_LEN = 80;
+
+    /// <summary>
+    /// Creates a shareable plugin archive from a local plugin and hands it over to the user.
+    /// The archive contains the plugin root contents, so <c>plugin.lua</c> is located at the archive root.
+    /// </summary>
+    /// <remarks>
+    /// On Windows and macOS, the archive is created in a temporary directory and handed over to the
+    /// native share sheet. Linux has no such share sheet, since the XDG desktop portals do not provide
+    /// a share interface. Thus, the archive is exported to a location of the user's choice there.
+    /// </remarks>
+    /// <param name="plugin">The local plugin to archive and share.</param>
+    /// <param name="token">Cancellation token for archive creation.</param>
+    /// <returns>The share result, including the archive path when successful.</returns>
+    public async Task<PluginShareResult> ShareAsync(IAvailablePlugin plugin, CancellationToken token)
+    {
+        if (plugin.IsInternal)
+            return ShareError(plugin, TB("Internal plugins cannot be shared."));
+
+        if (plugin.IsManagedByConfigServer)
+            return ShareError(plugin, TB("Config Server managed plugins cannot be shared."));
+
+        if (!settingsManager.ConfigurationData.App.AllowUserToSharePlugins)
+            return ShareError(plugin, TB("Your organization has disabled sharing plugins."));
+
+        if (!TryGetPluginRoot(plugin, out var pluginRoot, out var issue))
+            return ShareError(plugin, issue);
+
+        if (OperatingSystem.IsLinux())
+            return await this.ExportAsync(plugin, pluginRoot, token);
+
+        return await this.ShareViaNativeSheetAsync(plugin, pluginRoot, token);
+    }
+
+    /// <summary>
+    /// Asks the user for a target location and writes the plugin archive to it.
+    /// </summary>
+    /// <param name="plugin">The local plugin to archive.</param>
+    /// <param name="pluginRoot">The validated plugin root directory.</param>
+    /// <param name="token">Cancellation token for archive creation.</param>
+    /// <returns>The share result, including the chosen archive path when successful.</returns>
+    private async Task<PluginShareResult> ExportAsync(IAvailablePlugin plugin, string pluginRoot, CancellationToken token)
+    {
+        var suggestedFileName = $"{CreateSafeFileNamePrefix(plugin.Name)}{PluginArchive.PLUGIN_FILE_EXTENSION}";
+        var saveResponse = await rustService.SaveFile(TB("Export plugin archive"), [FileTypes.PLUGIN_ARCHIVE], suggestedFileName);
+        if (saveResponse.UserCancelled)
+            return new(false, plugin.Name, string.Empty, string.Empty, true);
+
+        var archivePath = saveResponse.SaveFilePath;
+        try
+        {
+            token.ThrowIfCancellationRequested();
+            await Task.Run(() =>
+            {
+                token.ThrowIfCancellationRequested();
+
+                // The save dialog already asked the user about overwriting an existing file.
+                // ZipFile.CreateFromDirectory would fail on an existing file, though:
+                if (File.Exists(archivePath))
+                    File.Delete(archivePath);
+
+                ZipFile.CreateFromDirectory(pluginRoot, archivePath, CompressionLevel.Optimal, false);
+            }, token);
+
+            logger.LogInformation("Exported plugin '{PluginName}' ({PluginId}) to the archive '{ArchivePath}'.", plugin.Name, plugin.Id, archivePath);
+            return new(true, plugin.Name, archivePath, string.Empty);
+        }
+        catch (OperationCanceledException)
+        {
+            this.TryDeleteArchive(archivePath);
+            throw;
+        }
+        catch (Exception exception)
+        {
+            this.TryDeleteArchive(archivePath);
+            logger.LogError(exception, "Failed to export plugin '{PluginName}' ({PluginId}).", plugin.Name, plugin.Id);
+            return ShareError(plugin, string.Format(TB("Unexpected error: {0}"), exception.Message));
+        }
+    }
+
+    /// <summary>
+    /// Creates the plugin archive in a temporary directory and opens the native share sheet for it.
+    /// </summary>
+    /// <param name="plugin">The local plugin to archive and share.</param>
+    /// <param name="pluginRoot">The validated plugin root directory.</param>
+    /// <param name="token">Cancellation token for archive creation.</param>
+    /// <returns>The share result, including the retained temporary archive path when successful.</returns>
+    private async Task<PluginShareResult> ShareViaNativeSheetAsync(IAvailablePlugin plugin, string pluginRoot, CancellationToken token)
+    {
+        var archiveDirectory = Path.Join(Path.GetTempPath(), TEMPORARY_ARCHIVE_DIRECTORY);
+        var archivePath = Path.Join(archiveDirectory, $"{CreateSafeFileNamePrefix(plugin.Name)}-{plugin.Id:N}-{Guid.NewGuid():N}{PluginArchive.PLUGIN_FILE_EXTENSION}");
+
+        try
+        {
+            token.ThrowIfCancellationRequested();
+            Directory.CreateDirectory(archiveDirectory);
+            this.CleanUpExpiredArchives(archiveDirectory);
+
+            await Task.Run(() =>
+            {
+                token.ThrowIfCancellationRequested();
+                ZipFile.CreateFromDirectory(pluginRoot, archivePath, CompressionLevel.Optimal, false);
+            }, token);
+
+            token.ThrowIfCancellationRequested();
+            if (!await nativeShareService.Share(archivePath))
+            {
+                this.TryDeleteArchive(archivePath);
+                return ShareError(plugin, TB("The native share dialog could not be opened."));
+            }
+
+            logger.LogInformation("Created plugin archive '{ArchivePath}' for plugin '{PluginName}' ({PluginId}).", archivePath, plugin.Name, plugin.Id);
+            return new(true, plugin.Name, archivePath, string.Empty);
+        }
+        catch (OperationCanceledException)
+        {
+            this.TryDeleteArchive(archivePath);
+            throw;
+        }
+        catch (Exception exception)
+        {
+            this.TryDeleteArchive(archivePath);
+            logger.LogError(exception, "Failed to create a share archive for plugin '{PluginName}' ({PluginId}).", plugin.Name, plugin.Id);
+            return ShareError(plugin, string.Format(TB("Unexpected error: {0}"), exception.Message));
+        }
+    }
+
+    private static bool TryGetPluginRoot(IAvailablePlugin plugin, out string pluginRoot, out string issue)
+    {
+        pluginRoot = string.Empty;
+        issue = string.Empty;
+
+        if (string.IsNullOrWhiteSpace(plugin.LocalPath))
+        {
+            issue = TB("The plugin has no local directory.");
+            return false;
+        }
+
+        try
+        {
+            pluginRoot = Path.GetFullPath(plugin.LocalPath);
+        }
+        catch (Exception exception)
+        {
+            issue = string.Format(TB("The plugin directory is invalid: {0}"), exception.Message);
+            return false;
+        }
+
+        if (!Directory.Exists(pluginRoot))
+        {
+            issue = TB("The plugin directory does not exist.");
+            return false;
+        }
+
+        var pluginFile = Path.Join(pluginRoot, PLUGIN_FILE_NAME);
+        if (!IsPathInsideDirectory(pluginRoot, pluginFile) || !File.Exists(pluginFile))
+        {
+            issue = TB("The plugin directory does not contain a plugin.lua file.");
+            return false;
+        }
+
+        return true;
+    }
+
+    private void CleanUpExpiredArchives(string archiveDirectory)
+    {
+        var expiry = DateTime.UtcNow.AddHours(-TEMPORARY_ARCHIVE_RETENTION_HOURS);
+        foreach (var archivePath in Directory.EnumerateFiles(archiveDirectory, $"*{PluginArchive.PLUGIN_FILE_EXTENSION}", SearchOption.TopDirectoryOnly))
+        {
+            try
+            {
+                if (File.GetLastWriteTimeUtc(archivePath) < expiry)
+                    File.Delete(archivePath);
+            }
+            catch (Exception exception)
+            {
+                logger.LogWarning(exception, "Failed to delete expired plugin archive '{ArchivePath}'.", archivePath);
+            }
+        }
+    }
+
+    private static string CreateSafeFileNamePrefix(string pluginName)
+    {
+        var invalidCharacters = Path.GetInvalidFileNameChars().ToHashSet();
+        var fileName = new string(pluginName
+            .Trim()
+            .Select(character => char.IsLetterOrDigit(character) || ((character is '-' or '_' or '.') && !invalidCharacters.Contains(character))
+                ? character
+                : '-')
+            .ToArray())
+            .Trim('-', '.');
+
+        if (fileName.Length > FILE_NAME_PREFIX_MAX_LEN)
+            fileName = fileName[..FILE_NAME_PREFIX_MAX_LEN].Trim('-', '.');
+
+        return string.IsNullOrWhiteSpace(fileName) ? "plugin" : fileName;
+    }
+
+    private static bool IsPathInsideDirectory(string parentDirectory, string path)
+    {
+        var parentPath = Path.GetFullPath(parentDirectory).TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar) + Path.DirectorySeparatorChar;
+        var childPath = Path.GetFullPath(path).TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar) + Path.DirectorySeparatorChar;
+        return childPath.StartsWith(parentPath, StringComparison.OrdinalIgnoreCase);
+    }
+
+    private void TryDeleteArchive(string archivePath)
+    {
+        if (!File.Exists(archivePath))
+            return;
+
+        try
+        {
+            File.Delete(archivePath);
+        }
+        catch (Exception exception)
+        {
+            logger.LogWarning(exception, "Failed to delete temporary plugin archive '{ArchivePath}'.", archivePath);
+        }
+    }
+}

app/MindWork AI Studio/Tools/Services/RustService.Share.cs

@@ -0,0 +1,44 @@
+// ReSharper disable NotAccessedPositionalProperty.Local
+namespace AIStudio.Tools.Services;
+
+public sealed partial class RustService
+{
+    public async Task<bool> ShareFile(string filePath)
+    {
+        try
+        {
+            using var response = await this.http.PostAsJsonAsync("/share/file", new ShareFileRequest(filePath), this.jsonRustSerializerOptions);
+            if (!response.IsSuccessStatusCode)
+            {
+                this.logger?.LogError($"The Rust runtime rejected the share request: {response.StatusCode}.");
+                return false;
+            }
+
+            var result = await response.Content.ReadFromJsonAsync<ShareFileResponse>(this.jsonRustSerializerOptions);
+            if (result?.Success == true)
+                return true;
+
+            this.logger?.LogError($"The native share sheet could not be opened: {result?.Issue ?? "Unknown error"}");
+            return false;
+        }
+        catch (HttpRequestException exception)
+        {
+            this.logger?.LogWarning(exception, "Failed to reach the Rust runtime share endpoint.");
+            return false;
+        }
+        catch (TaskCanceledException exception)
+        {
+            this.logger?.LogWarning(exception, "Timed out while reaching the Rust runtime share endpoint.");
+            return false;
+        }
+        catch (Exception exception)
+        {
+            this.logger?.LogError(exception, "Failed to process the Rust runtime share response.");
+            return false;
+        }
+    }
+
+    private sealed record ShareFileRequest(string FilePath);
+    
+    private sealed record ShareFileResponse(bool Success, string Issue);
+}