Update for async export and refresh

README.md

@@ -17,6 +17,8 @@ This thing is called "World Manager," and it happens to pertain to someone else'
 - Detect worlds, resource packs, behavior packs, and world templates.
 - Inspect package metadata, pack relationships, icons, versions, UUIDs, and basic world facts.
 - Export worlds and packs as portable `.mcworld`, `.mcpack`, `.mctemplate`, and `.mcaddon` packages, or share them via Messages, AirDrop, etc. via the "Share" sheet.
+- Import `.mcworld`, `.mcpack`, `.mctemplate`, and nested-package `.mcaddon` files into writable folder and connected-device sources.
+- Copy an item between sources by dragging it onto the destination source in the sidebar.
 - Preview and thumbnail supported Minecraft package files with Quick Look extensions.
 
 ## Usage
@@ -43,6 +45,14 @@ From an item's detail view, you can export it to a Minecraft package file on you
 
 If you share to another device with AirDrop, Messages, or a similar route, opening the received file on that device should launch Minecraft and begin Minecraft's normal import flow.
 
+### Importing and Copying
+
+Select a source and use `Import...` on its overview, or drop a supported Minecraft package onto the source row in the sidebar. World Manager inspects the package and places each item in the collection appropriate to its content type.
+
+You can also drag an existing world or pack from the item list onto another source. The app exports a temporary portable representation, validates it through the same import path, and installs it in the destination.
+
+Imports are additive. Existing worlds are never overwritten. A second world import receives a unique directory name. Packs with a UUID already present in the destination are rejected instead of being silently replaced.
+
 ## Requirements
 
 - macOS 26.2 or newer, based on the current Xcode project deployment target. Could work with older macOS. I don't have any so I don't know.
@@ -97,7 +107,7 @@ See [docs/ios-device-access.md](docs/ios-device-access.md) for the current devic
 
 ## Project Status
 
-This is pre-release software. Make sure Minecraft worlds and packs are being backed up by other means before using this app. The project is currently focused on read-only library access and export, and connected-device discovery, so it shouldn't be doing anything that can break your existing libraries.
+This is pre-release software. Make sure Minecraft worlds and packs are being backed up by other means before using this app. Connected-device installation writes through private Apple MobileDevice interfaces and should be treated as best-effort. The initial implementation installs only into new directories and does not replace or remove existing content.
 
 ## Trademarks
 

World Manager for Minecraft.xcodeproj/xcshareddata/xcschemes/MinecraftPackagePreviewExtension.xcscheme

@@ -74,6 +74,7 @@
       savedToolIdentifier = ""
       useCustomWorkingDirectory = "NO"
       debugDocumentVersioning = "YES"
+      askForAppToLaunch = "Yes"
       launchAutomaticallySubstyle = "2">
       <BuildableProductRunnable
          runnableDebuggingMode = "0">

World Manager for Minecraft.xcodeproj/xcshareddata/xcschemes/MinecraftPackageThumbnailExtension.xcscheme

@@ -73,6 +73,7 @@
       savedToolIdentifier = ""
       useCustomWorkingDirectory = "NO"
       debugDocumentVersioning = "YES"
+      askForAppToLaunch = "Yes"
       launchAutomaticallySubstyle = "2">
       <BuildableProductRunnable
          runnableDebuggingMode = "0">

World Manager for Minecraft/Models/Sources/SourceCapabilities.swift

@@ -7,16 +7,19 @@ nonisolated struct SourceCapabilities: Hashable, Sendable, Codable {
     var canScan: Bool = true
     var canMaterializeItems: Bool = true
     var canExportPortablePackages: Bool = true
+    var canInstallItems: Bool = false
 
     static let localFolder = SourceCapabilities(
         canScan: true,
         canMaterializeItems: true,
-        canExportPortablePackages: true
+        canExportPortablePackages: true,
+        canInstallItems: true
     )
 
     static let connectedDevice = SourceCapabilities(
         canScan: true,
         canMaterializeItems: true,
-        canExportPortablePackages: true
+        canExportPortablePackages: true,
+        canInstallItems: true
     )
 }

World Manager for Minecraft/Services/AppSupport/Import/MinecraftPackageInstaller.swift

@@ -0,0 +1,361 @@
+// SPDX-FileCopyrightText: 2026 John Burwell and contributors
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import Foundation
+
+nonisolated struct InstallationPayload: Sendable {
+    let contentType: MinecraftContentType
+    let preparedDirectoryURL: URL
+    let displayName: String
+    let packUUID: String?
+    let packVersion: String?
+    let suggestedFolderName: String
+}
+
+nonisolated struct InstallationPlan: Sendable {
+    let payloads: [InstallationPayload]
+    let stagingRootURL: URL
+
+    func cleanup(fileManager: FileManager = .default) {
+        try? fileManager.removeItem(at: stagingRootURL)
+    }
+}
+
+nonisolated struct InstalledContentItem: Sendable {
+    let contentType: MinecraftContentType
+    let displayName: String
+    let destinationName: String
+}
+
+nonisolated struct SourceInstallationState: Hashable, Sendable {
+    let completedCount: Int
+    let totalCount: Int
+    let status: String
+}
+
+enum MinecraftPackageInstaller {
+    enum InstallError: LocalizedError {
+        case emptyPackage
+        case unsupportedAddonLayout
+        case archiveTooLarge
+        case tooManyEntries
+        case symbolicLinksNotSupported
+        case invalidPreparedContent
+        case duplicatePack(name: String, version: String?)
+        case duplicateArchivePath(String)
+        case partialInstallation(completed: Int, total: Int, reason: String)
+
+        var errorDescription: String? {
+            switch self {
+            case .emptyPackage:
+                return "The Minecraft package does not contain any files."
+            case .unsupportedAddonLayout:
+                return "The .mcaddon package does not contain any supported Minecraft package files."
+            case .archiveTooLarge:
+                return "The expanded Minecraft package is too large to import safely."
+            case .tooManyEntries:
+                return "The Minecraft package contains too many files to import safely."
+            case .symbolicLinksNotSupported:
+                return "Minecraft packages containing symbolic links are not supported."
+            case .invalidPreparedContent:
+                return "The prepared content does not contain a valid Minecraft world, pack, or template."
+            case .duplicatePack(let name, let version):
+                if let version, !version.isEmpty {
+                    return "\(name) version \(version) is already installed in this source."
+                }
+                return "\(name) is already installed in this source."
+            case .duplicateArchivePath(let path):
+                return "The Minecraft package contains more than one entry for \(path)."
+            case .partialInstallation(let completed, let total, let reason):
+                return "Installed \(completed) of \(total) items before the import stopped: \(reason)"
+            }
+        }
+    }
+
+    private static let maximumEntryCount = 100_000
+    private static let maximumExpandedSize: UInt64 = 16 * 1_024 * 1_024 * 1_024
+
+    nonisolated static func preparePackage(at packageURL: URL) throws -> InstallationPlan {
+        let fileManager = FileManager.default
+        let stagingRootURL = fileManager.temporaryDirectory
+            .appendingPathComponent("MinecraftPackageInstallation", isDirectory: true)
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+        try fileManager.createDirectory(at: stagingRootURL, withIntermediateDirectories: true)
+
+        do {
+            let payloads = try preparePackage(
+                at: packageURL.standardizedFileURL,
+                inside: stagingRootURL,
+                fileManager: fileManager
+            )
+            guard !payloads.isEmpty else {
+                throw InstallError.emptyPackage
+            }
+            return InstallationPlan(payloads: payloads, stagingRootURL: stagingRootURL)
+        } catch {
+            try? fileManager.removeItem(at: stagingRootURL)
+            throw error
+        }
+    }
+
+    nonisolated static func prepareDirectory(
+        at directoryURL: URL,
+        contentType: MinecraftContentType
+    ) throws -> InstallationPlan {
+        let fileManager = FileManager.default
+        let stagingRootURL = fileManager.temporaryDirectory
+            .appendingPathComponent("MinecraftDirectoryInstallation", isDirectory: true)
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+        let payloadDirectoryURL = stagingRootURL.appendingPathComponent("payload", isDirectory: true)
+
+        do {
+            try validateDirectoryTree(at: directoryURL, fileManager: fileManager)
+            try fileManager.createDirectory(at: stagingRootURL, withIntermediateDirectories: true)
+            try fileManager.copyItem(at: directoryURL, to: payloadDirectoryURL)
+            let payload = try makePayload(
+                contentRootURL: payloadDirectoryURL,
+                contentType: contentType,
+                fallbackName: directoryURL.lastPathComponent,
+                fileManager: fileManager
+            )
+            return InstallationPlan(payloads: [payload], stagingRootURL: stagingRootURL)
+        } catch {
+            try? fileManager.removeItem(at: stagingRootURL)
+            throw error
+        }
+    }
+
+    private nonisolated static func preparePackage(
+        at packageURL: URL,
+        inside stagingRootURL: URL,
+        fileManager: FileManager
+    ) throws -> [InstallationPayload] {
+        let pathExtension = packageURL.pathExtension.lowercased()
+        guard MinecraftPackageInspector.supportedPathExtensions.contains(pathExtension) else {
+            throw MinecraftPackageInspector.InspectionError.unsupportedFileType(pathExtension)
+        }
+
+        let archive = try ZipArchiveReader(url: packageURL)
+        try validate(entries: archive.entries)
+
+        if pathExtension == "mcaddon" {
+            return try prepareAddon(
+                archive: archive,
+                packageURL: packageURL,
+                stagingRootURL: stagingRootURL,
+                fileManager: fileManager
+            )
+        }
+
+        let contentRootPath = try MinecraftPackageInspector.resolvedContentRootPath(
+            in: archive.entries,
+            archivePathExtension: pathExtension
+        )
+        let payloadDirectoryURL = stagingRootURL
+            .appendingPathComponent("payload-\(UUID().uuidString)", isDirectory: true)
+        try extract(
+            archive: archive,
+            contentRootPath: contentRootPath,
+            to: payloadDirectoryURL,
+            fileManager: fileManager
+        )
+
+        let contentType: MinecraftContentType
+        switch pathExtension {
+        case "mcworld":
+            contentType = .world
+        case "mctemplate":
+            contentType = .worldTemplate
+        case "mcpack":
+            contentType = MinecraftContentMetadataReader.inferredPackContentType(
+                for: payloadDirectoryURL,
+                fileManager: fileManager
+            )
+        default:
+            throw MinecraftPackageInspector.InspectionError.unsupportedFileType(pathExtension)
+        }
+
+        return [
+            try makePayload(
+                contentRootURL: payloadDirectoryURL,
+                contentType: contentType,
+                fallbackName: packageURL.deletingPathExtension().lastPathComponent,
+                fileManager: fileManager
+            )
+        ]
+    }
+
+    private nonisolated static func prepareAddon(
+        archive: ZipArchiveReader,
+        packageURL: URL,
+        stagingRootURL: URL,
+        fileManager: FileManager
+    ) throws -> [InstallationPayload] {
+        let nestedEntries = archive.entries.filter { entry in
+            guard !entry.isDirectory else {
+                return false
+            }
+            return ["mcpack", "mcworld", "mctemplate"].contains(
+                URL(fileURLWithPath: entry.path).pathExtension.lowercased()
+            )
+        }
+
+        guard !nestedEntries.isEmpty else {
+            throw InstallError.unsupportedAddonLayout
+        }
+
+        var payloads: [InstallationPayload] = []
+        for nestedEntry in nestedEntries {
+            let nestedPackageURL = stagingRootURL
+                .appendingPathComponent("nested-\(UUID().uuidString)")
+                .appendingPathExtension(URL(fileURLWithPath: nestedEntry.path).pathExtension)
+            try archive.extract(nestedEntry).write(to: nestedPackageURL, options: .atomic)
+            payloads.append(
+                contentsOf: try preparePackage(
+                    at: nestedPackageURL,
+                    inside: stagingRootURL,
+                    fileManager: fileManager
+                )
+            )
+            try? fileManager.removeItem(at: nestedPackageURL)
+        }
+
+        _ = packageURL
+        return payloads
+    }
+
+    private nonisolated static func validate(entries: [ZipArchiveEntry]) throws {
+        guard !entries.isEmpty else {
+            throw InstallError.emptyPackage
+        }
+        guard entries.count <= maximumEntryCount else {
+            throw InstallError.tooManyEntries
+        }
+        guard !entries.contains(where: \.isSymbolicLink) else {
+            throw InstallError.symbolicLinksNotSupported
+        }
+        var paths = Set<String>()
+        for entry in entries where !entry.isDirectory {
+            guard paths.insert(entry.path).inserted else {
+                throw InstallError.duplicateArchivePath(entry.path)
+            }
+        }
+
+        let expandedSize = entries.reduce(UInt64(0)) { partial, entry in
+            partial + UInt64(entry.uncompressedSize)
+        }
+        guard expandedSize <= maximumExpandedSize else {
+            throw InstallError.archiveTooLarge
+        }
+    }
+
+    private nonisolated static func extract(
+        archive: ZipArchiveReader,
+        contentRootPath: String,
+        to destinationRootURL: URL,
+        fileManager: FileManager
+    ) throws {
+        try fileManager.createDirectory(at: destinationRootURL, withIntermediateDirectories: true)
+        let prefix = contentRootPath.isEmpty ? "" : contentRootPath + "/"
+
+        for entry in archive.entries {
+            guard entry.path.hasPrefix(prefix) else {
+                continue
+            }
+            let relativePath = String(entry.path.dropFirst(prefix.count))
+            guard !relativePath.isEmpty else {
+                continue
+            }
+
+            let destinationURL = destinationRootURL.appendingPathComponent(relativePath)
+            if entry.isDirectory {
+                try fileManager.createDirectory(at: destinationURL, withIntermediateDirectories: true)
+                continue
+            }
+
+            try fileManager.createDirectory(
+                at: destinationURL.deletingLastPathComponent(),
+                withIntermediateDirectories: true
+            )
+            try archive.extract(entry).write(to: destinationURL, options: .atomic)
+        }
+    }
+
+    private nonisolated static func makePayload(
+        contentRootURL: URL,
+        contentType: MinecraftContentType,
+        fallbackName: String,
+        fileManager: FileManager
+    ) throws -> InstallationPayload {
+        guard isValidContent(at: contentRootURL, type: contentType, fileManager: fileManager) else {
+            throw InstallError.invalidPreparedContent
+        }
+
+        let manifest = MinecraftContentMetadataReader.manifestMetadata(
+            in: contentRootURL,
+            fileManager: fileManager
+        )
+        let displayName = MinecraftContentMetadataReader.displayName(
+            for: contentRootURL,
+            contentType: contentType,
+            fallbackName: fallbackName,
+            fileManager: fileManager
+        )
+        let preferredFolderName = manifest?.uuid ?? fallbackName
+
+        return InstallationPayload(
+            contentType: contentType,
+            preparedDirectoryURL: contentRootURL,
+            displayName: displayName,
+            packUUID: manifest?.uuid,
+            packVersion: manifest?.version,
+            suggestedFolderName: sanitizedFolderName(preferredFolderName)
+        )
+    }
+
+    private nonisolated static func isValidContent(
+        at directoryURL: URL,
+        type: MinecraftContentType,
+        fileManager: FileManager
+    ) -> Bool {
+        switch type {
+        case .world:
+            return fileManager.fileExists(atPath: directoryURL.appendingPathComponent("level.dat").path)
+                || fileManager.fileExists(atPath: directoryURL.appendingPathComponent("db", isDirectory: true).path)
+        case .behaviorPack, .resourcePack, .skinPack, .worldTemplate:
+            return fileManager.fileExists(atPath: directoryURL.appendingPathComponent("manifest.json").path)
+        }
+    }
+
+    private nonisolated static func sanitizedFolderName(_ value: String) -> String {
+        let invalidCharacters = CharacterSet(charactersIn: "/:\\?%*|\"<>")
+        let components = value.components(separatedBy: invalidCharacters)
+        let sanitized = components.joined(separator: "-")
+            .trimmingCharacters(in: .whitespacesAndNewlines)
+        return sanitized.isEmpty ? UUID().uuidString : String(sanitized.prefix(80))
+    }
+
+    private nonisolated static func validateDirectoryTree(
+        at directoryURL: URL,
+        fileManager: FileManager
+    ) throws {
+        guard let enumerator = fileManager.enumerator(
+            at: directoryURL,
+            includingPropertiesForKeys: [.isSymbolicLinkKey],
+            options: []
+        ) else {
+            throw InstallError.invalidPreparedContent
+        }
+
+        var entryCount = 0
+        for case let entryURL as URL in enumerator {
+            entryCount += 1
+            guard entryCount <= maximumEntryCount else {
+                throw InstallError.tooManyEntries
+            }
+            if (try entryURL.resourceValues(forKeys: [.isSymbolicLinkKey]).isSymbolicLink) == true {
+                throw InstallError.symbolicLinksNotSupported
+            }
+        }
+    }
+}

World Manager for Minecraft/Services/ArchiveInspection/MinecraftPackageInspector.swift

@@ -147,7 +147,7 @@ enum MinecraftPackageInspector {
         return contentRootURL
     }
 
-    nonisolated private static func resolvedContentRootPath(
+    nonisolated static func resolvedContentRootPath(
         in entries: [ZipArchiveEntry],
         archivePathExtension: String
     ) throws -> String {
@@ -181,7 +181,7 @@ enum MinecraftPackageInspector {
         return root
     }
 
-    nonisolated private static func containsContentMarkers(in filePaths: [String], prefix: String) -> Bool {
+    nonisolated static func containsContentMarkers(in filePaths: [String], prefix: String) -> Bool {
         let normalizedPrefix = prefix.isEmpty ? "" : prefix + "/"
 
         let worldMarkers = ["level.dat", "levelname.txt"]

World Manager for Minecraft/Services/ArchiveInspection/ZipArchiveReader.swift

@@ -11,12 +11,14 @@ nonisolated struct ZipArchiveEntry: Sendable, Hashable {
     let uncompressedSize: UInt32
     let localHeaderOffset: UInt32
     let isDirectory: Bool
+    let isSymbolicLink: Bool
 }
 
 nonisolated enum ZipArchiveReaderError: LocalizedError {
     case invalidArchive
     case unsupportedCompressionMethod(UInt16)
     case unsupportedFeatures(String)
+    case unsafeEntryPath(String)
     case entryNotFound(String)
     case decompressionFailed(Int32)
 
@@ -28,6 +30,8 @@ nonisolated enum ZipArchiveReaderError: LocalizedError {
             return "Unsupported ZIP compression method: \(method)."
         case .unsupportedFeatures(let message):
             return message
+        case .unsafeEntryPath(let path):
+            return "The ZIP archive contains an unsafe entry path: \(path)"
         case .entryNotFound(let path):
             return "ZIP entry not found: \(path)"
         case .decompressionFailed(let code):
@@ -41,7 +45,7 @@ nonisolated struct ZipArchiveReader {
     let entries: [ZipArchiveEntry]
 
     init(url: URL) throws {
-        self.data = try Data(contentsOf: url)
+        self.data = try Data(contentsOf: url, options: .mappedIfSafe)
         self.entries = try ZipArchiveReader.parseEntries(in: data)
     }
 
@@ -78,6 +82,9 @@ nonisolated struct ZipArchiveReader {
 
         switch entry.compressionMethod {
         case 0:
+            guard compressedData.count == Int(entry.uncompressedSize) else {
+                throw ZipArchiveReaderError.invalidArchive
+            }
             return compressedData
         case 8:
             return try Self.inflateRawDeflate(compressedData, expectedSize: Int(entry.uncompressedSize))
@@ -115,6 +122,7 @@ nonisolated struct ZipArchiveReader {
             let extraFieldLength = Int(data.readUInt16LE(at: offset + 30))
             let fileCommentLength = Int(data.readUInt16LE(at: offset + 32))
             let localHeaderOffset = data.readUInt32LE(at: offset + 42)
+            let externalAttributes = data.readUInt32LE(at: offset + 38)
 
             let filenameStart = offset + 46
             let filenameEnd = filenameStart + filenameLength
@@ -127,7 +135,9 @@ nonisolated struct ZipArchiveReader {
                 throw ZipArchiveReaderError.invalidArchive
             }
 
+            try validateEntryPath(filename)
             let normalizedPath = Self.normalizedPath(filename)
+            let unixMode = UInt16((externalAttributes >> 16) & 0xffff)
             entries.append(
                 ZipArchiveEntry(
                     path: normalizedPath,
@@ -135,7 +145,8 @@ nonisolated struct ZipArchiveReader {
                     compressedSize: compressedSize,
                     uncompressedSize: uncompressedSize,
                     localHeaderOffset: localHeaderOffset,
-                    isDirectory: normalizedPath.hasSuffix("/")
+                    isDirectory: normalizedPath.hasSuffix("/"),
+                    isSymbolicLink: unixMode & 0o170000 == 0o120000
                 )
             )
 
@@ -178,6 +189,18 @@ nonisolated struct ZipArchiveReader {
         return joined
     }
 
+    private static func validateEntryPath(_ path: String) throws {
+        let replaced = path.replacingOccurrences(of: "\\", with: "/")
+        let components = replaced.split(separator: "/", omittingEmptySubsequences: false)
+        guard
+            !replaced.hasPrefix("/"),
+            !replaced.contains("\0"),
+            !components.contains(where: { $0 == ".." })
+        else {
+            throw ZipArchiveReaderError.unsafeEntryPath(path)
+        }
+    }
+
     private static func inflateRawDeflate(_ data: Data, expectedSize: Int) throws -> Data {
         if data.isEmpty {
             return Data()
@@ -228,11 +251,17 @@ nonisolated struct ZipArchiveReader {
                     let producedByteCount = bufferPointer.count - Int(stream.avail_out)
                     if producedByteCount > 0 {
                         output.append(contentsOf: bufferPointer.prefix(producedByteCount))
+                        guard output.count <= expectedSize else {
+                            throw ZipArchiveReaderError.invalidArchive
+                        }
                     }
                 }
             } while status != Z_STREAM_END
         }
 
+        guard output.count == expectedSize else {
+            throw ZipArchiveReaderError.invalidArchive
+        }
         return output
     }
 }

World Manager for Minecraft/Services/Sources/Core/SourceLibrary.swift

@@ -29,6 +29,7 @@ final class SourceLibrary: ObservableObject, SourceScanSessionHosting, SourcePer
     }
     @Published var connectedDevices: [ConnectedDeviceSidebarEntry] = []
     @Published var isRestoringPersistedSources = true
+    @Published var installationStateBySourceID: [URL: SourceInstallationState] = [:]
 
     private var scanTasks: [URL: Task<Void, Never>] = [:]
     private var automaticSyncTasks: [URL: Task<Void, Never>] = [:]
@@ -250,6 +251,143 @@ final class SourceLibrary: ObservableObject, SourceScanSessionHosting, SourcePer
         }
     }
 
+    func installPackages(at packageURLs: [URL], into sourceID: URL) async throws -> [InstalledContentItem] {
+        guard
+            let destinationSource = source(withID: sourceID),
+            destinationSource.availability == .available,
+            destinationSource.capabilities.canInstallItems
+        else {
+            throw SourceAccessError.accessFailed(reason: "This source is not currently available for installation.")
+        }
+        guard !packageURLs.isEmpty else {
+            return []
+        }
+
+        scanTasks[sourceID]?.cancel()
+        installationStateBySourceID[sourceID] = SourceInstallationState(
+            completedCount: 0,
+            totalCount: packageURLs.count,
+            status: "Preparing import..."
+        )
+
+        var plans: [InstallationPlan] = []
+        var installedItems: [InstalledContentItem] = []
+        var totalPayloadCount = 0
+        do {
+            for packageURL in packageURLs {
+                let plan = try await Task.detached(priority: .userInitiated) {
+                    let accessedSecurityScope = packageURL.startAccessingSecurityScopedResource()
+                    defer {
+                        if accessedSecurityScope {
+                            packageURL.stopAccessingSecurityScopedResource()
+                        }
+                    }
+                    return try MinecraftPackageInstaller.preparePackage(at: packageURL)
+                }.value
+                plans.append(plan)
+            }
+
+            let payloads = plans.flatMap(\.payloads)
+            totalPayloadCount = payloads.count
+            try validatePackConflicts(payloads, destinationSource: destinationSource)
+            installationStateBySourceID[sourceID] = SourceInstallationState(
+                completedCount: 0,
+                totalCount: payloads.count,
+                status: payloads.count == 1 ? "Installing item..." : "Installing \(payloads.count) items..."
+            )
+
+            for payload in payloads {
+                guard let currentDestination = source(withID: sourceID) else {
+                    throw SourceAccessError.accessFailed(reason: "The destination source was removed during installation.")
+                }
+                let installedItem = try await sourceAccessMethod.install(payload, in: currentDestination)
+                installedItems.append(installedItem)
+                installationStateBySourceID[sourceID] = SourceInstallationState(
+                    completedCount: installedItems.count,
+                    totalCount: payloads.count,
+                    status: "Installed \(installedItems.count) of \(payloads.count)..."
+                )
+            }
+
+            plans.forEach { $0.cleanup() }
+            installationStateBySourceID[sourceID] = nil
+            startScan(for: sourceID, mode: .fullScan)
+            return installedItems
+        } catch {
+            plans.forEach { $0.cleanup() }
+            installationStateBySourceID[sourceID] = nil
+            if !installedItems.isEmpty {
+                startScan(for: sourceID, mode: .fullScan)
+                throw MinecraftPackageInstaller.InstallError.partialInstallation(
+                    completed: installedItems.count,
+                    total: totalPayloadCount,
+                    reason: error.localizedDescription
+                )
+            }
+            throw error
+        }
+    }
+
+    func copyItem(
+        _ item: MinecraftContentItem,
+        from sourceID: URL,
+        into destinationSourceID: URL
+    ) async throws -> [InstalledContentItem] {
+        guard let source = source(withID: sourceID) else {
+            throw SourceAccessError.accessFailed(reason: "The source item is no longer available.")
+        }
+
+        let representation = try await externalRepresentation(
+            for: item,
+            in: source,
+            preferredKind: .portablePackage
+        )
+        defer {
+            if representation.isTemporary {
+                try? FileManager.default.removeItem(at: representation.url)
+            }
+        }
+        return try await installPackages(at: [representation.url], into: destinationSourceID)
+    }
+
+    private func validatePackConflicts(
+        _ payloads: [InstallationPayload],
+        destinationSource: MinecraftSource
+    ) throws {
+        var existingIdentities = Set(
+            destinationSource.rawItems.compactMap { item -> String? in
+                guard
+                    item.contentType == .behaviorPack ||
+                    item.contentType == .resourcePack ||
+                    item.contentType == .skinPack,
+                    let uuid = item.packUUID?.lowercased()
+                else {
+                    return nil
+                }
+                return "\(item.contentType.rawValue)::\(uuid)"
+            }
+        )
+
+        for payload in payloads {
+            guard
+                payload.contentType == .behaviorPack ||
+                payload.contentType == .resourcePack ||
+                payload.contentType == .skinPack,
+                let uuid = payload.packUUID?.lowercased()
+            else {
+                continue
+            }
+            let identity = "\(payload.contentType.rawValue)::\(uuid)"
+            guard !existingIdentities.contains(identity) else {
+                throw MinecraftPackageInstaller.InstallError.duplicatePack(
+                    name: payload.displayName,
+                    version: payload.packVersion
+                )
+            }
+            existingIdentities.insert(identity)
+        }
+    }
+
     func removeSource(withID sourceID: URL) {
         let removedSource = source(withID: sourceID)
         scanTasks[sourceID]?.cancel()

World Manager for Minecraft/Services/Sources/Core/SourcePresentation.swift

@@ -120,7 +120,8 @@ enum SourcePresentation {
         case .discovering, .metadata, .previews:
             return "Loading previews for \(source.previewLoadedCount) of \(source.indexedItemCount) items..."
         case .sizing:
-            return "Calculating sizes for \(source.sizeLoadedCount) of \(source.indexedItemCount) items..."
+            let remainingCount = max(source.indexedItemCount - source.sizeLoadedCount, 0)
+            return "Calculating sizes for \(remainingCount) of \(source.indexedItemCount) items..."
         case .completed:
             return source.indexedItemCount == 0 ? "No Minecraft items found." : "Loaded \(source.indexedDetailCount) items."
         case .idle:

World Manager for Minecraft/Services/Sources/Scanning/SourceScanExecution.swift

@@ -750,7 +750,8 @@ private actor SourceIndexActor {
             } else if sizeLoadedCount == 0 {
                 scanStatus = "Preparing size calculations..."
             } else {
-                scanStatus = "Calculating sizes for \(sizeLoadedCount) of \(indexedItemCount) items..."
+                let remainingCount = max(indexedItemCount - sizeLoadedCount, 0)
+                scanStatus = "Calculating sizes for \(remainingCount) of \(indexedItemCount) items..."
             }
         } else {
             scanStatus = indexedItemCount == 0

World Manager for Minecraft/SourceAccess/ConnectedDevice/AppleMobileDevice/AppleMobileDeviceAccess.swift

@@ -177,6 +177,37 @@ enum AppleMobileDeviceAccess {
         }
     }
 
+    static func installDirectory(
+        deviceIdentifier: String,
+        bundleIdentifier: String,
+        minecraftRootRelativePath: String,
+        collectionFolderName: String,
+        preferredDestinationName: String,
+        sourceDirectoryURL: URL
+    ) async throws -> String {
+        try await AppleMobileDeviceOperationLimiter.shared.run(for: deviceIdentifier) {
+            try await Task.detached(priority: .userInitiated) {
+                var error: NSError?
+                guard let installedName = WMMInstallLocalDirectoryInConnectedDeviceApp(
+                    deviceIdentifier,
+                    bundleIdentifier,
+                    minecraftRootRelativePath,
+                    collectionFolderName,
+                    preferredDestinationName,
+                    sourceDirectoryURL,
+                    &error
+                ) else {
+                    throw error ?? NSError(
+                        domain: "AppleMobileDeviceAccess",
+                        code: 16,
+                        userInfo: [NSLocalizedDescriptionKey: "The MobileDevice content installation failed."]
+                    )
+                }
+                return installedName
+            }.value
+        }
+    }
+
     static func listApplications(deviceIdentifier: String) async throws -> [AppleMobileDeviceApplicationSummary] {
         try await AppleMobileDeviceOperationLimiter.shared.run(for: deviceIdentifier) {
             try await Task.detached(priority: .userInitiated) {

World Manager for Minecraft/SourceAccess/ConnectedDevice/AppleMobileDevice/AppleMobileDeviceBridge.h

@@ -98,4 +98,15 @@ WMMCopyConnectedDeviceAppSubtreeToLocalDirectory(
     NSError **error
 );
 
+FOUNDATION_EXPORT NSString * _Nullable
+WMMInstallLocalDirectoryInConnectedDeviceApp(
+    NSString *deviceIdentifier,
+    NSString *bundleIdentifier,
+    NSString *minecraftRootRelativePath,
+    NSString *collectionFolderName,
+    NSString *preferredDestinationName,
+    NSURL *sourceDirectoryURL,
+    NSError **error
+);
+
 NS_ASSUME_NONNULL_END

World Manager for Minecraft/SourceAccess/ConnectedDevice/AppleMobileDevice/AppleMobileDeviceBridge.m

@@ -122,7 +122,11 @@ typedef int (*AFCKeyValueReadFn)(AFCIteratorRef iterator, char **key, char **val
 typedef int (*AFCKeyValueCloseFn)(AFCIteratorRef iterator);
 typedef int (*AFCFileRefOpenFn)(AFCConnectionRef connection, const char *path, uint64_t mode, AFCFileDescriptorRef *fileDescriptor);
 typedef int (*AFCFileRefReadFn)(AFCConnectionRef connection, AFCFileDescriptorRef fileDescriptor, void *buffer, size_t *length);
+typedef int (*AFCFileRefWriteFn)(AFCConnectionRef connection, AFCFileDescriptorRef fileDescriptor, const void *buffer, uint32_t length);
 typedef int (*AFCFileRefCloseFn)(AFCConnectionRef connection, AFCFileDescriptorRef fileDescriptor);
+typedef int (*AFCDirectoryCreateFn)(AFCConnectionRef connection, const char *path);
+typedef int (*AFCRenamePathFn)(AFCConnectionRef connection, const char *sourcePath, const char *destinationPath);
+typedef int (*AFCRemovePathFn)(AFCConnectionRef connection, const char *path);
 
 typedef struct {
     void *handle;
@@ -159,7 +163,11 @@ typedef struct {
     AFCKeyValueCloseFn AFCKeyValueClose;
     AFCFileRefOpenFn AFCFileRefOpen;
     AFCFileRefReadFn AFCFileRefRead;
+    AFCFileRefWriteFn AFCFileRefWrite;
     AFCFileRefCloseFn AFCFileRefClose;
+    AFCDirectoryCreateFn AFCDirectoryCreate;
+    AFCRenamePathFn AFCRenamePath;
+    AFCRemovePathFn AFCRemovePath;
 } WMMMobileDeviceFunctions;
 
 typedef struct {
@@ -237,7 +245,11 @@ static BOOL WMMLoadFunctions(WMMMobileDeviceFunctions *functions, NSError **erro
     functions->AFCKeyValueClose = (AFCKeyValueCloseFn)WMMLoadSymbol(frameworkHandle, "AFCKeyValueClose");
     functions->AFCFileRefOpen = (AFCFileRefOpenFn)WMMLoadSymbol(frameworkHandle, "AFCFileRefOpen");
     functions->AFCFileRefRead = (AFCFileRefReadFn)WMMLoadSymbol(frameworkHandle, "AFCFileRefRead");
+    functions->AFCFileRefWrite = (AFCFileRefWriteFn)WMMLoadSymbol(frameworkHandle, "AFCFileRefWrite");
     functions->AFCFileRefClose = (AFCFileRefCloseFn)WMMLoadSymbol(frameworkHandle, "AFCFileRefClose");
+    functions->AFCDirectoryCreate = (AFCDirectoryCreateFn)WMMLoadSymbol(frameworkHandle, "AFCDirectoryCreate");
+    functions->AFCRenamePath = (AFCRenamePathFn)WMMLoadSymbol(frameworkHandle, "AFCRenamePath");
+    functions->AFCRemovePath = (AFCRemovePathFn)WMMLoadSymbol(frameworkHandle, "AFCRemovePath");
 
     if (functions->AMDeviceNotificationSubscribe == NULL ||
         functions->AMDeviceNotificationUnsubscribe == NULL ||
@@ -1036,6 +1048,163 @@ static BOOL WMMCopyAFCTreeToLocalURL(
     return WMMCopyAFCFileToLocalURL(functions, afcConnection, remotePath, localURL, error);
 }
 
+static BOOL WMMEnsureAFCDirectory(
+    WMMMobileDeviceFunctions *functions,
+    AFCConnectionRef afcConnection,
+    NSString *remotePath,
+    NSError **error
+) {
+    NSMutableArray<NSString *> *existingEntries = nil;
+    if (WMMReadAFCDirectory(functions, afcConnection, remotePath, &existingEntries) == 0) {
+        return YES;
+    }
+
+    const int createStatus = functions->AFCDirectoryCreate(
+        afcConnection,
+        remotePath.fileSystemRepresentation
+    );
+    if (createStatus != 0) {
+        if (error != NULL) {
+            *error = WMMMakeError(
+                createStatus,
+                [NSString stringWithFormat:@"AFCDirectoryCreate failed for %@ (%d).", remotePath, createStatus]
+            );
+        }
+        return NO;
+    }
+    return YES;
+}
+
+static BOOL WMMCopyLocalFileToAFCPath(
+    WMMMobileDeviceFunctions *functions,
+    AFCConnectionRef afcConnection,
+    NSURL *localFileURL,
+    NSString *remotePath,
+    NSError **error
+) {
+    AFCFileDescriptorRef fileDescriptor = NULL;
+    const int openStatus = functions->AFCFileRefOpen(
+        afcConnection,
+        remotePath.fileSystemRepresentation,
+        3,
+        &fileDescriptor
+    );
+    if (openStatus != 0 || fileDescriptor == NULL) {
+        if (error != NULL) {
+            *error = WMMMakeError(
+                openStatus,
+                [NSString stringWithFormat:@"AFCFileRefOpen for writing failed for %@ (%d).", remotePath, openStatus]
+            );
+        }
+        return NO;
+    }
+
+    NSFileHandle *handle = [NSFileHandle fileHandleForReadingFromURL:localFileURL error:error];
+    if (handle == nil) {
+        functions->AFCFileRefClose(afcConnection, fileDescriptor);
+        return NO;
+    }
+
+    BOOL success = YES;
+    while (true) {
+        @autoreleasepool {
+            NSData *chunk = [handle readDataOfLength:64 * 1024];
+            if (chunk.length == 0) {
+                break;
+            }
+            const int writeStatus = functions->AFCFileRefWrite(
+                afcConnection,
+                fileDescriptor,
+                chunk.bytes,
+                (uint32_t)chunk.length
+            );
+            if (writeStatus != 0) {
+                if (error != NULL) {
+                    *error = WMMMakeError(
+                        writeStatus,
+                        [NSString stringWithFormat:@"AFCFileRefWrite failed for %@ (%d).", remotePath, writeStatus]
+                    );
+                }
+                success = NO;
+                break;
+            }
+        }
+    }
+
+    [handle closeFile];
+    functions->AFCFileRefClose(afcConnection, fileDescriptor);
+    return success;
+}
+
+static BOOL WMMCopyLocalTreeToAFCPath(
+    WMMMobileDeviceFunctions *functions,
+    AFCConnectionRef afcConnection,
+    NSURL *localURL,
+    NSString *remotePath,
+    NSError **error
+) {
+    NSNumber *isDirectory = nil;
+    if (![localURL getResourceValue:&isDirectory forKey:NSURLIsDirectoryKey error:error]) {
+        return NO;
+    }
+
+    if (!isDirectory.boolValue) {
+        return WMMCopyLocalFileToAFCPath(functions, afcConnection, localURL, remotePath, error);
+    }
+
+    if (!WMMEnsureAFCDirectory(functions, afcConnection, remotePath, error)) {
+        return NO;
+    }
+
+    NSArray<NSURL *> *children = [[NSFileManager defaultManager] contentsOfDirectoryAtURL:localURL
+                                                              includingPropertiesForKeys:@[NSURLIsDirectoryKey, NSURLIsSymbolicLinkKey]
+                                                                                 options:0
+                                                                                   error:error];
+    if (children == nil) {
+        return NO;
+    }
+
+    for (NSURL *childURL in children) {
+        NSNumber *isSymbolicLink = nil;
+        if (![childURL getResourceValue:&isSymbolicLink forKey:NSURLIsSymbolicLinkKey error:error]) {
+            return NO;
+        }
+        if (isSymbolicLink.boolValue) {
+            if (error != NULL) {
+                *error = WMMMakeError(17, [NSString stringWithFormat:@"Symbolic links cannot be installed: %@", childURL.path]);
+            }
+            return NO;
+        }
+
+        NSString *childRemotePath = [remotePath stringByAppendingPathComponent:childURL.lastPathComponent];
+        if (!WMMCopyLocalTreeToAFCPath(functions, afcConnection, childURL, childRemotePath, error)) {
+            return NO;
+        }
+    }
+    return YES;
+}
+
+static BOOL WMMRemoveAFCTree(
+    WMMMobileDeviceFunctions *functions,
+    AFCConnectionRef afcConnection,
+    NSString *remotePath
+) {
+    NSMutableArray<NSString *> *entries = nil;
+    if (WMMReadAFCDirectory(functions, afcConnection, remotePath, &entries) == 0) {
+        for (NSString *entry in entries) {
+            if ([entry isEqualToString:@"."] || [entry isEqualToString:@".."]) {
+                continue;
+            }
+            WMMRemoveAFCTree(
+                functions,
+                afcConnection,
+                [remotePath stringByAppendingPathComponent:entry]
+            );
+        }
+    }
+    return functions->AFCRemovePath(afcConnection, remotePath.fileSystemRepresentation) == 0;
+}
+
 static NSString *WMMNormalizedAFCPath(NSString *path) {
     NSString *normalizedPath = path.length == 0 ? @"/" : path;
     if (![normalizedPath hasPrefix:@"/"]) {
@@ -2381,3 +2550,122 @@ WMMCopyConnectedDeviceAppSubtreeToLocalDirectory(
 
     return success;
 }
+
+NSString * _Nullable
+WMMInstallLocalDirectoryInConnectedDeviceApp(
+    NSString *deviceIdentifier,
+    NSString *bundleIdentifier,
+    NSString *minecraftRootRelativePath,
+    NSString *collectionFolderName,
+    NSString *preferredDestinationName,
+    NSURL *sourceDirectoryURL,
+    NSError **error
+) {
+    if (bundleIdentifier.length == 0 ||
+        minecraftRootRelativePath.length == 0 ||
+        collectionFolderName.length == 0 ||
+        preferredDestinationName.length == 0 ||
+        sourceDirectoryURL == nil ||
+        !sourceDirectoryURL.isFileURL) {
+        if (error != NULL) {
+            *error = WMMMakeError(16, @"A device, Minecraft path, collection, destination name, and local source directory are required.");
+        }
+        return nil;
+    }
+
+    WMMMobileDeviceFunctions functions;
+    if (!WMMLoadFunctions(&functions, error)) {
+        return nil;
+    }
+    if (functions.AFCFileRefWrite == NULL ||
+        functions.AFCDirectoryCreate == NULL ||
+        functions.AFCRenamePath == NULL ||
+        functions.AFCRemovePath == NULL) {
+        if (error != NULL) {
+            *error = WMMMakeError(17, @"This version of MobileDevice.framework does not provide the required AFC write operations.");
+        }
+        return nil;
+    }
+
+    AMDeviceRef device = WMMCopyConnectedDevice(&functions, deviceIdentifier, error);
+    if (device == NULL) {
+        return nil;
+    }
+    if (!WMMConnectAndValidateDevice(&functions, device, YES, error)) {
+        functions.AMDeviceRelease(device);
+        return nil;
+    }
+
+    AMDServiceConnectionRef backingServiceConnection = NULL;
+    AFCConnectionRef afcConnection = WMMCreateVendAFCConnection(
+        &functions,
+        device,
+        bundleIdentifier,
+        &backingServiceConnection,
+        error
+    );
+    if (afcConnection == NULL) {
+        WMMCloseVendSession(&functions, device, YES, NULL, backingServiceConnection);
+        functions.AMDeviceRelease(device);
+        return nil;
+    }
+
+    NSString *minecraftRoot = WMMNormalizedAFCPath(minecraftRootRelativePath);
+    NSString *stagingRoot = [minecraftRoot stringByAppendingPathComponent:@".world-manager-staging"];
+    NSString *stagedItemPath = [stagingRoot stringByAppendingPathComponent:NSUUID.UUID.UUIDString];
+    NSString *collectionPath = [minecraftRoot stringByAppendingPathComponent:collectionFolderName];
+
+    BOOL success =
+        WMMEnsureAFCDirectory(&functions, afcConnection, stagingRoot, error) &&
+        WMMEnsureAFCDirectory(&functions, afcConnection, stagedItemPath, error) &&
+        WMMCopyLocalTreeToAFCPath(&functions, afcConnection, sourceDirectoryURL, stagedItemPath, error) &&
+        WMMEnsureAFCDirectory(&functions, afcConnection, collectionPath, error);
+
+    NSString *destinationName = nil;
+    if (success) {
+        NSMutableArray<NSString *> *existingEntries = nil;
+        const int listStatus = WMMReadAFCDirectory(&functions, afcConnection, collectionPath, &existingEntries);
+        if (listStatus != 0) {
+            if (error != NULL) {
+                *error = WMMMakeError(
+                    listStatus,
+                    [NSString stringWithFormat:@"Could not list the destination collection %@ (%d).", collectionPath, listStatus]
+                );
+            }
+            success = NO;
+        } else {
+            NSSet<NSString *> *existingNames = [NSSet setWithArray:existingEntries ?: @[]];
+            destinationName = preferredDestinationName;
+            NSUInteger suffix = 2;
+            while ([existingNames containsObject:destinationName]) {
+                destinationName = [NSString stringWithFormat:@"%@-%lu", preferredDestinationName, (unsigned long)suffix];
+                suffix += 1;
+            }
+
+            NSString *destinationPath = [collectionPath stringByAppendingPathComponent:destinationName];
+            const int renameStatus = functions.AFCRenamePath(
+                afcConnection,
+                stagedItemPath.fileSystemRepresentation,
+                destinationPath.fileSystemRepresentation
+            );
+            if (renameStatus != 0) {
+                if (error != NULL) {
+                    *error = WMMMakeError(
+                        renameStatus,
+                        [NSString stringWithFormat:@"AFCRenamePath failed from %@ to %@ (%d).", stagedItemPath, destinationPath, renameStatus]
+                    );
+                }
+                success = NO;
+            }
+        }
+    }
+
+    if (!success) {
+        WMMRemoveAFCTree(&functions, afcConnection, stagedItemPath);
+        destinationName = nil;
+    }
+
+    WMMCloseVendSession(&functions, device, YES, afcConnection, backingServiceConnection);
+    functions.AMDeviceRelease(device);
+    return destinationName;
+}

World Manager for Minecraft/SourceAccess/ConnectedDevice/AppleMobileDevice/AppleMobileDeviceSourceAccess.swift

@@ -365,6 +365,31 @@ struct AppleMobileDeviceSourceAccess: ConnectedDeviceSourceAccessMethod {
         }
     }
 
+    nonisolated func install(_ payload: InstallationPayload, in source: MinecraftSource) async throws -> InstalledContentItem {
+        guard case .connectedDevice(_, let container) = source.origin else {
+            throw SourceAccessError.accessFailed(reason: "The selected source is not a connected device.")
+        }
+        let minecraftRoot = container.minecraftFolderRelativePath?
+            .trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
+        guard !minecraftRoot.isEmpty else {
+            throw SourceAccessError.accessFailed(reason: "The connected device is missing its Minecraft content path.")
+        }
+
+        let destinationName = try await AppleMobileDeviceAccess.installDirectory(
+            deviceIdentifier: container.deviceUDID,
+            bundleIdentifier: container.appID,
+            minecraftRootRelativePath: minecraftRoot,
+            collectionFolderName: payload.contentType.collectionFolderName,
+            preferredDestinationName: payload.suggestedFolderName,
+            sourceDirectoryURL: payload.preparedDirectoryURL
+        )
+        return InstalledContentItem(
+            contentType: payload.contentType,
+            displayName: payload.displayName,
+            destinationName: destinationName
+        )
+    }
+
     nonisolated func purgeCachedArtifacts(for source: MinecraftSource) async {
         guard source.origin.kind == .connectedDevice else {
             return

World Manager for Minecraft/SourceAccess/Core/SourceAccessCoordinator.swift

@@ -25,6 +25,7 @@ protocol SourceAccessMethod: Sendable {
     nonisolated func loadSizeAssets(for items: [MinecraftContentItem], in source: MinecraftSource) async -> [MinecraftContentItem]
     nonisolated func listItemContents(for item: MinecraftContentItem, in source: MinecraftSource) async throws -> [DirectoryEntry]
     nonisolated func materializeItem(for item: MinecraftContentItem, in source: MinecraftSource) async throws -> URL
+    nonisolated func install(_ payload: InstallationPayload, in source: MinecraftSource) async throws -> InstalledContentItem
     nonisolated func purgeCachedArtifacts(for source: MinecraftSource) async
 }
 
@@ -108,6 +109,12 @@ extension SourceAccessMethod {
         return item.folderURL
     }
 
+    nonisolated func install(_ payload: InstallationPayload, in source: MinecraftSource) async throws -> InstalledContentItem {
+        _ = payload
+        _ = source
+        throw SourceAccessError.accessFailed(reason: "This source does not support installing Minecraft content.")
+    }
+
     nonisolated func purgeCachedArtifacts(for source: MinecraftSource) async {
         _ = source
     }
@@ -204,6 +211,10 @@ struct SourceAccessCoordinator: SourceAccessMethod {
         return try await accessMethod(for: source).materializeItem(for: item, in: source)
     }
 
+    nonisolated func install(_ payload: InstallationPayload, in source: MinecraftSource) async throws -> InstalledContentItem {
+        return try await accessMethod(for: source).install(payload, in: source)
+    }
+
     nonisolated func purgeCachedArtifacts(for source: MinecraftSource) async {
         await accessMethod(for: source).purgeCachedArtifacts(for: source)
     }

World Manager for Minecraft/SourceAccess/LocalFolder/LocalFolderSourceAccess.swift

@@ -133,6 +133,97 @@ struct LocalFolderSourceAccess: SourceAccessMethod {
         return item.folderURL
     }
 
+    nonisolated func install(_ payload: InstallationPayload, in source: MinecraftSource) async throws -> InstalledContentItem {
+        let sourceRootURL = try resolvedSourceRootURL(for: source)
+        let accessedSecurityScope = sourceRootURL.startAccessingSecurityScopedResource()
+        defer {
+            if accessedSecurityScope {
+                sourceRootURL.stopAccessingSecurityScopedResource()
+            }
+        }
+
+        let fileManager = FileManager.default
+        let contentRootURL = try resolvedContentRootURL(for: source, sourceRootURL: sourceRootURL)
+        let collectionURL = contentRootURL.appendingPathComponent(
+            payload.contentType.collectionFolderName,
+            isDirectory: true
+        )
+        let stagingRootURL = contentRootURL
+            .appendingPathComponent(".world-manager-staging", isDirectory: true)
+        let stagedItemURL = stagingRootURL
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+
+        try fileManager.createDirectory(at: stagingRootURL, withIntermediateDirectories: true)
+        do {
+            try fileManager.copyItem(at: payload.preparedDirectoryURL, to: stagedItemURL)
+            try fileManager.createDirectory(at: collectionURL, withIntermediateDirectories: true)
+            let destinationURL = uniqueDestinationURL(
+                in: collectionURL,
+                preferredName: payload.suggestedFolderName,
+                fileManager: fileManager
+            )
+            try fileManager.moveItem(at: stagedItemURL, to: destinationURL)
+            return InstalledContentItem(
+                contentType: payload.contentType,
+                displayName: payload.displayName,
+                destinationName: destinationURL.lastPathComponent
+            )
+        } catch {
+            try? fileManager.removeItem(at: stagedItemURL)
+            throw error
+        }
+    }
+
+    nonisolated private func resolvedSourceRootURL(for source: MinecraftSource) throws -> URL {
+        guard case .localFolder(let bookmarkData) = source.origin, let bookmarkData else {
+            return source.folderURL
+        }
+
+        var isStale = false
+        return try URL(
+            resolvingBookmarkData: bookmarkData,
+            options: [.withSecurityScope],
+            relativeTo: nil,
+            bookmarkDataIsStale: &isStale
+        ).standardizedFileURL
+    }
+
+    nonisolated private func resolvedContentRootURL(
+        for source: MinecraftSource,
+        sourceRootURL: URL
+    ) throws -> URL {
+        let observedRoots = Set(source.rawItems.map {
+            $0.collectionRootURL.deletingLastPathComponent().standardizedFileURL
+        })
+        if let minimumDepth = observedRoots.map(\.pathComponents.count).min() {
+            let shallowestRoots = observedRoots.filter { $0.pathComponents.count == minimumDepth }
+            if shallowestRoots.count == 1, let observedRoot = shallowestRoots.first {
+                return observedRoot
+            }
+            if shallowestRoots.count > 1 {
+                throw SourceAccessError.accessFailed(
+                    reason: "This source contains more than one Minecraft content root. Choose the specific com.mojang folder before importing."
+                )
+            }
+        }
+
+        return sourceRootURL
+    }
+
+    nonisolated private func uniqueDestinationURL(
+        in collectionURL: URL,
+        preferredName: String,
+        fileManager: FileManager
+    ) -> URL {
+        var candidateURL = collectionURL.appendingPathComponent(preferredName, isDirectory: true)
+        var suffix = 2
+        while fileManager.fileExists(atPath: candidateURL.path) {
+            candidateURL = collectionURL.appendingPathComponent("\(preferredName)-\(suffix)", isDirectory: true)
+            suffix += 1
+        }
+        return candidateURL
+    }
+
     nonisolated private func discoverItemsByReconcilingCache(
         for source: MinecraftSource,
         snapshot: SourceSnapshot,

World Manager for Minecraft/UI/Detail/ItemDetailColumnViews.swift

@@ -7,6 +7,7 @@ import SwiftUI
 struct ItemDetailColumnView: View {
     let item: MinecraftContentItem?
     let source: MinecraftSource?
+    let installationState: SourceInstallationState?
     let showsSourceDetails: Bool
     let behaviorPacks: [ContentPackReference]
     let resourcePacks: [ContentPackReference]
@@ -22,6 +23,7 @@ struct ItemDetailColumnView: View {
     let exportAction: () -> Void
     let revealAction: () -> Void
     let shareAction: (NSView?) -> Void
+    let importAction: (MinecraftSource) -> Void
 
     var body: some View {
         Group {
@@ -45,7 +47,13 @@ struct ItemDetailColumnView: View {
                     shareAction: shareAction
                 )
             } else if showsSourceDetails, let source {
-                SourceDetailView(source: source)
+                SourceDetailView(
+                    source: source,
+                    installationState: installationState,
+                    importAction: {
+                        importAction(source)
+                    }
+                )
             } else {
                 Text("Select a world or pack to see details")
                     .foregroundStyle(.secondary)

World Manager for Minecraft/UI/Detail/SourceDetailView.swift

@@ -20,13 +20,38 @@ struct SourceDetailView: View {
     }
 
     let source: MinecraftSource
+    let installationState: SourceInstallationState?
+    let importAction: () -> Void
 
     var body: some View {
         ScrollView {
             VStack(alignment: .leading, spacing: 24) {
+                HStack(alignment: .firstTextBaseline) {
                     Text(source.displayName)
                         .font(.largeTitle.weight(.semibold))
 
+                    Spacer()
+
+                    Button("Import...", action: importAction)
+                        .disabled(
+                            source.availability != .available ||
+                            !source.capabilities.canInstallItems ||
+                            installationState != nil
+                        )
+                }
+
+                if let installationState {
+                    VStack(alignment: .leading, spacing: 8) {
+                        ProgressView(
+                            value: Double(installationState.completedCount),
+                            total: Double(max(installationState.totalCount, 1))
+                        )
+                        Text(installationState.status)
+                            .appTextStyle(.supporting)
+                    }
+                    .appDetailSectionCard()
+                }
+
                 if showsStatusSection {
                     sourceStatusSection
                 }

World Manager for Minecraft/UI/List/ItemListColumnViews.swift

@@ -41,6 +41,7 @@ struct ItemListColumnView<MenuContent: View>: View {
     let searchPrompt: String
     let chooseFolderAction: () -> Void
     let dropAction: ([NSItemProvider]) -> Bool
+    let dragProvider: (MinecraftContentItem) -> NSItemProvider
     let itemContextMenu: (MinecraftContentItem) -> MenuContent
 
     var body: some View {
@@ -55,6 +56,14 @@ struct ItemListColumnView<MenuContent: View>: View {
                 List(items, selection: $selectedItemID) { item in
                     ContentRowView(item: item)
                         .tag(item.id)
+                        .onDrag {
+                            dragProvider(item)
+                        }
+                        .simultaneousGesture(
+                            TapGesture().onEnded {
+                                selectedItemID = item.id
+                            }
+                        )
                         .contextMenu {
                             itemContextMenu(item)
                         }

World Manager for Minecraft/UI/Preview/PreviewFixtures.swift

@@ -262,6 +262,9 @@ struct SidebarColumnPreviewContainer: View {
                 addConnectedDeviceAction: { _ in },
                 rescanSourceAction: { _ in },
                 removeSourceAction: { _ in },
+                importSourceAction: { _ in },
+                importDropAction: { _, _ in false },
+                installationState: { _ in nil },
                 filters: { source in
                     let allFilter = SidebarFilter(
                         title: "All Content",
@@ -331,6 +334,7 @@ struct ItemListColumnPreviewContainer: View {
                 searchPrompt: "Search Worlds",
                 chooseFolderAction: {},
                 dropAction: { _ in false },
+                dragProvider: { _ in NSItemProvider() },
                 itemContextMenu: { item in
                     Button("Reveal \(item.displayName)") {}
                 }
@@ -345,6 +349,7 @@ struct ItemDetailColumnPreviewContainer: View {
             ItemDetailColumnView(
                 item: PreviewFixtures.featuredWorld,
                 source: PreviewFixtures.primarySource,
+                installationState: nil,
                 showsSourceDetails: false,
                 behaviorPacks: PreviewFixtures.primarySource.resolvedPackReferences(for: PreviewFixtures.featuredWorld.id, type: .behaviorPack),
                 resourcePacks: PreviewFixtures.primarySource.resolvedPackReferences(for: PreviewFixtures.featuredWorld.id, type: .resourcePack),
@@ -359,7 +364,8 @@ struct ItemDetailColumnPreviewContainer: View {
                 exportTitle: PreviewFixtures.featuredWorld.contentType.exportTitle,
                 exportAction: {},
                 revealAction: {},
-                shareAction: { _ in }
+                shareAction: { _ in },
+                importAction: { _ in }
             )
         }
     }

World Manager for Minecraft/UI/Root/ContentView.swift

@@ -14,6 +14,7 @@ struct ContentView: View {
     @State private var isDropTargeted = false
     @State private var isPerformingItemAction = false
     @State private var isShowingDeviceSourceSheet = false
+    @State private var importErrorMessage: String?
     @State private var sortMode: ItemSortMode = .name
     @State private var directoryPreviewContents: [DirectoryEntry] = []
     @State private var showsProjectionLoadingState = false
@@ -87,6 +88,11 @@ struct ContentView: View {
                 removeSourceAction: { source in
                     removeSource(source.id)
                 },
+                importSourceAction: importIntoSource(_:),
+                importDropAction: handleImportDrop(on:providers:),
+                installationState: { source in
+                    library.installationStateBySourceID[source.id]
+                },
                 filters: sidebarFilters(for:)
             )
             .navigationSplitViewColumnWidth(min: 280, ideal: 320, max: 380)
@@ -109,6 +115,7 @@ struct ContentView: View {
                 searchPrompt: resolvedItemListProjection.searchPrompt,
                 chooseFolderAction: pickFolder,
                 dropAction: handleDroppedProviders(_:),
+                dragProvider: dragProvider(for:),
                 itemContextMenu: itemContextMenu(for:)
             )
             .navigationSplitViewColumnWidth(min: 340, ideal: 400, max: 460)
@@ -116,6 +123,7 @@ struct ContentView: View {
             ItemDetailColumnView(
                 item: resolvedCurrentSelectedItem,
                 source: resolvedCurrentSource,
+                installationState: resolvedCurrentSource.flatMap { library.installationStateBySourceID[$0.id] },
                 showsSourceDetails: resolvedCurrentSelectedItem == nil && isSourceOverviewSelection,
                 behaviorPacks: resolvedCurrentSelectedItem.map { logicalPackReferences(for: $0, type: .behaviorPack) } ?? [],
                 resourcePacks: resolvedCurrentSelectedItem.map { logicalPackReferences(for: $0, type: .resourcePack) } ?? [],
@@ -148,7 +156,8 @@ struct ContentView: View {
                     }
 
                     shareItem(item, from: anchorView)
-                }
+                },
+                importAction: importIntoSource(_:)
             )
             .frame(minWidth: 450)
         }
@@ -169,6 +178,23 @@ struct ContentView: View {
                 }
             )
         }
+        .alert(
+            "Import Failed",
+            isPresented: Binding(
+                get: { importErrorMessage != nil },
+                set: { isPresented in
+                    if !isPresented {
+                        importErrorMessage = nil
+                    }
+                }
+            )
+        ) {
+            Button("OK") {
+                importErrorMessage = nil
+            }
+        } message: {
+            Text(importErrorMessage ?? "The Minecraft content could not be imported.")
+        }
         .task {
             AppTerminationCoordinator.shared.register(library: library)
         }
@@ -526,6 +552,166 @@ struct ContentView: View {
         }
     }
 
+    private func importIntoSource(_ source: MinecraftSource) {
+        guard source.availability == .available, source.capabilities.canInstallItems else {
+            return
+        }
+
+        let panel = NSOpenPanel()
+        panel.allowsMultipleSelection = true
+        panel.canChooseDirectories = false
+        panel.canChooseFiles = true
+        panel.title = "Import Minecraft Content into \(source.displayName)"
+        panel.prompt = "Import"
+        panel.allowedContentTypes = [
+            .minecraftWorld,
+            .minecraftPack,
+            .minecraftTemplate,
+            .minecraftAddon
+        ]
+
+        guard panel.runModal() == .OK else {
+            return
+        }
+        Task {
+            await performImport(packageURLs: panel.urls, into: source.id)
+        }
+    }
+
+    private func handleImportDrop(
+        on source: MinecraftSource,
+        providers: [NSItemProvider]
+    ) -> Bool {
+        guard
+            source.availability == .available,
+            source.capabilities.canInstallItems,
+            providers.contains(where: isSupportedImportProvider(_:))
+        else {
+            return false
+        }
+
+        Task {
+            let materializedDrop = await materializeDroppedPackages(from: providers)
+            defer {
+                try? FileManager.default.removeItem(at: materializedDrop.temporaryRootURL)
+            }
+            guard !materializedDrop.packageURLs.isEmpty else {
+                await MainActor.run {
+                    importErrorMessage = "The dropped items did not contain a supported .mcworld, .mcpack, .mctemplate, or .mcaddon file."
+                }
+                return
+            }
+            await performImport(packageURLs: materializedDrop.packageURLs, into: source.id)
+        }
+        return true
+    }
+
+    @MainActor
+    private func performImport(packageURLs: [URL], into sourceID: URL) async {
+        do {
+            _ = try await library.installPackages(at: packageURLs, into: sourceID)
+            selectedSidebarSelection = .source(sourceID: sourceID)
+            selectedItemID = nil
+        } catch {
+            importErrorMessage = error.localizedDescription
+        }
+    }
+
+    private func isSupportedImportProvider(_ provider: NSItemProvider) -> Bool {
+        importTypeIdentifiers.contains {
+            provider.hasItemConformingToTypeIdentifier($0)
+        }
+    }
+
+    private var importTypeIdentifiers: [String] {
+        [
+            UTType.minecraftWorld.identifier,
+            UTType.minecraftPack.identifier,
+            UTType.minecraftTemplate.identifier,
+            UTType.minecraftAddon.identifier,
+            UTType.fileURL.identifier
+        ]
+    }
+
+    private func materializeDroppedPackages(
+        from providers: [NSItemProvider]
+    ) async -> (packageURLs: [URL], temporaryRootURL: URL) {
+        let temporaryRootURL = FileManager.default.temporaryDirectory
+            .appendingPathComponent("MinecraftImportDrop", isDirectory: true)
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+        try? FileManager.default.createDirectory(at: temporaryRootURL, withIntermediateDirectories: true)
+
+        var packageURLs: [URL] = []
+        for provider in providers where isSupportedImportProvider(provider) {
+            if let packageURL = await materializeDroppedPackage(
+                from: provider,
+                in: temporaryRootURL
+            ) {
+                packageURLs.append(packageURL)
+            }
+        }
+        return (packageURLs, temporaryRootURL)
+    }
+
+    private func materializeDroppedPackage(
+        from provider: NSItemProvider,
+        in temporaryRootURL: URL
+    ) async -> URL? {
+        let packageDefinitions = MinecraftPackageTypes.all
+        if let definition = packageDefinitions.first(where: {
+            provider.hasItemConformingToTypeIdentifier($0.utTypeIdentifier)
+        }) {
+            return await withCheckedContinuation { continuation in
+                provider.loadFileRepresentation(forTypeIdentifier: definition.utTypeIdentifier) { url, _ in
+                    guard let url else {
+                        continuation.resume(returning: nil)
+                        return
+                    }
+                    let baseName = provider.suggestedName.map {
+                        URL(fileURLWithPath: $0).deletingPathExtension().lastPathComponent
+                    } ?? UUID().uuidString
+                    let destinationURL = temporaryRootURL
+                        .appendingPathComponent(baseName)
+                        .appendingPathExtension(definition.pathExtension)
+                    do {
+                        try FileManager.default.copyItem(at: url, to: destinationURL)
+                        continuation.resume(returning: destinationURL)
+                    } catch {
+                        continuation.resume(returning: nil)
+                    }
+                }
+            }
+        }
+
+        guard provider.hasItemConformingToTypeIdentifier(UTType.fileURL.identifier) else {
+            return nil
+        }
+        return await withCheckedContinuation { continuation in
+            provider.loadDataRepresentation(forTypeIdentifier: UTType.fileURL.identifier) { data, _ in
+                guard
+                    let data,
+                    let sourceURL = NSURL(
+                        absoluteURLWithDataRepresentation: data,
+                        relativeTo: nil
+                    ) as URL?,
+                    MinecraftPackageInspector.supportedPathExtensions.contains(
+                        sourceURL.pathExtension.lowercased()
+                    )
+                else {
+                    continuation.resume(returning: nil)
+                    return
+                }
+                let destinationURL = temporaryRootURL.appendingPathComponent(sourceURL.lastPathComponent)
+                do {
+                    try FileManager.default.copyItem(at: sourceURL, to: destinationURL)
+                    continuation.resume(returning: destinationURL)
+                } catch {
+                    continuation.resume(returning: nil)
+                }
+            }
+        }
+    }
+
     private func handleDroppedProviders(_ providers: [NSItemProvider]) -> Bool {
         let fileURLType = UTType.fileURL.identifier
         let supportedProviders = providers.filter { $0.hasItemConformingToTypeIdentifier(fileURLType) }

World Manager for Minecraft/UI/Sidebar/SidebarColumnViews.swift

@@ -2,6 +2,7 @@
 // SPDX-License-Identifier: AGPL-3.0-or-later
 
 import SwiftUI
+import UniformTypeIdentifiers
 
 enum SidebarSelection: Hashable, Sendable {
     case source(sourceID: URL)
@@ -33,6 +34,9 @@ struct SourcesSidebarView: View {
     let addConnectedDeviceAction: (ConnectedDeviceSidebarEntry) -> Void
     let rescanSourceAction: (MinecraftSource) -> Void
     let removeSourceAction: (MinecraftSource) -> Void
+    let importSourceAction: (MinecraftSource) -> Void
+    let importDropAction: (MinecraftSource, [NSItemProvider]) -> Bool
+    let installationState: (MinecraftSource) -> SourceInstallationState?
     let filters: (MinecraftSource) -> [SidebarFilter]
 
     var body: some View {
@@ -81,8 +85,12 @@ struct SourcesSidebarView: View {
 
         SourceHeaderRow(
             source: source,
+            installationState: installationState(source),
             onSelect: {
                 selection = .source(sourceID: source.id)
+            },
+            dropAction: { providers in
+                importDropAction(source, providers)
             }
         )
             .tag(SidebarSelection.source(sourceID: source.id) as SidebarSelection?)
@@ -93,6 +101,11 @@ struct SourcesSidebarView: View {
                     rescanSourceAction(source)
                 }
 
+                Button("Import into \"\(source.displayName)\"...") {
+                    importSourceAction(source)
+                }
+                .disabled(source.availability != .available || !source.capabilities.canInstallItems)
+
                 Divider()
 
                 Button("Remove \"\(source.displayName)\"", role: .destructive) {
@@ -150,7 +163,10 @@ private struct SidebarSourcesSectionHeaderView: View {
 
 private struct SourceHeaderRow: View {
     let source: MinecraftSource
+    let installationState: SourceInstallationState?
     let onSelect: () -> Void
+    let dropAction: ([NSItemProvider]) -> Bool
+    @State private var isDropTargeted = false
 
     var body: some View {
         HStack(spacing: 8) {
@@ -179,8 +195,23 @@ private struct SourceHeaderRow: View {
         .frame(maxWidth: .infinity, alignment: .leading)
         .padding(.leading, 5)
         .padding(.vertical, 6)
+        .background(
+            isDropTargeted ? Color.accentColor.opacity(0.16) : Color.clear,
+            in: RoundedRectangle(cornerRadius: 7, style: .continuous)
+        )
         .contentShape(Rectangle())
         .onTapGesture(perform: onSelect)
+        .onDrop(
+            of: [
+                UTType.fileURL.identifier,
+                UTType.minecraftWorld.identifier,
+                UTType.minecraftPack.identifier,
+                UTType.minecraftTemplate.identifier,
+                UTType.minecraftAddon.identifier
+            ],
+            isTargeted: $isDropTargeted,
+            perform: dropAction
+        )
     }
 
     private var connection: DeviceConnection? {
@@ -224,12 +255,23 @@ private struct SourceHeaderRow: View {
     }
 
     private var showsStatusAccessory: Bool {
-        source.isScanning
+        source.isScanning || installationState != nil
     }
 
     @ViewBuilder
     private var statusAccessory: some View {
-            if source.isScanning {
+            if let installationState {
+                if installationState.totalCount > 0 {
+                    CircularScanProgressView(
+                        progress: Double(installationState.completedCount) / Double(installationState.totalCount)
+                    )
+                    .help(installationState.status)
+                } else {
+                    ProgressView()
+                        .appActivityIndicatorStyle(.small)
+                        .help(installationState.status)
+                }
+            } else if source.isScanning {
                 if let scanProgress = source.scanProgress {
                     CircularScanProgressView(progress: scanProgress)
                 } else {

World Manager for MinecraftTests/World_Manager_for_MinecraftTests.swift

@@ -771,6 +771,119 @@ struct World_Manager_for_MinecraftTests {
         }
     }
 
+    @Test func packageInstallerPreparesCompleteWorldContents() async throws {
+        let fileManager = FileManager.default
+        let workingURL = fileManager.temporaryDirectory.appendingPathComponent(UUID().uuidString, isDirectory: true)
+        let worldURL = workingURL.appendingPathComponent("World", isDirectory: true)
+        let archiveURL = workingURL.appendingPathComponent("World.mcworld", isDirectory: false)
+        defer { try? fileManager.removeItem(at: workingURL) }
+
+        try fileManager.createDirectory(
+            at: worldURL.appendingPathComponent("db", isDirectory: true),
+            withIntermediateDirectories: true
+        )
+        try Data([1, 2, 3]).write(to: worldURL.appendingPathComponent("level.dat"))
+        try Data([4, 5, 6]).write(to: worldURL.appendingPathComponent("db/chunk.bin"))
+        try makeArchive(from: worldURL, to: archiveURL)
+
+        let plan = try MinecraftPackageInstaller.preparePackage(at: archiveURL)
+        defer { plan.cleanup() }
+
+        #expect(plan.payloads.count == 1)
+        #expect(plan.payloads[0].contentType == .world)
+        #expect(
+            fileManager.fileExists(
+                atPath: plan.payloads[0].preparedDirectoryURL.appendingPathComponent("db/chunk.bin").path
+            )
+        )
+    }
+
+    @Test func packageInstallerExpandsNestedAddonPackages() async throws {
+        let fileManager = FileManager.default
+        let workingURL = fileManager.temporaryDirectory.appendingPathComponent(UUID().uuidString, isDirectory: true)
+        let behaviorURL = workingURL.appendingPathComponent("Behavior", isDirectory: true)
+        let resourceURL = workingURL.appendingPathComponent("Resource", isDirectory: true)
+        let addonRootURL = workingURL.appendingPathComponent("Addon", isDirectory: true)
+        let behaviorArchiveURL = addonRootURL.appendingPathComponent("Behavior.mcpack")
+        let resourceArchiveURL = addonRootURL.appendingPathComponent("Resource.mcpack")
+        let addonURL = workingURL.appendingPathComponent("Combined.mcaddon")
+        defer { try? fileManager.removeItem(at: workingURL) }
+
+        try fileManager.createDirectory(at: behaviorURL, withIntermediateDirectories: true)
+        try fileManager.createDirectory(at: resourceURL, withIntermediateDirectories: true)
+        try fileManager.createDirectory(at: addonRootURL, withIntermediateDirectories: true)
+        try testPackManifest(name: "Behavior", uuid: "11111111-1111-1111-1111-111111111111", moduleType: "data")
+            .write(to: behaviorURL.appendingPathComponent("manifest.json"), atomically: true, encoding: .utf8)
+        try testPackManifest(name: "Resource", uuid: "22222222-2222-2222-2222-222222222222", moduleType: "resources")
+            .write(to: resourceURL.appendingPathComponent("manifest.json"), atomically: true, encoding: .utf8)
+        try makeArchive(from: behaviorURL, to: behaviorArchiveURL)
+        try makeArchive(from: resourceURL, to: resourceArchiveURL)
+        try makeArchive(from: addonRootURL, to: addonURL)
+
+        let plan = try MinecraftPackageInstaller.preparePackage(at: addonURL)
+        defer { plan.cleanup() }
+
+        #expect(Set(plan.payloads.map(\.contentType)) == [.behaviorPack, .resourcePack])
+    }
+
+    @Test func localFolderInstallerUsesUniqueAdditiveDestinations() async throws {
+        let fileManager = FileManager.default
+        let workingURL = fileManager.temporaryDirectory.appendingPathComponent(UUID().uuidString, isDirectory: true)
+        let sourceWorldURL = workingURL.appendingPathComponent("PreparedWorld", isDirectory: true)
+        let destinationRootURL = workingURL.appendingPathComponent("Destination", isDirectory: true)
+        defer { try? fileManager.removeItem(at: workingURL) }
+
+        try fileManager.createDirectory(at: sourceWorldURL, withIntermediateDirectories: true)
+        try fileManager.createDirectory(at: destinationRootURL, withIntermediateDirectories: true)
+        try Data([1]).write(to: sourceWorldURL.appendingPathComponent("level.dat"))
+
+        let plan = try MinecraftPackageInstaller.prepareDirectory(at: sourceWorldURL, contentType: .world)
+        defer { plan.cleanup() }
+        let source = MinecraftSource(folderURL: destinationRootURL, availability: .available)
+        let access = LocalFolderSourceAccess()
+
+        let first = try await access.install(plan.payloads[0], in: source)
+        let second = try await access.install(plan.payloads[0], in: source)
+
+        #expect(first.destinationName != second.destinationName)
+        #expect(
+            fileManager.fileExists(
+                atPath: destinationRootURL
+                    .appendingPathComponent("minecraftWorlds/\(first.destinationName)/level.dat")
+                    .path
+            )
+        )
+        #expect(
+            fileManager.fileExists(
+                atPath: destinationRootURL
+                    .appendingPathComponent("minecraftWorlds/\(second.destinationName)/level.dat")
+                    .path
+            )
+        )
+    }
+
+    @Test func zipReaderRejectsParentTraversalEntry() async throws {
+        let fileManager = FileManager.default
+        let workingURL = fileManager.temporaryDirectory.appendingPathComponent(UUID().uuidString, isDirectory: true)
+        let archiveURL = workingURL.appendingPathComponent("Unsafe.mcworld")
+        defer { try? fileManager.removeItem(at: workingURL) }
+
+        try fileManager.createDirectory(at: workingURL, withIntermediateDirectories: true)
+        try makeStoredArchive(entries: [("../escape.txt", Data("escape".utf8))], to: archiveURL)
+
+        do {
+            _ = try ZipArchiveReader(url: archiveURL)
+            Issue.record("Expected the unsafe archive path to be rejected.")
+        } catch let error as ZipArchiveReaderError {
+            switch error {
+            case .unsafeEntryPath(let path):
+                #expect(path == "../escape.txt")
+            default:
+                Issue.record("Expected unsafeEntryPath but received \(error).")
+            }
+        }
+    }
+
     @Test func sourcePersistenceStoreRoundTripsCachedSource() async throws {
         let fileManager = FileManager.default
         let workingURL = fileManager.temporaryDirectory.appendingPathComponent(UUID().uuidString, isDirectory: true)
@@ -1122,6 +1235,24 @@ struct World_Manager_for_MinecraftTests {
         #expect(ScanNotificationService.completionMessage(itemCount: 42) == "Found 42 items.")
     }
 
+    @Test func liveScanStatusCountsItemsRemainingDuringSizeCalculation() async throws {
+        var source = MinecraftSource(
+            folderURL: URL(fileURLWithPath: "/tmp/test-source", isDirectory: true)
+        )
+        source.displayName = "Test Source"
+        source.isScanning = true
+        source.indexedItemCount = 22
+        source.previewLoadedCount = 22
+        source.sizeLoadedCount = 12
+        source.scanProgress = 0.88
+        source.scanStatus = "Calculating sizes"
+
+        #expect(
+            SourcePresentation.liveScanStatusTitle(for: source)
+                == "Calculating sizes for 10 of 22 items..."
+        )
+    }
+
     @Test func scanNotificationServiceOnlyNotifiesForLongBackgroundScans() async throws {
         let service = ScanNotificationService()
 
@@ -1251,6 +1382,82 @@ private func makeArchive(from sourceDirectoryURL: URL, to archiveURL: URL) throw
     }
 }
 
+private func testPackManifest(name: String, uuid: String, moduleType: String) -> String {
+    """
+    {
+      "format_version": 2,
+      "header": {
+        "name": "\(name)",
+        "description": "\(name)",
+        "uuid": "\(uuid)",
+        "version": [1, 0, 0]
+      },
+      "modules": [
+        {
+          "type": "\(moduleType)",
+          "uuid": "\(UUID().uuidString)",
+          "version": [1, 0, 0]
+        }
+      ]
+    }
+    """
+}
+
+private func makeStoredArchive(entries: [(String, Data)], to archiveURL: URL) throws {
+    var archive = Data()
+    var centralDirectory = Data()
+
+    for (path, contents) in entries {
+        let pathData = Data(path.utf8)
+        let localHeaderOffset = UInt32(archive.count)
+
+        appendLE(UInt32(0x04034b50), to: &archive)
+        appendLE(UInt16(20), to: &archive)
+        appendLE(UInt16(0), to: &archive)
+        appendLE(UInt16(0), to: &archive)
+        appendLE(UInt16(0), to: &archive)
+        appendLE(UInt16(0), to: &archive)
+        appendLE(UInt32(0), to: &archive)
+        appendLE(UInt32(contents.count), to: &archive)
+        appendLE(UInt32(contents.count), to: &archive)
+        appendLE(UInt16(pathData.count), to: &archive)
+        appendLE(UInt16(0), to: &archive)
+        archive.append(pathData)
+        archive.append(contents)
+
+        appendLE(UInt32(0x02014b50), to: &centralDirectory)
+        appendLE(UInt16(20), to: &centralDirectory)
+        appendLE(UInt16(20), to: &centralDirectory)
+        appendLE(UInt16(0), to: &centralDirectory)
+        appendLE(UInt16(0), to: &centralDirectory)
+        appendLE(UInt16(0), to: &centralDirectory)
+        appendLE(UInt16(0), to: &centralDirectory)
+        appendLE(UInt32(0), to: &centralDirectory)
+        appendLE(UInt32(contents.count), to: &centralDirectory)
+        appendLE(UInt32(contents.count), to: &centralDirectory)
+        appendLE(UInt16(pathData.count), to: &centralDirectory)
+        appendLE(UInt16(0), to: &centralDirectory)
+        appendLE(UInt16(0), to: &centralDirectory)
+        appendLE(UInt16(0), to: &centralDirectory)
+        appendLE(UInt16(0), to: &centralDirectory)
+        appendLE(UInt32(0), to: &centralDirectory)
+        appendLE(localHeaderOffset, to: &centralDirectory)
+        centralDirectory.append(pathData)
+    }
+
+    let centralDirectoryOffset = UInt32(archive.count)
+    archive.append(centralDirectory)
+    appendLE(UInt32(0x06054b50), to: &archive)
+    appendLE(UInt16(0), to: &archive)
+    appendLE(UInt16(0), to: &archive)
+    appendLE(UInt16(entries.count), to: &archive)
+    appendLE(UInt16(entries.count), to: &archive)
+    appendLE(UInt32(centralDirectory.count), to: &archive)
+    appendLE(centralDirectoryOffset, to: &archive)
+    appendLE(UInt16(0), to: &archive)
+    try archive.write(to: archiveURL, options: .atomic)
+}
+
 private enum ArchiveTestError: LocalizedError {
     case failedToCreateArchive(String)
 

docs/ios-device-access.md

@@ -2,7 +2,7 @@
 
 ## Summary
 
-World Manager can browse Minecraft Bedrock content from a trusted iPhone or iPad on macOS using Apple's private `MobileDevice.framework` and the House Arrest service.
+World Manager can browse and install Minecraft Bedrock content on a trusted iPhone or iPad from macOS using Apple's private `MobileDevice.framework` and the House Arrest service.
 
 Connected-device sources are modeled as normal `MinecraftSource` values, but they are not scanned through a live filesystem mirror. The current implementation asks the device for library item summaries, metadata, icons, sizes, and directory listings through `AppleMobileDeviceSourceAccess`. Only explicit materialization operations, such as reveal/export/share, mirror an item subtree into a temporary local directory.
 
@@ -87,6 +87,18 @@ During materialization:
 - `ContentPackageExporter` mirrors the selected item into archive staging when exporting connected-device content.
 - Temporary materialized folders are treated as disposable.
 
+During installation:
+
+- Package contents are fully extracted and validated on the Mac.
+- The bridge creates an operation directory under `Documents/games/com.mojang/.world-manager-staging`.
+- Files are uploaded through `AFCFileRefWrite`.
+- The destination collection is created if needed.
+- `AFCRenamePath` moves the completed staging directory into the appropriate collection.
+- A unique destination directory is selected, so an existing world or folder is not overwritten.
+- Failed staging trees are removed recursively through AFC.
+
+The write symbols are loaded opportunistically. Their absence prevents installation but does not disable read-only device access.
+
 ## Persistence
 
 Connected-device sources are persisted in the SQLite source cache with:
@@ -132,3 +144,6 @@ These commands require a trusted connected device and generally need to run outs
 - Behavior can change across macOS, iOS, iPadOS, and Minecraft releases.
 - Device access requires trust, unlock state, and a vendable app container.
 - Connected-device export/reveal operations may be slower than local folder operations because they materialize remote content on demand.
+- Device writes are serialized with scans and exports for the same device.
+- Multi-item imports can be partially completed if the device disconnects between items. The app reports the completed count and rescans the destination when it reconnects.
+- Pack replacement and removal are intentionally not implemented in the additive first version.