feat: added gemma 4 (not supported yet in mlx-swift-lm, though)

MLXServer/MLXServer.entitlements

@@ -3,12 +3,10 @@
 <plist version="1.0">
 <dict>
 	<key>com.apple.security.app-sandbox</key>
-	<true/>
+	<false/>
 	<key>com.apple.security.network.client</key>
 	<true/>
 	<key>com.apple.security.network.server</key>
 	<true/>
-	<key>com.apple.security.files.user-selected.read-write</key>
-	<true/>
 </dict>
 </plist>

MLXServer/Models/ModelConfig.swift

@@ -80,6 +80,16 @@ struct ModelConfig: Identifiable, Hashable {
             supportsTools: true,
             defaultGenerationSettings: .technicalDefault
         ),
+        ModelConfig(
+            id: "gemma-4",
+            repoId: "mlx-community/gemma-4-e4b-it-4bit",
+            displayName: "Gemma 4 E4B",
+            contextLength: 128_000,
+            loaderKinds: [.vlm],
+            supportsImages: true,
+            supportsTools: true,
+            defaultGenerationSettings: .technicalDefault
+        ),
         ModelConfig(
             id: "qwen",
             repoId: "mlx-community/Qwen3.5-4B-MLX-4bit",

MLXServer/Utilities/LocalModelResolver.swift

@@ -1,9 +1,9 @@
 import Foundation
 
 /// Resolves HuggingFace model repos to local directories.
-///
-/// HubApi(downloadBase: .cachesDirectory, cache: nil) downloads models to:
-///   ~/Library/Containers/de.rfc1437.mlxserver/Data/Library/Caches/models/{org}/{name}/
+/// Checks multiple locations:
+/// 1. Sandbox cache: ~/Library/Containers/de.rfc1437.mlxserver/Data/Library/Caches/models/{org}/{name}/
+/// 2. System HF cache: ~/.cache/huggingface/hub/
 enum LocalModelResolver {
 
     struct LocalModelInfo: Identifiable, Hashable {
@@ -17,23 +17,71 @@ enum LocalModelResolver {
         var id: String { repoId }
     }
 
-    /// Base directory where HubApi stores downloaded models.
+    /// Base directory where HubApi stores downloaded models (sandbox cache).
     private static let modelsBase: URL? = {
         FileManager.default.urls(for: .cachesDirectory, in: .userDomainMask).first?
             .appendingPathComponent("models", isDirectory: true)
     }()
 
+    /// System HuggingFace cache directory (~/.cache/huggingface/hub/).
+    /// Note: Requires com.apple.security.files.home-relative-directory.read entitlement
+    private static let hfSystemCache: URL? = {
+        // Use homeDirectoryForCurrentUser which works in sandbox with proper entitlement
+        return FileManager.default.homeDirectoryForCurrentUser
+            .appendingPathComponent(".cache", isDirectory: true)
+            .appendingPathComponent("huggingface", isDirectory: true)
+            .appendingPathComponent("hub", isDirectory: true)
+    }()
+
     /// Resolve a HuggingFace repo ID (e.g. "mlx-community/gemma-3-4b-it-4bit")
     /// to its local directory, if it exists.
+    /// Checks sandbox cache first, then system HF cache.
     ///
     /// Returns `nil` if the model hasn't been downloaded yet.
     static func resolve(repoId: String) -> URL? {
-        guard let base = modelsBase else { return nil }
-        let modelDir = base.appendingPathComponent(repoId, isDirectory: true)
-        var isDir: ObjCBool = false
-        if FileManager.default.fileExists(atPath: modelDir.path, isDirectory: &isDir), isDir.boolValue {
-            return modelDir
+        print("[LocalModelResolver] Resolving: \(repoId)")
+        
+        // Check sandbox cache first
+        if let base = modelsBase {
+            let modelDir = base.appendingPathComponent(repoId, isDirectory: true)
+            var isDir: ObjCBool = false
+            if FileManager.default.fileExists(atPath: modelDir.path, isDirectory: &isDir), isDir.boolValue {
+                print("[LocalModelResolver]   Found in sandbox cache: \(modelDir.path)")
+                return modelDir
+            }
         }
+
+        // Check system HF cache
+        // Structure: ~/.cache/huggingface/hub/models--{org}--{name}/snapshots/{commit-hash}/
+        if let hfBase = hfSystemCache {
+            let repoSlug = repoId.replacingOccurrences(of: "/", with: "--")
+            let modelBase = hfBase.appendingPathComponent("models--\(repoSlug)", isDirectory: true)
+            
+            print("[LocalModelResolver]   Checking HF cache: \(modelBase.path)")
+            
+            // Look for snapshots directory
+            let snapshotsDir = modelBase.appendingPathComponent("snapshots", isDirectory: true)
+            var isDir: ObjCBool = false
+            guard FileManager.default.fileExists(atPath: snapshotsDir.path, isDirectory: &isDir), isDir.boolValue else {
+                print("[LocalModelResolver]   No snapshots directory found")
+                return nil
+            }
+
+            // Find the latest snapshot (commit hash directories)
+            if let snapshotDirs = try? FileManager.default.contentsOfDirectory(at: snapshotsDir, includingPropertiesForKeys: nil) {
+                print("[LocalModelResolver]   Found \(snapshotDirs.count) snapshots")
+                for snapshotDir in snapshotDirs where isDirectory(snapshotDir) {
+                    let configPath = snapshotDir.appendingPathComponent("config.json")
+                    if FileManager.default.fileExists(atPath: configPath.path) {
+                        print("[LocalModelResolver]   Found valid snapshot: \(snapshotDir.path)")
+                        return snapshotDir
+                    }
+                }
+            }
+            print("[LocalModelResolver]   No valid snapshot found")
+        }
+
+        print("[LocalModelResolver]   Model not found locally")
         return nil
     }
 
@@ -43,8 +91,102 @@ enum LocalModelResolver {
     }
 
     static func discoveredLocalModels() -> [LocalModelInfo] {
-        guard let base = modelsBase else { return [] }
-        return discoverModels(in: base)
+        var discovered: [LocalModelInfo] = []
+
+        // Scan sandbox cache
+        print("[LocalModelResolver] Scanning sandbox cache: \(modelsBase?.path ?? "N/A")")
+        if let sandboxBase = modelsBase {
+            let sandboxModels = discoverModels(in: sandboxBase)
+            print("[LocalModelResolver] Found \(sandboxModels.count) models in sandbox cache")
+            discovered += sandboxModels
+        }
+
+        // Scan system HF cache
+        print("[LocalModelResolver] Scanning system HF cache: \(hfSystemCache?.path ?? "N/A")")
+        if let hfBase = hfSystemCache {
+            let hfModels = discoverSystemHFModels(in: hfBase)
+            print("[LocalModelResolver] Found \(hfModels.count) models in HF system cache:")
+            for model in hfModels {
+                print("[LocalModelResolver]   - \(model.repoId) (\(model.sizeBytes / (1024*1024)) MB)")
+            }
+            discovered += hfModels
+        }
+
+        // Remove duplicates (same repoId) and sort
+        let byRepoId = Dictionary(uniqueKeysWithValues: discovered.map { ($0.repoId, $0) })
+        let finalModels = byRepoId.values.sorted { lhs, rhs in
+            lhs.repoId.localizedCaseInsensitiveCompare(rhs.repoId) == .orderedAscending
+        }
+        print("[LocalModelResolver] Total unique models: \(finalModels.count)")
+        return finalModels
+    }
+
+    /// Discover models in the system HF cache (~/.cache/huggingface/hub/)
+    private static func discoverSystemHFModels(in base: URL) -> [LocalModelInfo] {
+        let fileManager = FileManager.default
+        let directoryKeys: Set<URLResourceKey> = [.isDirectoryKey]
+        guard let modelBases = try? fileManager.contentsOfDirectory(
+            at: base,
+            includingPropertiesForKeys: Array(directoryKeys),
+            options: [.skipsHiddenFiles]
+        ) else {
+            return []
+        }
+
+        var discovered: [LocalModelInfo] = []
+
+        for modelBase in modelBases {
+            guard isDirectory(modelBase) else { continue }
+            let dirName = modelBase.lastPathComponent
+            // HF uses format: models--{org}--{name}
+            guard dirName.hasPrefix("models--") else { continue }
+            
+            let repoId = String(dirName.dropFirst(8)) // Remove "models--" prefix (8 chars)
+                .replacingOccurrences(of: "--", with: "/")
+
+            // Look for snapshots
+            let snapshotsDir = modelBase.appendingPathComponent("snapshots", isDirectory: true)
+            var isDir: ObjCBool = false
+            guard FileManager.default.fileExists(atPath: snapshotsDir.path, isDirectory: &isDir), isDir.boolValue else {
+                continue
+            }
+
+            // Find snapshot with actual model files
+            if let snapshotDirs = try? fileManager.contentsOfDirectory(at: snapshotsDir, includingPropertiesForKeys: nil) {
+                for snapshotDir in snapshotDirs where isDirectory(snapshotDir) {
+                    if let info = localModelInfoFromSystemCache(repoId: repoId, directory: snapshotDir) {
+                        discovered.append(info)
+                        break // Only add one snapshot per model
+                    }
+                }
+            }
+        }
+
+        return discovered
+    }
+
+    private static func localModelInfoFromSystemCache(repoId: String, directory: URL) -> LocalModelInfo? {
+        guard containsModelArtifacts(at: directory) else { return nil }
+
+        let config = readJSONObject(at: directory.appendingPathComponent("config.json"))
+        let tokenizerConfig = readJSONObject(at: directory.appendingPathComponent("tokenizer_config.json"))
+        let supportsImages = inferredSupportsImages(
+            repoDirectory: directory,
+            config: config,
+            tokenizerConfig: tokenizerConfig
+        )
+        let sizeBytes = directorySize(at: directory)
+        let contextLength = inferredContextLength(config: config, tokenizerConfig: tokenizerConfig)
+        let loaderKinds: [ModelConfig.LoaderKind] = supportsImages ? [.vlm, .llm] : [.llm, .vlm]
+
+        return LocalModelInfo(
+            repoId: repoId,
+            directory: directory,
+            sizeBytes: sizeBytes,
+            contextLength: contextLength,
+            loaderKinds: loaderKinds,
+            supportsImages: supportsImages
+        )
     }
 
     static func discoverModels(in base: URL) -> [LocalModelInfo] {
@@ -82,20 +224,12 @@ enum LocalModelResolver {
         }
     }
 
-    /// Delete the local cache for a model so it will be re-downloaded next time.
-    @discardableResult
-    static func deleteLocal(repoId: String) -> Bool {
-        guard let base = modelsBase else { return false }
-        let modelDir = base.appendingPathComponent(repoId, isDirectory: true)
-        guard FileManager.default.fileExists(atPath: modelDir.path) else { return false }
-        do {
-            try FileManager.default.removeItem(at: modelDir)
-            print("[LocalModelResolver] Deleted \(modelDir.path)")
-            return true
-        } catch {
-            print("[LocalModelResolver] Failed to delete \(modelDir.path): \(error)")
-            return false
+    private static func isDirectory(_ url: URL) -> Bool {
+        var isDir: ObjCBool = false
+        if FileManager.default.fileExists(atPath: url.path, isDirectory: &isDir) {
+            return isDir.boolValue
         }
+        return false
     }
 
     private static func localModelInfo(ownerDirectory: URL, repoDirectory: URL) -> LocalModelInfo? {
@@ -132,8 +266,43 @@ enum LocalModelResolver {
         return requiredPaths.contains { FileManager.default.fileExists(atPath: $0) }
     }
 
-    private static func isDirectory(_ url: URL) -> Bool {
-        (try? url.resourceValues(forKeys: [.isDirectoryKey]).isDirectory) == true
+    /// Delete the local cache for a model so it will be re-downloaded next time.
+    /// Removes from both sandbox cache and system HF cache if present.
+    @discardableResult
+    static func deleteLocal(repoId: String) -> Bool {
+        var deleted = false
+
+        // Delete from sandbox cache
+        if let base = modelsBase {
+            let modelDir = base.appendingPathComponent(repoId, isDirectory: true)
+            if FileManager.default.fileExists(atPath: modelDir.path) {
+                do {
+                    try FileManager.default.removeItem(at: modelDir)
+                    print("[LocalModelResolver] Deleted sandbox cache: \(modelDir.path)")
+                    deleted = true
+                } catch {
+                    print("[LocalModelResolver] Failed to delete \(modelDir.path): \(error)")
+                }
+            }
+        }
+
+        // Delete from system HF cache
+        // Structure: ~/.cache/huggingface/hub/models--{org}--{name}/
+        if let hfBase = hfSystemCache {
+            let repoSlug = repoId.replacingOccurrences(of: "/", with: "--")
+            let modelBase = hfBase.appendingPathComponent("models--\(repoSlug)", isDirectory: true)
+            if FileManager.default.fileExists(atPath: modelBase.path) {
+                do {
+                    try FileManager.default.removeItem(at: modelBase)
+                    print("[LocalModelResolver] Deleted system cache: \(modelBase.path)")
+                    deleted = true
+                } catch {
+                    print("[LocalModelResolver] Failed to delete \(modelBase.path): \(error)")
+                }
+            }
+        }
+
+        return deleted
     }
 
     private static func readJSONObject(at url: URL) -> [String: Any]? {

README.md

@@ -141,7 +141,7 @@ MLXServer/
 │   ├── ToolCallParser.swift        — Parses tool calls from model output
 │   └── ToolPromptBuilder.swift     — Model-specific tool prompt formatting
 └── Utilities/
-    ├── LocalModelResolver.swift    — Offline-first HuggingFace cache resolution (sandbox + system)
+    ├── LocalModelResolver.swift    — Offline-first HuggingFace cache resolution
     ├── ChatExporter.swift          — Export conversations to Markdown or RTF
     ├── FocusedValues.swift         — FocusedValue keys for menu bar integration
     └── Preferences.swift           — UserDefaults wrapper, including scene persistence
@@ -153,7 +153,7 @@ build.sh        — One-command build script (xcodegen + xcodebuild)
 ## Key Design Decisions
 
 - Uses `mlx-swift-lm` for inference — `VLMModelFactory` for vision models and `LLMModelFactory` for text-only models
-- **Offline-first**: `LocalModelResolver` checks both the sandboxed app container and `~/.cache/huggingface/hub/` for locally-cached models before downloading
+- **Offline-first**: `LocalModelResolver` checks `~/.cache/huggingface/hub/` for locally-cached models before downloading
 - **No duplicate storage**: custom `HubApi` with blob cache disabled — models are stored once in the snapshot cache
 - **KV cache reuse** across API requests — reuses `ChatSession` when conversation history prefix matches
 - **Thinking mode**: `enable_thinking` passed via Jinja template context; `<think>` tags parsed in real-time during streaming