diff --git a/体己/AI/ModelStore.swift b/体己/AI/ModelStore.swift
new file mode 100644
index 0000000..ee13c9c
--- /dev/null
+++ b/体己/AI/ModelStore.swift
@@ -0,0 +1,76 @@
+import Foundation
+
+enum ModelKind: String, CaseIterable {
+    case llm = "Qwen3-1.7B-MLX-4bit"
+    case vl  = "Qwen2.5-VL-3B-MLX-4bit"
+
+    var displayName: String {
+        switch self {
+        case .llm: return "Qwen3-1.7B"
+        case .vl:  return "Qwen2.5-VL-3B"
+        }
+    }
+
+    /// 用于判定该模型是否已就绪的最小标志文件
+    var sentinelFilename: String { "config.json" }
+}
+
+final class ModelStore {
+    static let shared: ModelStore = {
+        do {
+            let appSupport = try FileManager.default.url(
+                for: .applicationSupportDirectory,
+                in: .userDomainMask,
+                appropriateFor: nil,
+                create: true
+            )
+            let root = appSupport.appendingPathComponent("Models", isDirectory: true)
+            return try ModelStore(rootURL: root)
+        } catch {
+            fatalError("ModelStore.shared init failed: \(error)")
+        }
+    }()
+
+    let rootURL: URL
+
+    init(rootURL: URL) throws {
+        self.rootURL = rootURL
+        try FileManager.default.createDirectory(at: rootURL, withIntermediateDirectories: true)
+    }
+
+    func localURL(for kind: ModelKind) -> URL {
+        rootURL.appendingPathComponent(kind.rawValue, isDirectory: true)
+    }
+
+    func isReady(_ kind: ModelKind) -> Bool {
+        let sentinel = localURL(for: kind).appendingPathComponent(kind.sentinelFilename)
+        return FileManager.default.fileExists(atPath: sentinel.path)
+    }
+
+    func totalBytes(for kind: ModelKind) -> Int {
+        let folder = localURL(for: kind)
+        guard let enumerator = FileManager.default.enumerator(
+            at: folder,
+            includingPropertiesForKeys: [.fileSizeKey]
+        ) else { return 0 }
+        var sum = 0
+        for case let url as URL in enumerator {
+            if let size = try? url.resourceValues(forKeys: [.fileSizeKey]).fileSize {
+                sum += size
+            }
+        }
+        return sum
+    }
+
+    /// Demo 现场旁路:从 Bundle 拷贝预装模型(W6 才真正使用,本周占位)
+    func seedFromBundle(_ kind: ModelKind) throws {
+        guard let bundleURL = Bundle.main.url(forResource: kind.rawValue, withExtension: nil) else {
+            return
+        }
+        let target = localURL(for: kind)
+        if FileManager.default.fileExists(atPath: target.path) {
+            try FileManager.default.removeItem(at: target)
+        }
+        try FileManager.default.copyItem(at: bundleURL, to: target)
+    }
+}
diff --git a/体己Tests/ModelStoreTests.swift b/体己Tests/ModelStoreTests.swift
new file mode 100644
index 0000000..d1f95cf
--- /dev/null
+++ b/体己Tests/ModelStoreTests.swift
@@ -0,0 +1,46 @@
+import Testing
+import Foundation
+@testable import 体己
+
+struct ModelStoreTests {
+
+    private func isolatedStore() throws -> ModelStore {
+        let temp = FileManager.default.temporaryDirectory
+            .appendingPathComponent(UUID().uuidString, isDirectory: true)
+        return try ModelStore(rootURL: temp)
+    }
+
+    @Test func freshStoreReportsBothModelsMissing() throws {
+        let store = try isolatedStore()
+        defer { try? FileManager.default.removeItem(at: store.rootURL) }
+
+        #expect(store.isReady(.llm) == false)
+        #expect(store.isReady(.vl) == false)
+    }
+
+    @Test func markReadyAfterFolderCreated() throws {
+        let store = try isolatedStore()
+        defer { try? FileManager.default.removeItem(at: store.rootURL) }
+
+        let llmFolder = store.localURL(for: .llm)
+        try FileManager.default.createDirectory(at: llmFolder, withIntermediateDirectories: true)
+        let configURL = llmFolder.appendingPathComponent("config.json")
+        try "{}".write(to: configURL, atomically: true, encoding: .utf8)
+
+        #expect(store.isReady(.llm) == true)
+        #expect(store.isReady(.vl) == false)
+    }
+
+    @Test func totalBytesSumsExistingFiles() throws {
+        let store = try isolatedStore()
+        defer { try? FileManager.default.removeItem(at: store.rootURL) }
+
+        let folder = store.localURL(for: .llm)
+        try FileManager.default.createDirectory(at: folder, withIntermediateDirectories: true)
+        let data = Data(repeating: 0, count: 1024)
+        try data.write(to: folder.appendingPathComponent("a.bin"))
+        try data.write(to: folder.appendingPathComponent("b.bin"))
+
+        #expect(store.totalBytes(for: .llm) == 2048)
+    }
+}