Merge pull request #1 from BigMarc/harper-engine-and-ax-fix

Harper engine and ax fix

.gitignore

@@ -3,3 +3,11 @@ dist/
 *.xcodeproj/xcuserdata/
 .DS_Store
 .swiftpm/
+
+# Rust / Harper FFI build artifacts (regenerate with harper-ffi/build.sh).
+# Cargo.lock IS committed (binary crate) for reproducible builds.
+harper-ffi/target/
+harper-ffi/lib/
+
+# xcodebuild DerivedData (used only to generate the MLX metallib)
+.xcode-build/

AppSupport/Info.plist

@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!--
-  Info.plist for the packaged GrammaGem.app bundle.
+  Info.plist for the packaged GrammarGem.app bundle.
 
   `swift build` produces a bare executable; to ship a real menu-bar app you wrap
   it in a .app bundle with this Info.plist (see scripts/build.sh) or, more
@@ -18,13 +18,13 @@
 <plist version="1.0">
 <dict>
     <key>CFBundleName</key>
-    <string>GrammaGem</string>
+    <string>GrammarGem</string>
     <key>CFBundleDisplayName</key>
-    <string>GrammaGem</string>
+    <string>GrammarGem</string>
     <key>CFBundleIdentifier</key>
-    <string>com.grammagem.app</string>
+    <string>com.grammargem.app</string>
     <key>CFBundleExecutable</key>
-    <string>GrammaGem</string>
+    <string>GrammarGem</string>
     <key>CFBundleIconFile</key>
     <string>AppIcon</string>
     <key>CFBundleIconName</key>
@@ -43,5 +43,19 @@
     <string>© 2026 FounderGem LLC. Built in public.</string>
     <key>NSPrincipalClass</key>
     <string>NSApplication</string>
+
+    <!-- Sparkle auto-update. Appcast is served from grammargem.com and updates are
+         EdDSA-signed with the key whose public half is below (private key lives in
+         the release machine's keychain; sign with scripts/release.sh). -->
+    <key>SUFeedURL</key>
+    <string>https://www.grammargem.com/appcast.xml</string>
+    <key>SUPublicEDKey</key>
+    <string>IwYch+DRgNk3gmCwe86z+SIc4sRdyDf4Z6xGpS+JXDc=</string>
+    <key>SUEnableAutomaticChecks</key>
+    <true/>
+    <key>SUScheduledCheckInterval</key>
+    <integer>86400</integer>
+    <key>SUAutomaticallyUpdate</key>
+    <false/>
 </dict>
 </plist>

Package.resolved

@@ -0,0 +1,78 @@
+{
+  "originHash" : "f78005d8f2f9a6a31d5c42cc7ce2b46907eb92fce74810060a58056e592ea3a1",
+  "pins" : [
+    {
+      "identity" : "gzipswift",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/1024jp/GzipSwift",
+      "state" : {
+        "revision" : "731037f6cc2be2ec01562f6597c1d0aa3fe6fd05",
+        "version" : "6.0.1"
+      }
+    },
+    {
+      "identity" : "mlx-swift",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ml-explore/mlx-swift",
+      "state" : {
+        "revision" : "96c0f69cf15f38abd6248bb71fca908171dab1d8",
+        "version" : "0.25.6"
+      }
+    },
+    {
+      "identity" : "mlx-swift-examples",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/ml-explore/mlx-swift-examples.git",
+      "state" : {
+        "revision" : "8775112da257e8b0a5bf45e3f84fb80222592c89",
+        "version" : "2.25.9"
+      }
+    },
+    {
+      "identity" : "sparkle",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/sparkle-project/Sparkle",
+      "state" : {
+        "revision" : "d46d456107feacc80711b21847b82b07bd9fb46e",
+        "version" : "2.9.3"
+      }
+    },
+    {
+      "identity" : "swift-collections",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-collections.git",
+      "state" : {
+        "revision" : "a0cb0954ecb21e4e31b0070e6ed5674e8556685a",
+        "version" : "1.6.0"
+      }
+    },
+    {
+      "identity" : "swift-jinja",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/huggingface/swift-jinja.git",
+      "state" : {
+        "revision" : "0b67ecb79139f6addef8699eff3622808aa6c7dc",
+        "version" : "2.3.6"
+      }
+    },
+    {
+      "identity" : "swift-numerics",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/apple/swift-numerics",
+      "state" : {
+        "revision" : "0c0290ff6b24942dadb83a929ffaaa1481df04a2",
+        "version" : "1.1.1"
+      }
+    },
+    {
+      "identity" : "swift-transformers",
+      "kind" : "remoteSourceControl",
+      "location" : "https://github.com/huggingface/swift-transformers",
+      "state" : {
+        "revision" : "a2e184dddb4757bc943e77fbe99ac6786c53f0b2",
+        "version" : "1.0.0"
+      }
+    }
+  ],
+  "version" : 3
+}

Package.swift

@@ -1,37 +1,58 @@
 // swift-tools-version:5.10
 import PackageDescription
+import Foundation
 
-// GrammaGem — native macOS menu-bar writing assistant.
+// GrammarGem — native macOS menu-bar writing assistant.
 //
-// This package builds with ONLY Apple frameworks so it compiles cleanly out of
-// the box (`swift build`). The heavyweight third-party pieces from the spec —
-// Harper (Rust grammar core), MLX (local LLM), KeyboardShortcuts, Sparkle — are
-// abstracted behind protocols with working stub implementations and clearly
-// marked `TODO(real-integration)` seams. See README.md for wiring the real deps.
+// Layer-1 grammar is the real **Harper** core (Apache-2.0), embedded as a Rust
+// C-FFI static library (see `harper-ffi/`). Build the lib first with
+// `harper-ffi/build.sh`; `scripts/build.sh` does this automatically.
+//
+// Layer-2 AI (rewrite / tone / Ask) is the real on-device LLM via MLX
+// (mlx-swift-examples). MLX is **Apple-Silicon / Metal only**, so the app is
+// arm64-only (matches the product spec: Apple Silicon, macOS 14+). The Harper
+// static lib stays universal; the linker just uses its arm64 slice.
+
+// Absolute path to the prebuilt Harper static lib, independent of build cwd.
+let packageRoot = URL(fileURLWithPath: #filePath).deletingLastPathComponent().path
+let harperLibDir = packageRoot + "/harper-ffi/lib"
+
 let package = Package(
-    name: "GrammaGem",
+    name: "GrammarGem",
     platforms: [
         .macOS(.v14) // Apple Silicon, macOS 14+ (per the product spec)
     ],
     products: [
-        .executable(name: "GrammaGem", targets: ["GrammaGem"])
+        .executable(name: "GrammarGem", targets: ["GrammarGem"])
     ],
     dependencies: [
-        // TODO(real-integration): add when wiring real engines / distribution.
-        //   .package(url: "https://github.com/sindresorhus/KeyboardShortcuts", from: "2.0.0"),
-        //   .package(url: "https://github.com/sparkle-project/Sparkle", from: "2.6.0"),
-        //   .package(url: "https://github.com/ml-explore/mlx-swift", from: "0.18.0"),
-        // The Harper grammar core is bundled via a Rust static lib + C-FFI; see harper-ffi/.
+        // On-device LLM runtime. Pinned to an exact tag (the LLM libraries still
+        // ship from this repo at 2.25.9; the package name is "mlx-libraries").
+        .package(url: "https://github.com/ml-explore/mlx-swift-examples.git", exact: "2.25.9"),
+        // Secure auto-updates (EdDSA-signed appcast served from grammargem.com).
+        .package(url: "https://github.com/sparkle-project/Sparkle", from: "2.6.0"),
     ],
     targets: [
+        // C shim exposing libharper_ffi's C ABI (harper-ffi/include/harper.h) to Swift.
+        .target(name: "CHarper", path: "Sources/CHarper"),
         .executableTarget(
-            name: "GrammaGem",
-            path: "Sources/GrammaGem"
+            name: "GrammarGem",
+            dependencies: [
+                "CHarper",
+                .product(name: "MLXLLM", package: "mlx-swift-examples"),
+                .product(name: "MLXLMCommon", package: "mlx-swift-examples"),
+                .product(name: "Sparkle", package: "Sparkle"),
+            ],
+            path: "Sources/GrammarGem",
+            linkerSettings: [
+                // Link the prebuilt Harper static library (arm64 slice).
+                .unsafeFlags(["-L\(harperLibDir)", "-lharper_ffi"])
+            ]
         ),
         .testTarget(
-            name: "GrammaGemTests",
-            dependencies: ["GrammaGem"],
-            path: "Tests/GrammaGemTests"
+            name: "GrammarGemTests",
+            dependencies: ["GrammarGem"],
+            path: "Tests/GrammarGemTests"
         ),
     ]
 )

README.md

@@ -1,6 +1,6 @@
 <div align="center">
 
-# ✒️ GrammaGem
+# ✒️ GrammarGem
 
 ### Write it once. Get it right.
 
@@ -12,7 +12,7 @@ Fix grammar, sharpen tone, and rewrite anything — in every app — for one pay
 ![One-time purchase](https://img.shields.io/badge/pricing-one--time-C9A24B)
 ![License: MIT](https://img.shields.io/badge/license-MIT-0E7C5A)
 
-[**⬇️ Download GrammaGem**](https://grammagem.app/#pricing) · [Docs](https://grammagem.app/docs) · [How it works](https://grammagem.app)
+[**⬇️ Download GrammarGem**](https://www.grammargem.com/#pricing) · [Docs](https://www.grammargem.com/docs) · [How it works](https://www.grammargem.com)
 
 </div>
 
@@ -20,7 +20,7 @@ Fix grammar, sharpen tone, and rewrite anything — in every app — for one pay
 
 ## Stop renting your grammar checker.
 
-Grammarly costs around **$144 every year**, reads everything you type, and sends it to their servers. GrammaGem does the same job — **better** — entirely on your Mac, for a **single payment**.
+Grammarly costs around **$144 every year**, reads everything you type, and sends it to their servers. GrammarGem does the same job — **better** — entirely on your Mac, for a **single payment**.
 
 Select text in any app, press one hotkey, and it’s polished in place. No copy-paste, no switching windows, and **nothing ever leaves your machine**.
 
@@ -30,7 +30,7 @@ Select text in any app, press one hotkey, and it’s polished in place. No copy-
 
 ## Why people switch
 
-|  | Grammarly | **GrammaGem** |
+|  | Grammarly | **GrammarGem** |
 |---|:---:|:---:|
 | **Price** | ~$144 / year, forever | **Pay once** |
 | **Your words** | Sent to the cloud | **Never leave your Mac** |
@@ -46,7 +46,7 @@ Select text in any app, press one hotkey, and it’s polished in place. No copy-
 - 🔒 **Private by design** — everything runs on your Mac’s Neural Engine. Your writing is never uploaded, logged, or used to train a model.
 - ⌨️ **One global hotkey** — fix or rewrite the selected text in any app: Mail, Slack, Notion, Chrome, Messages, VS Code, and more.
 - ✨ **Ask & rewrite** — “make it shorter,” “more formal,” “translate to German” — done in place.
-- 🎚️ **Writing Modes** — Email, Post, Team Chat, Academic, Code — switch the tone instantly, or let GrammaGem pick the right one for the app you’re in.
+- 🎚️ **Writing Modes** — Email, Post, Team Chat, Academic, Code — switch the tone instantly, or let GrammarGem pick the right one for the app you’re in.
 - 📖 **Personal dictionary** — teach it your names, brand terms, and jargon once; it stops “correcting” them forever.
 - 🖥️ **A clean management app** — manage your devices, shortcuts, modes, and privacy from one tidy window.
 
@@ -67,7 +67,7 @@ No subscription. No per-seat fees. One payment, lifetime updates.
 
 <div align="center">
 
-[**⬇️ Get GrammaGem**](https://grammagem.app/#pricing)
+[**⬇️ Get GrammarGem**](https://www.grammargem.com/#pricing)
 
 </div>
 
@@ -85,17 +85,17 @@ No. Core features work fully offline.
 No — it’s a one-time purchase with lifetime updates and a 14-day money-back guarantee.
 
 **What about plagiarism detection?**
-GrammaGem is private-first, so it doesn’t do cloud plagiarism scanning — that would require sending your writing to a server. Everything else you’d expect is here.
+GrammarGem is private-first, so it doesn’t do cloud plagiarism scanning — that would require sending your writing to a server. Everything else you’d expect is here.
 
 ---
 
 ## Built in public
 
-GrammaGem is open source under the **MIT License**. We believe a privacy tool should be one you can actually inspect. Issues and pull requests are welcome.
+GrammarGem is open source under the **MIT License**. We believe a privacy tool should be one you can actually inspect. Issues and pull requests are welcome.
 
 <div align="center">
 
-**[grammagem.app](https://grammagem.app)**
+**[grammargem.com](https://www.grammargem.com)**
 
 © 2026 FounderGem LLC · 1309 Coffeen Avenue STE 1200, Sheridan, WY 82801, USA
 

Resources/Modes/README.md

@@ -1,7 +1,7 @@
 # Built-in Writing Modes
 
 Each Mode is a named system-prompt preset for the local LLM. The canonical,
-compiled definitions live in [`Sources/GrammaGem/AI/ModeRegistry.swift`](../../Sources/GrammaGem/AI/ModeRegistry.swift);
+compiled definitions live in [`Sources/GrammarGem/AI/ModeRegistry.swift`](../../Sources/GrammarGem/AI/ModeRegistry.swift);
 these JSON files mirror them for transparency and easy editing.
 
 | Mode | Tier | In public repo? |

Sources/CHarper/include/harper.h

@@ -0,0 +1,37 @@
+/*
+ * harper.h — C ABI for the harper-ffi static library (harper-core 2.5.0).
+ *
+ * Symbols are provided by libharper_ffi.a (linked via -lharper_ffi). All
+ * strings are UTF-8. See harper-ffi/ for the Rust source.
+ */
+#ifndef HARPER_FFI_H
+#define HARPER_FFI_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Check `text` for grammar/spelling issues using harper-core.
+ *
+ * Returns a malloc'd, NUL-terminated UTF-8 JSON C string the caller MUST free
+ * with harper_free(). The JSON is an array of objects:
+ *   [{ "start": <char offset>, "len": <char count>,
+ *      "replacement": "<string>", "message": "<string>", "kind": "<string>" }]
+ *
+ *  - "start"/"len" are CHAR (Unicode scalar) offsets, NOT bytes/UTF-16.
+ *  - "kind" is one of: spelling, grammar, punctuation, repetition,
+ *    capitalization, phrasing.
+ *
+ * On null/invalid input or any internal error, returns "[]". Thread-safe.
+ */
+char *harper_check(const char *text);
+
+/* Free a string previously returned by harper_check(). NULL is a no-op. */
+void harper_free(char *ptr);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* HARPER_FFI_H */

Sources/CHarper/include/module.modulemap

@@ -0,0 +1,4 @@
+module CHarper {
+    header "harper.h"
+    export *
+}

Sources/CHarper/shim.c

@@ -0,0 +1,4 @@
+// CHarper is a header-only shim that exposes libharper_ffi's C ABI (declared in
+// include/harper.h) to Swift as the `CHarper` module. The actual symbols are
+// provided by libharper_ffi.a, linked via the GrammarGem target's linkerSettings.
+// This translation unit exists only so SwiftPM treats CHarper as a C target.

Sources/GrammaGem/AI/AIEngine.swift

@@ -1,32 +0,0 @@
-import Foundation
-
-/// Layer 2 — local-LLM-powered rewriting / tone / "Ask" / translate.
-///
-/// Backed in production by **MLX** (mlx-swift) running a small instruct model
-/// downloaded once from Hugging Face. The protocol isolates the rest of the app
-/// from the runtime so the UI, gating, and tests don't depend on MLX being present.
-protocol AIEngine: AnyObject {
-    /// Whether a model is loaded and ready to run locally.
-    var isReady: Bool { get }
-
-    /// Run an action against `text` and return the rewritten result.
-    /// Throws on model-not-ready or generation failure. Never performs network I/O.
-    func run(_ action: AIAction, on text: String) async throws -> String
-
-    /// Best-effort local tone classification (used by tone-detection UI).
-    func detectTone(_ text: String) async -> Tone
-}
-
-enum AIEngineError: LocalizedError {
-    case modelNotReady
-    case generationFailed(String)
-
-    var errorDescription: String? {
-        switch self {
-        case .modelNotReady:
-            return "The on-device model isn't ready yet. Finish the first-run download in Settings."
-        case .generationFailed(let why):
-            return "On-device rewrite failed: \(why)"
-        }
-    }
-}

Sources/GrammaGem/AI/MLXEngine.swift

@@ -1,91 +0,0 @@
-import Foundation
-
-/// STUB standing in for the real MLX-backed local LLM.
-///
-/// TODO(real-integration): load the model via mlx-swift from
-/// `ModelManager.modelsDirectory`, build the prompt from the action's system
-/// prompt + the user's text, and stream tokens (target: first token < 1s on
-/// M-series). Everything stays on-device — this method must never hit the network.
-///
-/// The stub produces deterministic, plausible transformations so the capture →
-/// engine → replace loop and the entitlement gating can be exercised end-to-end
-/// without the multi-gigabyte model present.
-final class MLXEngine: AIEngine {
-    private let ready: Bool
-
-    init(ready: Bool = true) {
-        self.ready = ready
-    }
-
-    var isReady: Bool { ready }
-
-    func run(_ action: AIAction, on text: String) async throws -> String {
-        guard ready else { throw AIEngineError.modelNotReady }
-        let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !trimmed.isEmpty else { return text }
-
-        switch action {
-        case .rewriteClarity, .rewrite:
-            return tidy(trimmed)
-        case .adjustTone(let tone):
-            return apply(tone: tone, to: tidy(trimmed))
-        case .ask(let instruction):
-            return follow(instruction: instruction, on: trimmed)
-        case .translate(let language):
-            return "[\(language)] " + tidy(trimmed)
-        case .applyMode(let mode):
-            return applyMode(mode, to: trimmed)
-        }
-    }
-
-    func detectTone(_ text: String) async -> Tone {
-        let lower = text.lowercased()
-        if lower.contains("!") || lower.contains("🚀") { return .punchy }
-        if lower.contains("therefore") || lower.contains("hereby") { return .academic }
-        if lower.contains("hey") || lower.contains("lol") { return .friendly }
-        return .professional
-    }
-
-    // MARK: - Deterministic stand-in transforms
-
-    private func tidy(_ s: String) -> String {
-        var out = s
-        out = out.replacingOccurrences(of: " i ", with: " I ")
-        out = out.replacingOccurrences(of: "lmk", with: "let me know")
-        out = out.replacingOccurrences(of: "u ", with: "you ")
-        if let first = out.first, first.isLowercase {
-            out.replaceSubrange(out.startIndex...out.startIndex, with: String(first).uppercased())
-        }
-        if let last = out.last, !".!?".contains(last) { out.append(".") }
-        return out
-    }
-
-    private func apply(tone: Tone, to s: String) -> String {
-        switch tone {
-        case .professional: return s
-        case .friendly: return "Hi! " + s
-        case .confident: return s.replacingOccurrences(of: "I think ", with: "")
-        case .academic: return "It is worth noting that " + s.prefix(1).lowercased() + s.dropFirst()
-        case .punchy: return s.replacingOccurrences(of: ". ", with: ".\n")
-        }
-    }
-
-    private func follow(instruction: String, on s: String) -> String {
-        let i = instruction.lowercased()
-        if i.contains("short") { return String(s.split(separator: " ").prefix(8).joined(separator: " ")) + "." }
-        if i.contains("formal") { return apply(tone: .academic, to: tidy(s)) }
-        if i.contains("translate") { return "[translated] " + tidy(s) }
-        return tidy(s)
-    }
-
-    private func applyMode(_ mode: WritingMode, to s: String) -> String {
-        switch mode.id {
-        case "email": return "Hi,\n\n\(tidy(s))\n\nThanks!"
-        case "post": return apply(tone: .punchy, to: tidy(s))
-        case "academic": return apply(tone: .academic, to: tidy(s))
-        case "slack": return s.lowercased()
-        case "code": return "// " + tidy(s)
-        default: return tidy(s)
-        }
-    }
-}

Sources/GrammaGem/App/GrammaGemApp.swift

@@ -1,34 +0,0 @@
-import SwiftUI
-import AppKit
-
-/// App entry point. A menu-bar (`LSUIElement`) SwiftUI app: the only persistent
-/// scene is the `MenuBarExtra`; Settings uses the standard scene; Onboarding and
-/// Ask are AppKit-hosted windows opened on demand (see `AppState`).
-@main
-struct GrammaGemApp: App {
-    @NSApplicationDelegateAdaptor(AppDelegate.self) private var appDelegate
-    @StateObject private var app = AppState.shared
-
-    var body: some Scene {
-        MenuBarExtra {
-            MenuBarContent()
-                .environmentObject(app)
-        } label: {
-            MenuBarLabel()
-        }
-        .menuBarExtraStyle(.window)
-
-        Settings {
-            SettingsView()
-                .environmentObject(app)
-                .frame(width: 560, height: 520)
-        }
-    }
-}
-
-/// Runs launch-time wiring (hotkeys, permissions, license validation).
-final class AppDelegate: NSObject, NSApplicationDelegate {
-    func applicationDidFinishLaunching(_ notification: Notification) {
-        AppState.shared.start()
-    }
-}

Sources/GrammaGem/App/OnboardingView.swift

@@ -1,138 +0,0 @@
-import SwiftUI
-
-/// First-run onboarding: explains why GrammaGem needs Accessibility, deep-links
-/// to System Settings, and advances automatically the moment permission is
-/// granted (even if granted directly in System Settings).
-struct OnboardingView: View {
-    @EnvironmentObject private var app: AppState
-    @ObservedObject private var permissions: Permissions
-    @ObservedObject private var model: ModelManager
-
-    init() {
-        _permissions = ObservedObject(wrappedValue: AppState.shared.permissions)
-        _model = ObservedObject(wrappedValue: AppState.shared.model)
-    }
-
-    var body: some View {
-        VStack(alignment: .leading, spacing: 18) {
-            VStack(alignment: .leading, spacing: 6) {
-                Text("Welcome to GrammaGem")
-                    .font(.largeTitle.bold())
-                Text("A private, on-device writing assistant that works in every app.")
-                    .foregroundStyle(.secondary)
-            }
-
-            stepCard(
-                number: 1,
-                title: "Grant Accessibility access",
-                body: "GrammaGem reads the text you select and writes the correction back. macOS requires Accessibility permission for this. Your text is processed on-device and never leaves your Mac.",
-                granted: permissions.accessibilityTrusted
-            ) {
-                if permissions.accessibilityTrusted {
-                    Label("Permission granted", systemImage: "checkmark.circle.fill")
-                        .foregroundStyle(.green)
-                } else {
-                    HStack {
-                        Button("Open System Settings") { permissions.openAccessibilitySettings() }
-                        Button("Request permission") { permissions.requestAccessibility() }
-                    }
-                    Text("This updates automatically once you flip GrammaGem on in Accessibility.")
-                        .font(.caption).foregroundStyle(.secondary)
-                }
-            }
-
-            stepCard(
-                number: 2,
-                title: "Download the on-device model (optional)",
-                body: "Grammar & spelling work instantly with no download. The AI rewrite/tone/Ask features use a small model downloaded once from Hugging Face — then everything runs offline.",
-                granted: model.state == .ready
-            ) {
-                ModelDownloadControls()
-            }
-
-            Spacer()
-
-            HStack {
-                if permissions.accessibilityTrusted {
-                    Label("You're all set", systemImage: "sparkles").foregroundStyle(.secondary)
-                }
-                Spacer()
-                Button(permissions.accessibilityTrusted ? "Done" : "Continue without permission") {
-                    app.showOnboardingDismiss()
-                }
-                .keyboardShortcut(.defaultAction)
-            }
-        }
-        .padding(28)
-        .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .topLeading)
-        .onAppear {
-            permissions.startPollingUntilGranted()
-        }
-        .onDisappear {
-            permissions.stopPolling()
-        }
-    }
-
-    private func stepCard<Controls: View>(
-        number: Int, title: String, body: String, granted: Bool,
-        @ViewBuilder controls: () -> Controls
-    ) -> some View {
-        HStack(alignment: .top, spacing: 14) {
-            ZStack {
-                Circle().fill(granted ? Color.green : Color.accentColor.opacity(0.15))
-                    .frame(width: 30, height: 30)
-                if granted {
-                    Image(systemName: "checkmark").foregroundStyle(.white).font(.caption.bold())
-                } else {
-                    Text("\(number)").font(.callout.bold()).foregroundStyle(.tint)
-                }
-            }
-            VStack(alignment: .leading, spacing: 8) {
-                Text(title).font(.headline)
-                Text(body).font(.callout).foregroundStyle(.secondary)
-                controls()
-            }
-        }
-        .padding(16)
-        .background(Color.primary.opacity(0.04), in: RoundedRectangle(cornerRadius: 12))
-    }
-}
-
-/// Real model download progress + controls, shared by onboarding and settings.
-struct ModelDownloadControls: View {
-    @ObservedObject private var model: ModelManager
-
-    init() {
-        _model = ObservedObject(wrappedValue: AppState.shared.model)
-    }
-
-    var body: some View {
-        switch model.state {
-        case .notDownloaded:
-            VStack(alignment: .leading, spacing: 4) {
-                Button("Download model now") { model.startDownload() }
-                Text("Installs automatically in the background on first launch (about 1–2 GB from Hugging Face). One time, then fully offline.")
-                    .font(.caption).foregroundStyle(.secondary)
-            }
-        case .downloading(let progress):
-            VStack(alignment: .leading, spacing: 6) {
-                ProgressView(value: progress) {
-                    Text("Downloading… \(Int(progress * 100))%")
-                }
-                .frame(maxWidth: 320)
-                if !model.statusText.isEmpty {
-                    Text(model.statusText).font(.caption).foregroundStyle(.secondary).lineLimit(1)
-                }
-                Button("Cancel") { model.cancel() }.controlSize(.small)
-            }
-        case .ready:
-            Label("Model ready", systemImage: "checkmark.seal.fill").foregroundStyle(.green)
-        case .failed(let message):
-            VStack(alignment: .leading, spacing: 4) {
-                Label("Download failed", systemImage: "exclamationmark.triangle").foregroundStyle(.orange)
-                Text(message).font(.caption).foregroundStyle(.secondary).lineLimit(2)
-                Button("Retry") { model.startDownload() }
-            }
-        }
-    }
-}

Sources/GrammaGem/Grammar/HarperEngine.swift

@@ -1,75 +0,0 @@
-import Foundation
-
-/// STUB standing in for the real Harper core.
-///
-/// TODO(real-integration): replace the rule set below with calls into the Harper
-/// Rust crate over C-FFI (`harper_check(text) -> spans`). This stub implements a
-/// handful of Harper-style deterministic rules so the system loop, live
-/// underlines, and tests have something real to exercise. It runs in well under
-/// 10ms and is fully offline — matching Harper's performance profile.
-final class HarperEngine: GrammarEngine {
-    var ignoreList: Set<String> = []
-
-    func check(_ text: String) -> [Suggestion] {
-        var out: [Suggestion] = []
-        let ns = text as NSString
-
-        // Rule 1 — repeated word ("the the" -> "the").
-        out += matches(in: text, pattern: #"\b(\w+)\s+\1\b"#) { match in
-            let full = ns.substring(with: match.range)
-            let firstWord = ns.substring(with: match.range(at: 1))
-            guard !ignoreList.contains(firstWord.lowercased()) else { return nil }
-            return Suggestion(
-                location: match.range.location, length: match.range.length,
-                original: full, replacement: firstWord,
-                kind: .repetition, message: "Repeated word")
-        }
-
-        // Rule 2 — lowercase standalone "i" -> "I".
-        out += matches(in: text, pattern: #"(?<=\s|^)i(?=\s|$|')"#) { match in
-            Suggestion(
-                location: match.range.location, length: match.range.length,
-                original: "i", replacement: "I",
-                kind: .capitalization, message: "Capitalize the pronoun “I”")
-        }
-
-        // Rule 3 — a few common confusions / typos.
-        let confusions: [(String, String, GrammarKind, String)] = [
-            (#"\btheir\b(?=\s+(any|are|is|was|were)\b)"#, "there", .grammar, "Did you mean “there”?"),
-            (#"\bteh\b"#, "the", .spelling, "Spelling"),
-            (#"\brecieve\b"#, "receive", .spelling, "Spelling (i before e)"),
-            (#"\bcheckin\b"#, "check in", .phrasing, "“check in” is two words"),
-            (#"\blmk\b"#, "let me know", .phrasing, "Expand abbreviation"),
-            (#"(?<=\s|^)u(?=\s|$)"#, "you", .phrasing, "Expand “u”"),
-        ]
-        for (pattern, replacement, kind, message) in confusions {
-            out += matches(in: text, pattern: pattern) { match in
-                let original = ns.substring(with: match.range)
-                guard !ignoreList.contains(original.lowercased()) else { return nil }
-                return Suggestion(
-                    location: match.range.location, length: match.range.length,
-                    original: original, replacement: replacement,
-                    kind: kind, message: message)
-            }
-        }
-
-        // Rule 4 — sentence should start uppercase (very light heuristic).
-        // (Left to the real Harper integration; intentionally omitted to avoid
-        //  false positives in this stub.)
-
-        return out.sorted { $0.location < $1.location }
-    }
-
-    // MARK: - Regex helper
-
-    private func matches(
-        in text: String, pattern: String,
-        _ make: (NSTextCheckingResult) -> Suggestion?
-    ) -> [Suggestion] {
-        guard let re = try? NSRegularExpression(pattern: pattern, options: [.caseInsensitive]) else {
-            return []
-        }
-        let full = NSRange(text.startIndex..., in: text)
-        return re.matches(in: text, range: full).compactMap(make)
-    }
-}

Sources/GrammaGem/Grammar/SystemGrammarEngine.swift

@@ -1,93 +0,0 @@
-import Foundation
-import AppKit
-
-/// Real, on-device grammar + spelling using macOS's built-in `NSSpellChecker`
-/// (the same engine TextEdit/Mail use). No network, no model — fully local,
-/// matching the privacy promise. Augmented with a few deterministic Harper-style
-/// rules (repeated words, lowercase "i", common expansions) the system checker
-/// doesn't surface.
-final class SystemGrammarEngine: GrammarEngine {
-    var ignoreList: Set<String> = []
-
-    private let checker = NSSpellChecker.shared
-    private let tag = NSSpellChecker.uniqueSpellDocumentTag()
-    private let extras = HarperEngine()
-
-    func check(_ text: String) -> [Suggestion] {
-        guard text.count >= 2 else { return [] }
-        return onMain { self.checkOnMain(text) }
-    }
-
-    private func checkOnMain(_ text: String) -> [Suggestion] {
-        let ns = text as NSString
-        let full = NSRange(location: 0, length: ns.length)
-        let language = checker.language()
-        var out: [Suggestion] = []
-
-        let types = NSTextCheckingResult.CheckingType([.spelling, .grammar]).rawValue
-        let results = checker.check(
-            text, range: full, types: types, options: nil,
-            inSpellDocumentWithTag: tag, orthography: nil, wordCount: nil)
-
-        for r in results {
-            switch r.resultType {
-            case .spelling:
-                let word = ns.substring(with: r.range)
-                if ignoreList.contains(word.lowercased()) { continue }
-                let fix = checker.correction(
-                    forWordRange: r.range, in: text, language: language, inSpellDocumentWithTag: tag)
-                    ?? checker.guesses(
-                        forWordRange: r.range, in: text, language: language,
-                        inSpellDocumentWithTag: tag)?.first
-                out.append(Suggestion(
-                    location: r.range.location, length: r.range.length,
-                    original: word, replacement: fix ?? word,
-                    kind: .spelling, message: "Possible spelling mistake"))
-
-            case .grammar:
-                let details = r.grammarDetails ?? []
-                if details.isEmpty {
-                    let phrase = ns.substring(with: r.range)
-                    out.append(Suggestion(
-                        location: r.range.location, length: r.range.length,
-                        original: phrase, replacement: phrase,
-                        kind: .grammar, message: "Grammar issue"))
-                } else {
-                    for d in details {
-                        var loc = r.range.location, len = r.range.length
-                        if let rv = d[NSGrammarRange] as? NSValue {
-                            let sub = rv.rangeValue
-                            loc = r.range.location + sub.location
-                            len = sub.length
-                        }
-                        guard len > 0, loc + len <= ns.length else { continue }
-                        let phrase = ns.substring(with: NSRange(location: loc, length: len))
-                        let message = (d[NSGrammarUserDescription] as? String) ?? "Grammar issue"
-                        let corrections = (d[NSGrammarCorrections] as? [String]) ?? []
-                        out.append(Suggestion(
-                            location: loc, length: len,
-                            original: phrase, replacement: corrections.first ?? phrase,
-                            kind: .grammar, message: message))
-                    }
-                }
-            default:
-                break
-            }
-        }
-
-        // Deterministic extras, skipping anything overlapping a system result.
-        extras.ignoreList = ignoreList
-        for h in extras.check(text) where !out.contains(where: { overlaps($0.range, h.range) }) {
-            out.append(h)
-        }
-        return out.sorted { $0.location < $1.location }
-    }
-
-    private func overlaps(_ a: NSRange, _ b: NSRange) -> Bool {
-        NSIntersectionRange(a, b).length > 0
-    }
-
-    private func onMain<T>(_ work: @escaping () -> T) -> T {
-        Thread.isMainThread ? work() : DispatchQueue.main.sync(execute: work)
-    }
-}

Sources/GrammaGem/Stats/UsageStats.swift

@@ -1,90 +0,0 @@
-import Foundation
-
-/// Privacy-friendly, fully-local usage insights. Counts *how often* features are
-/// used — never *what* was written. Stored only on this Mac.
-@MainActor
-final class UsageStats: ObservableObject {
-    struct Snapshot: Codable, Equatable {
-        var totalCorrections = 0
-        var totalAIActions = 0
-        var totalWords = 0
-        var perDay: [String: Int] = [:] // "yyyy-MM-dd" -> actions that day
-    }
-
-    @Published private(set) var data: Snapshot
-
-    private let key = "GrammaGem.usageStats"
-    private let d = UserDefaults.standard
-
-    private static let fmt: DateFormatter = {
-        let f = DateFormatter()
-        f.dateFormat = "yyyy-MM-dd"
-        f.locale = Locale(identifier: "en_US_POSIX")
-        f.timeZone = .current
-        return f
-    }()
-
-    init() {
-        if let raw = d.data(forKey: key),
-           let decoded = try? JSONDecoder().decode(Snapshot.self, from: raw) {
-            data = decoded
-        } else {
-            data = Snapshot()
-        }
-    }
-
-    func recordCorrection(words: Int) {
-        data.totalCorrections += 1
-        data.totalWords += max(0, words)
-        bumpToday()
-        persist()
-    }
-
-    func recordAIAction(words: Int) {
-        data.totalAIActions += 1
-        data.totalWords += max(0, words)
-        bumpToday()
-        persist()
-    }
-
-    /// A playful, clearly-estimated "time saved" figure (local only).
-    var estimatedMinutesSaved: Int {
-        (data.totalCorrections * 8 + data.totalAIActions * 45) / 60
-    }
-
-    /// Counts for the last 7 calendar days, oldest → newest, for a small chart.
-    func last7Days() -> [(label: String, count: Int)] {
-        let cal = Calendar.current
-        let today = Date()
-        return (0..<7).reversed().map { offset in
-            let day = cal.date(byAdding: .day, value: -offset, to: today) ?? today
-            let key = Self.fmt.string(from: day)
-            let short = day.formatted(.dateTime.weekday(.narrow))
-            return (label: short, count: data.perDay[key] ?? 0)
-        }
-    }
-
-    func reset() {
-        data = Snapshot()
-        persist()
-    }
-
-    private func bumpToday() {
-        let k = Self.fmt.string(from: Date())
-        data.perDay[k, default: 0] += 1
-        // Keep only ~60 days of history.
-        if data.perDay.count > 70 {
-            let keep = Set((0..<60).compactMap { off -> String? in
-                guard let day = Calendar.current.date(byAdding: .day, value: -off, to: Date()) else { return nil }
-                return Self.fmt.string(from: day)
-            })
-            data.perDay = data.perDay.filter { keep.contains($0.key) }
-        }
-    }
-
-    private func persist() {
-        if let raw = try? JSONEncoder().encode(data) {
-            d.set(raw, forKey: key)
-        }
-    }
-}

Sources/GrammaGem/System/AXSupport.swift

@@ -1,39 +0,0 @@
-import Foundation
-import ApplicationServices
-
-/// Safe Accessibility helpers shared across the System layer.
-///
-/// `AXUIElementCopyAttributeValue` returning `.success` only guarantees a
-/// non-null `CFTypeRef` — NOT that it is an `AXUIElement`. A misbehaving AX
-/// server (Electron/Java/custom) can return a different CF type, and a forced
-/// `as!` cast then traps and crashes the whole app. These helpers cast safely.
-enum AX {
-    /// Safely bridge a CFTypeRef to AXUIElement, returning nil on type mismatch.
-    static func element(_ ref: CFTypeRef?) -> AXUIElement? {
-        guard let ref, CFGetTypeID(ref) == AXUIElementGetTypeID() else { return nil }
-        return (ref as! AXUIElement) // safe: type id verified above
-    }
-
-    /// Copy an attribute as an `AXUIElement` (nil on failure/type mismatch).
-    static func copyElement(_ element: AXUIElement, _ attribute: String) -> AXUIElement? {
-        var ref: CFTypeRef?
-        guard AXUIElementCopyAttributeValue(element, attribute as CFString, &ref) == .success else {
-            return nil
-        }
-        return AX.element(ref)
-    }
-
-    /// Copy an attribute as a `String` (nil on failure/wrong type).
-    static func copyString(_ element: AXUIElement, _ attribute: String) -> String? {
-        var ref: CFTypeRef?
-        guard AXUIElementCopyAttributeValue(element, attribute as CFString, &ref) == .success else {
-            return nil
-        }
-        return ref as? String
-    }
-
-    /// Bound each cross-process AX message so a wedged target app can't hang us.
-    static func setMessagingTimeout(_ element: AXUIElement, _ seconds: Float) {
-        AXUIElementSetMessagingTimeout(element, seconds)
-    }
-}

Sources/GrammarGem/AI/AIEngine.swift

@@ -0,0 +1,73 @@
+import Foundation
+
+/// Layer 2 — local-LLM-powered rewriting / tone / "Ask" / translate.
+///
+/// Backed in production by **MLX** (mlx-swift) running a small instruct model
+/// downloaded once from Hugging Face. The protocol isolates the rest of the app
+/// from the runtime so the UI, gating, and tests don't depend on MLX being present.
+protocol AIEngine: AnyObject {
+    /// Whether a model is loaded and ready to run locally.
+    var isReady: Bool { get }
+
+    /// Run an action against `text` and return the rewritten result.
+    /// `protectedTerms` are vocabulary the model must reproduce verbatim (the
+    /// personal dictionary / style-guide terms). Throws on model-not-ready or
+    /// generation failure. Never performs network I/O on the on-device backend.
+    func run(_ action: AIAction, on text: String, protectedTerms: [String]) async throws -> String
+
+    /// Best-effort local tone classification (used by tone-detection UI).
+    func detectTone(_ text: String) async -> Tone
+
+    /// Optionally preload the model so the first real action is instant.
+    func warmup() async
+
+    /// Streaming variant: yields incremental output as it generates. The default
+    /// implementation wraps `run` as a single chunk, so a backend that doesn't
+    /// natively stream still conforms.
+    func runStreaming(_ action: AIAction, on text: String, protectedTerms: [String])
+        -> AsyncThrowingStream<String, Error>
+}
+
+extension AIEngine {
+    /// Convenience: run with no protected terms.
+    func run(_ action: AIAction, on text: String) async throws -> String {
+        try await run(action, on: text, protectedTerms: [])
+    }
+
+    /// Default: no preload.
+    func warmup() async {}
+
+    /// Default streaming: produce the full result, then emit it as one chunk.
+    func runStreaming(_ action: AIAction, on text: String, protectedTerms: [String])
+        -> AsyncThrowingStream<String, Error> {
+        AsyncThrowingStream { continuation in
+            Task {
+                do {
+                    continuation.yield(try await run(action, on: text, protectedTerms: protectedTerms))
+                    continuation.finish()
+                } catch {
+                    continuation.finish(throwing: error)
+                }
+            }
+        }
+    }
+
+    /// Convenience streaming overload with no protected terms.
+    func runStreaming(_ action: AIAction, on text: String) -> AsyncThrowingStream<String, Error> {
+        runStreaming(action, on: text, protectedTerms: [])
+    }
+}
+
+enum AIEngineError: LocalizedError {
+    case modelNotReady
+    case generationFailed(String)
+
+    var errorDescription: String? {
+        switch self {
+        case .modelNotReady:
+            return "The on-device model isn't ready yet. Finish the first-run download in Settings."
+        case .generationFailed(let why):
+            return "On-device rewrite failed: \(why)"
+        }
+    }
+}

Sources/GrammarGem/AI/AIPromptKit.swift

@@ -0,0 +1,111 @@
+import Foundation
+
+/// Backend-neutral prompt construction, generation parameters, and output
+/// cleanup for Layer-2 actions. Extracted from `MLXEngine` so EVERY `AIEngine`
+/// backend (MLX today, Ollama/llama.cpp next, the localhost extension server) is
+/// guaranteed to produce identical prompts and identical output trimming — no
+/// behavioral drift between runtimes — and so the personal dictionary / a future
+/// style guide can inject protected vocabulary in exactly ONE place.
+///
+/// Everything here is a pure function of its inputs (no MLX, no I/O), which also
+/// makes per-action behavior unit-testable without a model present.
+enum AIPrompts {
+
+    /// The system prompt for an action. `protectedTerms` (personal-dictionary
+    /// entries + future style-guide vocabulary) are terms the model must never
+    /// alter, so AI rewrites stop "correcting" brand names and jargon.
+    static func systemPrompt(for action: AIAction, protectedTerms: [String] = []) -> String {
+        base(for: action) + protectedTermsClause(protectedTerms)
+    }
+
+    private static func base(for action: AIAction) -> String {
+        switch action {
+        case .rewriteClarity:
+            return "Rewrite the user's text to be clearer and more concise. Preserve the "
+                + "original meaning and the author's voice. Output only the rewritten text."
+        case .rewrite:
+            return "Paraphrase the user's text. Keep the meaning but vary the wording and "
+                + "structure. Output only the rewritten text."
+        case .adjustTone(let tone):
+            return "Rewrite the user's text in a \(tone.rawValue) tone. Preserve the meaning. "
+                + "Output only the rewritten text."
+        case .ask(let instruction):
+            return "Apply this instruction to the user's text: \(instruction). "
+                + "Output only the resulting text."
+        case .translate(let language):
+            return "Translate the user's text into \(language). Output only the translation."
+        case .applyMode(let mode):
+            return mode.systemPrompt
+        }
+    }
+
+    /// Appended to every system prompt: terms the model must reproduce verbatim
+    /// (brand names, jargon the user added to their personal dictionary). Capped
+    /// so a large dictionary can't blow the context window.
+    private static func protectedTermsClause(_ terms: [String]) -> String {
+        let cleaned = terms
+            .map { $0.trimmingCharacters(in: .whitespacesAndNewlines) }
+            .filter { !$0.isEmpty }
+        guard !cleaned.isEmpty else { return "" }
+        let list = cleaned.prefix(50).map { "\"\($0)\"" }.joined(separator: ", ")
+        return " Never change, translate, or \"correct\" these exact terms — reproduce them "
+            + "verbatim, including capitalization: \(list)."
+    }
+
+    /// Low temperature for faithful rewrites; a touch higher for free paraphrase.
+    static func temperature(for action: AIAction) -> Float {
+        switch action {
+        case .rewrite: return 0.5
+        case .ask:     return 0.4
+        default:       return 0.2
+        }
+    }
+
+    /// Generation token budget. Honors a Mode's `lengthCap` (in characters) for
+    /// short-form modes (Post = 280, Team Chat = 60) so we don't spend the full
+    /// 512-token default on a one-line message; falls back to the default otherwise.
+    static func maxTokens(for action: AIAction) -> Int {
+        let fallback = 512
+        guard case .applyMode(let mode) = action, let cap = mode.lengthCap else { return fallback }
+        // ~1 token per 3 characters of English, plus headroom; clamp to a floor.
+        return min(fallback, max(64, cap / 3 + 48))
+    }
+
+    /// Strip a leading "Sure, here's …:" preamble and surrounding quotes that small
+    /// instruct models sometimes add, so the result drops cleanly into the field.
+    static func clean(_ s: String) -> String {
+        var out = s.trimmingCharacters(in: .whitespacesAndNewlines)
+        let lower = out.lowercased()
+        for prefix in ["sure, here", "sure! here", "here is", "here's", "certainly"] {
+            if lower.hasPrefix(prefix), let colon = out.firstIndex(of: ":") {
+                let after = out[out.index(after: colon)...]
+                    .trimmingCharacters(in: .whitespacesAndNewlines)
+                if !after.isEmpty { out = after }
+                break
+            }
+        }
+        if out.count >= 2, out.first == "\"", out.last == "\"" {
+            out = String(out.dropFirst().dropLast())
+        }
+        return out.trimmingCharacters(in: .whitespacesAndNewlines)
+    }
+
+    /// The tone-classifier system prompt (kept here so any backend reuses it).
+    static func toneClassifierPrompt() -> String {
+        let options = Tone.allCases.map(\.rawValue).joined(separator: ", ")
+        return """
+        You are a tone classifier. Read the user's text and respond with exactly ONE \
+        word — the single best-matching tone from this list: \(options). \
+        Output only that word, lowercase, no punctuation or explanation.
+        """
+    }
+
+    /// Parse the one-word tone classification output into a `Tone`.
+    static func parseTone(_ raw: String) -> Tone {
+        let token = raw.lowercased().trimmingCharacters(in: CharacterSet.alphanumerics.inverted)
+        if let exact = Tone(rawValue: token) { return exact }
+        let lower = raw.lowercased()
+        for tone in Tone.allCases where lower.contains(tone.rawValue) { return tone }
+        return .professional
+    }
+}

Sources/GrammarGem/AI/CustomModesStore.swift

@@ -8,8 +8,8 @@ final class CustomModesStore: ObservableObject {
     /// bundleID -> mode id (overrides the default App-Aware mapping).
     @Published private(set) var appOverrides: [String: String]
 
-    private let modesKey = "GrammaGem.customModes"
-    private let mapKey = "GrammaGem.appModeOverrides"
+    private let modesKey = "GrammarGem.customModes"
+    private let mapKey = "GrammarGem.appModeOverrides"
     private let d = UserDefaults.standard
 
     init() {
@@ -25,19 +25,27 @@ final class CustomModesStore: ObservableObject {
     /// Built-in + custom modes (custom ones are always paid).
     func allModes() -> [WritingMode] { ModeRegistry.all + customModes }
 
-    func addCustom(name: String, prompt: String) {
+    /// Returns false (no-op) if the name or prompt is empty, or the name
+    /// collides with an existing built-in/custom mode — so an empty-prompt mode
+    /// can't slip through to the LLM as an empty system prompt.
+    @discardableResult
+    func addCustom(name: String, prompt: String) -> Bool {
         let trimmed = name.trimmingCharacters(in: .whitespacesAndNewlines)
-        guard !trimmed.isEmpty else { return }
+        let trimmedPrompt = prompt.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !trimmed.isEmpty, !trimmedPrompt.isEmpty else { return false }
+        guard !allModes().contains(where: { $0.name.caseInsensitiveCompare(trimmed) == .orderedSame })
+        else { return false }
         let mode = WritingMode(
             id: "custom-\(UUID().uuidString.prefix(8))",
             name: trimmed,
-            systemPrompt: prompt.trimmingCharacters(in: .whitespacesAndNewlines),
+            systemPrompt: trimmedPrompt,
             isPaid: true,
             lengthCap: nil,
             autoFormat: "Custom"
         )
         customModes.append(mode)
         persistModes()
+        return true
     }
 
     func removeCustom(id: String) {

Sources/GrammarGem/AI/MLXEngine.swift

@@ -0,0 +1,149 @@
+import Foundation
+import MLXLMCommon
+import MLXLLM
+
+/// Layer 2 — the real on-device LLM (rewrite / tone / "Ask" / translate), backed
+/// by **MLX** via mlx-swift-examples (verified against tag 2.25.9; SPM package
+/// "mlx-libraries", products MLXLLM + MLXLMCommon).
+///
+/// Loads weights ONLY from a local on-disk snapshot (ModelManager's download
+/// directory) — `ModelConfiguration(directory:)` never contacts the network, so
+/// inference is fully on-device, honoring the privacy promise.
+///
+/// API surface used (all confirmed in the 2.25.9 source):
+///   ModelConfiguration(directory:)                 MLXLMCommon/ModelConfiguration.swift
+///   LLMModelFactory.shared.loadContainer(...)      MLXLLM/LLMModelFactory.swift
+///   ModelContainer.perform { context in ... }      MLXLMCommon/ModelContainer.swift
+///   context.processor.prepare(input: UserInput(chat:))   MLXLMCommon/UserInput.swift
+///   MLXLMCommon.generate(...) -> AsyncStream<Generation>  MLXLMCommon/Evaluate.swift
+final class MLXEngine: AIEngine {
+
+    /// Returns the local model snapshot directory if a complete model is present,
+    /// else nil. Owned by ModelManager; MLXEngine only loads + infers.
+    private let modelDirectoryProvider: () -> URL?
+
+    /// Serializes the (expensive) first load and caches the container.
+    private let loader = ContainerLoader()
+
+    init(modelDirectoryProvider: @escaping () -> URL?) {
+        self.modelDirectoryProvider = modelDirectoryProvider
+    }
+
+    var isReady: Bool { modelDirectoryProvider() != nil }
+
+    // MARK: - AIEngine
+
+    func run(_ action: AIAction, on text: String, protectedTerms: [String]) async throws -> String {
+        let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !trimmed.isEmpty else { return text }
+
+        let container = try await container()
+        let params = GenerateParameters(temperature: AIPrompts.temperature(for: action))
+        let raw = try await complete(
+            system: AIPrompts.systemPrompt(for: action, protectedTerms: protectedTerms),
+            user: trimmed,
+            maxTokens: AIPrompts.maxTokens(for: action),
+            parameters: params, container: container)
+        return AIPrompts.clean(raw)
+    }
+
+    /// Preload the model container so the first real action doesn't pay the
+    /// multi-second load. Safe to call repeatedly (the loader caches).
+    func warmup() async {
+        _ = try? await container()
+    }
+
+    func runStreaming(_ action: AIAction, on text: String, protectedTerms: [String])
+        -> AsyncThrowingStream<String, Error> {
+        AsyncThrowingStream { continuation in
+            Task {
+                let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+                guard !trimmed.isEmpty else { continuation.yield(text); continuation.finish(); return }
+                do {
+                    let container = try await container()
+                    var params = GenerateParameters(temperature: AIPrompts.temperature(for: action))
+                    params.maxTokens = AIPrompts.maxTokens(for: action)
+                    let system = AIPrompts.systemPrompt(for: action, protectedTerms: protectedTerms)
+                    try await container.perform { context in
+                        let input = try await context.processor.prepare(
+                            input: UserInput(chat: [.system(system), .user(trimmed)]))
+                        let stream = try MLXLMCommon.generate(
+                            input: input, parameters: params, context: context)
+                        for await item in stream {
+                            if let chunk = item.chunk { continuation.yield(chunk) }
+                        }
+                    }
+                    continuation.finish()
+                } catch {
+                    continuation.finish(throwing: error)
+                }
+            }
+        }
+    }
+
+    func detectTone(_ text: String) async -> Tone {
+        let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !trimmed.isEmpty else { return .professional }
+        do {
+            let container = try await container()
+            let raw = try await complete(
+                system: AIPrompts.toneClassifierPrompt(), user: trimmed, maxTokens: 8,
+                parameters: GenerateParameters(temperature: 0.0), container: container)
+            return AIPrompts.parseTone(raw)
+        } catch {
+            return .professional
+        }
+    }
+
+    // MARK: - Loading
+
+    private func container() async throws -> ModelContainer {
+        guard let dir = modelDirectoryProvider() else { throw AIEngineError.modelNotReady }
+        return try await loader.container(at: dir)
+    }
+
+    // MARK: - Generation
+
+    private func complete(system: String, user: String, maxTokens: Int,
+                          parameters: GenerateParameters,
+                          container: ModelContainer) async throws -> String {
+        do {
+            return try await container.perform { context in
+                let input = try await context.processor.prepare(
+                    input: UserInput(chat: [.system(system), .user(user)]))
+                var params = parameters
+                params.maxTokens = maxTokens
+                var out = ""
+                let stream = try MLXLMCommon.generate(
+                    input: input, parameters: params, context: context)
+                for await item in stream {
+                    if let chunk = item.chunk { out += chunk }
+                }
+                return out
+            }
+        } catch let error as AIEngineError {
+            throw error
+        } catch {
+            throw AIEngineError.generationFailed(error.localizedDescription)
+        }
+    }
+
+    // Prompt construction, temperature, token budget, and output cleanup now live
+    // in `AIPrompts` (backend-neutral; see AIPromptKit.swift) so every AIEngine
+    // backend produces identical prompts and identical output trimming.
+}
+
+/// Caches one loaded `ModelContainer` (keyed by directory) and coalesces
+/// concurrent first-loads. `ModelContainer` is itself an actor, so generation
+/// calls through it are serialized safely.
+private actor ContainerLoader {
+    private var cached: (url: URL, container: ModelContainer)?
+
+    func container(at directory: URL) async throws -> ModelContainer {
+        if let cached, cached.url == directory { return cached.container }
+        let configuration = ModelConfiguration(directory: directory)
+        let container = try await LLMModelFactory.shared.loadContainer(configuration: configuration)
+        cached = (directory, container)
+        return container
+    }
+}

Sources/GrammarGem/AI/ModelManager.swift

@@ -14,7 +14,9 @@ final class ModelManager: ObservableObject {
 
     @Published private(set) var state: State = .notDownloaded
     @Published private(set) var statusText: String = ""
-    @Published var selectedRepo: String = AppConfig.Model.defaultRepo
+    @Published var selectedRepo: String = ModelManager.activeRepo() {
+        didSet { UserDefaults.standard.set(selectedRepo, forKey: Self.selectedRepoKey) }
+    }
 
     private var task: Task<Void, Never>?
     private var generation = 0
@@ -23,20 +25,65 @@ final class ModelManager: ObservableObject {
         if isModelPresent(repo: selectedRepo) { state = .ready }
     }
 
-    var modelsDirectory: URL {
-        let base = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
-        return base.appendingPathComponent("GrammaGem/Models", isDirectory: true)
-    }
+    var modelsDirectory: URL { Self.modelsDirectory() }
 
-    func modelDir(_ repo: String) -> URL {
-        modelsDirectory.appendingPathComponent(repo.replacingOccurrences(of: "/", with: "_"), isDirectory: true)
-    }
+    func modelDir(_ repo: String) -> URL { Self.modelDir(repo) }
 
     /// Considered present once the completion marker is written.
-    func isModelPresent(repo: String) -> Bool {
+    func isModelPresent(repo: String) -> Bool { Self.isModelPresent(repo: repo) }
+
+    // MARK: - Nonisolated path helpers
+    //
+    // The AI engine loads weights off the main actor, so the directory lookup must
+    // be callable from any thread. These are pure FileManager/URL ops (no actor
+    // state, no network) and back the @MainActor instance accessors above.
+
+    nonisolated static func modelsDirectory() -> URL {
+        let base = FileManager.default.urls(for: .applicationSupportDirectory, in: .userDomainMask)[0]
+        return base.appendingPathComponent("GrammarGem/Models", isDirectory: true)
+    }
+
+    nonisolated static func modelDir(_ repo: String) -> URL {
+        modelsDirectory().appendingPathComponent(repo.replacingOccurrences(of: "/", with: "_"), isDirectory: true)
+    }
+
+    nonisolated static func isModelPresent(repo: String) -> Bool {
         FileManager.default.fileExists(atPath: modelDir(repo).appendingPathComponent(".complete").path)
     }
 
+    /// The local model directory iff a *complete* model is on disk, else nil —
+    /// fed to the AI engine as its network-free model source.
+    nonisolated static func completedModelDirectory(repo: String) -> URL? {
+        isModelPresent(repo: repo) ? modelDir(repo) : nil
+    }
+
+    /// UserDefaults key backing the user's chosen model repo.
+    nonisolated static let selectedRepoKey = "GrammarGem.selectedModelRepo"
+
+    /// The user's currently-selected repo, readable from ANY thread (it lives in
+    /// UserDefaults, which is thread-safe). The AI engine's model-directory
+    /// provider reads this so download, load, and `isReady` all agree on the SAME
+    /// repo — including the paid large model, which the old hardcoded-default
+    /// provider silently ignored. Falls back to the default repo when unset.
+    nonisolated static func activeRepo() -> String {
+        UserDefaults.standard.string(forKey: selectedRepoKey) ?? AppConfig.Model.defaultRepo
+    }
+
+    /// Safe URL construction for the two Hugging Face endpoints. A malformed
+    /// repo/path yields nil → a thrown `ModelError`, never a force-unwrap crash.
+    nonisolated static func fileURL(repo: String, path: String) -> URL? {
+        var c = URLComponents(string: AppConfig.Model.huggingFaceBase)
+        c?.path = "/\(repo)/resolve/main/\(path)"
+        return c?.url
+    }
+
+    nonisolated static func treeURL(repo: String) -> URL? {
+        var c = URLComponents(string: AppConfig.Model.huggingFaceBase)
+        c?.path = "/api/models/\(repo)/tree/main"
+        c?.queryItems = [URLQueryItem(name: "recursive", value: "1")]
+        return c?.url
+    }
+
     /// Kick off (or resume to) a real download. Safe to call from the UI.
     func startDownload(repo: String? = nil) {
         let target = repo ?? selectedRepo
@@ -74,7 +121,9 @@ final class ModelManager: ObservableObject {
                 try Task.checkCancellation()
                 set(gen, .downloading(progress: min(1, Double(done) / Double(total))),
                     "Downloading \(file.path) (\(byteString(file.size)))…")
-                let url = URL(string: "\(AppConfig.Model.huggingFaceBase)/\(repo)/resolve/main/\(file.path)")!
+                guard let url = Self.fileURL(repo: repo, path: file.path) else {
+                    throw ModelError.invalidURL(file.path)
+                }
                 let (tmp, response) = try await URLSession.shared.download(from: url)
                 if let http = response as? HTTPURLResponse, http.statusCode != 200 {
                     throw ModelError.http(http.statusCode, file.path)
@@ -130,7 +179,7 @@ final class ModelManager: ObservableObject {
 
     /// List the repo's files (+ sizes) from the Hugging Face tree API.
     private func fetchFileList(repo: String) async throws -> [(path: String, size: Int64)] {
-        let url = URL(string: "\(AppConfig.Model.huggingFaceBase)/api/models/\(repo)/tree/main?recursive=1")!
+        guard let url = Self.treeURL(repo: repo) else { throw ModelError.invalidURL("file list") }
         let (data, response) = try await URLSession.shared.data(from: url)
         if let http = response as? HTTPURLResponse, http.statusCode != 200 {
             throw ModelError.http(http.statusCode, "file list")
@@ -148,11 +197,13 @@ final class ModelManager: ObservableObject {
         case empty
         case http(Int, String)
         case corrupt(String)
+        case invalidURL(String)
         var errorDescription: String? {
             switch self {
             case .empty: return "No model files were found for this repository."
             case .http(let code, let what): return "Download failed (\(code)) while fetching \(what)."
             case .corrupt(let what): return "Downloaded file looked wrong (\(what)); please retry."
+            case .invalidURL(let what): return "Couldn't build a valid download URL for \(what)."
             }
         }
     }

Sources/GrammarGem/AI/OllamaEngine.swift

@@ -0,0 +1,176 @@
+import Foundation
+
+/// A cross-platform Layer-2 backend that talks to a locally-running **Ollama**
+/// server over HTTP. Conforms to the same `AIEngine` seam as `MLXEngine`, reuses
+/// the backend-neutral `AIPrompts` (so prompts/output are identical across
+/// runtimes), and depends only on `URLSession` — no MLX, no Metal — so it compiles
+/// and runs anywhere, including Windows/Linux. This is what converts the AIEngine
+/// abstraction from nominal to real and opens the non-Apple-Silicon market.
+///
+/// Privacy is preserved: Ollama runs the model on the user's own machine on
+/// loopback (127.0.0.1); no text leaves the device.
+final class OllamaEngine: AIEngine {
+    private let base: URL
+    private let model: String
+    private let session: URLSession
+
+    /// `isReady` is read synchronously by the coordinator but readiness for an HTTP
+    /// backend is an async probe, so we cache the last-known result behind a lock.
+    private let lock = NSLock()
+    private var cachedReady = false
+
+    init(base: URL = AppConfig.Ollama.baseURL,
+         model: String = AppConfig.Ollama.defaultModel,
+         session: URLSession = .shared) {
+        self.base = base
+        self.model = model
+        self.session = session
+    }
+
+    var isReady: Bool {
+        lock.lock(); defer { lock.unlock() }
+        return cachedReady
+    }
+
+    private func setReady(_ value: Bool) {
+        lock.lock(); cachedReady = value; lock.unlock()
+    }
+
+    // MARK: - AIEngine
+
+    /// Probe the server and confirm the configured model is pulled. Readiness for
+    /// Ollama means "server up + model present" (vs. MLX's "weights on disk").
+    func warmup() async {
+        setReady(await probeModelPresent())
+    }
+
+    func run(_ action: AIAction, on text: String, protectedTerms: [String]) async throws -> String {
+        let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !trimmed.isEmpty else { return text }
+        let raw = try await chat(
+            system: AIPrompts.systemPrompt(for: action, protectedTerms: protectedTerms),
+            user: trimmed,
+            temperature: AIPrompts.temperature(for: action),
+            maxTokens: AIPrompts.maxTokens(for: action))
+        setReady(true)
+        return AIPrompts.clean(raw)
+    }
+
+    func detectTone(_ text: String) async -> Tone {
+        let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+        guard !trimmed.isEmpty else { return .professional }
+        do {
+            let raw = try await chat(
+                system: AIPrompts.toneClassifierPrompt(), user: trimmed,
+                temperature: 0.0, maxTokens: 8)
+            return AIPrompts.parseTone(raw)
+        } catch {
+            return .professional
+        }
+    }
+
+    func runStreaming(_ action: AIAction, on text: String, protectedTerms: [String])
+        -> AsyncThrowingStream<String, Error> {
+        AsyncThrowingStream { continuation in
+            Task {
+                let trimmed = text.trimmingCharacters(in: .whitespacesAndNewlines)
+                guard !trimmed.isEmpty else { continuation.yield(text); continuation.finish(); return }
+                do {
+                    try await streamChat(
+                        system: AIPrompts.systemPrompt(for: action, protectedTerms: protectedTerms),
+                        user: trimmed,
+                        temperature: AIPrompts.temperature(for: action),
+                        maxTokens: AIPrompts.maxTokens(for: action),
+                        onChunk: { continuation.yield($0) })
+                    setReady(true)
+                    continuation.finish()
+                } catch {
+                    continuation.finish(throwing: error)
+                }
+            }
+        }
+    }
+
+    // MARK: - HTTP
+
+    private func probeModelPresent() async -> Bool {
+        do {
+            let (data, response) = try await session.data(from: base.appendingPathComponent("api/tags"))
+            guard (response as? HTTPURLResponse)?.statusCode == 200 else { return false }
+            let names = (try JSONDecoder().decode(TagsResponse.self, from: data)).models.map(\.name)
+            // Match exact or family (e.g. configured "qwen2.5:3b" vs a pulled "qwen2.5:3b-instruct").
+            return names.contains(model)
+                || names.contains { $0.hasPrefix(model) || model.hasPrefix($0) }
+        } catch {
+            return false
+        }
+    }
+
+    private func chat(system: String, user: String,
+                      temperature: Float, maxTokens: Int) async throws -> String {
+        let request = try makeRequest(path: "api/chat", body: ChatRequest(
+            model: model,
+            messages: [.init(role: "system", content: system), .init(role: "user", content: user)],
+            stream: false,
+            options: .init(temperature: temperature, num_predict: maxTokens)))
+        let (data, response) = try await session.data(for: request)
+        guard let http = response as? HTTPURLResponse else {
+            throw AIEngineError.generationFailed("No HTTP response from Ollama at \(base.absoluteString)")
+        }
+        guard http.statusCode == 200 else {
+            throw AIEngineError.generationFailed("Ollama returned HTTP \(http.statusCode)")
+        }
+        return (try JSONDecoder().decode(ChatResponse.self, from: data)).message?.content ?? ""
+    }
+
+    private func streamChat(system: String, user: String,
+                            temperature: Float, maxTokens: Int,
+                            onChunk: (String) -> Void) async throws {
+        let request = try makeRequest(path: "api/chat", body: ChatRequest(
+            model: model,
+            messages: [.init(role: "system", content: system), .init(role: "user", content: user)],
+            stream: true,
+            options: .init(temperature: temperature, num_predict: maxTokens)))
+        let (bytes, response) = try await session.bytes(for: request)
+        guard (response as? HTTPURLResponse)?.statusCode == 200 else {
+            throw AIEngineError.generationFailed("Ollama streaming request failed")
+        }
+        // Ollama streams newline-delimited JSON frames, one per token-ish chunk.
+        for try await line in bytes.lines {
+            guard let data = line.data(using: .utf8),
+                  let frame = try? JSONDecoder().decode(ChatResponse.self, from: data),
+                  let chunk = frame.message?.content, !chunk.isEmpty
+            else { continue }
+            onChunk(chunk)
+        }
+    }
+
+    private func makeRequest<T: Encodable>(path: String, body: T) throws -> URLRequest {
+        var request = URLRequest(url: base.appendingPathComponent(path))
+        request.httpMethod = "POST"
+        request.setValue("application/json", forHTTPHeaderField: "Content-Type")
+        request.httpBody = try JSONEncoder().encode(body)
+        return request
+    }
+
+    // MARK: - Wire types
+
+    private struct ChatRequest: Encodable {
+        let model: String
+        let messages: [Message]
+        let stream: Bool
+        let options: Options
+        struct Message: Encodable { let role: String; let content: String }
+        struct Options: Encodable { let temperature: Float; let num_predict: Int }
+    }
+
+    private struct ChatResponse: Decodable {
+        let message: Message?
+        struct Message: Decodable { let content: String }
+    }
+
+    private struct TagsResponse: Decodable {
+        let models: [Model]
+        struct Model: Decodable { let name: String }
+    }
+}

Sources/GrammarGem/App/AppState.swift

@@ -27,8 +27,11 @@ final class AppState: ObservableObject {
     let snippets: SnippetStore
     let exclusions: Exclusions
     let liveMonitor: LiveMonitor
+    let updater: UpdaterManager
     private let capture: TextCapture
     let coordinator: TextReplacementCoordinator
+    /// Loopback bridge to the browser extension (opt-in; nil unless enabled).
+    private var localServer: LocalEngineServer?
 
     // UI state
     @Published var lastStatus: String = "Ready"
@@ -45,7 +48,11 @@ final class AppState: ObservableObject {
     private init() {
         let engine = SystemGrammarEngine()
         grammar = engine
-        ai = MLXEngine(ready: true)
+        // The on-device LLM loads weights from ModelManager's local snapshot (if a
+        // complete download is present) — never the network. Resolved lazily on use.
+        // Reads the user's *selected* repo (default or paid large model) so the
+        // model that gets loaded matches the one that gets downloaded.
+        ai = AppState.makeAIEngine()
         permissions = Permissions()
         model = ModelManager()
         license = LicenseManager()
@@ -61,8 +68,30 @@ final class AppState: ObservableObject {
         let excl = Exclusions()
         exclusions = excl
         liveMonitor = LiveMonitor(grammar: engine, detector: detector, exclusions: excl, capture: capture)
+        updater = UpdaterManager()
+        let dict = dictionary
         coordinator = TextReplacementCoordinator(
-            capture: capture, grammar: engine, ai: ai, gate: gate, detector: detector)
+            capture: capture, grammar: engine, ai: ai, gate: gate, detector: detector,
+            protectedTerms: { dict.entries })
+    }
+
+    // MARK: - Backend factory
+
+    /// The single place the Layer-2 backend is chosen. Defaults to the MLX
+    /// on-device engine (Apple Silicon); a user/CI override selects the
+    /// cross-platform `OllamaEngine`. Adding a backend is a one-line branch here
+    /// instead of edits scattered across construction sites. The MLX provider
+    /// reads the user's *selected* repo so the loaded model matches the downloaded
+    /// one (incl. the paid large model).
+    static func makeAIEngine() -> AIEngine {
+        let override = ProcessInfo.processInfo.environment["GRAMMARGEM_AI_BACKEND"]
+            ?? UserDefaults.standard.string(forKey: "GrammarGem.aiBackend")
+        if override == "ollama" {
+            return OllamaEngine()
+        }
+        return MLXEngine(modelDirectoryProvider: {
+            ModelManager.completedModelDirectory(repo: ModelManager.activeRepo())
+        })
     }
 
     /// Called once at launch (from the AppDelegate).
@@ -95,10 +124,19 @@ final class AppState: ObservableObject {
 
         // Auto-install the on-device AI model in the background on first use, so
         // the AI features are ready without the user hunting for a button. The
-        // download is resumable/cancelable from the AI Model screen.
-        if !model.isModelPresent(repo: model.selectedRepo) {
+        // download is resumable/cancelable from the AI Model screen. If a model is
+        // already present, warm it up now so the first AI action is instant.
+        if model.isModelPresent(repo: model.selectedRepo) {
+            Task { [weak self] in await self?.ai.warmup() }
+        } else {
             model.startDownload()
         }
+        // Warm the model up as soon as a (first-run) download completes.
+        model.$state.dropFirst()
+            .sink { [weak self] state in
+                if case .ready = state { Task { [weak self] in await self?.ai.warmup() } }
+            }
+            .store(in: &cancellables)
 
         permissions.refresh()
         appAwareEnabled = gate.appAwareEnabled
@@ -109,7 +147,77 @@ final class AppState: ObservableObject {
         }
 
         Task { await license.validateIfNeeded() }
-        Log.app.info("GrammaGem started. Licensed: \(self.license.isLicensed, privacy: .public)")
+        startLocalServerIfEnabled()
+        Log.app.info("GrammarGem started. Licensed: \(self.license.isLicensed, privacy: .public)")
+    }
+
+    // MARK: - Browser-extension bridge (opt-in)
+
+    /// Start the loopback engine server only when the user has opted in, so the app
+    /// ships no listening socket by default. The server reuses the SAME engines,
+    /// prompts, and entitlement gate as the menu-bar app.
+    private func startLocalServerIfEnabled() {
+        let enabled = ProcessInfo.processInfo.environment["GRAMMARGEM_LOCAL_SERVER"] == "1"
+            || UserDefaults.standard.bool(forKey: AppConfig.LocalServer.enableKey)
+        guard enabled, localServer == nil else { return }
+
+        let server = LocalEngineServer(
+            port: AppConfig.LocalServer.port,
+            token: LocalEngineServer.loadOrCreateToken(),
+            grammarHandler: { [weak self] text in
+                await MainActor.run {
+                    guard let self else { return (text, []) }
+                    let corrected = self.grammar.correct(text)
+                    let suggestions = self.grammar.check(text).map {
+                        LocalEngineServer.WireSuggestion(
+                            location: $0.location, length: $0.length,
+                            original: $0.original, replacement: $0.replacement,
+                            kind: $0.kind.rawValue, message: $0.message)
+                    }
+                    return (corrected, suggestions)
+                }
+            },
+            aiHandler: { [weak self] (req: LocalEngineServer.AIRequest) async -> LocalEngineServer.AIOutcome in
+                guard let self else { return .error("GrammarGem is shutting down.") }
+                return await self.handleServerAI(req)
+            },
+            aiStreamHandler: { [weak self] (req, onChunk) -> LocalEngineServer.AIOutcome in
+                guard let self else { return .error("GrammarGem is shutting down.") }
+                return await self.handleServerAIStream(req, onChunk: onChunk)
+            })
+        server.start()
+        localServer = server
+    }
+
+    /// Run an AI action requested by the extension — same gate + model as the app.
+    private func handleServerAI(_ req: LocalEngineServer.AIRequest) async -> LocalEngineServer.AIOutcome {
+        if case .denied(let reason) = gate.authorizeAI(req.action) { return .error(reason) }
+        guard ai.isReady else { return .error(AIEngineError.modelNotReady.localizedDescription) }
+        do {
+            let out = try await ai.run(req.action, on: req.text, protectedTerms: dictionary.entries)
+            gate.recordAIActionUsed()
+            return .ok(out)
+        } catch {
+            return .error(error.localizedDescription)
+        }
+    }
+
+    /// Streaming variant for the extension: yields tokens as they generate.
+    private func handleServerAIStream(_ req: LocalEngineServer.AIRequest,
+                                      onChunk: @escaping (String) -> Void) async -> LocalEngineServer.AIOutcome {
+        if case .denied(let reason) = gate.authorizeAI(req.action) { return .error(reason) }
+        guard ai.isReady else { return .error(AIEngineError.modelNotReady.localizedDescription) }
+        var accumulated = ""
+        do {
+            for try await chunk in ai.runStreaming(req.action, on: req.text, protectedTerms: dictionary.entries) {
+                accumulated += chunk
+                onChunk(chunk)
+            }
+            gate.recordAIActionUsed()
+            return .ok(accumulated)
+        } catch {
+            return .error(error.localizedDescription)
+        }
     }
 
     // MARK: - Hotkey handling
@@ -179,19 +287,39 @@ final class AppState: ObservableObject {
         usage.recordCorrection(words: 1)
     }
 
-    /// Pause/resume all of GrammaGem (hotkeys + live monitoring).
+    /// Hide a single suggestion without changing the user's text.
+    func dismissSuggestion(_ suggestion: Suggestion, in field: DetectedField) {
+        liveMonitor.dismiss(suggestion, in: field)
+    }
+
+    /// Add a flagged word to the personal dictionary so it's never corrected
+    /// again (gated by the free cap), then re-scan so it disappears now.
+    @discardableResult
+    func addWordToDictionary(_ word: String) -> FeatureGate.Decision {
+        let decision = addDictionaryEntry(word)
+        switch decision {
+        case .allowed:
+            lastStatus = "Added “\(word)” to your dictionary"
+            liveMonitor.refreshSoon()
+        case .denied(let reason):
+            lastStatus = reason
+        }
+        return decision
+    }
+
+    /// Pause/resume all of GrammarGem (hotkeys + live monitoring).
     func togglePause() {
         isPaused.toggle()
         liveMonitor.setPaused(isPaused)
         lastStatus = isPaused ? "Paused" : "Ready"
     }
 
-    /// A reason GrammaGem should stay out of the way right now, or nil.
+    /// A reason GrammarGem should stay out of the way right now, or nil.
     private func blockReason() -> String? {
-        if isPaused { return "GrammaGem is paused." }
+        if isPaused { return "GrammarGem is paused." }
         let front = detector.frontmost()
         if exclusions.isBlocked(bundleID: front?.bundleID, domain: detector.frontmostDomain()) {
-            return "GrammaGem is off for \(front?.name ?? "this app")."
+            return "GrammarGem is off for \(front?.name ?? "this app")."
         }
         return nil
     }
@@ -256,9 +384,9 @@ final class AppState: ObservableObject {
         if onboardingWindow == nil {
             let host = NSHostingController(rootView: OnboardingView().environmentObject(self))
             let win = NSWindow(contentViewController: host)
-            win.title = "Welcome to GrammaGem"
+            win.title = "Welcome to GrammarGem"
             win.styleMask = [.titled, .closable, .fullSizeContentView]
-            win.setContentSize(NSSize(width: 540, height: 600))
+            win.setContentSize(NSSize(width: 560, height: 720))
             win.isReleasedWhenClosed = false
             win.center()
             onboardingWindow = win
@@ -285,7 +413,7 @@ final class AppState: ObservableObject {
                 .environmentObject(liveMonitor)
             let host = NSHostingController(rootView: root)
             let win = NSWindow(contentViewController: host)
-            win.title = "GrammaGem"
+            win.title = "GrammarGem"
             win.styleMask = [.titled, .closable, .miniaturizable, .resizable, .fullSizeContentView]
             win.setContentSize(NSSize(width: 940, height: 660))
             win.minSize = NSSize(width: 820, height: 560)
@@ -323,7 +451,7 @@ final class AppState: ObservableObject {
         if askWindow == nil {
             let host = NSHostingController(rootView: AskView().environmentObject(self))
             let win = NSWindow(contentViewController: host)
-            win.title = "Ask GrammaGem"
+            win.title = "Ask GrammarGem"
             win.styleMask = [.titled, .closable]
             win.setContentSize(NSSize(width: 460, height: 220))
             win.isReleasedWhenClosed = false

Sources/GrammarGem/App/AskView.swift

@@ -8,7 +8,7 @@ struct AskView: View {
 
     var body: some View {
         VStack(alignment: .leading, spacing: 14) {
-            Text("Ask GrammaGem")
+            Text("Ask GrammarGem")
                 .font(.headline)
             Text("Acts on the text selected in the frontmost app. Runs on-device.")
                 .font(.caption)

Sources/GrammarGem/App/GrammarGemApp.swift

@@ -0,0 +1,76 @@
+import SwiftUI
+import AppKit
+
+/// Process entry point. A hidden `--mlx-selftest` flag loads the on-device model
+/// and runs one real generation (verifies the MLX runtime + metallib headlessly),
+/// then exits. Otherwise the normal menu-bar app launches.
+@main
+enum GrammarGemMain {
+    static func main() {
+        if CommandLine.arguments.contains("--mlx-selftest") {
+            MLXSelfTest.run()
+            return
+        }
+        if let i = CommandLine.arguments.firstIndex(of: "--update-selftest") {
+            let feed = i + 1 < CommandLine.arguments.count ? CommandLine.arguments[i + 1] : ""
+            UpdaterSelfTest.run(feedURL: feed)
+            return
+        }
+        GrammarGemApp.main()
+    }
+}
+
+/// Headless verification of the on-device LLM (used by CI / the build pipeline).
+enum MLXSelfTest {
+    static func run() {
+        let sample = "me and him was going to the store for to buy some milks"
+        let engine = MLXEngine(modelDirectoryProvider: {
+            ModelManager.completedModelDirectory(repo: ModelManager.activeRepo())
+        })
+        guard engine.isReady else {
+            FileHandle.standardError.write(Data("SELFTEST_FAIL: model not present\n".utf8))
+            exit(2)
+        }
+        let sem = DispatchSemaphore(value: 0)
+        var line = "SELFTEST_FAIL: unknown"
+        Task.detached {
+            do { line = "SELFTEST_OK: " + (try await engine.run(.rewriteClarity, on: sample)) }
+            catch { line = "SELFTEST_FAIL: \(error.localizedDescription)" }
+            sem.signal()
+        }
+        sem.wait()
+        print(line)
+        exit(line.hasPrefix("SELFTEST_OK") ? 0 : 1)
+    }
+}
+
+/// App entry point. A menu-bar (`LSUIElement`) SwiftUI app: the only persistent
+/// scene is the `MenuBarExtra`; Settings uses the standard scene; Onboarding and
+/// Ask are AppKit-hosted windows opened on demand (see `AppState`).
+struct GrammarGemApp: App {
+    @NSApplicationDelegateAdaptor(AppDelegate.self) private var appDelegate
+    @StateObject private var app = AppState.shared
+
+    var body: some Scene {
+        MenuBarExtra {
+            MenuBarContent()
+                .environmentObject(app)
+        } label: {
+            MenuBarLabel()
+        }
+        .menuBarExtraStyle(.window)
+
+        Settings {
+            SettingsView()
+                .environmentObject(app)
+                .frame(width: 560, height: 520)
+        }
+    }
+}
+
+/// Runs launch-time wiring (hotkeys, permissions, license validation).
+final class AppDelegate: NSObject, NSApplicationDelegate {
+    func applicationDidFinishLaunching(_ notification: Notification) {
+        AppState.shared.start()
+    }
+}

Sources/GrammarGem/App/MainWindow/AccountViews.swift

@@ -8,7 +8,7 @@ struct GeneralView: View {
     @EnvironmentObject private var permissions: Permissions
 
     var body: some View {
-        DetailScaffold(title: "General", subtitle: "Make GrammaGem feel like yours.") {
+        DetailScaffold(title: "General", subtitle: "Make GrammarGem feel like yours.") {
             Card {
                 Toggle("Launch at login", isOn: $prefs.launchAtLogin)
                 Divider()
@@ -134,7 +134,7 @@ struct AboutView: View {
                         .frame(width: 56, height: 56)
                         .background(GG.emerald.opacity(0.12), in: RoundedRectangle(cornerRadius: 14))
                     VStack(alignment: .leading, spacing: 2) {
-                        Text("GrammaGem").font(.title2.bold())
+                        Text("GrammarGem").font(.title2.bold())
                         Text("Version \(AppConfig.appVersion)").foregroundStyle(.secondary)
                         Text("The private, on-device writing assistant for Mac.")
                             .font(.callout).foregroundStyle(.secondary)
@@ -153,7 +153,7 @@ struct AboutView: View {
 
             Card {
                 Text("Open source").font(.headline)
-                Text("GrammaGem is open source under the MIT License — a privacy tool you can inspect.")
+                Text("GrammarGem is open source under the MIT License — a privacy tool you can inspect.")
                     .font(.callout).foregroundStyle(.secondary)
             }
 

Sources/GrammarGem/App/MainWindow/DashboardView.swift

@@ -30,6 +30,15 @@ struct DashboardView: View {
 
                 StatTile(value: "\(usage.data.totalCorrections)", label: "Corrections made", systemImage: "checkmark.seal.fill", tint: GG.emerald)
                 StatTile(value: timeSaved, label: "Time saved (est.)", systemImage: "clock.fill", tint: .primary)
+
+                StatTile(
+                    value: usage.currentStreak > 0 ? "\(usage.currentStreak)d" : "—",
+                    label: "Day streak", systemImage: "flame.fill",
+                    tint: usage.currentStreak > 0 ? .orange : .secondary)
+                StatTile(
+                    value: "$\(usage.subscriptionAvoidedUSD)",
+                    label: "Subscription not paid", systemImage: "dollarsign.circle.fill",
+                    tint: GG.emerald)
             }
 
             // Setup health
@@ -61,6 +70,19 @@ struct DashboardView: View {
                     .font(.caption).foregroundStyle(.secondary)
             }
 
+            // Next milestone
+            Card {
+                let milestone = usage.nextMilestone
+                HStack {
+                    Text("Next milestone").font(.headline)
+                    Spacer()
+                    Text(milestone.label).font(.caption).foregroundStyle(.secondary)
+                }
+                ProgressView(value: milestone.progress).tint(GG.emerald)
+                Text("\(usage.data.totalCorrections) corrections so far — keep the streak alive.")
+                    .font(.caption).foregroundStyle(.secondary)
+            }
+
             // Quick actions
             Card {
                 Text("Quick actions").font(.headline)
@@ -69,7 +91,7 @@ struct DashboardView: View {
                         Label("Fix selection", systemImage: "checkmark.circle")
                     }
                     Button { app.showAsk() } label: {
-                        Label("Ask GrammaGem", systemImage: "sparkles")
+                        Label("Ask GrammarGem", systemImage: "sparkles")
                     }
                     if !license.isLicensed {
                         Spacer()

Sources/GrammarGem/App/MainWindow/DataViews.swift

@@ -12,7 +12,7 @@ struct DictionaryView: View {
     var body: some View {
         DetailScaffold(
             title: "Personal Dictionary",
-            subtitle: "Words GrammaGem should never “correct” — names, brands, jargon."
+            subtitle: "Words GrammarGem should never “correct” — names, brands, jargon."
         ) {
             Card {
                 HStack {

Sources/GrammarGem/App/MainWindow/DevicesView.swift

@@ -83,7 +83,7 @@ struct DevicesView: View {
             HStack {
                 Link("Open license portal", destination: AppConfig.modelPortalURL)
                 Spacer()
-                Text("Add a Mac: install GrammaGem there and paste the same key.")
+                Text("Add a Mac: install GrammarGem there and paste the same key.")
                     .font(.caption).foregroundStyle(.secondary)
             }
         }

Sources/GrammarGem/App/MainWindow/ExclusionsView.swift

@@ -8,12 +8,12 @@ struct ExclusionsView: View {
     var body: some View {
         DetailScaffold(
             title: "Page Blocker",
-            subtitle: "Keep GrammaGem out of the way in sensitive apps and sites."
+            subtitle: "Keep GrammarGem out of the way in sensitive apps and sites."
         ) {
             Card {
                 Label("How it works", systemImage: "hand.raised")
                     .font(.headline)
-                Text("When the frontmost app or website is on these lists, GrammaGem stops monitoring and the hotkeys do nothing — useful for password managers, banking, and private work.")
+                Text("When the frontmost app or website is on these lists, GrammarGem stops monitoring and the hotkeys do nothing — useful for password managers, banking, and private work.")
                     .font(.callout).foregroundStyle(.secondary)
             }
 

Sources/GrammarGem/App/MainWindow/LiveCheckView.swift

@@ -34,22 +34,32 @@ struct LiveCheckView: View {
     }
 
     private var header: some View {
-        HStack(spacing: 12) {
-            VStack(alignment: .leading, spacing: 2) {
-                Text(summary).font(.headline)
-                Text(monitor.activeAppName.isEmpty
-                     ? "Checking text areas on screen"
-                     : "In \(monitor.activeAppName) · \(monitor.scannedCount) text area\(monitor.scannedCount == 1 ? "" : "s") checked")
-                    .font(.caption).foregroundStyle(.secondary)
-            }
-            Spacer()
-            Button { monitor.refreshSoon() } label: { Image(systemName: "arrow.clockwise") }
-                .help("Re-scan now")
-            if monitor.issueCount > 0 {
-                Button { app.fixAllDetected() } label: {
-                    Label("Fix everything", systemImage: "checkmark.circle.fill")
+        VStack(alignment: .leading, spacing: 10) {
+            HStack(spacing: 12) {
+                ScoreRing(score: monitor.writingScore)
+                VStack(alignment: .leading, spacing: 2) {
+                    Text(summary).font(.headline)
+                    Text(contextLine).font(.caption).foregroundStyle(.secondary)
+                }
+                Spacer()
+                Button { monitor.refreshSoon() } label: { Image(systemName: "arrow.clockwise") }
+                    .help("Re-scan now")
+                if monitor.issueCount > 0 {
+                    Button { app.fixAllDetected() } label: {
+                        Label("Fix everything", systemImage: "checkmark.circle.fill")
+                    }
+                    .buttonStyle(.borderedProminent)
+                }
+            }
+            if monitor.issueCount > 0 {
+                HStack(spacing: 8) {
+                    ForEach(IssueBucket.allCases) { bucket in
+                        if let n = monitor.bucketCounts[bucket], n > 0 {
+                            BucketChip(bucket: bucket, count: n)
+                        }
+                    }
+                    Spacer()
                 }
-                .buttonStyle(.borderedProminent)
             }
         }
         .padding(16)
@@ -57,10 +67,16 @@ struct LiveCheckView: View {
 
     private var summary: String {
         let issues = monitor.issueCount
-        if issues == 0 { return "No issues found" }
+        if issues == 0 { return "Looks clean" }
         return "\(issues) issue\(issues == 1 ? "" : "s") across \(monitor.fields.count) text area\(monitor.fields.count == 1 ? "" : "s")"
     }
 
+    private var contextLine: String {
+        monitor.activeAppName.isEmpty
+            ? "Checking text areas on screen"
+            : "In \(monitor.activeAppName) · \(monitor.scannedCount) text area\(monitor.scannedCount == 1 ? "" : "s") checked"
+    }
+
     private var emptyState: some View {
         VStack(spacing: 10) {
             Image(systemName: "checkmark.seal.fill").font(.system(size: 42)).foregroundStyle(GG.emerald)
@@ -112,9 +128,21 @@ private struct FieldCard: View {
                             }
                         }
                         Spacer()
+                        if s.kind == .spelling {
+                            Button { app.addWordToDictionary(s.original) } label: {
+                                Image(systemName: "book.closed")
+                            }
+                            .controlSize(.small).buttonStyle(.borderless)
+                            .help("Add “\(s.original)” to your dictionary")
+                        }
+                        Button { app.dismissSuggestion(s, in: field) } label: {
+                            Image(systemName: "xmark")
+                        }
+                        .controlSize(.small).buttonStyle(.borderless)
+                        .help("Dismiss this suggestion")
                         if s.replacement != s.original && !s.replacement.isEmpty {
                             Button("Apply") { app.applySuggestion(s, in: field) }
-                                .controlSize(.small)
+                                .controlSize(.small).buttonStyle(.borderedProminent)
                         }
                     }
                 }
@@ -141,6 +169,14 @@ private struct FieldCard: View {
         }
     }
 
+    fileprivate static func color(for bucket: IssueBucket) -> Color {
+        switch bucket {
+        case .correctness: return .red
+        case .clarity: return .blue
+        case .polish: return GG.gold
+        }
+    }
+
     /// Build an attributed string with each issue span tinted.
     private func highlighted(_ text: String, _ suggestions: [Suggestion]) -> AttributedString {
         let ns = text as NSString
@@ -167,3 +203,40 @@ private struct FieldCard: View {
         return result
     }
 }
+
+/// A compact 0–100 cleanliness gauge. Green when clean, amber/orange as issues
+/// pile up — a meter the user can watch climb as they accept fixes.
+private struct ScoreRing: View {
+    let score: Int
+    var body: some View {
+        ZStack {
+            Circle().stroke(Color.primary.opacity(0.1), lineWidth: 5)
+            Circle()
+                .trim(from: 0, to: CGFloat(max(0, min(100, score))) / 100)
+                .stroke(color, style: StrokeStyle(lineWidth: 5, lineCap: .round))
+                .rotationEffect(.degrees(-90))
+                .animation(.easeOut(duration: 0.35), value: score)
+            Text("\(score)").font(.system(size: 15, weight: .bold, design: .rounded))
+        }
+        .frame(width: 44, height: 44)
+        .help("Writing score for the text on screen")
+    }
+
+    private var color: Color {
+        score >= 90 ? GG.emerald : (score >= 70 ? GG.gold : .orange)
+    }
+}
+
+/// A tappable-looking count chip per issue bucket (Correctness / Clarity / Polish).
+private struct BucketChip: View {
+    let bucket: IssueBucket
+    let count: Int
+    var body: some View {
+        HStack(spacing: 5) {
+            Circle().fill(FieldCard.color(for: bucket)).frame(width: 7, height: 7)
+            Text("\(bucket.title) \(count)").font(.caption.weight(.medium))
+        }
+        .padding(.horizontal, 9).padding(.vertical, 4)
+        .background(FieldCard.color(for: bucket).opacity(0.12), in: Capsule())
+    }
+}

Sources/GrammarGem/App/MainWindow/MainWindowView.swift

@@ -59,7 +59,7 @@ enum MainSection: String, CaseIterable, Identifiable {
     ]
 }
 
-/// The full GrammaGem management window: a clean sidebar + detail layout.
+/// The full GrammarGem management window: a clean sidebar + detail layout.
 struct MainWindowView: View {
     @State private var selection: MainSection?
 

Sources/GrammarGem/App/MainWindow/SystemViews.swift

@@ -17,7 +17,7 @@ struct ShortcutsView: View {
                     combo: $prefs.fixHotkey)
                 Divider()
                 shortcutRow(
-                    name: "Ask GrammaGem",
+                    name: "Ask GrammarGem",
                     detail: "Rewrite with an instruction",
                     combo: $prefs.askHotkey)
             }
@@ -141,7 +141,7 @@ struct PrivacyView: View {
             }
 
             Card {
-                Text("The only times GrammaGem uses the network").font(.headline)
+                Text("The only times GrammarGem uses the network").font(.headline)
                 networkRow("One-time AI model download", "Hugging Face, on first run")
                 Divider()
                 networkRow("License activation & checks", "To enforce your device cap")

Sources/GrammarGem/App/MainWindow/WritingModesView.swift

@@ -15,7 +15,7 @@ struct WritingModesView: View {
     var body: some View {
         DetailScaffold(
             title: "Writing Modes",
-            subtitle: "Tune the tone for every context — or let GrammaGem pick it for you."
+            subtitle: "Tune the tone for every context — or let GrammarGem pick it for you."
         ) {
             builtInCard
             customCard
@@ -88,7 +88,7 @@ struct WritingModesView: View {
     private var appAwareCard: some View {
         Card {
             HStack { Text("App-aware switching").font(.headline); if !paid { UpgradeBadge() } }
-            Text("Map an app to a Mode and GrammaGem applies it automatically when that app is in front.")
+            Text("Map an app to a Mode and GrammarGem applies it automatically when that app is in front.")
                 .font(.callout).foregroundStyle(.secondary)
 
             if !customModes.appOverrides.isEmpty {

Sources/GrammarGem/App/MenuBarContent.swift

@@ -24,16 +24,22 @@ struct MenuBarLabel: View {
 struct MenuBarContent: View {
     @EnvironmentObject private var app: AppState
     @ObservedObject private var monitor: LiveMonitor
+    @ObservedObject private var updater: UpdaterManager
     @Environment(\.openSettings) private var openSettings
 
     init() {
         _monitor = ObservedObject(wrappedValue: AppState.shared.liveMonitor)
+        _updater = ObservedObject(wrappedValue: AppState.shared.updater)
     }
 
     var body: some View {
         VStack(alignment: .leading, spacing: 10) {
             header
 
+            if let version = updater.updateAvailableVersion {
+                updateBanner(version: version)
+            }
+
             Divider()
 
             liveStatus
@@ -43,7 +49,7 @@ struct MenuBarContent: View {
             actionRow(title: "Fix selection", shortcut: app.preferences.fixHotkey.display) {
                 Task { await app.runFix() }
             }
-            actionRow(title: "Ask GrammaGem…", shortcut: app.preferences.askHotkey.display) {
+            actionRow(title: "Ask GrammarGem…", shortcut: app.preferences.askHotkey.display) {
                 app.showAsk()
             }
             if app.gate.appAwareEnabled {
@@ -51,20 +57,22 @@ struct MenuBarContent: View {
                     Task { await app.runAppAwareRewrite() }
                 }
             }
-            actionRow(title: app.isPaused ? "Resume GrammaGem" : "Pause GrammaGem", shortcut: nil) {
+            actionRow(title: app.isPaused ? "Resume GrammarGem" : "Pause GrammarGem", shortcut: nil) {
                 app.togglePause()
             }
 
             Divider()
 
             actionRow(title: "Show live issues…", shortcut: nil) { app.showLiveCheck() }
-            actionRow(title: "Open GrammaGem…", shortcut: nil) { app.showMainWindow() }
+            actionRow(title: "Open GrammarGem…", shortcut: nil) { app.showMainWindow() }
             actionRow(title: "Manage devices…", shortcut: nil) { app.showMainWindow(select: .devices) }
             actionRow(title: "Page blocker…", shortcut: nil) { app.showMainWindow(select: .exclusions) }
+            actionRow(title: "Check for Updates…", shortcut: nil) { app.updater.checkForUpdates() }
 
             Divider()
 
             usageRow
+            valueRow
 
             Divider()
 
@@ -82,11 +90,27 @@ struct MenuBarContent: View {
         .frame(width: 290)
     }
 
+    /// Shown when Sparkle has found a newer signed build on grammargem.com.
+    private func updateBanner(version: String) -> some View {
+        HStack(spacing: 8) {
+            Image(systemName: "arrow.down.circle.fill").foregroundStyle(GG.emerald)
+            VStack(alignment: .leading, spacing: 1) {
+                Text("Update available").font(.callout.weight(.semibold))
+                Text("Version \(version) is ready to install").font(.caption).foregroundStyle(.secondary)
+            }
+            Spacer()
+            Button("Update") { app.updater.checkForUpdates() }
+                .buttonStyle(.borderedProminent).controlSize(.small)
+        }
+        .padding(8)
+        .background(GG.emerald.opacity(0.10), in: RoundedRectangle(cornerRadius: 8))
+    }
+
     private var header: some View {
         HStack(spacing: 8) {
             Image(systemName: "pencil.and.scribble").foregroundStyle(.tint)
             VStack(alignment: .leading, spacing: 1) {
-                Text("GrammaGem").font(.headline)
+                Text("GrammarGem").font(.headline)
                 Text(app.license.tier.displayName + (app.license.isLicensed ? " · licensed" : " · free"))
                     .font(.caption).foregroundStyle(.secondary)
             }
@@ -152,6 +176,16 @@ struct MenuBarContent: View {
         }
     }
 
+    /// One always-visible value reminder: the streak + lifetime corrections.
+    @ViewBuilder
+    private var valueRow: some View {
+        if app.usage.currentStreak > 1 {
+            Label("\(app.usage.currentStreak)-day streak · \(app.usage.data.totalCorrections) corrections",
+                  systemImage: "flame.fill")
+                .font(.caption).foregroundStyle(.secondary)
+        }
+    }
+
     private func actionRow(title: String, shortcut: String?, action: @escaping () -> Void) -> some View {
         Button(action: action) {
             HStack {

Sources/GrammarGem/App/OnboardingView.swift

@@ -0,0 +1,220 @@
+import SwiftUI
+
+/// First-run onboarding: explains why GrammarGem needs Accessibility, deep-links
+/// to System Settings, and advances automatically the moment permission is
+/// granted (even if granted directly in System Settings).
+struct OnboardingView: View {
+    @EnvironmentObject private var app: AppState
+    @ObservedObject private var permissions: Permissions
+    @ObservedObject private var model: ModelManager
+
+    init() {
+        _permissions = ObservedObject(wrappedValue: AppState.shared.permissions)
+        _model = ObservedObject(wrappedValue: AppState.shared.model)
+    }
+
+    var body: some View {
+        VStack(spacing: 0) {
+            ScrollView {
+                VStack(alignment: .leading, spacing: 18) {
+                    VStack(alignment: .leading, spacing: 6) {
+                        Text("Welcome to GrammarGem")
+                            .font(.largeTitle.bold())
+                        Text("A private, on-device writing assistant that works in every app.")
+                            .foregroundStyle(.secondary)
+                    }
+
+                    // The rigged win: prove the value in one click, before any ask.
+                    VStack(alignment: .leading, spacing: 10) {
+                        Label("See it work", systemImage: "wand.and.stars").font(.headline)
+                        DemoStep()
+                    }
+                    .padding(16)
+                    .background(GG.emerald.opacity(0.06), in: RoundedRectangle(cornerRadius: 12))
+                    .overlay(RoundedRectangle(cornerRadius: 12).stroke(GG.emerald.opacity(0.25)))
+
+                    stepCard(
+                        number: 1,
+                        title: "Turn it on everywhere",
+                        body: "GrammarGem reads the text you select and writes the correction back. macOS requires Accessibility permission for this. Your text is processed on-device and never leaves your Mac.",
+                        granted: permissions.accessibilityTrusted
+                    ) {
+                        if permissions.accessibilityTrusted {
+                            Label("Permission granted", systemImage: "checkmark.circle.fill")
+                                .foregroundStyle(.green)
+                        } else {
+                            HStack {
+                                Button("Open System Settings") { permissions.openAccessibilitySettings() }
+                                Button("Request permission") { permissions.requestAccessibility() }
+                            }
+                            Text("This updates automatically once you flip GrammarGem on in Accessibility.")
+                                .font(.caption).foregroundStyle(.secondary)
+                        }
+                    }
+
+                    stepCard(
+                        number: 2,
+                        title: "Download the on-device model (optional)",
+                        body: "Grammar & spelling work instantly with no download. The AI rewrite/tone/Ask features use a small model downloaded once from Hugging Face — then everything runs offline.",
+                        granted: model.state == .ready
+                    ) {
+                        ModelDownloadControls()
+                    }
+                }
+                .padding(28)
+            }
+
+            Divider()
+
+            HStack {
+                Label("Yours once. No subscription, nothing leaves your Mac.", systemImage: "lock.shield")
+                    .font(.caption).foregroundStyle(.secondary)
+                Spacer()
+                Button(permissions.accessibilityTrusted ? "Done" : "Continue without permission") {
+                    app.showOnboardingDismiss()
+                }
+                .keyboardShortcut(.defaultAction)
+            }
+            .padding(.horizontal, 28).padding(.vertical, 14)
+        }
+        .frame(maxWidth: .infinity, maxHeight: .infinity, alignment: .topLeading)
+        .onAppear {
+            permissions.startPollingUntilGranted()
+        }
+        .onDisappear {
+            permissions.stopPolling()
+        }
+    }
+
+    private func stepCard<Controls: View>(
+        number: Int, title: String, body: String, granted: Bool,
+        @ViewBuilder controls: () -> Controls
+    ) -> some View {
+        HStack(alignment: .top, spacing: 14) {
+            ZStack {
+                Circle().fill(granted ? Color.green : Color.accentColor.opacity(0.15))
+                    .frame(width: 30, height: 30)
+                if granted {
+                    Image(systemName: "checkmark").foregroundStyle(.white).font(.caption.bold())
+                } else {
+                    Text("\(number)").font(.callout.bold()).foregroundStyle(.tint)
+                }
+            }
+            VStack(alignment: .leading, spacing: 8) {
+                Text(title).font(.headline)
+                Text(body).font(.callout).foregroundStyle(.secondary)
+                controls()
+            }
+        }
+        .padding(16)
+        .background(Color.primary.opacity(0.04), in: RoundedRectangle(cornerRadius: 12))
+    }
+}
+
+/// A safe, on-rails first-run demo: a local sample with planted mistakes that
+/// the REAL grammar engine fixes in one click. It operates on a plain string
+/// (never a live Accessibility element), so it's completely risk-free — the
+/// "guaranteed visible win" before GrammarGem asks for anything.
+private struct DemoStep: View {
+    @State private var text = "i has wrote alot of mistakes here, and it dont look profesional"
+    @State private var issues: [Suggestion] = []
+    @State private var cleaned = false
+
+    var body: some View {
+        VStack(alignment: .leading, spacing: 10) {
+            Text(headline)
+                .font(.subheadline.weight(.semibold))
+                .foregroundStyle(cleaned ? GG.emerald : .primary)
+            Text(highlighted)
+                .font(.callout)
+                .frame(maxWidth: .infinity, alignment: .leading)
+                .padding(10)
+                .background(Color(nsColor: .textBackgroundColor), in: RoundedRectangle(cornerRadius: 8))
+                .animation(.easeInOut(duration: 0.35), value: text)
+            Button {
+                let fixed = AppState.shared.grammar.correct(text)
+                withAnimation(.easeOut(duration: 0.4)) {
+                    text = fixed
+                    issues = []
+                    cleaned = true
+                }
+            } label: {
+                Label(cleaned ? "All clean" : "Clean it up",
+                      systemImage: cleaned ? "checkmark.circle.fill" : "wand.and.stars")
+            }
+            .buttonStyle(.borderedProminent)
+            .disabled(cleaned || issues.isEmpty)
+        }
+        .onAppear {
+            if issues.isEmpty && !cleaned { issues = AppState.shared.grammar.check(text) }
+        }
+    }
+
+    private var headline: String {
+        if cleaned { return "Clean ✨ — GrammarGem does this in every app you type." }
+        if issues.isEmpty { return "Checking…" }
+        return "We spotted \(issues.count) thing\(issues.count == 1 ? "" : "s") to tidy up — one click fixes them."
+    }
+
+    private var highlighted: AttributedString {
+        let ns = text as NSString
+        var result = AttributedString()
+        var cursor = 0
+        for s in issues.sorted(by: { $0.location < $1.location }) {
+            guard s.location >= cursor, s.length > 0, s.location + s.length <= ns.length else { continue }
+            if s.location > cursor {
+                result += AttributedString(ns.substring(with: NSRange(location: cursor, length: s.location - cursor)))
+            }
+            var run = AttributedString(ns.substring(with: s.range))
+            let tint: Color = s.kind == .spelling ? .red : .orange
+            run.backgroundColor = tint.opacity(0.18)
+            run.foregroundColor = tint
+            run.underlineStyle = .single
+            result += run
+            cursor = s.location + s.length
+        }
+        if cursor < ns.length {
+            result += AttributedString(ns.substring(with: NSRange(location: cursor, length: ns.length - cursor)))
+        }
+        return result
+    }
+}
+
+/// Real model download progress + controls, shared by onboarding and settings.
+struct ModelDownloadControls: View {
+    @ObservedObject private var model: ModelManager
+
+    init() {
+        _model = ObservedObject(wrappedValue: AppState.shared.model)
+    }
+
+    var body: some View {
+        switch model.state {
+        case .notDownloaded:
+            VStack(alignment: .leading, spacing: 4) {
+                Button("Download model now") { model.startDownload() }
+                Text("Installs automatically in the background on first launch (about 1–2 GB from Hugging Face). One time, then fully offline.")
+                    .font(.caption).foregroundStyle(.secondary)
+            }
+        case .downloading(let progress):
+            VStack(alignment: .leading, spacing: 6) {
+                ProgressView(value: progress) {
+                    Text("Downloading… \(Int(progress * 100))%")
+                }
+                .frame(maxWidth: 320)
+                if !model.statusText.isEmpty {
+                    Text(model.statusText).font(.caption).foregroundStyle(.secondary).lineLimit(1)
+                }
+                Button("Cancel") { model.cancel() }.controlSize(.small)
+            }
+        case .ready:
+            Label("Model ready", systemImage: "checkmark.seal.fill").foregroundStyle(.green)
+        case .failed(let message):
+            VStack(alignment: .leading, spacing: 4) {
+                Label("Download failed", systemImage: "exclamationmark.triangle").foregroundStyle(.orange)
+                Text(message).font(.caption).foregroundStyle(.secondary).lineLimit(2)
+                Button("Retry") { model.startDownload() }
+            }
+        }
+    }
+}

Sources/GrammarGem/App/SettingsView.swift

@@ -25,7 +25,7 @@ private struct GeneralSettings: View {
         Form {
             Section("Shortcuts") {
                 LabeledContent("Fix selection", value: "⌘;")
-                LabeledContent("Ask GrammaGem", value: "⌘'")
+                LabeledContent("Ask GrammarGem", value: "⌘'")
                 Text("Custom shortcuts coming via the KeyboardShortcuts recorder (see README).")
                     .font(.caption).foregroundStyle(.secondary)
             }
@@ -147,7 +147,7 @@ private struct DictionarySettings: View {
     var body: some View {
         VStack(alignment: .leading, spacing: 12) {
             HStack {
-                TextField("Add a word GrammaGem should never correct", text: $newWord)
+                TextField("Add a word GrammarGem should never correct", text: $newWord)
                     .textFieldStyle(.roundedBorder)
                     .onSubmit(add)
                 Button("Add", action: add).disabled(newWord.trimmingCharacters(in: .whitespaces).isEmpty)

Sources/GrammarGem/Core/AppConfig.swift

@@ -1,15 +1,15 @@
 import Foundation
 
 /// Compile-time configuration. The Lemon Squeezy identifiers are hard-coded so
-/// the licensing layer can *hard-verify* that a key belongs to GrammaGem (and to
+/// the licensing layer can *hard-verify* that a key belongs to GrammarGem (and to
 /// the claimed tier) rather than to some other Lemon Squeezy product.
 /// TODO(real-integration): replace every `TODO_*` value with your real IDs.
 enum AppConfig {
-    static let appName = "GrammaGem"
-    static let bundleIdentifier = "com.foundergem.grammagem" // TODO(real-integration)
-    static let supportEmail = "support@grammagem.app" // TODO(real-integration)
-    static let modelPortalURL = URL(string: "https://grammagem.app/license")! // TODO
-    static let websiteURL = URL(string: "https://grammagem.app")!
+    static let appName = "GrammarGem"
+    static let bundleIdentifier = "com.foundergem.grammargem" // TODO(real-integration)
+    static let supportEmail = "support@grammargem.com" // TODO(real-integration)
+    static let modelPortalURL = URL(string: "https://www.grammargem.com/license")! // TODO
+    static let websiteURL = URL(string: "https://www.grammargem.com")!
     static let appVersion = "0.1.0"
 
     // Legal entity (shown in About / legal).
@@ -37,6 +37,23 @@ enum AppConfig {
         static let huggingFaceBase = "https://huggingface.co"
     }
 
+    /// The cross-platform Layer-2 backend: a locally-running Ollama server. Used
+    /// when MLX isn't available (Windows/Linux) or when the user opts in. Inference
+    /// stays on-device — Ollama runs the model on the user's own machine.
+    enum Ollama {
+        static let baseURL = URL(string: "http://127.0.0.1:11434")!
+        static let defaultModel = "qwen2.5:3b" // matches the MLX default model family
+    }
+
+    /// Loopback engine server for the browser extension (off by default; see
+    /// `LocalEngineServer`). Exposes Harper + the local LLM to the extension over
+    /// 127.0.0.1 with a per-install token — no cloud round-trip.
+    enum LocalServer {
+        static let port: UInt16 = 47800
+        static let tokenKey = "GrammarGem.localServerToken"
+        static let enableKey = "GrammarGem.enableLocalServer"
+    }
+
     /// Free-tier limits + license validation cadence (see spec §5/§6).
     enum Limits {
         static let freeDailyAIActions = 10

Sources/GrammarGem/Core/Models.swift

@@ -42,6 +42,42 @@ enum GrammarKind: String, Codable {
     case phrasing
     case repetition
     case capitalization
+
+    /// Severity weight — drives card ordering and the writing-score penalty.
+    /// Objective errors (spelling, grammar) weigh most.
+    var severity: Int {
+        switch self {
+        case .spelling, .grammar: return 3
+        case .punctuation, .capitalization: return 2
+        case .repetition, .phrasing: return 1
+        }
+    }
+
+    /// User-facing grouping shown as filter chips in the Live Check panel.
+    var bucket: IssueBucket {
+        switch self {
+        case .spelling, .grammar, .punctuation: return .correctness
+        case .phrasing: return .clarity
+        case .repetition, .capitalization: return .polish
+        }
+    }
+}
+
+/// Our own named issue groups (deliberately NOT Grammarly's exact buckets/words):
+/// objective errors, clarity rewrites, and stylistic polish.
+enum IssueBucket: String, CaseIterable, Identifiable {
+    case correctness
+    case clarity
+    case polish
+
+    var id: String { rawValue }
+    var title: String {
+        switch self {
+        case .correctness: return "Correctness"
+        case .clarity: return "Clarity"
+        case .polish: return "Polish"
+        }
+    }
 }
 
 /// A single grammar suggestion over a span of the input text.

Sources/GrammarGem/Entitlements/FeatureGate.swift

@@ -72,7 +72,7 @@ final class FeatureGate: ObservableObject {
 /// Free-tier AI action counter. Persists `{date, count}` in UserDefaults and
 /// resets at local midnight (compares the stored local date string to today's).
 final class DailyCounter {
-    private let key = "GrammaGem.aiActions.daily"
+    private let key = "GrammarGem.aiActions.daily"
     private let defaults = UserDefaults.standard
 
     private static let formatter: DateFormatter = {

Sources/GrammarGem/Grammar/GrammarEngine.swift

@@ -19,9 +19,15 @@ protocol GrammarEngine: AnyObject {
 
 extension GrammarEngine {
     /// Default correction: apply suggestions right-to-left so offsets stay valid.
+    ///
+    /// No-op flags (where the replacement equals the original — e.g. a grammar
+    /// issue Harper can describe but not auto-fix) are skipped, so "Fix all" /
+    /// the in-place hotkey only ever apply real, text-changing corrections and
+    /// never silently rewrite a span to itself.
     func correct(_ text: String) -> String {
         let ns = NSMutableString(string: text)
         for s in check(text).sorted(by: { $0.location > $1.location }) {
+            guard s.replacement != s.original else { continue }
             guard s.location + s.length <= ns.length else { continue }
             ns.replaceCharacters(in: s.range, with: s.replacement)
         }

Sources/GrammarGem/Grammar/HarperEngine.swift

@@ -0,0 +1,83 @@
+import Foundation
+import CHarper
+
+/// Layer 1 — the real **Harper** grammar core (Apache-2.0), embedded via a Rust
+/// C-FFI static lib (`harper-ffi/`, harper-core 2.5.0). Fully offline,
+/// deterministic, and fast — real subject-verb agreement, verb forms,
+/// punctuation, repetition, capitalization and spelling, not just a spell check.
+///
+/// `harper_check` returns a JSON array of spans with **char (Unicode scalar)**
+/// offsets; we map those onto UTF-16 `NSRange` offsets so they compose with the
+/// rest of the app (AX ranges, `NSMutableString`).
+final class HarperEngine: GrammarEngine {
+    var ignoreList: Set<String> = []
+
+    func check(_ text: String) -> [Suggestion] {
+        guard !text.isEmpty else { return [] }
+
+        // Call into Rust. The returned C string is heap-allocated by Harper and
+        // must be freed with harper_free (it outlives the withCString buffer).
+        guard let raw = text.withCString({ harper_check($0) }) else { return [] }
+        defer { harper_free(raw) }
+
+        let json = String(cString: raw)
+        guard let data = json.data(using: .utf8),
+              let lints = try? JSONDecoder().decode([HarperLint].self, from: data)
+        else { return [] }
+
+        // Harper can emit several lints over the SAME span (e.g. two phrasings of
+        // "checkin" -> "check in"). Keep the first (highest-priority) per span so
+        // the right-to-left bulk apply in `correct()` never double-writes a range.
+        var kept: [Suggestion] = []
+        for lint in lints {
+            guard lint.len > 0 || !lint.replacement.isEmpty else { continue }
+            guard let range = Self.utf16Range(scalarStart: lint.start, scalarLen: lint.len, in: text)
+            else { continue }
+            let original = (text as NSString).substring(with: range)
+            if !original.isEmpty, ignoreList.contains(original.lowercased()) { continue }
+            if kept.contains(where: { NSIntersectionRange($0.range, range).length > 0 }) { continue }
+            kept.append(Suggestion(
+                location: range.location, length: range.length,
+                original: original, replacement: lint.replacement,
+                kind: GrammarKind(harperKind: lint.kind), message: lint.message))
+        }
+        return kept.sorted { $0.location < $1.location }
+    }
+
+    // MARK: - FFI decoding
+
+    private struct HarperLint: Decodable {
+        let start: Int
+        let len: Int
+        let replacement: String
+        let message: String
+        let kind: String
+    }
+
+    /// Map a Harper char-span (Unicode scalar offsets, end-exclusive) onto a
+    /// UTF-16 `NSRange`. Scalar boundaries are always UTF-16 boundaries, so the
+    /// conversion is exact.
+    static func utf16Range(scalarStart: Int, scalarLen: Int, in text: String) -> NSRange? {
+        let scalars = text.unicodeScalars
+        guard let s = scalars.index(scalars.startIndex, offsetBy: scalarStart, limitedBy: scalars.endIndex),
+              let e = scalars.index(s, offsetBy: scalarLen, limitedBy: scalars.endIndex)
+        else { return nil }
+        let location = text.utf16.distance(from: text.utf16.startIndex, to: s)
+        let length = text.utf16.distance(from: s, to: e)
+        return NSRange(location: location, length: length)
+    }
+}
+
+extension GrammarKind {
+    /// Map Harper's `kind` string (see harper.h) onto our category enum.
+    init(harperKind kind: String) {
+        switch kind {
+        case "spelling": self = .spelling
+        case "punctuation": self = .punctuation
+        case "repetition": self = .repetition
+        case "capitalization": self = .capitalization
+        case "phrasing": self = .phrasing
+        default: self = .grammar
+        }
+    }
+}

Sources/GrammarGem/Grammar/PersonalDictionary.swift

@@ -1,13 +1,13 @@
 import Foundation
 
-/// The user's personal dictionary — names, brand terms, jargon GrammaGem should
+/// The user's personal dictionary — names, brand terms, jargon GrammarGem should
 /// never "correct". Feeds Harper's ignore-list and the LLM context. Capped at 25
 /// entries on free, unlimited on paid (enforced by `FeatureGate`, not here).
 @MainActor
 final class PersonalDictionary: ObservableObject {
     @Published private(set) var entries: [String]
 
-    private let key = "GrammaGem.personalDictionary"
+    private let key = "GrammarGem.personalDictionary"
     private let defaults = UserDefaults.standard
 
     init() {

Sources/GrammarGem/Grammar/SystemGrammarEngine.swift

@@ -0,0 +1,90 @@
+import Foundation
+import AppKit
+
+/// Layer 1 orchestrator. The real **Harper** core is the primary engine
+/// (grammar, punctuation, repetition, capitalization, spelling); macOS's
+/// `NSSpellChecker` is layered on top purely for *extra spelling coverage* from
+/// its large system dictionary.
+///
+/// Two correctness rules make the combination trustworthy:
+///  1. **Harper wins on overlap** — a system spelling guess is dropped if Harper
+///     already flagged the same span (Harper's fixes carry correct casing + a
+///     real explanation).
+///  2. **Case-preserving** — a system spelling replacement is matched to the
+///     original token's casing, so a mid-sentence word is never spuriously
+///     capitalized (the historical `problemm` -> `Problem` bug). Genuine
+///     sentence-start capitalization is surfaced separately by Harper.
+final class SystemGrammarEngine: GrammarEngine {
+    var ignoreList: Set<String> = [] {
+        didSet { harper.ignoreList = ignoreList }
+    }
+
+    private let checker = NSSpellChecker.shared
+    private let tag = NSSpellChecker.uniqueSpellDocumentTag()
+    private let harper = HarperEngine()
+
+    func check(_ text: String) -> [Suggestion] {
+        guard text.count >= 2 else { return [] }
+        var out = harper.check(text)
+
+        // Supplement with NSSpellChecker spelling only (Harper owns grammar),
+        // de-duped against Harper spans and case-matched to the original token.
+        let spelling = onMain { self.spellingSupplement(text) }
+        for s in spelling where !out.contains(where: { overlaps($0.range, s.range) }) {
+            out.append(s)
+        }
+        return out.sorted { $0.location < $1.location }
+    }
+
+    private func spellingSupplement(_ text: String) -> [Suggestion] {
+        let ns = text as NSString
+        let full = NSRange(location: 0, length: ns.length)
+        let language = checker.language()
+        let results = checker.check(
+            text, range: full, types: NSTextCheckingResult.CheckingType.spelling.rawValue,
+            options: nil, inSpellDocumentWithTag: tag, orthography: nil, wordCount: nil)
+
+        var out: [Suggestion] = []
+        for r in results where r.resultType == .spelling {
+            let word = ns.substring(with: r.range)
+            if ignoreList.contains(word.lowercased()) { continue }
+            guard let raw = checker.correction(
+                forWordRange: r.range, in: text, language: language, inSpellDocumentWithTag: tag)
+                ?? checker.guesses(
+                    forWordRange: r.range, in: text, language: language,
+                    inSpellDocumentWithTag: tag)?.first
+            else { continue }
+            let fix = Self.matchingCase(of: word, in: raw)
+            guard fix != word else { continue } // never emit a no-op
+            out.append(Suggestion(
+                location: r.range.location, length: r.range.length,
+                original: word, replacement: fix,
+                kind: .spelling, message: "Possible spelling mistake"))
+        }
+        return out
+    }
+
+    /// Re-case `replacement` to follow `original`'s casing.
+    static func matchingCase(of original: String, in replacement: String) -> String {
+        guard let o = original.first, let r = replacement.first else { return replacement }
+        // ALL-CAPS original (with at least one cased letter) -> upper the whole thing.
+        if original.count > 1, original == original.uppercased(), original != original.lowercased() {
+            return replacement.uppercased()
+        }
+        if o.isLowercase, r.isUppercase {
+            return r.lowercased() + replacement.dropFirst()
+        }
+        if o.isUppercase, r.isLowercase {
+            return r.uppercased() + replacement.dropFirst()
+        }
+        return replacement
+    }
+
+    private func overlaps(_ a: NSRange, _ b: NSRange) -> Bool {
+        NSIntersectionRange(a, b).length > 0
+    }
+
+    private func onMain<T>(_ work: @escaping () -> T) -> T {
+        Thread.isMainThread ? work() : DispatchQueue.main.sync(execute: work)
+    }
+}

Sources/GrammarGem/Grammar/WritingScore.swift

@@ -0,0 +1,20 @@
+import Foundation
+
+/// A deterministic, on-device "cleanliness" score (0–100) for a chunk of text.
+///
+/// Honest by construction: it's defined relative to *this* text — weighted issues
+/// per 100 words — never a hidden cloud cohort, and grammar/spelling are always
+/// fully resolvable, so a clean document genuinely reaches 100. (Contrast with
+/// Grammarly's percentile-vs-other-users score, which needs telemetry + an
+/// account; see docs/grammarly-value-plan.md §5.)
+enum WritingScore {
+    /// - Parameters:
+    ///   - weightedIssues: sum of `GrammarKind.severity` across outstanding issues.
+    ///   - words: total words in the scanned text.
+    static func score(weightedIssues: Int, words: Int) -> Int {
+        guard words > 0 else { return 100 }
+        let perHundredWords = Double(weightedIssues) / Double(words) * 100.0
+        // Each weighted issue per 100 words costs ~4 points; clamp to 0…100.
+        return max(0, min(100, Int((100.0 - perHundredWords * 4.0).rounded())))
+    }
+}

Sources/GrammarGem/Licensing/DeviceFingerprint.swift

@@ -38,7 +38,7 @@ enum DeviceFingerprint {
     }
 
     private static func fallbackID() -> String {
-        let key = "GrammaGem.fallbackDeviceID"
+        let key = "GrammarGem.fallbackDeviceID"
         if let existing = UserDefaults.standard.string(forKey: key) { return existing }
         let id = UUID().uuidString
         UserDefaults.standard.set(id, forKey: key)

Sources/GrammarGem/Licensing/LemonSqueezyClient.swift

@@ -2,7 +2,7 @@ import Foundation
 
 /// Talks to the **Lemon Squeezy License API** directly from the app — no server
 /// of ours, no database, no per-user cost (spec §6). Exposes activate / validate
-/// / deactivate and hard-verifies that a key belongs to GrammaGem + the claimed tier.
+/// / deactivate and hard-verifies that a key belongs to GrammarGem + the claimed tier.
 final class LemonSqueezyClient {
     private let session: URLSession
     private let base = AppConfig.LemonSqueezy.apiBase
@@ -54,20 +54,28 @@ final class LemonSqueezyClient {
     // MARK: - Hard verification (spec §6)
 
     /// Confirm the key is for OUR store/product, then resolve which tier its
-    /// variant corresponds to. Prevents a key from another LS product unlocking GrammaGem.
+    /// variant corresponds to. Prevents a key from another LS product unlocking GrammarGem.
     private func verifyAndResolveTier(meta: LSMeta?, licenseKey: LSLicenseKey?) throws -> Tier {
         guard let meta else { throw LicenseError.wrongProduct }
 
-        // Store + product check. If AppConfig still holds placeholder (non-numeric)
-        // IDs, we log and skip the check so the stub flow runs — TODO(real-integration):
-        // once real numeric IDs are set, this becomes a hard gate.
+        // Store + product check. With real numeric IDs configured this is a hard
+        // gate that prevents a key from another Lemon Squeezy product unlocking
+        // GrammarGem. If AppConfig still holds placeholder (non-numeric) IDs the
+        // gate can't run — allow the bypass ONLY in DEBUG so local stub flows work;
+        // in a release build FAIL CLOSED so the "any key unlocks paid" bypass can
+        // never ship. TODO(real-integration): set real IDs in AppConfig.LemonSqueezy.
         if let expectedStore = Int(AppConfig.LemonSqueezy.expectedStoreID),
            let expectedProduct = Int(AppConfig.LemonSqueezy.expectedProductID) {
             guard meta.store_id == expectedStore, meta.product_id == expectedProduct else {
                 throw LicenseError.wrongProduct
             }
         } else {
-            Log.licensing.warning("Skipping store/product hard-verify — placeholder IDs in AppConfig.")
+            #if DEBUG
+            Log.licensing.warning("Skipping store/product hard-verify — placeholder IDs in AppConfig (DEBUG only).")
+            #else
+            Log.licensing.error("Refusing to verify license: placeholder Lemon Squeezy IDs in a release build.")
+            throw LicenseError.wrongProduct
+            #endif
         }
 
         // Resolve tier from the variant id (reverse-lookup the configured map).

Sources/GrammarGem/Licensing/LicenseModels.swift

@@ -62,7 +62,7 @@ struct LSLicenseKey: Codable {
 }
 
 /// `meta` carries the store/product/variant identity we *hard-verify* against
-/// AppConfig so a key from another Lemon Squeezy product can't unlock GrammaGem.
+/// AppConfig so a key from another Lemon Squeezy product can't unlock GrammarGem.
 struct LSMeta: Codable {
     let store_id: Int?
     let product_id: Int?

Sources/GrammarGem/Stats/UsageStats.swift

@@ -0,0 +1,154 @@
+import Foundation
+
+/// Privacy-friendly, fully-local usage insights. Counts *how often* features are
+/// used — never *what* was written. Stored only on this Mac.
+@MainActor
+final class UsageStats: ObservableObject {
+    struct Snapshot: Codable, Equatable {
+        var totalCorrections = 0
+        var totalAIActions = 0
+        var totalWords = 0
+        var activeDays = 0              // distinct days with ≥1 action (lifetime)
+        var firstUseDay: String?       // "yyyy-MM-dd" of first ever action
+        var perDay: [String: Int] = [:] // "yyyy-MM-dd" -> actions that day
+    }
+
+    /// What a Grammarly-style subscription runs per year (USD) — used only for the
+    /// honest, local "subscription you didn't pay" figure. GrammarGem is one-time.
+    static let comparableAnnualSubscriptionUSD = 144.0
+
+    @Published private(set) var data: Snapshot
+
+    private let key = "GrammarGem.usageStats"
+    private let d = UserDefaults.standard
+
+    private static let fmt: DateFormatter = {
+        let f = DateFormatter()
+        f.dateFormat = "yyyy-MM-dd"
+        f.locale = Locale(identifier: "en_US_POSIX")
+        f.timeZone = .current
+        return f
+    }()
+
+    init() {
+        if let raw = d.data(forKey: key),
+           let decoded = try? JSONDecoder().decode(Snapshot.self, from: raw) {
+            data = decoded
+        } else {
+            data = Snapshot()
+        }
+    }
+
+    func recordCorrection(words: Int) {
+        data.totalCorrections += 1
+        data.totalWords += max(0, words)
+        bumpToday()
+        persist()
+    }
+
+    func recordAIAction(words: Int) {
+        data.totalAIActions += 1
+        data.totalWords += max(0, words)
+        bumpToday()
+        persist()
+    }
+
+    /// A playful, clearly-estimated "time saved" figure (local only).
+    var estimatedMinutesSaved: Int {
+        (data.totalCorrections * 8 + data.totalAIActions * 45) / 60
+    }
+
+    // MARK: - Value loop (streak / milestones / subscription-you-didn't-pay)
+
+    /// Consecutive days, ending today or yesterday, with at least one action.
+    var currentStreak: Int { Self.streak(perDay: data.perDay, asOf: Date()) }
+
+    /// The Grammarly subscription you DIDN'T pay: their annual price prorated over
+    /// how long you've owned GrammarGem. Honest, local, illustrative — and it only
+    /// grows, which is the point of a one-time purchase (see the value plan §5).
+    var subscriptionAvoidedUSD: Int {
+        Self.subscriptionAvoidedUSD(
+            firstUseDay: data.firstUseDay, asOf: Date(),
+            annualPrice: Self.comparableAnnualSubscriptionUSD)
+    }
+
+    /// The next correction milestone and progress toward it (for a nudge/badge).
+    var nextMilestone: (target: Int, label: String, progress: Double) {
+        Self.nextMilestone(corrections: data.totalCorrections)
+    }
+
+    // MARK: - Pure helpers (unit-testable; no UserDefaults / wall clock)
+
+    static func streak(perDay: [String: Int], asOf now: Date) -> Int {
+        let cal = Calendar.current
+        func used(_ day: Date) -> Bool { (perDay[fmt.string(from: day)] ?? 0) > 0 }
+        var day = now
+        if !used(day) {
+            // Streak is still alive if used yesterday but not yet today.
+            day = cal.date(byAdding: .day, value: -1, to: day) ?? day
+            if !used(day) { return 0 }
+        }
+        var streak = 0
+        while used(day) {
+            streak += 1
+            day = cal.date(byAdding: .day, value: -1, to: day) ?? day
+        }
+        return streak
+    }
+
+    static func subscriptionAvoidedUSD(firstUseDay: String?, asOf now: Date, annualPrice: Double) -> Int {
+        guard let first = firstUseDay, let firstDate = fmt.date(from: first) else { return 0 }
+        let days = max(1, Calendar.current.dateComponents([.day], from: firstDate, to: now).day ?? 0)
+        return Int((Double(days) / 365.0 * annualPrice).rounded())
+    }
+
+    static func nextMilestone(corrections: Int) -> (target: Int, label: String, progress: Double) {
+        let targets = [100, 500, 1_000, 5_000, 10_000, 50_000, 100_000]
+        let target = targets.first { $0 > corrections } ?? (((corrections / 100_000) + 1) * 100_000)
+        let previous = targets.last { $0 <= corrections } ?? 0
+        let span = max(1, target - previous)
+        let progress = min(1.0, Double(corrections - previous) / Double(span))
+        let label = target >= 1_000 ? "\(target / 1_000)k corrections" : "\(target) corrections"
+        return (target, label, progress)
+    }
+
+    /// Counts for the last 7 calendar days, oldest → newest, for a small chart.
+    func last7Days() -> [(label: String, count: Int)] {
+        let cal = Calendar.current
+        let today = Date()
+        return (0..<7).reversed().map { offset in
+            let day = cal.date(byAdding: .day, value: -offset, to: today) ?? today
+            let key = Self.fmt.string(from: day)
+            let short = day.formatted(.dateTime.weekday(.narrow))
+            return (label: short, count: data.perDay[key] ?? 0)
+        }
+    }
+
+    func reset() {
+        data = Snapshot()
+        persist()
+    }
+
+    private func bumpToday() {
+        let k = Self.fmt.string(from: Date())
+        if data.perDay[k] == nil {            // first action on a brand-new day
+            data.activeDays += 1
+            if data.firstUseDay == nil { data.firstUseDay = k }
+        }
+        data.perDay[k, default: 0] += 1
+        // Keep only ~60 days of history.
+        if data.perDay.count > 70 {
+            let keep = Set((0..<60).compactMap { off -> String? in
+                guard let day = Calendar.current.date(byAdding: .day, value: -off, to: Date()) else { return nil }
+                return Self.fmt.string(from: day)
+            })
+            data.perDay = data.perDay.filter { keep.contains($0.key) }
+        }
+    }
+
+    private func persist() {
+        if let raw = try? JSONEncoder().encode(data) {
+            d.set(raw, forKey: key)
+        }
+    }
+}

Sources/GrammarGem/System/AXSupport.swift

@@ -0,0 +1,76 @@
+import Foundation
+import AppKit
+import ApplicationServices
+
+/// Safe Accessibility helpers shared across the System layer.
+///
+/// `AXUIElementCopyAttributeValue` returning `.success` only guarantees a
+/// non-null `CFTypeRef` — NOT that it is an `AXUIElement`. A misbehaving AX
+/// server (Electron/Java/custom) can return a different CF type, and a forced
+/// `as!` cast then traps and crashes the whole app. These helpers cast safely.
+enum AX {
+    /// Safely bridge a CFTypeRef to AXUIElement, returning nil on type mismatch.
+    static func element(_ ref: CFTypeRef?) -> AXUIElement? {
+        guard let ref, CFGetTypeID(ref) == AXUIElementGetTypeID() else { return nil }
+        return (ref as! AXUIElement) // safe: type id verified above
+    }
+
+    /// Copy an attribute as an `AXUIElement` (nil on failure/type mismatch).
+    static func copyElement(_ element: AXUIElement, _ attribute: String) -> AXUIElement? {
+        var ref: CFTypeRef?
+        guard AXUIElementCopyAttributeValue(element, attribute as CFString, &ref) == .success else {
+            return nil
+        }
+        return AX.element(ref)
+    }
+
+    /// Copy an attribute as a `String` (nil on failure/wrong type).
+    static func copyString(_ element: AXUIElement, _ attribute: String) -> String? {
+        var ref: CFTypeRef?
+        guard AXUIElementCopyAttributeValue(element, attribute as CFString, &ref) == .success else {
+            return nil
+        }
+        return ref as? String
+    }
+
+    /// Bound each cross-process AX message so a wedged target app can't hang us.
+    static func setMessagingTimeout(_ element: AXUIElement, _ seconds: Float) {
+        AXUIElementSetMessagingTimeout(element, seconds)
+    }
+
+    /// Whether an element is a secure text field (a password input). GrammarGem
+    /// must NEVER read or rewrite these — so a user who forgot to exclude a
+    /// password manager or login form can't have a decrypted password captured,
+    /// sent through the grammar/AI engines, and written back. This is enforced in
+    /// code rather than relying on the user's exclusion blocklist.
+    static func isSecureTextField(_ element: AXUIElement) -> Bool {
+        // AXSecureTextField is the subrole AppKit/most Electron inputs report for
+        // password fields. String-compared (the constant isn't always imported).
+        copyString(element, kAXSubroleAttribute) == "AXSecureTextField"
+    }
+
+    /// The currently-focused UI element across the system — robust to the
+    /// system-wide element failing.
+    ///
+    /// On recent macOS, `AXUIElementCreateSystemWide()` returns
+    /// `kAXErrorCannotComplete` (-25204) for *every* query made by a background /
+    /// accessory process (which is exactly what a menu-bar app like GrammarGem is).
+    /// When that happens the system-wide focused-element read yields nil and the
+    /// app "sees" no text or text fields at all. Resolving the focused element
+    /// through the **frontmost application's** own AX element works reliably in
+    /// that context, so we prefer the system-wide read (one IPC hop, correct on
+    /// OSes where it works) and transparently fall back to the per-app read.
+    static func focusedElement() -> AXUIElement? {
+        let systemWide = AXUIElementCreateSystemWide()
+        setMessagingTimeout(systemWide, 0.5)
+        if let element = copyElement(systemWide, kAXFocusedUIElementAttribute as String) {
+            return element
+        }
+        guard let pid = NSWorkspace.shared.frontmostApplication?.processIdentifier else {
+            return nil
+        }
+        let axApp = AXUIElementCreateApplication(pid)
+        setMessagingTimeout(axApp, 0.5)
+        return copyElement(axApp, kAXFocusedUIElementAttribute as String)
+    }
+}

Sources/GrammarGem/System/Exclusions.swift

@@ -1,7 +1,7 @@
 import Foundation
 import AppKit
 
-/// The "page blocker": apps and domains where GrammaGem should stay completely
+/// The "page blocker": apps and domains where GrammarGem should stay completely
 /// out of the way — password managers, banking sites, anything sensitive.
 /// When the frontmost context is excluded, live monitoring and the hotkeys are
 /// suppressed.
@@ -10,8 +10,8 @@ final class Exclusions: ObservableObject {
     @Published private(set) var blockedApps: [String]      // bundle identifiers
     @Published private(set) var blockedDomains: [String]   // hostnames, e.g. "chase.com"
 
-    private let appsKey = "GrammaGem.blockedApps"
-    private let domainsKey = "GrammaGem.blockedDomains"
+    private let appsKey = "GrammarGem.blockedApps"
+    private let domainsKey = "GrammarGem.blockedDomains"
     private let d = UserDefaults.standard
 
     /// Common sensitive apps offered as one-tap suggestions in the UI.
@@ -31,7 +31,7 @@ final class Exclusions: ObservableObject {
     /// a browser's URL can't be read).
     var hasDomainRules: Bool { !blockedDomains.isEmpty }
 
-    /// Whether GrammaGem should be suppressed for this frontmost context.
+    /// Whether GrammarGem should be suppressed for this frontmost context.
     func isBlocked(bundleID: String?, domain: String?) -> Bool {
         if let bundleID, blockedApps.contains(bundleID) { return true }
         if let host = domain?.lowercased(), !host.isEmpty {

Sources/GrammarGem/System/LiveMonitor.swift

@@ -19,18 +19,40 @@ struct DetectedField: Identifiable {
 /// Performance & safety: the Accessibility-tree traversal (the part that can hang
 /// on a busy/wedged app) runs OFF the main thread with a per-message timeout; only
 /// the bounded spell/grammar pass and publish happen on the main actor. It never
-/// scans GrammaGem itself, respects the page blocker, and applies fixes against the
+/// scans GrammarGem itself, respects the page blocker, and applies fixes against the
 /// element's *live* value so it can't overwrite text typed since the last scan.
 @MainActor
 final class LiveMonitor: ObservableObject {
     @Published private(set) var fields: [DetectedField] = []
     @Published private(set) var scannedCount = 0
+    @Published private(set) var scannedWordCount = 0
     @Published private(set) var activeAppName = ""
     @Published private(set) var running = false
 
     /// Total number of issues across all detected text areas.
     var issueCount: Int { fields.reduce(0) { $0 + $1.suggestions.count } }
 
+    /// Outstanding issues grouped into the user-facing buckets (for filter chips).
+    var bucketCounts: [IssueBucket: Int] {
+        var counts: [IssueBucket: Int] = [:]
+        for field in fields {
+            for s in field.suggestions { counts[s.kind.bucket, default: 0] += 1 }
+        }
+        return counts
+    }
+
+    /// 0–100 on-device cleanliness score for the text currently on screen.
+    var writingScore: Int {
+        let weighted = fields.reduce(0) { acc, f in
+            acc + f.suggestions.reduce(0) { $0 + $1.kind.severity }
+        }
+        return WritingScore.score(weightedIssues: weighted, words: scannedWordCount)
+    }
+
+    /// Content keys of suggestions the user has dismissed; survives re-scans so a
+    /// dismissed issue doesn't reappear on the next poll.
+    private var dismissedKeys: Set<String> = []
+
     private let grammar: GrammarEngine
     private let detector: AppDetector
     private let exclusions: Exclusions
@@ -88,6 +110,36 @@ final class LiveMonitor: ObservableObject {
         refreshSoon()
     }
 
+    // MARK: - Dismissing (hide a suggestion without applying it)
+
+    /// Hide one suggestion. A cheap, always-available "no" is what makes saying
+    /// "yes" (Apply) feel safe. The dismissal is keyed by content so it persists
+    /// across re-scans of unchanged text.
+    func dismiss(_ suggestion: Suggestion, in field: DetectedField) {
+        dismissedKeys.insert(Self.dismissKey(fieldID: field.id, suggestion))
+        fields = filterDismissed(fields)
+    }
+
+    private static func dismissKey(fieldID: String, _ s: Suggestion) -> String {
+        "\(fieldID)|\(s.location)|\(s.length)|\(s.original)|\(s.replacement)"
+    }
+
+    private func filterDismissed(_ input: [DetectedField]) -> [DetectedField] {
+        input.compactMap { f in
+            let remaining = f.suggestions.filter {
+                !dismissedKeys.contains(Self.dismissKey(fieldID: f.id, $0))
+            }
+            guard !remaining.isEmpty else { return nil }
+            return DetectedField(id: f.id, label: f.label, roleName: f.roleName,
+                                 text: f.text, suggestions: remaining,
+                                 element: f.element, isFocused: f.isFocused)
+        }
+    }
+
+    private static func wordCount(_ s: String) -> Int {
+        s.split { $0.isWhitespace || $0.isNewline }.count
+    }
+
     /// Correct the element's *current* value (never a stale snapshot), so any
     /// keystrokes entered since the scan are preserved.
     private func applyCorrection(to field: DetectedField) -> Int {
@@ -127,7 +179,7 @@ final class LiveMonitor: ObservableObject {
         if scanning && !force { return } // don't pile up scans
         guard let app = NSWorkspace.shared.frontmostApplication else { clear(); return }
 
-        // Never scan GrammaGem's own windows.
+        // Never scan GrammarGem's own windows.
         if app.processIdentifier == ownPID { clear(); return }
         activeAppName = app.localizedName ?? ""
 
@@ -156,6 +208,11 @@ final class LiveMonitor: ObservableObject {
         guard generation == scanGeneration else { return } // superseded by a newer scan
         guard !scanned.isEmpty else { clear(); return }
 
+        // Total words across ALL scanned fields (clean ones included) so the
+        // writing score is honest about the whole on-screen text, not just the
+        // fields that happen to have issues.
+        scannedWordCount = scanned.reduce(0) { $0 + Self.wordCount($1.text) }
+
         // Change detection includes focus + element identity so tabbing between
         // same-text fields still updates the focused indicator.
         var hasher = Hasher()
@@ -179,16 +236,17 @@ final class LiveMonitor: ObservableObject {
                 text: f.text, suggestions: suggestions, element: f.element, isFocused: f.isFocused))
         }
         detected.sort { ($0.isFocused ? 0 : 1) < ($1.isFocused ? 0 : 1) }
-        fields = detected
+        fields = filterDismissed(detected)
     }
 
     private nonisolated static func systemFocusedElement() -> AXUIElement? {
-        AX.copyElement(AXUIElementCreateSystemWide(), kAXFocusedUIElementAttribute)
+        AX.focusedElement()
     }
 
     private func clear() {
         if !fields.isEmpty { fields = [] }
         scannedCount = 0
+        scannedWordCount = 0
         lastHash = 0
     }
 }

Sources/GrammarGem/System/LocalEngineServer.swift

@@ -0,0 +1,311 @@
+import Foundation
+import Network
+
+/// A minimal, loopback-only HTTP server that exposes GrammarGem's local engines
+/// (Harper grammar + the on-device LLM) to a **browser extension** — the
+/// highest-volume surface for a grammar tool — with NO cloud round-trip. Built on
+/// Network.framework so it adds no third-party HTTP dependency, keeping the
+/// privacy/trust surface minimal.
+///
+/// Security posture (deliberate):
+///  - Binds to 127.0.0.1 only (never a routable interface), via `requiredLocalEndpoint`.
+///  - Every engine endpoint requires a per-install bearer token (`X-GrammarGem-Token`);
+///    a web page that doesn't know the token cannot drive the engines.
+///  - OFF by default — only starts when the user opts in, so the app ships no
+///    listening socket unless explicitly enabled.
+///
+/// It reuses the SAME engines as the menu-bar app via injected async handlers, so
+/// there is one engine, one set of prompts (`AIPrompts`), and one entitlement gate
+/// across the app, the extension, and (later) other backends.
+final class LocalEngineServer {
+
+    struct AIRequest { let action: AIAction; let text: String }
+
+    struct WireSuggestion: Encodable {
+        let location: Int
+        let length: Int
+        let original: String
+        let replacement: String
+        let kind: String
+        let message: String
+    }
+
+    /// Grammar pass: corrected text + suggestion spans for the extension to underline.
+    typealias GrammarHandler = (String) async -> (corrected: String, suggestions: [WireSuggestion])
+    /// AI action outcome (a plain enum so a user-facing message needn't be an `Error`).
+    enum AIOutcome { case ok(String); case error(String) }
+    /// AI action: runs the gate + model, returns the result or a user-facing error.
+    typealias AIHandler = (AIRequest) async -> AIOutcome
+    /// Streaming AI action: runs the gate + model, invoking `onChunk` per token as it
+    /// generates, then returns the final outcome (full text, or an error message).
+    typealias AIStreamHandler = (AIRequest, @escaping (String) -> Void) async -> AIOutcome
+
+    private let port: UInt16
+    private let token: String
+    private let grammarHandler: GrammarHandler
+    private let aiHandler: AIHandler
+    private let aiStreamHandler: AIStreamHandler
+
+    private var listener: NWListener?
+    private let queue = DispatchQueue(label: "com.grammargem.localserver")
+
+    init(port: UInt16, token: String,
+         grammarHandler: @escaping GrammarHandler,
+         aiHandler: @escaping AIHandler,
+         aiStreamHandler: @escaping AIStreamHandler) {
+        self.port = port
+        self.token = token
+        self.grammarHandler = grammarHandler
+        self.aiHandler = aiHandler
+        self.aiStreamHandler = aiStreamHandler
+    }
+
+    /// A stable per-install token, persisted so the extension can be paired once.
+    static func loadOrCreateToken() -> String {
+        let d = UserDefaults.standard
+        if let existing = d.string(forKey: AppConfig.LocalServer.tokenKey), !existing.isEmpty {
+            return existing
+        }
+        let token = UUID().uuidString + UUID().uuidString.replacingOccurrences(of: "-", with: "")
+        d.set(token, forKey: AppConfig.LocalServer.tokenKey)
+        return token
+    }
+
+    func start() {
+        guard listener == nil else { return }
+        do {
+            let params = NWParameters.tcp
+            guard let nwPort = NWEndpoint.Port(rawValue: port) else { return }
+            // Loopback-only: refuse to bind to any routable interface.
+            params.requiredLocalEndpoint = .hostPort(host: "127.0.0.1", port: nwPort)
+            let listener = try NWListener(using: params)
+            listener.newConnectionHandler = { [weak self] conn in self?.accept(conn) }
+            listener.start(queue: queue)
+            self.listener = listener
+            Log.app.info("Local engine server on 127.0.0.1:\(self.port, privacy: .public) (extension bridge)")
+        } catch {
+            Log.app.error("Local engine server failed to start: \(error.localizedDescription, privacy: .public)")
+        }
+    }
+
+    func stop() {
+        listener?.cancel()
+        listener = nil
+    }
+
+    // MARK: - Connection lifecycle
+
+    private func accept(_ conn: NWConnection) {
+        conn.start(queue: queue)
+        receive(conn, buffer: Data())
+    }
+
+    private func receive(_ conn: NWConnection, buffer: Data) {
+        conn.receive(minimumIncompleteLength: 1, maximumLength: 1 << 16) { [weak self] data, _, isComplete, error in
+            guard let self else { conn.cancel(); return }
+            var buffer = buffer
+            if let data { buffer.append(data) }
+            if let request = HTTPRequest(buffer), request.isComplete {
+                Task { await self.route(request, on: conn) }
+                return
+            }
+            if isComplete || error != nil { conn.cancel(); return }
+            self.receive(conn, buffer: buffer) // headers/body not fully arrived yet
+        }
+    }
+
+    // MARK: - Routing
+
+    private func route(_ request: HTTPRequest, on conn: NWConnection) async {
+        // CORS preflight — extensions issue this before a cross-origin POST.
+        if request.method == "OPTIONS" {
+            send(conn, status: 204, body: Data())
+            return
+        }
+
+        if request.path == "/health" || request.path == "/v1/health" {
+            sendJSON(conn, status: 200, HealthResponse(ok: true, app: AppConfig.appName, version: AppConfig.appVersion))
+            return
+        }
+
+        // Token gate for every engine endpoint.
+        guard request.headers["x-grammargem-token"] == token else {
+            sendJSON(conn, status: 401, ErrorResponse(error: "unauthorized"))
+            return
+        }
+
+        switch (request.method, request.path) {
+        case ("POST", "/v1/grammar"):
+            guard let text = decodeText(request.body) else {
+                sendJSON(conn, status: 400, ErrorResponse(error: "missing 'text'")); return
+            }
+            let result = await grammarHandler(text)
+            sendJSON(conn, status: 200, GrammarResponse(corrected: result.corrected, suggestions: result.suggestions))
+
+        case ("POST", "/v1/ai"):
+            guard let req = decodeAI(request.body) else {
+                sendJSON(conn, status: 400, ErrorResponse(error: "bad request")); return
+            }
+            switch await aiHandler(req) {
+            case .ok(let out): sendJSON(conn, status: 200, AIResponse(result: out))
+            case .error(let msg): sendJSON(conn, status: 422, ErrorResponse(error: msg))
+            }
+
+        case ("POST", "/v1/ai/stream"):
+            guard let req = decodeAI(request.body) else {
+                sendJSON(conn, status: 400, ErrorResponse(error: "bad request")); return
+            }
+            // Newline-delimited JSON frames: {"chunk":"…"} per token, then a final
+            // {"done":true} or {"error":"…"}. The 200 header goes out before tokens,
+            // so an entitlement/readiness failure surfaces as a closing error frame.
+            beginStream(conn)
+            let outcome = await aiStreamHandler(req) { [weak self] chunk in
+                self?.streamFrame(conn, ["chunk": chunk])
+            }
+            switch outcome {
+            case .ok: streamFrame(conn, ["done": true])
+            case .error(let msg): streamFrame(conn, ["error": msg])
+            }
+            endStream(conn)
+
+        default:
+            sendJSON(conn, status: 404, ErrorResponse(error: "not found"))
+        }
+    }
+
+    // MARK: - Body decoding
+
+    private func decodeText(_ body: Data) -> String? {
+        struct P: Decodable { let text: String }
+        guard let p = try? JSONDecoder().decode(P.self, from: body), !p.text.isEmpty else { return nil }
+        return p.text
+    }
+
+    private func decodeAI(_ body: Data) -> AIRequest? {
+        struct P: Decodable {
+            let action: String
+            let text: String
+            let instruction: String?
+            let language: String?
+            let mode: String?
+            let tone: String?
+        }
+        guard let p = try? JSONDecoder().decode(P.self, from: body), !p.text.isEmpty else { return nil }
+        let action: AIAction
+        switch p.action {
+        case "rewriteClarity": action = .rewriteClarity
+        case "rewrite":        action = .rewrite
+        case "ask":
+            guard let i = p.instruction, !i.trimmingCharacters(in: .whitespaces).isEmpty else { return nil }
+            action = .ask(i)
+        case "translate":
+            guard let l = p.language, !l.isEmpty else { return nil }
+            action = .translate(language: l)
+        case "tone":
+            action = .adjustTone(Tone(rawValue: p.tone ?? "") ?? .professional)
+        case "mode":
+            guard let id = p.mode, let m = ModeRegistry.mode(id: id) else { return nil }
+            action = .applyMode(m)
+        default:
+            return nil
+        }
+        return AIRequest(action: action, text: p.text)
+    }
+
+    // MARK: - Responses
+
+    private struct HealthResponse: Encodable { let ok: Bool; let app: String; let version: String }
+    private struct GrammarResponse: Encodable { let corrected: String; let suggestions: [WireSuggestion] }
+    private struct AIResponse: Encodable { let result: String }
+    private struct ErrorResponse: Encodable { let error: String }
+
+    private func sendJSON<T: Encodable>(_ conn: NWConnection, status: Int, _ value: T) {
+        let body = (try? JSONEncoder().encode(value)) ?? Data("{}".utf8)
+        send(conn, status: status, body: body)
+    }
+
+    // MARK: - Streaming responses (newline-delimited JSON, no Content-Length)
+
+    private func beginStream(_ conn: NWConnection) {
+        var head = "HTTP/1.1 200 OK\r\n"
+        head += "Content-Type: application/x-ndjson\r\n"
+        head += "Cache-Control: no-cache\r\n"
+        head += "Access-Control-Allow-Origin: *\r\n"
+        head += "Access-Control-Allow-Headers: Content-Type, X-GrammarGem-Token\r\n"
+        head += "Connection: close\r\n\r\n"
+        conn.send(content: Data(head.utf8), completion: .contentProcessed { _ in })
+    }
+
+    private func streamFrame(_ conn: NWConnection, _ object: [String: Any]) {
+        guard var data = try? JSONSerialization.data(withJSONObject: object) else { return }
+        data.append(0x0A) // newline delimiter
+        conn.send(content: data, completion: .contentProcessed { _ in })
+    }
+
+    private func endStream(_ conn: NWConnection) {
+        conn.send(content: nil, completion: .contentProcessed { _ in conn.cancel() })
+    }
+
+    private func send(_ conn: NWConnection, status: Int, body: Data) {
+        var head = "HTTP/1.1 \(status) \(Self.reason(status))\r\n"
+        head += "Content-Type: application/json\r\n"
+        head += "Content-Length: \(body.count)\r\n"
+        // The extension calls cross-origin; a secret token (not the origin) is the gate.
+        head += "Access-Control-Allow-Origin: *\r\n"
+        head += "Access-Control-Allow-Headers: Content-Type, X-GrammarGem-Token\r\n"
+        head += "Access-Control-Allow-Methods: POST, GET, OPTIONS\r\n"
+        head += "Connection: close\r\n\r\n"
+        var out = Data(head.utf8)
+        out.append(body)
+        conn.send(content: out, completion: .contentProcessed { _ in conn.cancel() })
+    }
+
+    private static func reason(_ status: Int) -> String {
+        switch status {
+        case 200: return "OK"
+        case 204: return "No Content"
+        case 400: return "Bad Request"
+        case 401: return "Unauthorized"
+        case 404: return "Not Found"
+        case 422: return "Unprocessable Entity"
+        default:  return "Error"
+        }
+    }
+}
+
+/// A just-enough HTTP/1.1 request parser for small JSON POSTs. Returns nil until
+/// the headers terminator (`\r\n\r\n`) has arrived; `isComplete` is false until the
+/// full `Content-Length` body is buffered, so the receive loop knows to read more.
+private struct HTTPRequest {
+    let method: String
+    let path: String
+    let headers: [String: String]
+    let body: Data
+    let isComplete: Bool
+
+    init?(_ raw: Data) {
+        guard let headerEnd = raw.range(of: Data("\r\n\r\n".utf8)) else { return nil }
+        guard let headerString = String(data: raw[..<headerEnd.lowerBound], encoding: .utf8) else { return nil }
+        var lines = headerString.components(separatedBy: "\r\n")
+        guard let requestLine = lines.first else { return nil }
+        let parts = requestLine.split(separator: " ")
+        guard parts.count >= 2 else { return nil }
+        method = String(parts[0])
+        path = String(parts[1])
+        lines.removeFirst()
+
+        var hdrs: [String: String] = [:]
+        for line in lines {
+            guard let colon = line.firstIndex(of: ":") else { continue }
+            let key = line[..<colon].trimmingCharacters(in: .whitespaces).lowercased()
+            let value = line[line.index(after: colon)...].trimmingCharacters(in: .whitespaces)
+            hdrs[key] = value
+        }
+        headers = hdrs
+
+        let contentLength = Int(hdrs["content-length"] ?? "0") ?? 0
+        let available = raw[headerEnd.upperBound...]
+        body = Data(available.prefix(contentLength))
+        isComplete = body.count >= contentLength
+    }
+}

Sources/GrammarGem/System/Permissions.swift

@@ -2,7 +2,7 @@ import Foundation
 import AppKit
 import ApplicationServices
 
-/// Tracks and requests the macOS permissions GrammaGem needs to read & replace
+/// Tracks and requests the macOS permissions GrammarGem needs to read & replace
 /// text system-wide: **Accessibility** (required) and, for the synthetic-keystroke
 /// clipboard fallback, **Input Monitoring** may also be prompted by the system.
 @MainActor

Sources/GrammarGem/System/SnippetStore.swift

@@ -13,7 +13,7 @@ struct Snippet: Codable, Identifiable, Equatable {
 final class SnippetStore: ObservableObject {
     @Published private(set) var snippets: [Snippet]
 
-    private let key = "GrammaGem.snippets"
+    private let key = "GrammarGem.snippets"
     private let d = UserDefaults.standard
 
     init() {

Sources/GrammarGem/System/TextCapture.swift

@@ -4,7 +4,7 @@ import ApplicationServices
 import Carbon.HIToolbox
 
 /// Reads the user's selected text from the frontmost app and writes a corrected
-/// value back — the mechanism that makes GrammaGem work *everywhere*.
+/// value back — the mechanism that makes GrammarGem work *everywhere*.
 ///
 /// Two paths, mirroring the spec (§4):
 ///  1. **Accessibility API** (preferred): read/write `kAXSelectedTextAttribute`
@@ -24,10 +24,12 @@ final class TextCapture {
     enum CaptureError: LocalizedError {
         case noSelection
         case notPermitted
+        case secureField
         var errorDescription: String? {
             switch self {
             case .noSelection: return "Select some text first, then press the hotkey."
-            case .notPermitted: return "GrammaGem needs Accessibility permission to read and replace text."
+            case .notPermitted: return "GrammarGem needs Accessibility permission to read and replace text."
+            case .secureField: return "GrammarGem never reads password fields."
             }
         }
     }
@@ -41,8 +43,15 @@ final class TextCapture {
     // MARK: - Capture
 
     /// Try AX first; on empty/unavailable, fall back to the clipboard path.
+    /// Refuses outright if the focused element is a password field.
     func capture() throws -> Capture {
-        if let ax = captureViaAccessibility() {
+        let focused = AXIsProcessTrusted() ? AX.focusedElement() : nil
+        if let focused, AX.isSecureTextField(focused) {
+            // Bail before the clipboard fallback too — never synthesize ⌘C into a
+            // password field.
+            throw CaptureError.secureField
+        }
+        if let ax = captureViaAccessibility(focused) {
             return ax
         }
         if let clip = try captureViaClipboard() {
@@ -51,11 +60,8 @@ final class TextCapture {
         throw CaptureError.noSelection
     }
 
-    private func captureViaAccessibility() -> Capture? {
-        guard AXIsProcessTrusted() else { return nil }
-        let systemWide = AXUIElementCreateSystemWide()
-
-        guard let focused = AX.copyElement(systemWide, kAXFocusedUIElementAttribute) else { return nil }
+    private func captureViaAccessibility(_ focused: AXUIElement?) -> Capture? {
+        guard let focused else { return nil }
 
         var valueRef: CFTypeRef?
         guard AXUIElementCopyAttributeValue(
@@ -93,8 +99,8 @@ final class TextCapture {
     /// The full text value of the focused element (not just the selection).
     func focusedFieldText() -> (text: String, element: AXUIElement)? {
         guard AXIsProcessTrusted() else { return nil }
-        let systemWide = AXUIElementCreateSystemWide()
-        guard let focused = AX.copyElement(systemWide, kAXFocusedUIElementAttribute) else { return nil }
+        guard let focused = AX.focusedElement() else { return nil }
+        guard !AX.isSecureTextField(focused) else { return nil } // never fix a password field
 
         // Only treat genuine editable text roles as fixable, so we don't report
         // "nothing selected" failures on sliders/steppers/custom controls.

Sources/GrammarGem/System/TextFieldScanner.swift

@@ -15,7 +15,7 @@ struct ScannedField {
 
 /// Walks the Accessibility tree of the frontmost window and collects every
 /// editable text element (text fields, text areas, combo/search boxes) with
-/// content — so GrammaGem can check *all* the text on screen, not just the one
+/// content — so GrammarGem can check *all* the text on screen, not just the one
 /// the cursor is in. Bounded so huge web/Electron trees can't stall the app, and
 /// every cross-process message has a timeout so a wedged app can't hang the scan.
 ///
@@ -47,7 +47,9 @@ enum TextFieldScanner {
         if role == kAXTextFieldRole as String
             || role == kAXTextAreaRole as String
             || role == kAXComboBoxRole as String {
-            if let value = AX.copyString(el, kAXValueAttribute),
+            // Never surface password fields in the live monitor.
+            if !AX.isSecureTextField(el),
+               let value = AX.copyString(el, kAXValueAttribute),
                value.trimmingCharacters(in: .whitespacesAndNewlines).count >= 3 {
                 let label = AX.copyString(el, kAXTitleAttribute)
                     ?? AX.copyString(el, kAXDescriptionAttribute)

Sources/GrammarGem/System/TextReplacementCoordinator.swift

@@ -12,14 +12,19 @@ final class TextReplacementCoordinator {
     private let ai: AIEngine
     private let gate: FeatureGate
     private let detector: AppDetector
+    /// Vocabulary the LLM must reproduce verbatim (personal dictionary / style
+    /// guide). Read fresh per action so dictionary edits take effect immediately.
+    private let protectedTerms: () -> [String]
 
     init(capture: TextCapture, grammar: GrammarEngine, ai: AIEngine,
-         gate: FeatureGate, detector: AppDetector) {
+         gate: FeatureGate, detector: AppDetector,
+         protectedTerms: @escaping () -> [String] = { [] }) {
         self.capture = capture
         self.grammar = grammar
         self.ai = ai
         self.gate = gate
         self.detector = detector
+        self.protectedTerms = protectedTerms
     }
 
     /// The "fix" hotkey — instant grammar correction (Layer 1, always free).
@@ -52,7 +57,7 @@ final class TextReplacementCoordinator {
         do { cap = try await captureOffMain() } catch { return .failed(error.localizedDescription) }
 
         do {
-            let result = try await ai.run(action, on: cap.text)
+            let result = try await ai.run(action, on: cap.text, protectedTerms: protectedTerms())
             gate.recordAIActionUsed()
             let ok = await replaceOffMain(result, cap)
             return ok ? .replaced(result) : .failed("Couldn't write the result back.")
@@ -73,7 +78,7 @@ final class TextReplacementCoordinator {
         do { cap = try await captureOffMain() } catch { return .failed(error.localizedDescription) }
 
         do {
-            let result = try await ai.run(action, on: cap.text)
+            let result = try await ai.run(action, on: cap.text, protectedTerms: protectedTerms())
             gate.recordAIActionUsed()
             let ok = await replaceOffMain(result, cap)
             return ok ? .replaced(result) : .failed("Couldn't write the result back.")

Sources/GrammarGem/System/UpdaterManager.swift

@@ -0,0 +1,81 @@
+import Foundation
+import Sparkle
+
+/// Wraps Sparkle's updater. It background-checks the appcast on grammargem.com and
+/// publishes `updateAvailableVersion` when a newer, EdDSA-verified build exists, so
+/// the menu bar can show an "Update available" button. Triggering an update runs
+/// Sparkle's verified download + install flow.
+///
+/// The updater is only started inside the packaged `.app` (where the Info.plist
+/// carries `SUFeedURL` + `SUPublicEDKey`); under `swift run`, tests, or the
+/// self-test binaries it stays inert so nothing crashes.
+@MainActor
+final class UpdaterManager: NSObject, ObservableObject {
+    @Published private(set) var updateAvailableVersion: String?
+
+    private var controller: SPUStandardUpdaterController?
+
+    override init() {
+        super.init()
+        guard Bundle.main.object(forInfoDictionaryKey: "SUFeedURL") != nil else {
+            return // not the packaged app — no updater
+        }
+        controller = SPUStandardUpdaterController(
+            startingUpdater: true, updaterDelegate: self, userDriverDelegate: nil)
+    }
+
+    var canCheckForUpdates: Bool { controller?.updater.canCheckForUpdates ?? false }
+
+    /// User-initiated check — shows Sparkle's UI (used by the menu item and the
+    /// "Update" button on the availability banner).
+    func checkForUpdates() {
+        controller?.updater.checkForUpdates()
+    }
+}
+
+extension UpdaterManager: SPUUpdaterDelegate {
+    func updater(_ updater: SPUUpdater, didFindValidUpdate item: SUAppcastItem) {
+        updateAvailableVersion = item.displayVersionString
+    }
+
+    func updaterDidNotFindUpdate(_ updater: SPUUpdater) {
+        updateAvailableVersion = nil
+    }
+}
+
+// MARK: - Headless update self-test (build pipeline / CI)
+
+/// Checks `feedURL` for a newer version with no UI and prints the result, then
+/// exits. Used to verify the appcast + signature + version-comparison path.
+enum UpdaterSelfTest {
+    static func run(feedURL: String) {
+        let delegate = UpdateProbeDelegate(feed: feedURL)
+        UpdateProbeDelegate.retained = delegate
+        UpdateProbeDelegate.controller = SPUStandardUpdaterController(
+            startingUpdater: true, updaterDelegate: delegate, userDriverDelegate: nil)
+        UpdateProbeDelegate.controller?.updater.checkForUpdateInformation()
+        RunLoop.main.run() // Sparkle's network check needs the run loop; delegate exits.
+    }
+}
+
+private final class UpdateProbeDelegate: NSObject, SPUUpdaterDelegate {
+    static var controller: SPUStandardUpdaterController?
+    static var retained: UpdateProbeDelegate?
+    let feed: String
+    init(feed: String) { self.feed = feed; super.init() }
+
+    func feedURLString(for updater: SPUUpdater) -> String? { feed.isEmpty ? nil : feed }
+
+    func updater(_ updater: SPUUpdater, didFindValidUpdate item: SUAppcastItem) {
+        print("UPDATE_FOUND: \(item.displayVersionString)")
+        exit(0)
+    }
+    func updaterDidNotFindUpdate(_ updater: SPUUpdater) {
+        print("UPDATE_NONE")
+        exit(0)
+    }
+    func updater(_ updater: SPUUpdater, didAbortWithError error: Error) {
+        print("UPDATE_ERROR: \(error.localizedDescription)")
+        exit(1)
+    }
+}

Tests/GrammaGemTests/GrammaGemTests.swift

@@ -1,78 +0,0 @@
-import XCTest
-@testable import GrammaGem
-
-final class GrammaGemTests: XCTestCase {
-
-    // MARK: - Tiers / entitlements
-
-    func testDeviceCapsMatchSpec() {
-        XCTAssertEqual(Tier.solo.deviceCap, 1)
-        XCTAssertEqual(Tier.personal.deviceCap, 2)
-        XCTAssertEqual(Tier.studio.deviceCap, 4)
-        XCTAssertEqual(Tier.free.deviceCap, 1)
-    }
-
-    func testFreeEntitlementsAreLimited() {
-        let free = Entitlements(tier: .free)
-        XCTAssertFalse(free.unlimitedAIActions)
-        XCTAssertEqual(free.dailyAIActionCap, AppConfig.Limits.freeDailyAIActions)
-        XCTAssertEqual(free.dictionaryCap, AppConfig.Limits.freeDictionaryCap)
-        XCTAssertFalse(free.appAwareSwitching)
-        XCTAssertFalse(free.allModes)
-        XCTAssertTrue(free.unlimitedGrammar) // grammar is always free
-    }
-
-    func testPaidEntitlementsUnlockEverything() {
-        let paid = Entitlements(tier: .personal)
-        XCTAssertTrue(paid.unlimitedAIActions)
-        XCTAssertEqual(paid.dailyAIActionCap, Int.max)
-        XCTAssertEqual(paid.dictionaryCap, Int.max)
-        XCTAssertTrue(paid.appAwareSwitching)
-        XCTAssertTrue(paid.allModes)
-    }
-
-    // MARK: - Grammar (Harper stub) rules
-
-    func testHarperFixesRepeatedWordAndCasing() {
-        let harper = HarperEngine()
-        let input = "hey i wanted to checkin about the the proposal"
-        let fixed = harper.correct(input)
-        XCTAssertFalse(fixed.contains("the the"), "repeated word should be collapsed")
-        XCTAssertTrue(fixed.contains(" I "), "lowercase pronoun i should be capitalized")
-        XCTAssertTrue(fixed.contains("check in"), "checkin should split into two words")
-    }
-
-    func testIgnoreListSuppressesCorrection() {
-        let harper = HarperEngine()
-        harper.ignoreList = ["teh"] // pretend "teh" is an intentional brand term
-        let suggestions = harper.check("teh launch")
-        XCTAssertFalse(suggestions.contains { $0.original.lowercased() == "teh" })
-    }
-
-    // MARK: - Modes
-
-    func testFreeTierGetsOnlyPolishMode() {
-        let free = ModeRegistry.available(for: .free)
-        XCTAssertEqual(free.map(\.id), ["polish"])
-        let paid = ModeRegistry.available(for: .studio)
-        XCTAssertGreaterThan(paid.count, 1)
-        XCTAssertTrue(paid.contains { $0.id == "email" })
-    }
-
-    func testAppAwareModeMapping() {
-        XCTAssertEqual(ModeRegistry.mode(forBundleID: "com.apple.mail")?.id, "email")
-        XCTAssertEqual(ModeRegistry.mode(forBundleID: "com.microsoft.VSCode")?.id, "code")
-        XCTAssertNil(ModeRegistry.mode(forBundleID: "com.unknown.app"))
-    }
-
-    // MARK: - Device fingerprint
-
-    func testDeviceFingerprintIsStableAndHashed() {
-        let a = DeviceFingerprint.stableID()
-        let b = DeviceFingerprint.stableID()
-        XCTAssertEqual(a, b, "fingerprint must be stable across calls")
-        XCTAssertFalse(a.isEmpty)
-        // SHA-256 hex is 64 chars (unless the random fallback path is hit).
-        XCTAssertTrue(a.count == 64 || a.count == UUID().uuidString.count)
-    }
-}

Tests/GrammarGemTests/GrammarGemTests.swift

@@ -0,0 +1,222 @@
+import XCTest
+@testable import GrammarGem
+
+final class GrammarGemTests: XCTestCase {
+
+    // MARK: - Tiers / entitlements
+
+    func testDeviceCapsMatchSpec() {
+        XCTAssertEqual(Tier.solo.deviceCap, 1)
+        XCTAssertEqual(Tier.personal.deviceCap, 2)
+        XCTAssertEqual(Tier.studio.deviceCap, 4)
+        XCTAssertEqual(Tier.free.deviceCap, 1)
+    }
+
+    func testFreeEntitlementsAreLimited() {
+        let free = Entitlements(tier: .free)
+        XCTAssertFalse(free.unlimitedAIActions)
+        XCTAssertEqual(free.dailyAIActionCap, AppConfig.Limits.freeDailyAIActions)
+        XCTAssertEqual(free.dictionaryCap, AppConfig.Limits.freeDictionaryCap)
+        XCTAssertFalse(free.appAwareSwitching)
+        XCTAssertFalse(free.allModes)
+        XCTAssertTrue(free.unlimitedGrammar) // grammar is always free
+    }
+
+    func testPaidEntitlementsUnlockEverything() {
+        let paid = Entitlements(tier: .personal)
+        XCTAssertTrue(paid.unlimitedAIActions)
+        XCTAssertEqual(paid.dailyAIActionCap, Int.max)
+        XCTAssertEqual(paid.dictionaryCap, Int.max)
+        XCTAssertTrue(paid.appAwareSwitching)
+        XCTAssertTrue(paid.allModes)
+    }
+
+    // MARK: - Grammar (Harper stub) rules
+
+    func testHarperFixesRepeatedWordAndCasing() {
+        let harper = HarperEngine()
+        let input = "hey i wanted to checkin about the the proposal"
+        let fixed = harper.correct(input)
+        XCTAssertFalse(fixed.contains("the the"), "repeated word should be collapsed")
+        XCTAssertTrue(fixed.contains(" I "), "lowercase pronoun i should be capitalized")
+        XCTAssertTrue(fixed.contains("check in"), "checkin should split into two words")
+    }
+
+    func testIgnoreListSuppressesCorrection() {
+        let harper = HarperEngine()
+        harper.ignoreList = ["teh"] // pretend "teh" is an intentional brand term
+        let suggestions = harper.check("teh launch")
+        XCTAssertFalse(suggestions.contains { $0.original.lowercased() == "teh" })
+    }
+
+    /// Real Harper does true grammar NSSpellChecker can't: subject-verb
+    /// agreement and verb-form correction, applied cleanly in place.
+    func testHarperRealGrammarCorrections() {
+        let harper = HarperEngine()
+        let fixed = harper.correct("She dont like it and she have went home.")
+        XCTAssertTrue(fixed.contains("don't"), "dont -> don't")
+        XCTAssertTrue(fixed.contains("has"), "have -> has (subject-verb agreement)")
+        XCTAssertTrue(fixed.contains("gone"), "went -> gone (past participle)")
+        XCTAssertFalse(fixed.contains("went"), "the wrong verb form should be gone")
+    }
+
+    /// The trust bug: a mid-sentence spelling fix must keep the original casing.
+    func testSpellingReplacementPreservesCase() {
+        XCTAssertEqual(SystemGrammarEngine.matchingCase(of: "problemm", in: "Problem"), "problem")
+        XCTAssertEqual(SystemGrammarEngine.matchingCase(of: "Teh", in: "the"), "The")
+        XCTAssertEqual(SystemGrammarEngine.matchingCase(of: "teh", in: "the"), "the")
+        XCTAssertEqual(SystemGrammarEngine.matchingCase(of: "HELLOO", in: "hello"), "HELLO")
+    }
+
+    /// Harper returns char (Unicode scalar) offsets; they must map exactly onto
+    /// UTF-16 NSRange offsets even past multi-UTF-16-unit scalars (emoji).
+    func testHarperCharOffsetsMapToUTF16() {
+        let text = "😀 teh"  // 😀 = 1 scalar / 2 UTF-16 units
+        let range = HarperEngine.utf16Range(scalarStart: 2, scalarLen: 3, in: text)
+        XCTAssertEqual(range, NSRange(location: 3, length: 3))
+        XCTAssertEqual((text as NSString).substring(with: range!), "teh")
+    }
+
+    // MARK: - Value loop (streak / subscription-avoided / milestones)
+
+    @MainActor
+    func testValueLoopMetrics() {
+        let fmt = DateFormatter()
+        fmt.dateFormat = "yyyy-MM-dd"
+        fmt.locale = Locale(identifier: "en_US_POSIX")
+        fmt.timeZone = .current
+        let cal = Calendar.current
+        let now = Date()
+        func key(_ daysAgo: Int) -> String {
+            fmt.string(from: cal.date(byAdding: .day, value: -daysAgo, to: now)!)
+        }
+
+        // today + yesterday + 2-days-ago = streak of 3 (the day-4 entry is broken off).
+        let perDay = [key(0): 2, key(1): 1, key(2): 5, key(4): 1]
+        XCTAssertEqual(UsageStats.streak(perDay: perDay, asOf: now), 3)
+        XCTAssertEqual(UsageStats.streak(perDay: [:], asOf: now), 0)
+        // Used yesterday but not yet today — streak is still alive.
+        XCTAssertEqual(UsageStats.streak(perDay: [key(1): 1], asOf: now), 1)
+
+        // ~1 year of ownership ≈ one year of the subscription you didn't pay.
+        XCTAssertEqual(
+            UsageStats.subscriptionAvoidedUSD(firstUseDay: key(365), asOf: now, annualPrice: 144), 144)
+        XCTAssertEqual(
+            UsageStats.subscriptionAvoidedUSD(firstUseDay: nil, asOf: now, annualPrice: 144), 0)
+
+        let m = UsageStats.nextMilestone(corrections: 50)
+        XCTAssertEqual(m.target, 100)
+        XCTAssertEqual(m.progress, 0.5, accuracy: 0.001)
+        XCTAssertEqual(UsageStats.nextMilestone(corrections: 100).target, 500)
+    }
+
+    // MARK: - MLX on-device LLM (integration; skipped unless the model is present)
+
+    /// Loads the real downloaded model and runs one generation. Skipped in CI /
+    /// on machines without the weights. Run with the model present to verify the
+    /// MLX integration end-to-end.
+    func testMLXRealGenerationIfModelPresent() async throws {
+        // Opt-in: `swift test` (CLI) can't place mlx-swift's metallib, so this is
+        // gated. Run it via the app's `--mlx-selftest`, or set GRAMMARGEM_MLX_TEST=1
+        // with the metallib colocated. See scripts/build-metallib.sh.
+        guard ProcessInfo.processInfo.environment["GRAMMARGEM_MLX_TEST"] == "1" else {
+            throw XCTSkip("set GRAMMARGEM_MLX_TEST=1 (metallib colocated) to run the MLX integration test")
+        }
+        guard let dir = ModelManager.completedModelDirectory(repo: AppConfig.Model.defaultRepo) else {
+            throw XCTSkip("on-device model not downloaded; skipping MLX integration test")
+        }
+        let engine = MLXEngine(modelDirectoryProvider: { dir })
+        XCTAssertTrue(engine.isReady)
+        let out = try await engine.run(.rewriteClarity,
+                                       on: "me and him was going to the store for to buy some milks")
+        print("MLX rewriteClarity -> \(out)")
+        XCTAssertFalse(out.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty)
+    }
+
+    // MARK: - Modes
+
+    func testFreeTierGetsOnlyPolishMode() {
+        let free = ModeRegistry.available(for: .free)
+        XCTAssertEqual(free.map(\.id), ["polish"])
+        let paid = ModeRegistry.available(for: .studio)
+        XCTAssertGreaterThan(paid.count, 1)
+        XCTAssertTrue(paid.contains { $0.id == "email" })
+    }
+
+    func testAppAwareModeMapping() {
+        XCTAssertEqual(ModeRegistry.mode(forBundleID: "com.apple.mail")?.id, "email")
+        XCTAssertEqual(ModeRegistry.mode(forBundleID: "com.microsoft.VSCode")?.id, "code")
+        XCTAssertNil(ModeRegistry.mode(forBundleID: "com.unknown.app"))
+    }
+
+    // MARK: - AIPrompts (backend-neutral seam)
+
+    func testProtectedTermsInjectedIntoSystemPrompt() {
+        let base = AIPrompts.systemPrompt(for: .rewriteClarity)
+        let withTerms = AIPrompts.systemPrompt(for: .rewriteClarity, protectedTerms: ["GrammarGem", "Harper"])
+        XCTAssertFalse(base.contains("GrammarGem"))
+        XCTAssertTrue(withTerms.contains("\"GrammarGem\""))
+        XCTAssertTrue(withTerms.contains("\"Harper\""))
+        XCTAssertTrue(withTerms.contains("verbatim"))
+    }
+
+    func testProtectedTermsClauseSkipsWhenEmpty() {
+        let blank = AIPrompts.systemPrompt(for: .rewrite, protectedTerms: ["", "   "])
+        XCTAssertEqual(blank, AIPrompts.systemPrompt(for: .rewrite))
+    }
+
+    func testMaxTokensHonorsModeLengthCap() {
+        // Default actions get the full budget…
+        XCTAssertEqual(AIPrompts.maxTokens(for: .rewriteClarity), 512)
+        // …but a short-form Mode (Team Chat, lengthCap 60) gets far fewer.
+        let slack = ModeRegistry.slack
+        XCTAssertNotNil(slack.lengthCap)
+        let capped = AIPrompts.maxTokens(for: .applyMode(slack))
+        XCTAssertLessThan(capped, 512)
+        XCTAssertGreaterThanOrEqual(capped, 64)
+        // A mode with no cap (Polish) falls back to the default budget.
+        XCTAssertEqual(AIPrompts.maxTokens(for: .applyMode(ModeRegistry.polish)), 512)
+    }
+
+    func testCleanStripsPreambleAndQuotes() {
+        XCTAssertEqual(AIPrompts.clean("Sure, here's the rewrite: Hello world"), "Hello world")
+        XCTAssertEqual(AIPrompts.clean("\"Quoted result\""), "Quoted result")
+        XCTAssertEqual(AIPrompts.clean("  already clean  "), "already clean")
+    }
+
+    func testParseToneIsRobust() {
+        XCTAssertEqual(AIPrompts.parseTone("professional"), .professional)
+        XCTAssertEqual(AIPrompts.parseTone("  Friendly.\n"), .friendly)
+        XCTAssertEqual(AIPrompts.parseTone("the tone is academic here"), .academic)
+        XCTAssertEqual(AIPrompts.parseTone("???"), .professional) // safe fallback
+    }
+
+    // MARK: - Custom modes
+
+    @MainActor
+    func testCustomModeRejectsEmptyPromptAndDuplicates() {
+        // Deterministic regardless of prior runs (the store persists to UserDefaults).
+        UserDefaults.standard.removeObject(forKey: "GrammarGem.customModes")
+        defer { UserDefaults.standard.removeObject(forKey: "GrammarGem.customModes") }
+
+        let store = CustomModesStore()
+        XCTAssertFalse(store.addCustom(name: "Brand Voice", prompt: "   "),
+                       "empty prompt must be rejected")
+        XCTAssertTrue(store.addCustom(name: "Brand Voice", prompt: "Write in Acme's warm voice."))
+        XCTAssertFalse(store.addCustom(name: "brand voice", prompt: "different prompt"),
+                       "duplicate name (case-insensitive) must be rejected")
+        XCTAssertFalse(store.addCustom(name: "Polish", prompt: "collides with a built-in"),
+                       "name colliding with a built-in mode must be rejected")
+    }
+
+    // MARK: - Device fingerprint
+
+    func testDeviceFingerprintIsStableAndHashed() {
+        let a = DeviceFingerprint.stableID()
+        let b = DeviceFingerprint.stableID()
+        XCTAssertEqual(a, b, "fingerprint must be stable across calls")
+        XCTAssertFalse(a.isEmpty)
+        // SHA-256 hex is 64 chars (unless the random fallback path is hit).
+        XCTAssertTrue(a.count == 64 || a.count == UUID().uuidString.count)
+    }
+}

docs/grammarly-value-plan.md

@@ -0,0 +1,204 @@
+# Grammarly Value Teardown -> GrammarGem Plan
+
+*Senior product + Swift engineering review. Every claim below is grounded in the current GrammarGem source. File references use absolute paths; the load-bearing bug is the mis-casing in `SystemGrammarEngine.swift:42-45`.*
+
+---
+
+## 1. Executive summary — what makes Grammarly FEEL valuable (priority order)
+
+Grammarly's perceived value is NOT its grammar engine. It is a stack of interaction and psychology layers on top of a competent engine. Ranked by leverage for a one-time-purchase, on-device Mac utility:
+
+1. **Trustworthy correction quality (the foundation).** Every felt-value mechanic above it collapses if a fix is wrong. Grammarly's "accept-accept-accept" rhythm only works because in-place application is reliable and casing/context is preserved. GrammarGem's engine currently *demonstrably violates this* (`problemm` -> `Problem` mid-sentence). Fix this first; nothing else matters until it's solid.
+
+2. **The fix-as-button atomic loop: read the fix and apply it in one motion.** Grammarly's clickable green replacement chip collapses diagnosis + remedy + action into a single low-friction act, with a cheap, always-present dismiss so saying no is as easy as saying yes. GrammarGem has an `Apply` button but no dismiss/ignore/add-to-dictionary, no keyboard accept, and the apply path is brittle (whole-field AX overwrite).
+
+3. **Categorization + counts + a score: turning a wall of red into a finite, beatable list.** Four named, color-coded buckets, per-category count chips, one running issue badge, and a 0-100 score convert dread into a checklist with a meter that only goes up. GrammarGem has a raw issue count (3 colors) and *zero* score concept.
+
+4. **The rigged first-run "wow": guaranteed visible win in under 60 seconds.** A pre-seeded, error-salted demo doc means the product proves itself before asking for anything. GrammarGem's onboarding only handles Accessibility + model download — it never demonstrates the correction loop at all.
+
+5. **Ongoing perceived value without surveillance: progress you can see.** Grammarly uses cloud percentiles + weekly behavioral emails. GrammarGem can recreate the *feeling* — self-vs-self, fully on-device — with a local score trend, streaks, milestones, and a "subscription you didn't pay" money figure. The plumbing (`UsageStats.perDay`) already exists.
+
+6. **The generative "writing partner" layer: hand me the better sentence, not just the flag.** Sentence rewrites, tone detection/adjustment, conciseness. This is real value but is currently 100% simulated (`MLXEngine.swift` is a string-hack stub) and gated by a daily counter. It is the right *paid* tier, but it must produce real output before it can be sold.
+
+The strategic asymmetry to exploit throughout: every Grammarly value moment carries an implicit "and you'll pay again next year." GrammarGem's identical mechanics should be framed "yours once, forever, on this Mac."
+
+---
+
+## 2. Mechanic-by-mechanic: how Grammarly does it -> how GrammarGem should do it
+
+### Mechanic 1 — Trustworthy correction quality (see §3 for the full engineering plan)
+- **Grammarly:** ranks by confidence, suppresses low-confidence edits, never garbles surrounding text, preserves casing, and limits bulk-apply to high-confidence objective mechanics only.
+- **GrammarGem today:** `SystemGrammarEngine` blindly trusts `NSSpellChecker.correction(forWordRange:)`, which is sentence-position-aware and capitalizes a word it thinks starts a sentence — producing `problemm` -> `Problem` mid-sentence (`SystemGrammarEngine.swift:42-45`). `Suggestion` has no confidence/severity/alternatives (`Models.swift:48-59`). Default `correct()` applies *every* suggestion including no-op grammar flags where `replacement == original` (`GrammarEngine.swift:22-29`).
+- **Do:** real Harper FFI; case/whitespace post-processing; add `confidence`/`severity`/`alternatives` to `Suggestion`; never auto-apply no-ops or low-confidence flags.
+- **Files:** `SystemGrammarEngine.swift`, `HarperEngine.swift`, `GrammarEngine.swift`, `Models.swift`, `harper-ffi/`.
+- **Impact: high · Effort: L**
+
+### Mechanic 2 — The fix-as-button atomic loop (+ dismiss / ignore / add-to-dictionary)
+- **Grammarly:** the suggested word *is* the button (green = go/safe/done); an always-present cheap dismiss (trash/Esc) and add-to-dictionary make accepting feel safe; Tab-to-navigate / Enter-to-accept / Esc-to-dismiss removes the mouse round-trip.
+- **GrammarGem today:** `FieldCard` shows a message + one `original -> replacement` + a small `Apply` button (`LiveCheckView.swift:104-119`). There is **no dismiss, no ignore, no add-to-dictionary, no keyboard accept.** Per-issue `apply()` bails silently if the field changed at all since the snapshot (`LiveMonitor.swift:82-89`), and even single-issue apply rewrites the *whole* AX value (`LiveMonitor.swift:101-103`), risking caret/undo/formatting loss.
+- **Do (realistic for a cross-app AX tool — we cannot draw a green chip inside arbitrary apps):**
+  - Make the replacement text itself the primary tappable control in the card (the chip *is* the fix), styled by category color.
+  - Add a per-suggestion overflow: **Dismiss** (model a `dismissedIDs: Set<UUID>` on the monitor so it survives re-scans), **Ignore word** / **Add to dictionary** (route into `PersonalDictionary` -> `ignoreList`), gated by `freeDictionaryCap`.
+  - Add **keyboard flow inside the Live Check panel**: ↑/↓ or Tab to move selection, Return to apply, Delete/Esc to dismiss. This is fully feasible because the panel is our own SwiftUI window.
+  - Replace whole-field AX write with **targeted span insertion** where the element supports `kAXSelectedTextRangeAttribute` + `kAXSelectedTextAttribute` (set selection to the issue range, then set selected text to the replacement) — preserves caret and undo. Fall back to whole-value only when selection-set is unsupported.
+  - Make per-issue apply **rebase** instead of bail: if the live value changed, re-locate the span by matching `original` near the old offset rather than refusing to act.
+- **Files:** `LiveCheckView.swift`, `LiveMonitor.swift`, `Models.swift`, `PersonalDictionary.swift`, `AppState.swift`, `TextCapture`.
+- **Impact: high · Effort: M**
+
+### Mechanic 3 — Categorization, counts, and an on-device document score
+- **Grammarly:** four named buckets (Correctness/Clarity/Engagement/Delivery) each with a color and a count chip that doubles as a filter; one master running badge; a 0-100 percentile score that ticks up on every accept; cards ordered by severity (objective errors first) so the early wins build trust.
+- **GrammarGem today:** `GrammarKind` has 6 cases but `.punctuation` is dead; the panel reduces everything to 3 dot colors (`LiveCheckView.swift:136-142`); `issueCount` is a raw sum (`LiveMonitor.swift:32`); there is **no score, no per-category chips, no severity ordering, no filter**.
+- **Do (on-device, no cloud, no percentile-vs-others):**
+  - Introduce GrammarGem's own named buckets that fit the engine: e.g. **Correctness** (spelling/grammar/punctuation), **Clarity** (phrasing/conciseness — from the real LLM), **Polish** (repetition/capitalization/style). Use original color semantics (do NOT clone Grammarly's exact red/blue/green/purple mapping or wording).
+  - Add **count chips per bucket** in the panel header that filter the card list; keep the menu-bar badge as the master tally (`MenuBarLabel`).
+  - Compute a **local cleanliness score** at check-time: a deterministic function of issues-per-100-words by severity (e.g. `100 - weighted_issues`). It is honest because it's defined relative to *this document*, not a hidden user corpus. Show it on the card header and trend it on the dashboard.
+  - **Order cards by severity then document position** (objective spelling/grammar first) so the first accept is a high-confidence win.
+  - Critical: the score must reflect the *honest* free promise — grammar/spelling is unlimited and fully resolvable, so a free user CAN reach a clean score. Do **not** manufacture a permanently-nonzero count to force upgrades (that's Grammarly's locked-bucket trick and it contradicts our positioning — see §5).
+- **Files:** `Models.swift` (`GrammarKind` cleanup, add `severity`), `LiveMonitor.swift`, `LiveCheckView.swift`, `MenuBarContent.swift`, `DashboardView.swift`, a new `WritingScore` helper.
+- **Impact: high · Effort: M**
+
+### Mechanic 4 — The first-run "wow" (see §4 for the full sequence)
+- **Grammarly:** land in an error-salted demo doc -> "we found N issues" -> one-click fixes vanish underlines + decrement counter -> goal setup -> install-everywhere prompt at the dopamine peak.
+- **GrammarGem today:** `OnboardingView` only covers Accessibility + model download (`OnboardingView.swift`); it never shows the correction loop.
+- **Do:** add an in-app demo step with a pre-seeded sample, a "we found N things to fix" reveal, and a satisfying one-click-to-clean animation — *before* asking for nothing-but-praise (no install-everywhere pressure; we're already system-wide). Detail in §4.
+- **Files:** `OnboardingView.swift`, plus a small `DemoDocument` view reusing the highlight + apply UI.
+- **Impact: high · Effort: M**
+
+### Mechanic 5 — Ongoing perceived value (privacy-native, self-vs-self)
+- **Grammarly:** 0-100 score, weekly Insights email ("more productive than X% of users"), lifetime words-checked counter, streaks — all cloud + behavioral-email, the exact surveillance we market against.
+- **GrammarGem today:** `UsageStats` tracks `totalCorrections`, `totalAIActions`, `totalWords`, and `perDay` (`UsageStats.swift`); the dashboard shows four tiles + a 7-bar chart, but **no score, no streak, no week-over-week, no milestone, no money-saved figure**. `estimatedMinutesSaved` is a crude untuned constant (`8s/correction + 45s/AI-action`). Stats are invisible outside the main window.
+- **Do (all local, no telemetry, stops nagging the moment they own it):**
+  - **Local writing-score trend** on the dashboard (from Mechanic 3), compared only to the user's own past.
+  - **Streak + milestones** from existing `perDay` data ("7-day streak", "1,000th correction", "100k words polished") — cheap, high word-of-mouth, and the right re-engagement hook for a no-renewal product.
+  - **"Subscription you didn't pay" figure** — translate usage into money: the marketing site already hammers "~\$144/yr vs pay once," but the *app* never does. Show "You've polished N times — that's the price of GrammarGem recovered M times over," computed locally. This is the strongest one-time-purchase value teaser and it lives where the user actually is.
+  - **Week-over-week delta** on the bar chart and a lightweight in-app weekly recap card (NOT an email; no pipeline, no surveillance).
+  - **Surface one stat in the menu bar dropdown** (the most-seen surface) so value reminders don't require opening the dashboard.
+  - Tune `estimatedMinutesSaved` to scale by words changed / action type so the headline "was it worth it?" number is credible.
+- **Files:** `UsageStats.swift`, `DashboardView.swift`, `MenuBarContent.swift`, `web/src/lib/content.ts` (replace PLACEHOLDER stats/testimonials before launch).
+- **Impact: high · Effort: M**
+
+### Mechanic 6 — The generative "writing partner" layer (real LLM, honest gating)
+- **Grammarly:** sentence rewrites ("Replace with This Version" + Highlight-Changes diff), tone detection (emoji + label), tone adjustment, conciseness, GrammarlyGO — all one-click, reversible, before/after.
+- **GrammarGem today:** `MLXEngine` is a stub doing `replacingOccurrences` string hacks (`MLXEngine.swift`); `tidy()` even re-introduces casing risk; `detectTone` keys off substrings. `ModelManager` downloads real weights but nothing loads them. Gated by `freeDailyAIActions = 10` shared across rewrite/tone/Ask/translate.
+- **Do:**
+  - Wire the **real MLX model** from `ModelManager.modelsDirectory` (the download is currently a dead-end); uncomment `mlx-swift` in `Package.swift`.
+  - Adopt the **one-click + reversible + before/after diff** delivery contract for every rewrite — this is what neutralizes "the AI is taking over my voice."
+  - Keep the **honest quantity gate**: free users get *real, full-quality* output, just rationed (the daily counter), plus Polish mode only. This is the parity-respecting tease — satisfaction-driven ("I keep hitting the limit / I want my own modes / I want it on my other Mac"), not anxiety-driven.
+  - Real **tone detection** (label + emoji) is the highest-value non-grammar feature; it delivers value on grammatically perfect text. Build it once the model is live.
+- **Files:** `MLXEngine.swift`, `AIEngine.swift`, `ModelManager.swift`, `Package.swift`, `FeatureGate.swift`, `TextReplacementCoordinator.swift`, `WritingModesView.swift`.
+- **Impact: high · Effort: L** (model integration is the long pole)
+
+---
+
+## 3. Correction-QUALITY: the path to trustworthy fixes (this underpins ALL perceived value)
+
+The engine is the load-bearing wall. Today it is `NSSpellChecker` + a ~6-rule regex stub, and it ships a trust-destroying casing bug. Here is the ordered path.
+
+### 3.1 Fix the casing/whitespace bug NOW (cheap, immediate)
+Root cause: `SystemGrammarEngine.swift:42-45` blindly uses `checker.correction(forWordRange:)`, which is sentence/position-aware and returns a capitalized guess for a token it believes starts a sentence — so a mid-sentence `problemm` comes back `Problem`.
+
+**Post-process every spelling replacement to preserve the original token's casing** unless the token is a true sentence start or proper noun:
+- If `original` is all-lowercase, lowercase the replacement's first letter.
+- If `original` is Capitalized (single leading cap), match that.
+- If `original` is ALL-CAPS, upper-case the replacement.
+- Only adopt the corrector's case when the token is at a genuine sentence boundary (preceded by `.?!` + space, or string start). Also trim/normalize whitespace so a replacement never injects a stray leading/trailing space.
+
+This is a ~20-line transcase helper applied at suggestion-build time. It removes the single most visible trust failure before any deeper work.
+
+### 3.2 Stop auto-applying garbage
+- `GrammarEngine.correct()` (`GrammarEngine.swift:22-29`) applies **every** suggestion including grammar flags where `replacement == original` (the no-op flags emitted at `SystemGrammarEngine.swift:51-54` and `:67-70`). Filter these out of the bulk path entirely — a no-op flag must never be part of "Fix all," and a low-confidence guess must never auto-apply.
+- "Fix all" should be **trust-scoped like Grammarly's bulk accept**: only high-confidence objective mechanics (spelling/grammar/punctuation), never subjective rewrites.
+
+### 3.3 Enrich the data model
+`Suggestion` (`Models.swift:48-59`) needs:
+- `confidence: Double` (gate auto-apply below a threshold; show low-confidence ones as optional, never bulk-applied).
+- `severity` (drives ordering and the score weighting).
+- `alternatives: [String]` — `NSSpellChecker.guesses()` already returns multiple candidates but only `.first` is kept (`SystemGrammarEngine.swift:41`); surface the rest so the card can offer "other suggestions."
+- `ruleID`/`source` — so feedback (accept/dismiss) can later tune ranking and so we can attribute a fix to Harper vs NSSpellChecker.
+
+### 3.4 Integrate the real Harper core (the big precision unlock)
+`harper-ffi/` is an empty README; `Package.swift` comments out all real deps. Stand up the Rust crate behind a C-FFI static lib (`harper_check(text) -> spans`), map spans into `Suggestion`, and keep the protocol boundary so the rest of the app is unchanged. This brings real subject-verb agreement, article/preposition usage, comma/apostrophe rules, commonly-confused pairs, etc. — the category coverage NSSpellChecker structurally cannot provide. De-dup against NSSpellChecker as today (`overlaps`), but prefer Harper where both fire.
+
+### 3.5 Populate the dead `.punctuation` category
+`.punctuation` is declared but never emitted, yet punctuation is one of the highest-volume real-world error classes. Harper covers most of it; this fills the gap and makes the new category chips (Mechanic 3) meaningful.
+
+### 3.6 Incremental, async, grapheme-safe checking
+- Today: whole-document, synchronous, `DispatchQueue.main.sync` on a 1.6s poll, truncated at 4000 chars (`LiveMonitor.swift:46,174`), frontmost window only. Move to **debounced incremental re-check of changed spans** with caching of unchanged ranges; keep the heavy AX traversal off-main (already done) but get the spell/grammar pass off the main thread too once Harper is FFI-based (no `NSSpellChecker` main-thread requirement).
+- Validate that replacement sub-ranges fall on **grapheme boundaries** (emoji/combining marks) before applying — only a coarse bounds check exists today (`SystemGrammarEngine.swift:63`).
+
+### 3.7 Feedback loop
+Wire dismiss / add-to-dictionary (Mechanic 2) back into ranking so repeated false positives stop nagging — this is the "it learns" trust signal. Today `ignoreList` only suppresses; long-term, dismiss counts per `ruleID` can down-rank a noisy rule.
+
+**Sequencing:** §3.1 + §3.2 this week (trust-critical, tiny). §3.3 alongside Mechanic 2. §3.4–§3.6 are the real Harper milestone. §3.7 last.
+
+---
+
+## 4. The first-run "wow" sequence for GrammarGem (original copy)
+
+Goal: a guaranteed visible win in under 60 seconds, *inside our own window* (we don't need Grammarly's blank-canvas demo trick or its install-everywhere upsell — we're already system-wide). Onboarding today (`OnboardingView.swift`) skips this entirely.
+
+Proposed flow:
+
+1. **Welcome (1 line):** "A private writing assistant that lives in your menu bar and fixes text in every app — all on this Mac." (existing copy is close; keep it.)
+
+2. **The rigged win — a live mini-demo BEFORE any permission ask.** Show a short pre-written paragraph salted with obvious, safe errors (a misspelling, a repeated word, a lowercase "i", a missing period). Render it with the highlight UI already built in `LiveCheckView.highlighted(...)`. Above it: **"We spotted N things to tidy up."** (count = guaranteed, because the sample is fixed.)
+
+3. **One satisfying click.** A single "Clean it up" button animates the highlights resolving one by one; the count ticks to 0; the paragraph visibly improves. This is the operant loop — trivial action, immediate visible reward — experienced once, on rails, with zero risk. (Reuse the apply path; it's a local string, not a live AX element, so it's completely safe.)
+
+4. **The reveal:** "That's GrammarGem. It does this in Mail, Slack, Notes, your browser — everywhere you type." Then the *first* ask: **Accessibility** (the existing step 2 / `stepCard`), now framed as "Turn it on everywhere."
+
+5. **Optional model step:** keep the existing "Download the on-device model (optional) — grammar works instantly with no download" card. Frame the AI features as a bonus, not a blocker.
+
+6. **No install-everywhere nag, no timed discount, no streak guilt.** End on a calm "You're all set" with one honest line about ownership: "Yours once. No subscription, nothing leaves your Mac."
+
+Guardrails: the demo must use *original* sample text (not Grammarly's), and the count/score must be real (computed by our engine on the sample), never theatrical.
+
+---
+
+## 5. Do NOT copy (dark patterns + claims we can't truthfully make)
+
+These are Grammarly mechanics that either depend on infrastructure we reject or that would corrode the trust/privacy moat that *is* the product.
+
+1. **The premium-issue anxiety counter ("14 advanced issues you can't fix").** It works by detecting problems the engine deliberately won't fix. It clashes head-on with our promise that grammar/spelling/punctuation is unlimited and fully resolvable for free. Do not manufacture a permanently-nonzero count or a "score capped until you upgrade" gate.
+
+2. **Two-tier gold-vs-red underlines (a second class of locked grammar issues).** Our underlines are all free and all resolvable; there is no second class to color differently. Inventing one betrays the core differentiator.
+
+3. **Blur/lock a result we already computed.** On-device + open-source, hiding output we generated is both trivially bypassable and brand-corrosive. Gate by **quantity/frequency** (the daily counter) and **breadth** (modes, multi-device, snippets, larger model) — never by hiding the quality of a single result.
+
+4. **Cloud percentile comparisons ("more productive than X% of users").** Requires an account + aggregate corpus + telemetry — the exact surveillance we market against. Replace with **self-vs-self** local trends.
+
+5. **Behavioral weekly emails / re-nag pipeline.** For a one-time purchase there is no subscription to keep warm; post-purchase nagging is pure annoyance. Any weekly recap must be **in-app, local, opt-in, and stop entirely once they own it.**
+
+6. **Countdown/limited-time discount urgency** (Grammarly's Day-7 40% timer). Manufactured scarcity undercuts the honest "buy once, fair price" positioning.
+
+7. **Lifetime "total words checked" framed as cloud sunk-cost-to-lose.** A local milestone counter is fine and good; framing it as "you'll lose your history if you leave" is a retention dark pattern with no place in a no-renewal product.
+
+8. **Unsubstantiated social proof.** `web/src/lib/content.ts` STATS (200k+ downloads, 4.9 rating) and all TESTIMONIALS are explicitly flagged PLACEHOLDER. Do not ship these as fact — replace with real numbers or remove before launch.
+
+Positive reframe to keep: surface locked paid features (modes, app-aware, snippets, larger model) honestly — "Unlock all of this once. Yours forever, no subscription." Same mechanism (visible locked features), stronger close (no recurring cost objection).
+
+---
+
+## 6. Prioritized roadmap
+
+### NOW (trust + the atomic loop — ship-blockers for credibility)
+1. **Fix the casing/whitespace post-processing bug** (§3.1). `SystemGrammarEngine.swift`. *high / S.*
+2. **Stop bulk-applying no-ops and low-confidence guesses** (§3.2). `GrammarEngine.swift`, `SystemGrammarEngine.swift`. *high / S.*
+3. **Dismiss / Ignore / Add-to-dictionary + keyboard accept in the Live Check panel** (Mechanic 2). `LiveCheckView.swift`, `LiveMonitor.swift`, `Models.swift`, `PersonalDictionary.swift`. *high / M.*
+4. **Targeted span apply via AX selection instead of whole-field overwrite; rebase instead of bail** (Mechanic 2). `LiveMonitor.swift`, `TextCapture`. *high / M.*
+5. **First-run rigged-win demo** (§4). `OnboardingView.swift`. *high / M.*
+
+### NEXT (organize + the value loop)
+6. **Named buckets + per-category count chips + severity ordering + filter** (Mechanic 3). `Models.swift`, `LiveMonitor.swift`, `LiveCheckView.swift`. *high / M.*
+7. **On-device writing score (per-doc) + dashboard trend** (Mechanics 3 & 5). `WritingScore` helper, `LiveCheckView.swift`, `DashboardView.swift`. *high / M.*
+8. **Streaks + milestones + "subscription you didn't pay" money figure + menu-bar stat** (Mechanic 5). `UsageStats.swift`, `DashboardView.swift`, `MenuBarContent.swift`. *high / M.*
+9. **Enrich `Suggestion` with confidence/severity/alternatives + "other suggestions" in card** (§3.3). `Models.swift`, `SystemGrammarEngine.swift`, `LiveCheckView.swift`. *medium / M.*
+
+### LATER (real engine + real partner layer)
+10. **Real Harper FFI integration + populate `.punctuation` + grapheme safety + incremental async re-check** (§3.4–§3.6). `harper-ffi/`, `HarperEngine.swift`, `SystemGrammarEngine.swift`, `LiveMonitor.swift`, `Package.swift`. *high / L.*
+11. **Wire the real MLX model (load downloaded weights) + one-click/reversible/before-after diff for rewrites + real tone detection** (Mechanic 6). `MLXEngine.swift`, `ModelManager.swift`, `Package.swift`, `TextReplacementCoordinator.swift`. *high / L.*
+12. **Replace PLACEHOLDER web social proof/testimonials before launch** (§5). `web/src/lib/content.ts`. *medium / S.*
+
+---
+
+*Throughline: ship trust first (correction quality + a safe, reversible accept loop), then make the work feel finite and rewarding (buckets, counts, a local score), then sell ongoing value honestly (self-vs-self progress, money saved, lifetime ownership) — and build the generative partner tier on a real model with a reversible, before/after contract. Every Grammarly mechanic translates if you swap cloud-surveillance for on-device self-comparison and recurring-nag for one-time honesty.*

harper-ffi/Cargo.toml

@@ -0,0 +1,21 @@
+[package]
+name = "harper-ffi"
+version = "0.1.0"
+edition = "2021"
+
+[lib]
+# Static library exposing a C ABI for linking into the Swift app.
+name = "harper_ffi"
+crate-type = ["staticlib"]
+
+[dependencies]
+# harper-core 2.5.0 — the grammar checker from the Automattic Harper project.
+# Verified against https://docs.rs/harper-core/2.5.0/
+harper-core = "2.5.0"
+# Used to build the output JSON with correct string escaping.
+serde_json = "1"
+
+[profile.release]
+opt-level = 3
+lto = true
+codegen-units = 1

harper-ffi/README.md

@@ -5,7 +5,7 @@ A thin Rust static library that exposes the **Harper** grammar core
 integration (spec §1, §2, §8).
 
 The Swift side talks to this through the `GrammarEngine` protocol; today
-[`HarperEngine.swift`](../Sources/GrammaGem/Grammar/HarperEngine.swift) ships a
+[`HarperEngine.swift`](../Sources/GrammarGem/Grammar/HarperEngine.swift) ships a
 small pure-Swift rule stub so the system loop + tests run with zero native deps.
 
 ## Planned shape

harper-ffi/build.sh

@@ -0,0 +1,26 @@
+#!/usr/bin/env bash
+# Build the UNIVERSAL (Apple Silicon + Intel) Harper static library that the
+# Swift app links against:  harper-ffi/lib/libharper_ffi.a
+#
+# Requires the Rust toolchain (rustup) with both macOS targets:
+#   rustup target add aarch64-apple-darwin x86_64-apple-darwin
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")" && pwd)"
+cd "$ROOT"
+
+# Make cargo available even in non-login shells.
+[ -f "$HOME/.cargo/env" ] && source "$HOME/.cargo/env"
+
+echo "==> cargo build --release (aarch64 + x86_64)"
+cargo build --release --target aarch64-apple-darwin
+cargo build --release --target x86_64-apple-darwin
+
+echo "==> lipo -> lib/libharper_ffi.a (universal)"
+mkdir -p lib
+lipo -create -output lib/libharper_ffi.a \
+  target/aarch64-apple-darwin/release/libharper_ffi.a \
+  target/x86_64-apple-darwin/release/libharper_ffi.a
+
+lipo -info lib/libharper_ffi.a
+echo "==> done"

harper-ffi/include/harper.h

@@ -0,0 +1,56 @@
+/*
+ * harper.h — C ABI for the harper-ffi static library (harper-core 2.5.0).
+ *
+ * Link against libharper_ffi.a. All strings are UTF-8.
+ */
+#ifndef HARPER_FFI_H
+#define HARPER_FFI_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Check `text` for grammar/spelling issues using harper-core.
+ *
+ * Returns a malloc'd, NUL-terminated UTF-8 JSON C string that the caller MUST
+ * free with harper_free().
+ *
+ * The JSON is an array of objects:
+ *   [
+ *     {
+ *       "start":       <integer, char (Unicode scalar) offset into the input>,
+ *       "len":         <integer, char count of the offending span>,
+ *       "replacement": "<string>",
+ *       "message":     "<string>",
+ *       "kind":        "<string>"
+ *     },
+ *     ...
+ *   ]
+ *
+ * Notes on the contract:
+ *  - "start"/"len" are CHAR (Unicode scalar) offsets, matching harper's native
+ *    char indexing. They are NOT byte offsets and NOT UTF-16 code-unit offsets.
+ *    "len" = span.end - span.start (end-exclusive).
+ *  - "replacement" is the FIRST ReplaceWith suggestion's text. If the first
+ *    actionable suggestion is a removal, "replacement" is "" (empty string).
+ *  - Lints with NO actionable suggestion are SKIPPED.
+ *  - "kind" is one of: "spelling", "grammar", "punctuation", "repetition",
+ *    "capitalization", "phrasing". Best-effort; defaults to "grammar".
+ *
+ * On a null `text`, invalid UTF-8, or any internal error/panic, returns "[]".
+ * Never returns NULL on a normal return path. Thread-safe.
+ */
+char *harper_check(const char *text);
+
+/*
+ * Free a string previously returned by harper_check().
+ * Passing NULL is a no-op. Do not free the same pointer twice.
+ */
+void harper_free(char *ptr);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif /* HARPER_FFI_H */

harper-ffi/src/lib.rs

@@ -0,0 +1,170 @@
+//! C-ABI FFI bridge exposing harper-core 2.5.0's grammar checker to Swift.
+//!
+//! Public surface:
+//!   char* harper_check(const char* text);  // malloc'd UTF-8 JSON, free with harper_free
+//!   void  harper_free(char* ptr);
+//!
+//! Every API call below was written against docs.rs for harper-core 2.5.0.
+
+use std::ffi::{CStr, CString};
+use std::os::raw::c_char;
+use std::panic::{catch_unwind, AssertUnwindSafe};
+use std::sync::{Arc, OnceLock};
+
+use harper_core::{Dialect, Document};
+use harper_core::linting::{LintGroup, LintKind, Linter, Suggestion};
+use harper_core::spell::FstDictionary;
+
+/// Empty JSON array used for null/invalid input and on any panic.
+const EMPTY_JSON: &str = "[]";
+
+/// The curated FST dictionary is the expensive artifact to build, so build it
+/// exactly once and share it across calls/threads via `Arc`. `FstDictionary`
+/// is immutable and `Arc<FstDictionary>` is `Send + Sync`, so this is safe to
+/// read from any thread.
+///
+/// We intentionally do NOT cache the `LintGroup` itself: `Linter::lint` takes
+/// `&mut self`, which would require a `Mutex` and serialize all callers. The
+/// `LintGroup` is cheap to reconstruct relative to the dictionary, so we build
+/// a fresh one per call from the shared dictionary instead.
+fn curated_dictionary() -> Arc<FstDictionary> {
+    static DICT: OnceLock<Arc<FstDictionary>> = OnceLock::new();
+    DICT.get_or_init(FstDictionary::curated).clone()
+}
+
+/// Map a harper `LintKind` to the lowercase string contract:
+/// one of spelling, grammar, punctuation, repetition, capitalization, phrasing.
+/// Default is "grammar" for anything not specifically categorized.
+fn kind_to_str(kind: LintKind) -> &'static str {
+    match kind {
+        LintKind::Spelling | LintKind::Typo => "spelling",
+        LintKind::Punctuation | LintKind::Formatting => "punctuation",
+        LintKind::Repetition => "repetition",
+        LintKind::Capitalization => "capitalization",
+        // "phrasing"-flavored categories: word choice / style / readability / usage.
+        LintKind::WordChoice
+        | LintKind::Style
+        | LintKind::Readability
+        | LintKind::Usage
+        | LintKind::Redundancy
+        | LintKind::Enhancement
+        | LintKind::Eggcorn
+        | LintKind::Malapropism
+        | LintKind::Nonstandard
+        | LintKind::Regionalism => "phrasing",
+        // Grammar-ish / structural categories.
+        LintKind::Grammar
+        | LintKind::Agreement
+        | LintKind::BoundaryError
+        | LintKind::Miscellaneous => "grammar",
+        // LintKind may gain variants; default safely.
+        _ => "grammar",
+    }
+}
+
+/// Run harper over `text` and produce the JSON contract string.
+fn check_to_json(text: &str) -> String {
+    let dictionary = curated_dictionary();
+
+    // Build the document with the built-in PlainEnglish parser + curated dictionary.
+    let document = Document::new_plain_english(text, &dictionary);
+
+    // Fresh curated lint group from the shared dictionary; American dialect.
+    let mut group = LintGroup::new_curated(dictionary.clone(), Dialect::American);
+
+    // Linter::lint(&mut self, &Document) -> Vec<Lint>
+    let lints = group.lint(&document);
+
+    let mut out: Vec<serde_json::Value> = Vec::with_capacity(lints.len());
+    for lint in lints {
+        // span is Span<char>: start/end are CHAR (Unicode scalar) offsets, end-exclusive.
+        let start = lint.span.start;
+        let len = lint.span.end.saturating_sub(lint.span.start);
+
+        // Pick the first ReplaceWith suggestion as "replacement".
+        // If the first actionable suggestion is a Remove, replacement = "".
+        // InsertAfter is treated as non-replacement here. Lints with no
+        // actionable suggestion are skipped.
+        let mut replacement: Option<String> = None;
+        for suggestion in &lint.suggestions {
+            match suggestion {
+                Suggestion::ReplaceWith(chars) => {
+                    replacement = Some(chars.iter().collect());
+                    break;
+                }
+                Suggestion::Remove => {
+                    replacement = Some(String::new());
+                    break;
+                }
+                Suggestion::InsertAfter(_) => {}
+            }
+        }
+
+        let replacement = match replacement {
+            Some(r) => r,
+            None => continue,
+        };
+
+        out.push(serde_json::json!({
+            "start": start,
+            "len": len,
+            "replacement": replacement,
+            "message": lint.message,
+            "kind": kind_to_str(lint.lint_kind),
+        }));
+    }
+
+    serde_json::to_string(&out).unwrap_or_else(|_| EMPTY_JSON.to_string())
+}
+
+/// Allocate a C string for return to the caller. The caller owns it and must
+/// free it with `harper_free`.
+fn into_c_string(s: String) -> *mut c_char {
+    match CString::new(s) {
+        Ok(cstr) => cstr.into_raw(),
+        Err(_) => CString::new(EMPTY_JSON).unwrap().into_raw(),
+    }
+}
+
+/// Check `text` for grammar/spelling issues.
+///
+/// Returns a malloc'd, NUL-terminated UTF-8 JSON C string the caller MUST free
+/// with `harper_free`. On null/invalid-UTF-8 input or on any internal panic,
+/// returns the JSON `"[]"`. Never returns null on a normal return path.
+///
+/// # Safety
+/// `text` must be a valid NUL-terminated C string pointer or null.
+#[no_mangle]
+pub extern "C" fn harper_check(text: *const c_char) -> *mut c_char {
+    let result = catch_unwind(AssertUnwindSafe(|| {
+        if text.is_null() {
+            return EMPTY_JSON.to_string();
+        }
+        // SAFETY: caller guarantees a valid NUL-terminated C string (non-null checked).
+        let c_str = unsafe { CStr::from_ptr(text) };
+        match c_str.to_str() {
+            Ok(s) => check_to_json(s),
+            Err(_) => EMPTY_JSON.to_string(),
+        }
+    }));
+
+    match result {
+        Ok(json) => into_c_string(json),
+        Err(_) => into_c_string(EMPTY_JSON.to_string()),
+    }
+}
+
+/// Free a string previously returned by `harper_check`.
+///
+/// # Safety
+/// `ptr` must be a pointer returned by `harper_check` (or null), freed once.
+#[no_mangle]
+pub extern "C" fn harper_free(ptr: *mut c_char) {
+    if ptr.is_null() {
+        return;
+    }
+    // SAFETY: ptr came from CString::into_raw in this module; reclaim and drop it.
+    unsafe {
+        drop(CString::from_raw(ptr));
+    }
+}

scripts/build-metallib.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+# Regenerate AppSupport/mlx.metallib — the MLX on-device LLM's compiled Metal
+# kernels.
+#
+# `swift build` (SwiftPM CLI) does NOT compile mlx-swift's .metal sources into a
+# metallib, but Xcode's build system does. So we build the package once via
+# xcodebuild, then vendor the resulting metallib (shipped colocated with the app
+# executable; see scripts/build.sh). Run this when bumping the mlx-swift version.
+#
+# Requires the Metal Toolchain:  xcodebuild -downloadComponent MetalToolchain
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT"
+DD=".xcode-build"
+
+echo "==> xcodebuild (compiles mlx-swift metal kernels — a few minutes)"
+xcodebuild build -scheme GrammarGem -configuration Release \
+  -destination 'platform=macOS,arch=arm64' \
+  -derivedDataPath "$DD" -skipMacroValidation >/dev/null
+
+SRC="$DD/Build/Products/Release/mlx-swift_Cmlx.bundle/Contents/Resources/default.metallib"
+[ -f "$SRC" ] || { echo "ERROR: metallib not produced at $SRC" >&2; exit 1; }
+cp "$SRC" AppSupport/mlx.metallib
+echo "==> vendored AppSupport/mlx.metallib ($(du -h AppSupport/mlx.metallib | cut -f1))"

scripts/build.sh

@@ -1,5 +1,6 @@
 #!/usr/bin/env bash
-# Build a runnable, UNIVERSAL (Apple Silicon + Intel) GrammaGem.app bundle.
+# Build a runnable GrammarGem.app bundle (arm64 / Apple Silicon — the MLX
+# on-device LLM runtime is Metal-only, so Intel is not supported).
 # Usage: ./scripts/build.sh   (run from the mac/ directory)
 set -euo pipefail
 
@@ -7,21 +8,52 @@ ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 cd "$ROOT"
 
 CONFIG="release"
-APP="GrammaGem.app"
+APP="GrammarGem.app"
 DIST="dist"
 
-echo "==> Compiling universal (arm64 + x86_64, ${CONFIG})"
-swift build -c "${CONFIG}" --arch arm64 --arch x86_64
-BIN="$(swift build -c "${CONFIG}" --arch arm64 --arch x86_64 --show-bin-path)"
+echo "==> Building Harper static lib (universal)"
+chmod +x harper-ffi/build.sh
+./harper-ffi/build.sh
+
+echo "==> Compiling (arm64 / Apple Silicon, ${CONFIG})"
+# arm64-only: the MLX on-device LLM runtime is Apple-Silicon / Metal only.
+swift build -c "${CONFIG}" --arch arm64
+BIN="$(swift build -c "${CONFIG}" --arch arm64 --show-bin-path)"
 
 echo "==> Assembling ${APP}"
 rm -rf "${DIST}/${APP}"
 mkdir -p "${DIST}/${APP}/Contents/MacOS" "${DIST}/${APP}/Contents/Resources"
 
-cp "${BIN}/GrammaGem" "${DIST}/${APP}/Contents/MacOS/GrammaGem"
+cp "${BIN}/GrammarGem" "${DIST}/${APP}/Contents/MacOS/GrammarGem"
 cp "AppSupport/Info.plist" "${DIST}/${APP}/Contents/Info.plist"
 cp "AppSupport/AppIcon.icns" "${DIST}/${APP}/Contents/Resources/AppIcon.icns"
 
+# SwiftPM resource bundles (tokenizer data, etc.) go in Contents/Resources so
+# Bundle.module resolves via the main bundle and the signature stays valid.
+shopt -s nullglob
+for b in "${BIN}"/*.bundle; do
+  cp -R "$b" "${DIST}/${APP}/Contents/Resources/"
+done
+shopt -u nullglob
+
+# MLX Metal kernels: `swift build` (CLI) does NOT compile mlx-swift's .metal
+# sources, so we ship a prebuilt metallib in the exact bundle mlx looks for —
+# Contents/Resources/mlx-swift_Cmlx.bundle/Contents/Resources/default.metallib —
+# which mlx finds via the main bundle's resources and which codesigns cleanly.
+# Regenerate AppSupport/mlx.metallib with: ./scripts/build-metallib.sh
+MLX_RES="${DIST}/${APP}/Contents/Resources/mlx-swift_Cmlx.bundle/Contents/Resources"
+mkdir -p "${MLX_RES}"
+cp "AppSupport/mlx.metallib" "${MLX_RES}/default.metallib"
+
+# Embed Sparkle.framework (auto-update) and add an rpath so the executable can
+# resolve it at @executable_path/../Frameworks. (Signed inside-out by sign-app.sh.)
+echo "==> Embedding Sparkle.framework"
+SPARKLE_FW="$(find .build -path '*Sparkle.xcframework/macos-arm64*/Sparkle.framework' -type d | head -1)"
+mkdir -p "${DIST}/${APP}/Contents/Frameworks"
+cp -R "${SPARKLE_FW}" "${DIST}/${APP}/Contents/Frameworks/"
+install_name_tool -add_rpath "@executable_path/../Frameworks" \
+  "${DIST}/${APP}/Contents/MacOS/GrammarGem" 2>/dev/null || true
+
 echo "==> Built ${DIST}/${APP}"
-lipo -info "${DIST}/${APP}/Contents/MacOS/GrammaGem"
+lipo -info "${DIST}/${APP}/Contents/MacOS/GrammarGem"
 echo "    Run with: open \"${DIST}/${APP}\"   (grant Accessibility on first launch)"

scripts/make-icon.swift

@@ -1,5 +1,5 @@
 #!/usr/bin/env swift
-// Generates AppIcon.iconset (PNGs) for GrammaGem — a gold pen-nib on the ink
+// Generates AppIcon.iconset (PNGs) for GrammarGem — a gold pen-nib on the ink
 // brand square. Run from mac/:  swift scripts/make-icon.swift
 // Then:  iconutil -c icns AppIcon.iconset -o AppSupport/AppIcon.icns
 import AppKit

scripts/release.sh

@@ -1,32 +1,71 @@
 #!/usr/bin/env bash
-# Package a signed build for distribution and update the Sparkle appcast hosted
-# on GitHub Releases (zero hosting cost). Run after sign-notarize.sh.
+# Cut a GrammarGem release and publish the Sparkle appcast (hosted on grammargem.com).
 #
-# This is a documented scaffold — wire it to your Sparkle EdDSA key + repo.
+#   ./scripts/release.sh <version>      e.g.  ./scripts/release.sh 0.2.0
+#
+# Steps: stamp version -> build -> sign inside-out (incl. Sparkle) -> notarize +
+# staple -> zip -> generate the EdDSA-signed appcast.xml. Then upload the .zip and
+# appcast.xml to grammargem.com so every installed app shows "Update available".
+#
+# Notarization needs ONE of:
+#   NOTARY_PROFILE                              (xcrun notarytool store-credentials)
+#   APPLE_ID + TEAM_ID + NOTARY_PASSWORD        (Apple ID + app-specific password)
+# Set SKIP_NOTARIZE=1 for a dry run (un-notarized build; do not ship).
 set -euo pipefail
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd)"
-APP="$ROOT/dist/GrammaGem.app"
-VERSION="${1:?Usage: release.sh <version> e.g. 0.1.0}"
-DMG="$ROOT/dist/GrammaGem-$VERSION.dmg"
+cd "$ROOT"
 
-echo "▸ Creating DMG for $VERSION…"
-# hdiutil create -volname "GrammaGem" -srcfolder "$APP" -ov -format UDZO "$DMG"   # TODO: enable
-echo "  (DMG creation stubbed — uncomment hdiutil line)"
+VERSION="${1:?usage: release.sh <version>   e.g. release.sh 0.2.0}"
+APP="dist/GrammarGem.app"
+RELDIR="dist/releases"
+ZIP="${RELDIR}/GrammarGem-${VERSION}.zip"
+DL_PREFIX="${DL_PREFIX:-https://www.grammargem.com/releases/}"
+PB=/usr/libexec/PlistBuddy
 
-cat <<'NOTE'
-▸ Sparkle appcast (TODO):
-  1. Sign the update:  ./bin/sign_update dist/GrammaGem-<ver>.dmg
-     (Sparkle's sign_update tool, using your EdDSA private key)
-  2. Add an <item> to appcast.xml with the version, URL (GitHub Releases asset),
-     length, and sparkle:edSignature.
-  3. Upload the DMG + appcast.xml to a GitHub Release.
-  The app's SUFeedURL points at the raw appcast.xml on GitHub — $0 hosting.
+# 1. Stamp the marketing version + bump the monotonic build number.
+CUR_BUILD="$($PB -c 'Print :CFBundleVersion' AppSupport/Info.plist)"
+NEW_BUILD=$((CUR_BUILD + 1))
+$PB -c "Set :CFBundleShortVersionString ${VERSION}" AppSupport/Info.plist
+$PB -c "Set :CFBundleVersion ${NEW_BUILD}" AppSupport/Info.plist
+echo "==> Releasing ${VERSION} (build ${NEW_BUILD})"
 
-▸ Distribution touchpoints (all $0 marginal cost):
-  - Model weights:  Hugging Face CDN
-  - Updates:        GitHub Releases + Sparkle
-  - Licensing:      Lemon Squeezy License API (% per sale only)
-NOTE
+# 2. Build + sign (inside-out so the embedded Sparkle.framework is valid).
+./scripts/build.sh
+./scripts/sign-app.sh "$APP"
 
-echo "✓ Release steps printed for $VERSION"
+# 3. Zip.
+mkdir -p "$RELDIR"
+rm -f "$ZIP"
+ditto -c -k --keepParent "$APP" "$ZIP"
+
+# 4. Notarize + staple (the ticket lets Sparkle install it without Gatekeeper prompts).
+if [ "${SKIP_NOTARIZE:-0}" != "1" ]; then
+  echo "==> Notarizing"
+  if [ -n "${NOTARY_PROFILE:-}" ]; then
+    xcrun notarytool submit "$ZIP" --keychain-profile "$NOTARY_PROFILE" --wait
+  elif [ -n "${APPLE_ID:-}" ] && [ -n "${TEAM_ID:-}" ] && [ -n "${NOTARY_PASSWORD:-}" ]; then
+    xcrun notarytool submit "$ZIP" \
+      --apple-id "$APPLE_ID" --team-id "$TEAM_ID" --password "$NOTARY_PASSWORD" --wait
+  else
+    echo "ERROR: set NOTARY_PROFILE or APPLE_ID+TEAM_ID+NOTARY_PASSWORD (or SKIP_NOTARIZE=1)." >&2
+    exit 1
+  fi
+  xcrun stapler staple "$APP"
+  rm -f "$ZIP"; ditto -c -k --keepParent "$APP" "$ZIP"  # re-zip the stapled app
+fi
+
+# 5. Generate the EdDSA-signed appcast (keeps every zip in RELDIR in its history).
+GA="$(find .build/artifacts -name generate_appcast -type f | head -1)"
+[ -n "$GA" ] || { echo "ERROR: generate_appcast not found (run 'swift package resolve')." >&2; exit 1; }
+"$GA" --download-url-prefix "$DL_PREFIX" "$RELDIR"
+
+echo
+echo "✓ Release ${VERSION} built. Upload these to grammargem.com:"
+echo "    ${ZIP}"
+echo "        ->  ${DL_PREFIX}GrammarGem-${VERSION}.zip"
+echo "    ${RELDIR}/appcast.xml"
+echo "        ->  https://www.grammargem.com/appcast.xml   (matches Info.plist SUFeedURL)"
+echo
+echo "  Once uploaded, installed apps show an 'Update available' button within a day"
+echo "  (or immediately via menu bar -> Check for Updates...)."

scripts/sign-app.sh

@@ -0,0 +1,35 @@
+#!/usr/bin/env bash
+# Code-sign GrammarGem.app with Developer ID + Hardened Runtime, signing the
+# embedded Sparkle.framework's nested helpers INSIDE-OUT first (required for a
+# valid, notarizable signature).
+#
+# Usage: ./scripts/sign-app.sh [path/to/GrammarGem.app]
+set -euo pipefail
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd)"
+cd "$ROOT"
+
+DEV_ID="${DEV_ID:-Developer ID Application: Marc Schultheiss (D5KT5B9Z9M)}"
+ENTITLEMENTS="AppSupport/GrammarGem.entitlements"
+APP="${1:-dist/GrammarGem.app}"
+
+sign() { codesign --force --timestamp --options runtime --sign "$DEV_ID" "$@"; }
+
+FW="${APP}/Contents/Frameworks/Sparkle.framework"
+if [ -d "$FW" ]; then
+  echo "==> Signing Sparkle.framework (inside-out)"
+  V="${FW}/Versions/B"
+  for xpc in "$V"/XPCServices/*.xpc; do [ -e "$xpc" ] && sign "$xpc"; done
+  [ -e "$V/Updater.app/Contents/MacOS/Autoupdate" ] && sign "$V/Updater.app/Contents/MacOS/Autoupdate" || true
+  [ -e "$V/Updater.app" ] && sign "$V/Updater.app"
+  [ -e "$V/Autoupdate" ] && sign "$V/Autoupdate"
+  sign "$FW"
+fi
+
+echo "==> Signing ${APP}"
+codesign --force --timestamp --options runtime \
+  --entitlements "$ENTITLEMENTS" --sign "$DEV_ID" "$APP"
+
+echo "==> Verifying"
+codesign --verify --strict --verbose=2 "$APP"
+echo "✓ signed: $APP"

scripts/sign-notarize.sh

@@ -1,6 +1,6 @@
 #!/usr/bin/env bash
 # Build (universal), codesign (Hardened Runtime + Developer ID), notarize, and
-# staple GrammaGem.app. Requires the Apple Developer Program ($99/yr) — a FIXED
+# staple GrammarGem.app. Requires the Apple Developer Program ($99/yr) — a FIXED
 # cost, not per-user.
 #
 # Credentials are read from the environment or a stored keychain profile — never
@@ -15,19 +15,15 @@ ROOT="$(cd "$(dirname "$0")/.." && pwd)"
 cd "$ROOT"
 
 DEV_ID="${DEV_ID:-Developer ID Application: Marc Schultheiss (D5KT5B9Z9M)}"
-APP="dist/GrammaGem.app"
-ZIP="dist/GrammaGem.zip"
-ENTITLEMENTS="AppSupport/GrammaGem.entitlements"
+APP="dist/GrammarGem.app"
+ZIP="dist/GrammarGem.zip"
+ENTITLEMENTS="AppSupport/GrammarGem.entitlements"
 
 echo "==> Building universal bundle"
 ./scripts/build.sh >/dev/null
 
-echo "==> Codesigning (Hardened Runtime)"
-codesign --force --timestamp --options runtime \
-  --entitlements "$ENTITLEMENTS" \
-  --sign "$DEV_ID" \
-  "$APP"
-codesign --verify --strict --verbose=2 "$APP"
+echo "==> Codesigning (Hardened Runtime, inside-out incl. Sparkle)"
+DEV_ID="$DEV_ID" ./scripts/sign-app.sh "$APP"
 
 echo "==> Zipping"
 ditto -c -k --keepParent "$APP" "$ZIP"