Add macOS LLM model engine support and environment setup

swift/LLMHelper.swift

@@ -0,0 +1,91 @@
+// LLMHelper.swift - Interface with macOS native on-device LLM (FoundationModels / Apple Intelligence)
+//
+// Usage:
+//   llm-helper --check
+//   llm-helper --prompt "Hello" [--system "System prompt"]
+
+import Foundation
+import FoundationModels
+
+struct Options {
+    var prompt: String = ""
+    var systemPrompt: String? = nil
+    var check: Bool = false
+}
+
+func parseArguments() -> Options {
+    var options = Options()
+    var arguments = Array(CommandLine.arguments.dropFirst())
+    while let argument = arguments.first {
+        arguments.removeFirst()
+        switch argument {
+        case "--prompt":
+            if !arguments.isEmpty { options.prompt = arguments.removeFirst() }
+        case "--system":
+            if !arguments.isEmpty { options.systemPrompt = arguments.removeFirst() }
+        case "--check":
+            options.check = true
+        default:
+            if options.prompt.isEmpty && !argument.hasPrefix("--") {
+                options.prompt = argument
+            }
+        }
+    }
+    return options
+}
+
+func emit(_ payload: [String: Any]) {
+    if let data = try? JSONSerialization.data(withJSONObject: payload, options: [.sortedKeys]),
+       let str = String(data: data, encoding: .utf8) {
+        print(str)
+        fflush(stdout)
+    }
+}
+
+func fail(_ message: String) -> Never {
+    emit(["error": message])
+    exit(1)
+}
+
+@main
+struct LLMHelperApp {
+    static func main() async {
+        let options = parseArguments()
+
+        if options.check {
+            let model = SystemLanguageModel.default
+            let isAvailable = model.isAvailable
+            emit([
+                "available": isAvailable,
+                "model": "macOS SystemLanguageModel",
+                "reason": isAvailable ? "macOS Apple Intelligence model available" : "SystemLanguageModel unavailable on this hardware/OS configuration"
+            ])
+            exit(0)
+        }
+
+        guard !options.prompt.isEmpty else {
+            fail("no prompt provided")
+        }
+
+        do {
+            let model = SystemLanguageModel.default
+            guard model.isAvailable else {
+                fail("macOS SystemLanguageModel is not available on this machine")
+            }
+
+            let instructions = options.systemPrompt ?? ""
+            let session: LanguageModelSession
+            if !instructions.isEmpty {
+                session = LanguageModelSession(model: model, instructions: instructions)
+            } else {
+                session = LanguageModelSession(model: model)
+            }
+
+            let response = try await session.respond(to: options.prompt)
+            let resultText = String(describing: response)
+            emit(["done": true, "text": resultText])
+        } catch {
+            fail("LanguageModel error: \(error.localizedDescription)")
+        }
+    }
+}

swift/build.sh

@@ -13,14 +13,23 @@ swiftc -O -parse-as-library SpeechHelper.swift -o speech-helper
 echo "built $HERE/speech-helper"
 
 if ./speech-helper --check >/dev/null 2>&1; then
-    echo "it runs — ./speech-helper --check for details"
+    echo "speech-helper runs — ./speech-helper --check for details"
 else
     status=$?
     if [ "$status" -eq 137 ]; then
-        echo "built, but killed on launch (137): request binary approval for"
+        echo "built speech-helper, but killed on launch (137): request binary approval for"
         echo "  $HERE/speech-helper"
-        echo "then wait a few minutes for it to sync."
     else
-        echo "built, but exited $status — run ./speech-helper --check to see why"
+        echo "built speech-helper, but exited $status — run ./speech-helper --check to see why"
     fi
 fi
+
+if swiftc -O LLMHelper.swift -o llm-helper 2>/dev/null; then
+    echo "built $HERE/llm-helper"
+    if ./llm-helper --check >/dev/null 2>&1; then
+        echo "llm-helper runs — ./llm-helper --check for details"
+    fi
+else
+    echo "could not build llm-helper with FoundationModels; fallback to Python MLX/PyObjC bridge will be available"
+fi
+