diff --git a/src/ai_typewriter/app.py b/src/ai_typewriter/app.py
new file mode 100644
index 0000000..d40c741
--- /dev/null
+++ b/src/ai_typewriter/app.py
@@ -0,0 +1,87 @@
+from __future__ import annotations
+
+import argparse
+import logging
+import sys
+from threading import Lock
+
+import keyboard
+
+from .ai_client import AIClientError, ask_ai
+from .clipboard_capture import capture_selection
+from .config import AppConfig, load_config
+from .key_stepper import KeyStepper
+
+LOG = logging.getLogger("ai_typewriter")
+
+
+class AITypewriterApp:
+    def __init__(self, config: AppConfig) -> None:
+        self.config = config
+        self._busy = Lock()
+        self._stepper: KeyStepper | None = None
+
+    def run(self) -> None:
+        keyboard.add_hotkey(self.config.hotkey, self._handle_hotkey, suppress=False)
+        LOG.info("Prêt. Raccourci: %s. Quitter: Ctrl+C dans ce terminal.", self.config.hotkey)
+        keyboard.wait()
+
+    def _handle_hotkey(self) -> None:
+        if not self._busy.acquire(blocking=False):
+            LOG.warning("Requête déjà en cours, raccourci ignoré.")
+            return
+        try:
+            self._capture_ask_and_step()
+        finally:
+            self._busy.release()
+
+    def _capture_ask_and_step(self) -> None:
+        try:
+            selected = capture_selection(self.config.copy_wait_seconds, self.config.restore_clipboard)
+            LOG.info("Texte capturé: %d caractères.", len(selected))
+            answer = ask_ai(selected, self.config)
+            LOG.info("Réponse reçue: %d caractères. Mode dactylographie actif.", len(answer))
+            if self._stepper is not None:
+                self._stepper.stop()
+            self._stepper = KeyStepper(answer, delay=self.config.type_delay_seconds)
+            self._stepper.start()
+        except (AIClientError, FileNotFoundError, ValueError) as exc:
+            LOG.error("%s", exc)
+        except Exception:
+            LOG.exception("Erreur inattendue")
+
+
+def build_parser() -> argparse.ArgumentParser:
+    parser = argparse.ArgumentParser(description="AI Typewriter")
+    parser.add_argument("--config", default="config.json", help="Chemin du fichier config.json")
+    parser.add_argument("--debug", action="store_true", help="Logs détaillés")
+    parser.add_argument("--ask", help="Mode test: envoie ce texte à l'IA et imprime la réponse, sans hook clavier")
+    return parser
+
+
+def main(argv: list[str] | None = None) -> int:
+    args = build_parser().parse_args(argv)
+    logging.basicConfig(
+        level=logging.DEBUG if args.debug else logging.INFO,
+        format="%(asctime)s %(levelname)s %(message)s",
+    )
+    try:
+        config = load_config(args.config)
+    except Exception as exc:
+        LOG.error("%s", exc)
+        return 2
+
+    if args.ask is not None:
+        try:
+            print(ask_ai(args.ask, config))
+            return 0
+        except AIClientError as exc:
+            LOG.error("%s", exc)
+            return 1
+
+    AITypewriterApp(config).run()
+    return 0
+
+
+if __name__ == "__main__":
+    raise SystemExit(main(sys.argv[1:]))