diff --git a/src/ai_typewriter/key_stepper.py b/src/ai_typewriter/key_stepper.py
new file mode 100644
index 0000000..f305a80
--- /dev/null
+++ b/src/ai_typewriter/key_stepper.py
@@ -0,0 +1,59 @@
+from __future__ import annotations
+
+from dataclasses import dataclass, field
+from threading import Lock
+from typing import Optional
+
+import keyboard
+
+
+@dataclass
+class KeyStepper:
+    text: str
+    delay: float = 0.0
+    _index: int = 0
+    _hook: Optional[object] = None
+    _lock: Lock = field(default_factory=Lock)
+    _injecting: bool = False
+
+    def start(self) -> None:
+        if not self.text:
+            return
+        if self._hook is not None:
+            return
+        # suppress=True blocks the physical key while the callback types the next AI character.
+        self._hook = keyboard.hook(self._on_event, suppress=True)
+
+    def stop(self) -> None:
+        hook = self._hook
+        self._hook = None
+        if hook is not None:
+            keyboard.unhook(hook)
+
+    def _on_event(self, event: keyboard.KeyboardEvent) -> None:
+        if self._injecting or event.event_type != keyboard.KEY_DOWN:
+            return
+
+        with self._lock:
+            if self._index >= len(self.text):
+                self.stop()
+                return
+            char = self.text[self._index]
+            self._index += 1
+
+        self._injecting = True
+        try:
+            self._type_char(char)
+        finally:
+            self._injecting = False
+
+        if self._index >= len(self.text):
+            self.stop()
+
+    def _type_char(self, char: str) -> None:
+        if char == "\n":
+            keyboard.send("enter")
+        elif char == "\t":
+            keyboard.send("tab")
+        else:
+            keyboard.write(char, delay=self.delay, exact=True)