diff --git a/src/aipass/drone/apps/drone.py b/src/aipass/drone/apps/drone.py
index 896d7e21..adb851c7 100644
--- a/src/aipass/drone/apps/drone.py
+++ b/src/aipass/drone/apps/drone.py
@@ -358,14 +358,18 @@ def _handle_custom_command(args: list[str]) -> int:
 
 
 def _read_inbox_message_id(inbox: Path, n: int) -> str | None:
-    """Return the ID of the Nth message (1-based) from inbox.json, or None."""
+    """Return the ID of the Nth message (1-based, display order) from inbox.json.
+
+    The inbox display reverses the array (oldest first), so display position 1
+    is the last element in the JSON array, not the first.
+    """
     import json as _json
 
     try:
         data = _json.loads(inbox.read_text(encoding="utf-8"))
         messages = data.get("messages", [])
         if 1 <= n <= len(messages):
-            return messages[n - 1]["id"]
+            return messages[len(messages) - n]["id"]
     except Exception as exc:
         logger.warning("Failed to resolve mail index %d: %s", n, exc)
     return None
diff --git a/src/aipass/drone/tests/test_cli_routing.py b/src/aipass/drone/tests/test_cli_routing.py
index 9ce948ff..35de1945 100644
--- a/src/aipass/drone/tests/test_cli_routing.py
+++ b/src/aipass/drone/tests/test_cli_routing.py
@@ -751,16 +751,16 @@ class TestReadInboxMessageId:
     """_read_inbox_message_id() edge cases."""
 
     def test_valid_index(self, tmp_path: Path) -> None:
-        """Returns message ID for valid index."""
+        """Returns message ID for valid display-order index (reversed from array)."""
         inbox = tmp_path / "inbox.json"
         inbox.write_text(
-            json.dumps({"messages": [{"id": "abc123"}, {"id": "def456"}]}),
+            json.dumps({"messages": [{"id": "newest"}, {"id": "oldest"}]}),
             encoding="utf-8",
         )
         from aipass.drone.apps.drone import _read_inbox_message_id
 
-        assert _read_inbox_message_id(inbox, 1) == "abc123"
-        assert _read_inbox_message_id(inbox, 2) == "def456"
+        assert _read_inbox_message_id(inbox, 1) == "oldest"
+        assert _read_inbox_message_id(inbox, 2) == "newest"
 
     def test_out_of_range(self, tmp_path: Path) -> None:
         """Returns None for out-of-range index."""