diff --git a/src/dragonglass/tree.py b/src/dragonglass/tree.py
index eaaef6b..5edcf50 100644
--- a/src/dragonglass/tree.py
+++ b/src/dragonglass/tree.py
@@ -27,6 +27,18 @@ class SourceNode:
     def __str__(self) -> str:
         return f"SourceNode({self._path}, {self._is_dir}) [is_md={self._is_md}]"
 
+    @property
+    def is_dir(self) -> bool:
+        return self._is_dir
+
+    @property
+    def is_md(self) -> bool:
+        return self._is_md
+
+    @property
+    def path(self) -> Path:
+        return self._path
+
     def link_target(self, prefix: str = "/") -> str:
         xpath = self._path.with_suffix('.html') if self._is_md else self._path
         return urlquote(prefix + xpath.as_posix())
@@ -74,25 +86,24 @@ class SourceIndex:
         self._byname: dict[str, SourceNode] = {}
         self._byalias: dict[str, SourceNode] = {}
         for node in nodelist:
-            if node._is_dir:
+            if node.is_dir:
                 continue
-            if node._is_md:
-                tmp = node._path.with_suffix('')
+            if node.is_md:
+                tmp = node.path.with_suffix('')
                 key = tmp.name
                 if key not in self._byname:
                     self._byname[key] = node
                 self._byname[tmp.as_posix()] = node
                 if node.metadata:
-                    aliases = node.metadata.get('aliases', [])
-                    if isinstance(aliases, list):
-                        for alias in aliases:
-                            if alias not in self._byalias:
-                                self._byalias[alias] = node
+                    aliases: list[str] = node.metadata.get('aliases', [])
+                    for alias in aliases:
+                        if alias not in self._byalias:
+                            self._byalias[alias] = node
             else:
-                key = node._path.name
+                key = node.path.name
                 if key not in self._byname:
                     self._byname[key] = node
-                self._byname[node._path.as_posix()] = node
+                self._byname[node.path.as_posix()] = node
 
     def lookup(self, reference: str) -> tuple[SourceNode | None, str | None]:
         if reference in self._byname: