diff --git a/browse/js/tree.js b/browse/js/tree.js
index da8a372..ed6e804 100644
--- a/browse/js/tree.js
+++ b/browse/js/tree.js
@@ -43,7 +43,13 @@
             // True when this entry was synthesized client-side (e.g.
             // canonical project folders that don't exist on disk yet).
             // Rendered with a muted style + an "(empty)" hint.
-            virtual: !!raw.virtual
+            virtual: !!raw.virtual,
+            // Server-computed write authority. Editors (preview-yaml,
+            // preview-markdown) consult this via canSave() to decide
+            // whether to mount read-only. Dropping the field here
+            // silently makes every node read-only — the actual root
+            // cause behind "I'm admin but the editor says read-only".
+            writable: !!raw.writable
         };
         state.nodes.set(id, node);
         return node;