diff --git a/hosts/ocaml/bin/mcp_tree.ml b/hosts/ocaml/bin/mcp_tree.ml
index bb8be8f4..cf6bbcff 100644
--- a/hosts/ocaml/bin/mcp_tree.ml
+++ b/hosts/ocaml/bin/mcp_tree.ml
@@ -719,14 +719,15 @@ let rec handle_tool name args =
     let project_dir = try Sys.getenv "SX_PROJECT_DIR" with Not_found ->
       try Sys.getenv "SX_ROOT" with Not_found -> Sys.getcwd () in
     let sx_dir = project_dir ^ "/sx/sx" in
-    (* Extract all nav items from nav-data.sx by parsing and walking the AST *)
+    (* Extract all nav items from nav-data.sx AND nav-tree.sx *)
     let scan_nav () =
-      let src = try In_channel.with_open_text (sx_dir ^ "/nav-data.sx") In_channel.input_all with _ -> "" in
       let items = ref [] in
+      let seen = Hashtbl.create 64 in
       let rec walk = function
         | Dict d ->
           (match Hashtbl.find_opt d "href", Hashtbl.find_opt d "label" with
-           | Some (String href), Some (String label) ->
+           | Some (String href), Some (String label) when not (Hashtbl.mem seen href) ->
+             Hashtbl.replace seen href ();
              let summary = match Hashtbl.find_opt d "summary" with Some (String s) -> s | _ -> "" in
              items := (href, label, summary) :: !items
            | _ -> ());
@@ -734,7 +735,16 @@ let rec handle_tool name args =
         | List l | ListRef { contents = l } -> List.iter walk l
         | _ -> ()
       in
-      List.iter walk (try Sx_parser.parse_all src with _ -> []);
+      (* Scan both files — nav-data has the groups, nav-tree has the sidebar structure *)
+      List.iter (fun file ->
+        let src = try In_channel.with_open_text (sx_dir ^ "/" ^ file) In_channel.input_all with _ -> "" in
+        (* Evaluate defines so (dict :key val) calls produce Dict values *)
+        let exprs = try Sx_parser.parse_all src with _ -> [] in
+        List.iter (fun expr ->
+          try walk (Sx_ref.eval_expr expr (Env !env))
+          with _ -> walk expr  (* fallback: walk unevaluated AST *)
+        ) exprs
+      ) ["nav-data.sx"; "nav-tree.sx"];
       List.rev !items
     in
     let href_section href =