lib/jsonschema/default.nix

@@ -56,7 +56,13 @@ rec {
         inherit (option) description;
       };
     in
-    if option._type != "option"
+
+    # handle nested options (not a submodule)
+    if ! option ? _type
+    then parseOptions option
+
+    # throw if not an option
+    else if option._type != "option"
     then throw "parseOption: not an option"
 
     # parse nullOr

lib/jsonschema/test_parseOptions.nix

@@ -17,4 +17,30 @@ in
     expr = slib.parseOptions evaledOptions;
     expected = builtins.fromJSON (builtins.readFile ./example-schema.json);
   };
+
+  testParseNestedOptions =
+    let
+      evaled = lib.evalModules {
+        modules = [{
+          options.foo.bar = lib.mkOption {
+            type = lib.types.bool;
+          };
+        }];
+      };
+    in
+    {
+      expr = slib.parseOptions evaled.options;
+      expected = {
+        properties = {
+          foo = {
+            properties = {
+              bar = { type = "boolean"; };
+            };
+            required = [ "bar" ];
+            type = "object";
+          };
+        };
+        type = "object";
+      };
+    };
 }