diff --git a/src/browser/js/Snapshot.zig b/src/browser/js/Snapshot.zig
index a1cfd9d2e..27338ac1a 100644
--- a/src/browser/js/Snapshot.zig
+++ b/src/browser/js/Snapshot.zig
@@ -314,13 +314,8 @@ fn createSnapshotContext(
                 const name = JsApi.Meta.name;
                 const v8_class_name = v8.v8__String__NewFromUtf8(isolate, name.ptr, v8.kNormal, @intCast(name.len));
                 var maybe_result: v8.MaybeBool = undefined;
-                // Web IDL: interface objects on the global are non-enumerable
-                // by default. Opt back in via JsApi.Meta.enumerable = true.
-                var properties: v8.PropertyAttribute = v8.DontEnum;
-                if (@hasDecl(JsApi.Meta, "enumerable") and JsApi.Meta.enumerable == true) {
-                    properties = v8.None;
-                }
-                v8.v8__Object__DefineOwnProperty(global_obj, context, v8_class_name, func, properties, &maybe_result);
+                // Web IDL: interface objects on the global are non-enumerable.
+                v8.v8__Object__DefineOwnProperty(global_obj, context, v8_class_name, func, v8.DontEnum, &maybe_result);
             }
         }
 
@@ -759,12 +754,13 @@ fn attachClass(comptime JsApi: type, comptime flatten: bool, isolate: *v8.Isolat
                 if (value.static) {
                     v8.v8__Template__SetAccessorProperty(@ptrCast(template), js_name, getter_callback, setter_callback, attribute);
                 } else {
-                    const accessor_attr = if (own_properties) attribute else attribute | v8.DontEnum;
+                    // Web IDL: attributes on the interface prototype object
+                    // (and mirrored onto [Global] instances) are enumerable.
                     v8.v8__ObjectTemplate__SetAccessorProperty__Config(define_on orelse prototype, &.{
                         .key = js_name,
                         .getter = getter_callback,
                         .setter = setter_callback,
-                        .attribute = accessor_attr,
+                        .attribute = attribute,
                     });
                 }
             },
@@ -785,8 +781,9 @@ fn attachClass(comptime JsApi: type, comptime flatten: bool, isolate: *v8.Isolat
                 if (value.static and !own_properties) {
                     v8.v8__Template__Set(@ptrCast(template), js_name, @ptrCast(function_template), v8.None);
                 } else {
-                    const fn_attr: v8.PropertyAttribute = if (own_properties) v8.None else v8.DontEnum;
-                    v8.v8__Template__Set(@ptrCast(define_on orelse member_template), js_name, @ptrCast(function_template), fn_attr);
+                    // Web IDL: operations on the interface prototype object
+                    // (and mirrored onto [Global] instances) are enumerable.
+                    v8.v8__Template__Set(@ptrCast(define_on orelse member_template), js_name, @ptrCast(function_template), v8.None);
                 }
             },
             bridge.Indexed => {
@@ -825,7 +822,8 @@ fn attachClass(comptime JsApi: type, comptime flatten: bool, isolate: *v8.Isolat
                     v8.v8__Symbol__GetAsyncIterator(isolate)
                 else
                     v8.v8__Symbol__GetIterator(isolate);
-                v8.v8__Template__Set(@ptrCast(prototype), js_name, @ptrCast(function_template), v8.None);
+                // Web IDL: @@iterator is { writable, enumerable: false, configurable }.
+                v8.v8__Template__Set(@ptrCast(prototype), js_name, @ptrCast(function_template), v8.DontEnum);
             },
             bridge.Property => {
                 const js_value = switch (value.value) {
diff --git a/src/browser/tests/net/url_search_params.html b/src/browser/tests/net/url_search_params.html
index 08d28ec04..48442d221 100644
--- a/src/browser/tests/net/url_search_params.html
+++ b/src/browser/tests/net/url_search_params.html
@@ -489,23 +489,30 @@
 }
 </script>
 
-<script id=prototypeMembersAreNonEnumerable>
+<script id=prototypeMembersAreEnumerable>
 {
-  // Per WebIDL, interface prototype members are non-enumerable. Several
-  // libraries iterate caller-supplied objects with `for..in` or
-  // `Object.keys` to build querystrings; if prototype methods leak in,
-  // they end up serialized as URL params with values like
-  // "function has() { [native code] }". Real Chrome/Firefox return [].
-  testing.expectEqual([], Object.keys(URLSearchParams.prototype));
+  // Per WebIDL, operations and attributes on an interface prototype object
+  // are enumerable (unlike ES class methods). Real Chrome/Firefox list them
+  // in Object.keys(URLSearchParams.prototype) and in for..in over instances.
+  const proto_keys = Object.keys(URLSearchParams.prototype);
+  testing.expectEqual(true, proto_keys.includes('append'));
+  testing.expectEqual(true, proto_keys.includes('has'));
+  testing.expectEqual(true, proto_keys.includes('size'));
 
   const usp = new URLSearchParams('a=1&b=2');
   const keys = [];
   for (const k in usp) keys.push(k);
-  testing.expectEqual([], keys);
+  testing.expectEqual(true, keys.includes('get'));
 
-  // Sanity: instance own enumerable keys are still empty (entries live in
-  // the C++ side, exposed only via the iterator protocol).
+  // Instance own enumerable keys are still empty (entries live in the
+  // native side, exposed only via the iterator protocol).
   testing.expectEqual([], Object.keys(usp));
+
+  // But @@iterator and the interface object itself are non-enumerable.
+  const it_desc = Object.getOwnPropertyDescriptor(URLSearchParams.prototype, Symbol.iterator);
+  testing.expectEqual(false, it_desc.enumerable);
+  const iface_desc = Object.getOwnPropertyDescriptor(window, 'URLSearchParams');
+  testing.expectEqual(false, iface_desc.enumerable);
 }
 </script>
 
diff --git a/src/browser/webapi/AbortController.zig b/src/browser/webapi/AbortController.zig
index 6e0b62251..3d6a30040 100644
--- a/src/browser/webapi/AbortController.zig
+++ b/src/browser/webapi/AbortController.zig
@@ -49,7 +49,6 @@ pub const JsApi = struct {
 
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const constructor = bridge.constructor(AbortController.init, .{});
diff --git a/src/browser/webapi/AbortSignal.zig b/src/browser/webapi/AbortSignal.zig
index 88bc4ee46..ab92efe0d 100644
--- a/src/browser/webapi/AbortSignal.zig
+++ b/src/browser/webapi/AbortSignal.zig
@@ -233,7 +233,6 @@ pub const JsApi = struct {
 
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const Prototype = EventTarget;
diff --git a/src/browser/webapi/CData.zig b/src/browser/webapi/CData.zig
index eaa44120c..129b52d60 100644
--- a/src/browser/webapi/CData.zig
+++ b/src/browser/webapi/CData.zig
@@ -420,7 +420,6 @@ pub const JsApi = struct {
         pub const name = "CharacterData";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const data = bridge.accessor(CData.getData, CData._setData, .{ .ce_reactions = true });
diff --git a/src/browser/webapi/DOMImplementation.zig b/src/browser/webapi/DOMImplementation.zig
index 23eac9c98..a6e7a7a30 100644
--- a/src/browser/webapi/DOMImplementation.zig
+++ b/src/browser/webapi/DOMImplementation.zig
@@ -99,7 +99,6 @@ pub const JsApi = struct {
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
         pub const empty_with_no_proto = true;
-        pub const enumerable = false;
     };
 
     pub const createDocumentType = bridge.function(DOMImplementation.createDocumentType, .{ .dom_exception = true });
diff --git a/src/browser/webapi/DOMNodeIterator.zig b/src/browser/webapi/DOMNodeIterator.zig
index da46691f2..4ef60f678 100644
--- a/src/browser/webapi/DOMNodeIterator.zig
+++ b/src/browser/webapi/DOMNodeIterator.zig
@@ -191,7 +191,6 @@ pub const JsApi = struct {
         pub const name = "NodeIterator";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const root = bridge.accessor(DOMNodeIterator.getRoot, null, .{});
diff --git a/src/browser/webapi/DOMTreeWalker.zig b/src/browser/webapi/DOMTreeWalker.zig
index 7fd4b8502..29779fa68 100644
--- a/src/browser/webapi/DOMTreeWalker.zig
+++ b/src/browser/webapi/DOMTreeWalker.zig
@@ -343,7 +343,6 @@ pub const JsApi = struct {
         pub const name = "TreeWalker";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const root = bridge.accessor(DOMTreeWalker.getRoot, null, .{});
diff --git a/src/browser/webapi/Document.zig b/src/browser/webapi/Document.zig
index 9f02ce08e..c70e134a1 100644
--- a/src/browser/webapi/Document.zig
+++ b/src/browser/webapi/Document.zig
@@ -1254,7 +1254,6 @@ pub const JsApi = struct {
         pub const name = "Document";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const constructor = bridge.constructor(_constructor, .{});
diff --git a/src/browser/webapi/DocumentFragment.zig b/src/browser/webapi/DocumentFragment.zig
index da09e9bbc..75af0de1f 100644
--- a/src/browser/webapi/DocumentFragment.zig
+++ b/src/browser/webapi/DocumentFragment.zig
@@ -192,7 +192,6 @@ pub const JsApi = struct {
         pub const name = "DocumentFragment";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const constructor = bridge.constructor(DocumentFragment.init, .{});
diff --git a/src/browser/webapi/DocumentType.zig b/src/browser/webapi/DocumentType.zig
index 1a7bb30a5..670ca01d0 100644
--- a/src/browser/webapi/DocumentType.zig
+++ b/src/browser/webapi/DocumentType.zig
@@ -87,7 +87,6 @@ pub const JsApi = struct {
         pub const name = "DocumentType";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const name = bridge.accessor(DocumentType.getName, null, .{});
diff --git a/src/browser/webapi/Element.zig b/src/browser/webapi/Element.zig
index f4c16641d..ee50ca610 100644
--- a/src/browser/webapi/Element.zig
+++ b/src/browser/webapi/Element.zig
@@ -1913,7 +1913,6 @@ pub const JsApi = struct {
         pub const name = "Element";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const tagName = bridge.accessor(_tagName, null, .{});
diff --git a/src/browser/webapi/Event.zig b/src/browser/webapi/Event.zig
index 8ac412b3d..d47a54b48 100644
--- a/src/browser/webapi/Event.zig
+++ b/src/browser/webapi/Event.zig
@@ -465,7 +465,6 @@ pub const JsApi = struct {
 
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const constructor = bridge.constructor(Event.init, .{});
diff --git a/src/browser/webapi/EventTarget.zig b/src/browser/webapi/EventTarget.zig
index cf5238646..e3aca0cf1 100644
--- a/src/browser/webapi/EventTarget.zig
+++ b/src/browser/webapi/EventTarget.zig
@@ -201,7 +201,6 @@ pub const JsApi = struct {
 
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const constructor = bridge.constructor(EventTarget.init, .{});
diff --git a/src/browser/webapi/Node.zig b/src/browser/webapi/Node.zig
index e56209dd6..076d633e0 100644
--- a/src/browser/webapi/Node.zig
+++ b/src/browser/webapi/Node.zig
@@ -1276,7 +1276,6 @@ pub const JsApi = struct {
         pub const name = "Node";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const ELEMENT_NODE = bridge.property(1, .{ .template = true });
diff --git a/src/browser/webapi/NodeFilter.zig b/src/browser/webapi/NodeFilter.zig
index bd485ec87..a2519e718 100644
--- a/src/browser/webapi/NodeFilter.zig
+++ b/src/browser/webapi/NodeFilter.zig
@@ -87,7 +87,6 @@ pub const JsApi = struct {
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
         pub const empty_with_no_proto = true;
-        pub const enumerable = false;
     };
 
     pub const FILTER_ACCEPT = bridge.property(NodeFilter.FILTER_ACCEPT, .{ .template = true });
diff --git a/src/browser/webapi/cdata/Comment.zig b/src/browser/webapi/cdata/Comment.zig
index 3c9f7db3b..a77a1c57f 100644
--- a/src/browser/webapi/cdata/Comment.zig
+++ b/src/browser/webapi/cdata/Comment.zig
@@ -37,7 +37,6 @@ pub const JsApi = struct {
         pub const name = "Comment";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const constructor = bridge.constructor(Comment.init, .{});
diff --git a/src/browser/webapi/cdata/ProcessingInstruction.zig b/src/browser/webapi/cdata/ProcessingInstruction.zig
index 84cc711b9..97024d4ed 100644
--- a/src/browser/webapi/cdata/ProcessingInstruction.zig
+++ b/src/browser/webapi/cdata/ProcessingInstruction.zig
@@ -36,7 +36,6 @@ pub const JsApi = struct {
         pub const name = "ProcessingInstruction";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const target = bridge.accessor(ProcessingInstruction.getTarget, null, .{});
diff --git a/src/browser/webapi/cdata/Text.zig b/src/browser/webapi/cdata/Text.zig
index e358813b7..2c3a3e7d8 100644
--- a/src/browser/webapi/cdata/Text.zig
+++ b/src/browser/webapi/cdata/Text.zig
@@ -78,7 +78,6 @@ pub const JsApi = struct {
         pub const name = "Text";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const constructor = bridge.constructor(Text.init, .{});
diff --git a/src/browser/webapi/collections/DOMTokenList.zig b/src/browser/webapi/collections/DOMTokenList.zig
index 88acb1667..7cf7f85ba 100644
--- a/src/browser/webapi/collections/DOMTokenList.zig
+++ b/src/browser/webapi/collections/DOMTokenList.zig
@@ -298,7 +298,6 @@ pub const JsApi = struct {
         pub const name = "DOMTokenList";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const length = bridge.accessor(DOMTokenList.length, null, .{});
diff --git a/src/browser/webapi/collections/HTMLCollection.zig b/src/browser/webapi/collections/HTMLCollection.zig
index fc534bed1..509580289 100644
--- a/src/browser/webapi/collections/HTMLCollection.zig
+++ b/src/browser/webapi/collections/HTMLCollection.zig
@@ -143,7 +143,6 @@ pub const JsApi = struct {
         pub const name = "HTMLCollection";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const length = bridge.accessor(HTMLCollection.length, null, .{});
diff --git a/src/browser/webapi/collections/NodeList.zig b/src/browser/webapi/collections/NodeList.zig
index 17610d286..6a768a555 100644
--- a/src/browser/webapi/collections/NodeList.zig
+++ b/src/browser/webapi/collections/NodeList.zig
@@ -142,7 +142,6 @@ pub const JsApi = struct {
         pub const name = "NodeList";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const length = bridge.accessor(NodeList.length, null, .{});
diff --git a/src/browser/webapi/element/Attribute.zig b/src/browser/webapi/element/Attribute.zig
index d8623ba53..a1fc9683e 100644
--- a/src/browser/webapi/element/Attribute.zig
+++ b/src/browser/webapi/element/Attribute.zig
@@ -99,7 +99,6 @@ pub const JsApi = struct {
         pub const name = "Attr";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const name = bridge.accessor(Attribute.getName, null, .{});
diff --git a/src/browser/webapi/event/CustomEvent.zig b/src/browser/webapi/event/CustomEvent.zig
index 02c9b8a03..338451811 100644
--- a/src/browser/webapi/event/CustomEvent.zig
+++ b/src/browser/webapi/event/CustomEvent.zig
@@ -105,7 +105,6 @@ pub const JsApi = struct {
         pub const name = "CustomEvent";
         pub const prototype_chain = bridge.prototypeChain();
         pub var class_id: bridge.ClassId = undefined;
-        pub const enumerable = false;
     };
 
     pub const constructor = bridge.constructor(CustomEvent.init, .{});