diff --git a/src/bun.js/api/server.zig b/src/bun.js/api/server.zig
index a5b531022b..1aa556d9d6 100644
--- a/src/bun.js/api/server.zig
+++ b/src/bun.js/api/server.zig
@@ -1403,16 +1403,42 @@ fn NewRequestContext(comptime ssl_enabled: bool, comptime debug_mode: bool, comp
             return JSValue.jsUndefined();
         }
 
+        fn renderMissingInvalidResponse(ctx: *RequestContext, value: JSC.JSValue) void {
+            var class_name = value.getClassInfoName() orelse bun.String.empty;
+            defer class_name.deref();
+            const globalThis: *JSC.JSGlobalObject = ctx.server.globalThis;
+
+            Output.enableBuffering();
+            var writer = Output.errorWriter();
+
+            if (class_name.eqlComptime("Response")) {
+                Output.errGeneric("Expected a native Response object, but received a polyfilled Response object. Bun.serve() only supports native Response objects.", .{});
+            } else if (!value.isEmpty() and !globalThis.hasException()) {
+                var formatter = JSC.ConsoleObject.Formatter{
+                    .globalThis = globalThis,
+                    .quote_strings = true,
+                };
+                Output.errGeneric("Expected a Response object, but received '{}'", .{value.toFmt(formatter.globalThis, &formatter)});
+            } else {
+                Output.errGeneric("Expected a Response object", .{});
+            }
+
+            Output.flush();
+            if (!globalThis.hasException()) {
+                JSC.ConsoleObject.writeTrace(@TypeOf(&writer), &writer, globalThis);
+            }
+            Output.flush();
+            ctx.renderMissing();
+        }
+
         fn handleResolve(ctx: *RequestContext, value: JSC.JSValue) void {
             if (value.isEmptyOrUndefinedOrNull() or !value.isCell()) {
-                ctx.renderMissing();
+                ctx.renderMissingInvalidResponse(value);
                 return;
             }
 
             const response = value.as(JSC.WebCore.Response) orelse {
-                Output.prettyErrorln("Expected a Response object", .{});
-                Output.flush();
-                ctx.renderMissing();
+                ctx.renderMissingInvalidResponse(value);
                 return;
             };
             ctx.response_jsvalue = value;
@@ -2558,7 +2584,7 @@ fn NewRequestContext(comptime ssl_enabled: bool, comptime debug_mode: bool, comp
             }
 
             if (response_value.isEmptyOrUndefinedOrNull()) {
-                ctx.renderMissing();
+                ctx.renderMissingInvalidResponse(response_value);
                 return;
             }
 
@@ -2611,11 +2637,11 @@ fn NewRequestContext(comptime ssl_enabled: bool, comptime debug_mode: bool, comp
                         }
 
                         if (fulfilled_value.isEmptyOrUndefinedOrNull()) {
-                            ctx.renderMissing();
+                            ctx.renderMissingInvalidResponse(fulfilled_value);
                             return;
                         }
                         var response = fulfilled_value.as(JSC.WebCore.Response) orelse {
-                            ctx.renderMissing();
+                            ctx.renderMissingInvalidResponse(fulfilled_value);
                             return;
                         };
 
diff --git a/src/bun.js/bindings/bindings.zig b/src/bun.js/bindings/bindings.zig
index 648789dd92..19a6a28150 100644
--- a/src/bun.js/bindings/bindings.zig
+++ b/src/bun.js/bindings/bindings.zig
@@ -5600,16 +5600,12 @@ pub const JSValue = enum(JSValueReprInt) {
 
     extern fn JSC__JSValue__getClassInfoName(value: JSValue, out: *bun.String) bool;
 
-    /// Returned memory is read-only memory of the s_info assigned to a JSCell
-    pub fn getClassInfoName(this: JSValue) ?[]const u8 {
-        var out: bun.String = undefined;
+    /// For native C++ classes extending JSCell, this retrieves s_info's name
+    pub fn getClassInfoName(this: JSValue) ?bun.String {
+        if (!this.isObject()) return null;
+        var out: bun.String = bun.String.empty;
         if (!JSC__JSValue__getClassInfoName(this, &out)) return null;
-        // we assume the class name is ASCII text
-        const data = out.latin1();
-        if (bun.Environment.allow_assert) {
-            bun.assert(bun.strings.isAllASCII(data));
-        }
-        return data;
+        return out;
     }
 };
 
diff --git a/src/js_ast.zig b/src/js_ast.zig
index 5623b04435..974fd5084b 100644
--- a/src/js_ast.zig
+++ b/src/js_ast.zig
@@ -7422,12 +7422,15 @@ pub const Macro = struct {
                     .String => this.coerce(value, .String),
                     .Promise => this.coerce(value, .Promise),
                     else => brk: {
+                        var name = value.getClassInfoName() orelse bun.String.init("unknown");
+                        defer name.deref();
+
                         this.log.addErrorFmt(
                             this.source,
                             this.caller.loc,
                             this.allocator,
-                            "cannot coerce {s} ({s}) to Bun's AST. Please return a simpler type",
-                            .{ value.getClassInfoName() orelse "unknown", @tagName(value.jsType()) },
+                            "cannot coerce {} ({s}) to Bun's AST. Please return a simpler type",
+                            .{ name, @tagName(value.jsType()) },
                         ) catch unreachable;
                         break :brk error.MacroFailed;
                     },