diff --git a/src/masking/__benches__/types.bench.ts b/src/masking/__benches__/types.bench.ts
index 819ba17194..48428c7c83 100644
--- a/src/masking/__benches__/types.bench.ts
+++ b/src/masking/__benches__/types.bench.ts
@@ -2,6 +2,7 @@ import type { MaybeMasked, Unmasked } from "../index.js";
 import { attest, bench } from "@ark/attest";
 import { expectTypeOf } from "expect-type";
 import type { DeepPartial } from "../../utilities/index.js";
+import type { ContainsFragmentsRefs } from "../internal/types.js";
 
 import { setup } from "@ark/attest";
 
@@ -499,3 +500,81 @@ test("leaves tuples alone", (prefix) => {
     }>();
   });
 });
+
+test("does not detect `$fragmentRefs` if type is a record type", (prefix) => {
+  interface MetadataItem {
+    foo: string;
+  }
+
+  interface Source {
+    metadata: Record<string, MetadataItem>;
+    " $fragmentName": "Source";
+  }
+
+  bench(prefix + "instantiations", () => {
+    return {} as MaybeMasked<Source>;
+  }).types([6, "instantiations"]);
+
+  bench(prefix + "functionality", () => {
+    const x = {} as MaybeMasked<Source>;
+
+    expectTypeOf(x).branded.toEqualTypeOf<Source>();
+  });
+});
+
+test("does not detect `$fragmentRefs` on types with index signatures", (prefix) => {
+  interface Source {
+    foo: string;
+    " $fragmentName": "Source";
+    [key: string]: string;
+  }
+
+  bench(prefix + "instantiations", () => {
+    return {} as MaybeMasked<Source>;
+  }).types([6, "instantiations"]);
+
+  bench(prefix + "functionality", () => {
+    const x = {} as MaybeMasked<Source>;
+
+    expectTypeOf(x).branded.toEqualTypeOf<Source>();
+  });
+});
+
+test("detects `$fragmentRefs` on types with index signatures", (prefix) => {
+  type Source = {
+    __typename: "Foo";
+    id: number;
+    metadata: Record<string, number>;
+    structuredMetadata: StructuredMetadata;
+  } & { " $fragmentName"?: "UserFieldsFragment" } & {
+    " $fragmentRefs"?: {
+      FooFragment: FooFragment;
+    };
+  };
+
+  interface StructuredMetadata {
+    bar: number;
+    [index: string]: number;
+  }
+
+  type FooFragment = {
+    __typename: "Foo";
+    foo: string;
+  } & { " $fragmentName"?: "FooFragment" };
+
+  bench(prefix + "instantiations", () => {
+    return {} as MaybeMasked<Source>;
+  }).types([6, "instantiations"]);
+
+  bench(prefix + "functionality", () => {
+    const x = {} as MaybeMasked<Source>;
+
+    expectTypeOf(x).branded.toEqualTypeOf<{
+      __typename: "Foo";
+      id: number;
+      metadata: Record<string, number>;
+      foo: string;
+      structuredMetadata: StructuredMetadata;
+    }>();
+  });
+});
diff --git a/src/masking/internal/types.ts b/src/masking/internal/types.ts
index 2eba4a1af6..4c769de426 100644
--- a/src/masking/internal/types.ts
+++ b/src/masking/internal/types.ts
@@ -1,4 +1,4 @@
-import type { Prettify } from "../../utilities/index.js";
+import type { Prettify, RemoveIndexSignature } from "../../utilities/index.js";
 
 export type IsAny<T> = 0 extends 1 & T ? true : false;
 
@@ -185,7 +185,7 @@ export type RemoveFragmentName<T> =
 export type ContainsFragmentsRefs<TData> =
   true extends IsAny<TData> ? false
   : TData extends object ?
-    " $fragmentRefs" extends keyof TData ?
+    " $fragmentRefs" extends keyof RemoveIndexSignature<TData> ?
       true
     : ContainsFragmentsRefs<TData[keyof TData]>
   : false;
diff --git a/src/utilities/index.ts b/src/utilities/index.ts
index 300cafb0d5..f4e7705deb 100644
--- a/src/utilities/index.ts
+++ b/src/utilities/index.ts
@@ -139,6 +139,7 @@ export type { OnlyRequiredProperties } from "./types/OnlyRequiredProperties.js";
 export type { Prettify } from "./types/Prettify.js";
 export type { UnionToIntersection } from "./types/UnionToIntersection.js";
 export type { NoInfer } from "./types/NoInfer.js";
+export type { RemoveIndexSignature } from "./types/RemoveIndexSignature.js";
 
 export {
   AutoCleanedStrongCache,