diff --git a/packages/typegpu-gl/src/glslGenerator.ts b/packages/typegpu-gl/src/glslGenerator.ts
index deb15ac312..cfc5811b9b 100644
--- a/packages/typegpu-gl/src/glslGenerator.ts
+++ b/packages/typegpu-gl/src/glslGenerator.ts
@@ -10,6 +10,7 @@ import {
   withValue,
 } from 'typegpu/~internal';
 import type {
+  AutoStruct,
   ResolutionCtx,
   FunctionDefinitionOptions,
   ConstantDefinitionOptions,
@@ -1010,13 +1011,7 @@ export class GlslGenerator extends WgslGenerator {
     // Is this an auto-detected output struct? If so, register each prop so the
     // output struct's propTypes reflects what the body actually returns.
     const isAutoStruct = expectedReturnType?.type === 'auto-struct';
-    const autoStruct = isAutoStruct
-      ? (expectedReturnType as unknown as {
-          completeStruct: d.WgslStruct;
-          accessProp(key: string): { prop: string; type: d.BaseData } | undefined;
-          provideProp(key: string, type: d.BaseData): { prop: string; type: d.BaseData };
-        })
-      : undefined;
+    const autoStruct = isAutoStruct ? (expectedReturnType as unknown as AutoStruct) : undefined;
 
     // Resolve each RHS first so module-level references get reserved (and types become
     // available) before we allocate our LHS output identifiers.
diff --git a/packages/typegpu/src/data/autoStruct.ts b/packages/typegpu/src/data/autoStruct.ts
index 4fc745cccb..d08186bad5 100644
--- a/packages/typegpu/src/data/autoStruct.ts
+++ b/packages/typegpu/src/data/autoStruct.ts
@@ -35,6 +35,11 @@ export class AutoStruct implements BaseData, SelfResolvable {
   #cachedStruct: WgslStruct | undefined;
   #typeForExtraProps: BaseData | undefined;
 
+  static {
+    AutoStruct.prototype[$internal] = {};
+    AutoStruct.prototype.type = 'auto-struct';
+  }
+
   constructor(
     validProps: Record<string, BaseData>,
     typeForExtraProps: BaseData | undefined,
@@ -116,6 +121,3 @@ export class AutoStruct implements BaseData, SelfResolvable {
     return `auto-struct:${getName(this) ?? '<unnamed>'}`;
   }
 }
-
-AutoStruct.prototype[$internal] = {};
-AutoStruct.prototype.type = 'auto-struct';
diff --git a/packages/typegpu/src/internal.ts b/packages/typegpu/src/internal.ts
index e817e56692..472380f7bb 100644
--- a/packages/typegpu/src/internal.ts
+++ b/packages/typegpu/src/internal.ts
@@ -26,6 +26,7 @@ export {
 // types
 export type { ResolutionCtx, FunctionArgument } from './types.ts';
 export type { Snippet, ResolvedSnippet, Origin } from './data/snippet.ts';
+export type { AutoStruct } from './data/autoStruct.ts';
 
 export type {
   ShaderGenerator,