diff --git a/code/core/src/csf/story.ts b/code/core/src/csf/story.ts
index 0a128a1670a2..e29e3025883c 100644
--- a/code/core/src/csf/story.ts
+++ b/code/core/src/csf/story.ts
@@ -1,5 +1,6 @@
 import type { RemoveIndexSignature, Simplify, UnionToIntersection } from 'type-fest';
 
+import type { ToolbarArgType } from '../toolbar';
 import type { SBScalarType, SBType } from './SBType';
 import type { CoreTypes } from './core-annotations';
 
@@ -144,6 +145,8 @@ export interface InputType {
   [key: string]: any;
 }
 
+export type { ToolbarArgType };
+
 export interface StrictInputType extends InputType {
   name: string;
   type?: SBType;
@@ -165,10 +168,10 @@ export interface Globals {
   [name: string]: any;
 }
 export interface GlobalTypes {
-  [name: string]: InputType;
+  [name: string]: ToolbarArgType;
 }
 export interface StrictGlobalTypes {
-  [name: string]: StrictInputType;
+  [name: string]: StrictInputType & ToolbarArgType;
 }
 
 export interface AddonTypes {
diff --git a/code/core/src/manager-api/tests/globals.test.ts b/code/core/src/manager-api/tests/globals.test.ts
index 8045ad2526c8..41a78348b585 100644
--- a/code/core/src/manager-api/tests/globals.test.ts
+++ b/code/core/src/manager-api/tests/globals.test.ts
@@ -11,6 +11,7 @@ import type { GlobalsUpdatedPayload, SetGlobalsPayload } from 'storybook/interna
 
 import { EventEmitter } from 'events';
 
+import type { ToolbarArgType } from '../../toolbar';
 import { getEventMetadata as _getEventData } from '../lib/events';
 import type { ModuleArgs } from '../lib/types';
 import type { SubAPI } from '../modules/globals';
@@ -61,7 +62,7 @@ describe('globals API', () => {
 
     channel.emit(SET_GLOBALS, {
       globals: { a: 'b' },
-      globalTypes: { a: { type: { name: 'string' } } },
+      globalTypes: { a: { type: { name: 'string' } } as ToolbarArgType },
     } satisfies SetGlobalsPayload);
     expect(store.getState()).toEqual({
       userGlobals: { a: 'b' },
@@ -88,7 +89,7 @@ describe('globals API', () => {
 
     channel.emit(SET_GLOBALS, {
       globals: { a: 'b' },
-      globalTypes: { a: { type: { name: 'string' } } },
+      globalTypes: { a: { type: { name: 'string' } } as ToolbarArgType },
     } satisfies SetGlobalsPayload);
     expect(store.getState()).toEqual({
       userGlobals: { a: 'b' },
@@ -138,7 +139,7 @@ describe('globals API', () => {
     getEventMetadata.mockReturnValueOnce({ sourceType: 'external', ref: { id: 'ref' } } as any);
     channel.emit(SET_GLOBALS, {
       globals: { a: 'b' },
-      globalTypes: { a: { type: { name: 'string' } } },
+      globalTypes: { a: { type: { name: 'string' } } as ToolbarArgType },
     } satisfies SetGlobalsPayload);
     expect(store.getState()).toEqual({
       userGlobals: {},
diff --git a/code/core/src/preview-api/modules/store/GlobalsStore.test.ts b/code/core/src/preview-api/modules/store/GlobalsStore.test.ts
index 8a5ed12aa697..2146e908c9c1 100644
--- a/code/core/src/preview-api/modules/store/GlobalsStore.test.ts
+++ b/code/core/src/preview-api/modules/store/GlobalsStore.test.ts
@@ -1,5 +1,6 @@
 import { describe, expect, it, vi } from 'vitest';
 
+import type { ToolbarArgType } from '../../../toolbar';
 import { GlobalsStore } from './GlobalsStore';
 
 vi.mock('storybook/internal/client-logger', () => ({
@@ -33,8 +34,8 @@ describe('GlobalsStore', () => {
         arg2: 2,
       },
       globalTypes: {
-        arg2: { defaultValue: 'arg2' },
-        arg3: { defaultValue: { complex: { object: ['type'] } } },
+        arg2: { defaultValue: 'arg2' } as ToolbarArgType,
+        arg3: { defaultValue: { complex: { object: ['type'] } } } as ToolbarArgType,
       },
     });
 
@@ -48,7 +49,10 @@ describe('GlobalsStore', () => {
 
   describe('update', () => {
     it('changes the global args', () => {
-      const store = new GlobalsStore({ globals: { foo: 'old' }, globalTypes: { baz: {} } });
+      const store = new GlobalsStore({
+        globals: { foo: 'old' },
+        globalTypes: { baz: {} as ToolbarArgType },
+      });
 
       store.update({ foo: 'bar' });
       expect(store.get()).toEqual({ foo: 'bar' });
@@ -60,7 +64,7 @@ describe('GlobalsStore', () => {
     it('does not merge objects', () => {
       const store = new GlobalsStore({
         globals: { obj: { foo: 'old' } },
-        globalTypes: { baz: {} },
+        globalTypes: { baz: {} as ToolbarArgType },
       });
 
       store.update({ obj: { foo: 'bar' } });
@@ -78,7 +82,7 @@ describe('GlobalsStore', () => {
           arg1: 'arg1',
         },
         globalTypes: {
-          arg2: { defaultValue: 'arg2' },
+          arg2: { defaultValue: 'arg2' } as ToolbarArgType,
         },
       });
 
@@ -104,8 +108,8 @@ describe('GlobalsStore', () => {
           arg2: 2,
         },
         globalTypes: {
-          arg2: { defaultValue: 'arg2' },
-          arg3: { defaultValue: { complex: { object: ['type'] } } },
+          arg2: { defaultValue: 'arg2' } as ToolbarArgType,
+          arg3: { defaultValue: { complex: { object: ['type'] } } } as ToolbarArgType,
         },
       });
 
@@ -126,7 +130,7 @@ describe('GlobalsStore', () => {
             arg3: 'arg3',
           },
           globalTypes: {
-            arg2: { defaultValue: 'arg2' },
+            arg2: { defaultValue: 'arg2' } as ToolbarArgType,
           },
         });
 
@@ -144,7 +148,7 @@ describe('GlobalsStore', () => {
             arg1: 'arg1',
           },
           globalTypes: {
-            arg2: { defaultValue: 'arg2' },
+            arg2: { defaultValue: 'arg2' } as ToolbarArgType,
           },
         });
         // However undeclared values aren't persisted
@@ -162,7 +166,7 @@ describe('GlobalsStore', () => {
             arg4: 'arg4',
           },
           globalTypes: {
-            arg2: { defaultValue: 'arg2' },
+            arg2: { defaultValue: 'arg2' } as ToolbarArgType,
           },
         });
 
@@ -186,7 +190,7 @@ describe('GlobalsStore', () => {
             arg4: 'edited-arg4',
           },
           globalTypes: {
-            arg5: { defaultValue: 'edited-arg5' },
+            arg5: { defaultValue: 'edited-arg5' } as ToolbarArgType,
           },
         });
         // However undeclared values aren't persisted
diff --git a/code/core/src/preview-api/modules/store/csf/normalizeProjectAnnotations.ts b/code/core/src/preview-api/modules/store/csf/normalizeProjectAnnotations.ts
index ecdd6046f18e..6cf3a46f256e 100644
--- a/code/core/src/preview-api/modules/store/csf/normalizeProjectAnnotations.ts
+++ b/code/core/src/preview-api/modules/store/csf/normalizeProjectAnnotations.ts
@@ -3,6 +3,7 @@ import type {
   NormalizedProjectAnnotations,
   ProjectAnnotations,
   Renderer,
+  StrictGlobalTypes,
 } from 'storybook/internal/types';
 
 import { inferArgTypes } from '../inferArgTypes';
@@ -27,7 +28,7 @@ export function normalizeProjectAnnotations<TRenderer extends Renderer>({
 }: ProjectAnnotations<TRenderer>): NormalizedProjectAnnotations<TRenderer> {
   return {
     ...(argTypes && { argTypes: normalizeInputTypes(argTypes as ArgTypes) }),
-    ...(globalTypes && { globalTypes: normalizeInputTypes(globalTypes) }),
+    ...(globalTypes && { globalTypes: normalizeInputTypes(globalTypes) as StrictGlobalTypes }),
     decorators: normalizeArrays(decorators),
     loaders: normalizeArrays(loaders),
     beforeEach: normalizeArrays(beforeEach),
diff --git a/code/core/src/preview-api/modules/store/csf/portable-stories.test.ts b/code/core/src/preview-api/modules/store/csf/portable-stories.test.ts
index 8e1a40527a45..6fe6c3279960 100644
--- a/code/core/src/preview-api/modules/store/csf/portable-stories.test.ts
+++ b/code/core/src/preview-api/modules/store/csf/portable-stories.test.ts
@@ -8,6 +8,7 @@ import type {
   StoryAnnotationsOrFn as Story,
 } from 'storybook/internal/types';
 
+import type { ToolbarArgType } from '../../../../toolbar';
 import * as defaultExportAnnotations from './__mocks__/defaultExportAnnotations.mockfile';
 import * as namedExportAnnotations from './__mocks__/namedExportAnnotations.mockfile';
 import { composeStories, composeStory, setProjectAnnotations } from './portable-stories';
@@ -102,7 +103,7 @@ describe('composeStory', () => {
     const projectAnnotations = {
       parameters: { injected: true },
       globalTypes: {
-        locale: { defaultValue: 'en' },
+        locale: { defaultValue: 'en' } as ToolbarArgType,
       },
       decorators: [decoratorFromProjectAnnotations],
       tags: ['projectTag'],
@@ -235,7 +236,7 @@ describe('composeStory', () => {
         theme: {
           name: 'Theme',
           defaultValue: 'light',
-        },
+        } as ToolbarArgType,
       },
     };
 
diff --git a/code/core/src/types/modules/csf.ts b/code/core/src/types/modules/csf.ts
index ad2891060eca..5ec8314f15c3 100644
--- a/code/core/src/types/modules/csf.ts
+++ b/code/core/src/types/modules/csf.ts
@@ -65,6 +65,7 @@ export type {
   StrictGlobalTypes,
   StrictInputType,
   Tag,
+  ToolbarArgType,
 } from 'storybook/internal/csf';
 
 type OrString<T extends string> = T | (string & {});
diff --git a/code/renderers/svelte/src/__test__/composeStories/portable-stories.test.ts b/code/renderers/svelte/src/__test__/composeStories/portable-stories.test.ts
index fb4d5d3ab017..0778c899efa0 100644
--- a/code/renderers/svelte/src/__test__/composeStories/portable-stories.test.ts
+++ b/code/renderers/svelte/src/__test__/composeStories/portable-stories.test.ts
@@ -3,6 +3,8 @@
 import { cleanup, render, screen } from '@testing-library/svelte';
 import { afterEach, describe, expect, it } from 'vitest';
 
+import type { ToolbarArgType } from 'storybook/internal/csf';
+
 // import '@testing-library/svelte/vitest';
 import { expectTypeOf } from 'expect-type';
 
@@ -70,7 +72,7 @@ describe('projectAnnotations', () => {
       {
         parameters: { injected: true },
         globalTypes: {
-          locale: { defaultValue: 'en' },
+          locale: { defaultValue: 'en' } as ToolbarArgType,
         },
       },
     ]);