diff --git a/packages/react/src/contexts/ClerkProvider.tsx b/packages/react/src/contexts/ClerkProvider.tsx
index e349ee99c39..f2e2bccc97e 100644
--- a/packages/react/src/contexts/ClerkProvider.tsx
+++ b/packages/react/src/contexts/ClerkProvider.tsx
@@ -18,7 +18,6 @@ function ClerkProviderBase<TUi extends Ui>(props: ClerkProviderProps<TUi>) {
   return (
     <ClerkContextProvider
       initialState={initialState}
-      // @ts-expect-error - Fixme!
       clerk={isomorphicClerk}
       clerkStatus={clerkStatus}
     >
diff --git a/packages/shared/src/react/ClerkContextProvider.tsx b/packages/shared/src/react/ClerkContextProvider.tsx
index c0421728a90..61d4b974a2e 100644
--- a/packages/shared/src/react/ClerkContextProvider.tsx
+++ b/packages/shared/src/react/ClerkContextProvider.tsx
@@ -1,6 +1,6 @@
 import React from 'react';
 
-import type { Clerk, ClerkStatus, InitialState, LoadedClerk } from '../types';
+import type { ClerkProviderValue, ClerkStatus, InitialState, LoadedClerk } from '../types';
 import {
   __experimental_CheckoutProvider as CheckoutProvider,
   ClerkInstanceContext,
@@ -9,13 +9,21 @@ import {
 import { assertClerkSingletonExists } from './utils';
 
 type ClerkContextProps = {
-  clerk: Clerk;
+  /**
+   * The Clerk instance to provide to the application.
+   * Accepts ClerkProviderValue which is compatible with IsomorphicClerk.
+   */
+  clerk: ClerkProviderValue;
   clerkStatus?: ClerkStatus;
   children: React.ReactNode;
   initialState?: InitialState;
 };
 
 export function ClerkContextProvider(props: ClerkContextProps): JSX.Element | null {
+  // SAFETY: This cast is safe because ClerkProviderValue is structurally compatible
+  // with LoadedClerk at runtime. The type difference exists because IsomorphicClerk
+  // wraps methods to allow void returns during pre-mount queuing. By the time
+  // consumers access the clerk instance, it is fully functional.
   const clerk = props.clerk as LoadedClerk;
 
   assertClerkSingletonExists(clerk);
diff --git a/packages/shared/src/react/utils.ts b/packages/shared/src/react/utils.ts
index c404daa0b7b..17cd2bd9cf4 100644
--- a/packages/shared/src/react/utils.ts
+++ b/packages/shared/src/react/utils.ts
@@ -1,7 +1,7 @@
 import { clerkCoreErrorNoClerkSingleton } from '../internal/clerk-js/errors';
-import type { Clerk } from '../types';
+import type { LoadedClerk } from '../types';
 
-export function assertClerkSingletonExists(clerk: Clerk | undefined): asserts clerk is Clerk {
+export function assertClerkSingletonExists(clerk: LoadedClerk | undefined): asserts clerk is LoadedClerk {
   if (!clerk) {
     clerkCoreErrorNoClerkSingleton();
   }
diff --git a/packages/shared/src/types/clerk.ts b/packages/shared/src/types/clerk.ts
index d437652b38c..8d69432c822 100644
--- a/packages/shared/src/types/clerk.ts
+++ b/packages/shared/src/types/clerk.ts
@@ -188,13 +188,19 @@ export type SignOutOptions = {
 };
 
 /**
- * @inline
+ * Signs out the current user.
+ *
+ * Can be called in two ways:
+ * - `signOut()` or `signOut({ redirectUrl: '...' })` - with optional options
+ * - `signOut(callback)` or `signOut(callback, { redirectUrl: '...' })` - with callback and optional options
+ *
+ * @param optionsOrCallback - Either SignOutOptions or a callback function
+ * @param options - SignOutOptions when first param is a callback
  */
-export interface SignOut {
-  (options?: SignOutOptions): Promise<void>;
-
-  (signOutCallback?: SignOutCallback, options?: SignOutOptions): Promise<void>;
-}
+export type SignOut = (
+  optionsOrCallback?: SignOutOptions | SignOutCallback,
+  options?: SignOutOptions,
+) => Promise<void>;
 
 type ClerkEvent = keyof ClerkEventPayload;
 type EventHandler<E extends ClerkEvent> = (payload: ClerkEventPayload[E]) => void;
@@ -2498,3 +2504,50 @@ export type IsomorphicClerkOptions = Without<ClerkOptions, 'isSatellite'> & {
 export interface LoadedClerk extends Clerk {
   client: ClientResource;
 }
+
+/**
+ * Utility type that transforms function return types to allow void.
+ * This is needed for IsomorphicClerk which queues method calls when clerk-js
+ * isn't loaded yet, returning void immediately instead of the expected value.
+ */
+type WithVoidReturn<T> = T extends (...args: infer A) => infer R
+  ? (...args: A) => R extends Promise<infer U> ? Promise<U | void> : R | void
+  : T;
+
+/**
+ * Transforms all function properties of a type to allow void returns.
+ */
+type WithVoidReturnFunctions<T> = {
+  [K in keyof T]: WithVoidReturn<T[K]>;
+};
+
+/**
+ * Type representing what ClerkProvider passes to ClerkContextProvider.
+ *
+ * This is a relaxed version of LoadedClerk that:
+ * 1. Allows methods to return void (for pre-mount queuing in IsomorphicClerk)
+ * 2. Makes client, billing, apiKeys optional (may be undefined before clerk-js loads)
+ * 3. Omits internal browser-specific methods that IsomorphicClerk doesn't implement
+ *
+ * The ClerkContextProvider accepts this type and casts to LoadedClerk internally.
+ * This cast is safe because:
+ * - IsomorphicClerk implements all LoadedClerk methods at runtime
+ * - The mutable instance is fully functional by the time consumers use it
+ * - Consumers check status/loaded before calling methods
+ */
+export type ClerkProviderValue = WithVoidReturnFunctions<
+  Omit<
+    Clerk,
+    | '__internal_addNavigationListener'
+    | '__internal_getCachedResources'
+    | '__internal_reloadInitialResources'
+    | '__internal_setActiveInProgress'
+    | 'client'
+    | 'billing'
+    | 'apiKeys'
+  >
+> & {
+  client: ClientResource | undefined;
+  billing: BillingNamespace | undefined;
+  apiKeys: APIKeysNamespace | undefined;
+};