diff --git a/docs/src/test-api/class-testoptions.md b/docs/src/test-api/class-testoptions.md
index a7fa677a5d..df41058f36 100644
--- a/docs/src/test-api/class-testoptions.md
+++ b/docs/src/test-api/class-testoptions.md
@@ -679,7 +679,7 @@ export default defineConfig({
 
 ## property: TestOptions.mockingProxy
 * since: v1.51
-- type: <[boolean]> Enables the mocking proxy. Playwright will inject the proxy URL into all outgoing requests under the `x-playwright-proxy` header.
+- type: <[MockingProxyMode]<"off"|"inject-via-header">> Enables the mocking proxy. Playwright will inject the proxy URL into all outgoing requests under the `x-playwright-proxy` header.
 
 **Usage**
 
@@ -688,7 +688,7 @@ import { defineConfig } from '@playwright/test';
 
 export default defineConfig({
   use: {
-    mockingProxy: true
+    mockingProxy: 'inject-via-header'
   },
 });
 ```
\ No newline at end of file
diff --git a/packages/playwright-core/src/client/playwright.ts b/packages/playwright-core/src/client/playwright.ts
index f60df580ed..f3124fb385 100644
--- a/packages/playwright-core/src/client/playwright.ts
+++ b/packages/playwright-core/src/client/playwright.ts
@@ -74,8 +74,8 @@ export class Playwright extends ChannelOwner<channels.PlaywrightChannel> {
     return (channel as any)._object;
   }
 
-  async _startMockingProxy(requestContextOptions: NewContextOptions) {
-    const requestContext = await this.request._newContext(requestContextOptions, this._connection.localUtils()._channel);
+  async _startMockingProxy() {
+    const requestContext = await this.request._newContext(undefined, this._connection.localUtils()._channel);
     const { mockingProxy } = await this._connection.localUtils()._channel.newMockingProxy({ requestContext: requestContext._channel });
     return (mockingProxy as any)._object;
   }
diff --git a/packages/playwright/src/index.ts b/packages/playwright/src/index.ts
index 5665eb8fea..cd3d249ad0 100644
--- a/packages/playwright/src/index.ts
+++ b/packages/playwright/src/index.ts
@@ -125,7 +125,7 @@ const playwrightFixtures: Fixtures<TestFixtures, WorkerFixtures> = ({
   }, { scope: 'worker', timeout: 0 }],
 
   _mockingProxy: [async ({ mockingProxy: mockingProxyOption, playwright }, use) => {
-    if (!mockingProxyOption)
+    if (mockingProxyOption !== 'inject-via-header')
       return await use(undefined);
     const mockingProxy = await (playwright as PlaywrightImpl)._startMockingProxy();
     await use(mockingProxy);
diff --git a/packages/playwright/types/test.d.ts b/packages/playwright/types/test.d.ts
index 67df822010..391d9f56ab 100644
--- a/packages/playwright/types/test.d.ts
+++ b/packages/playwright/types/test.d.ts
@@ -6166,18 +6166,19 @@ export interface PlaywrightWorkerOptions {
    *
    * export default defineConfig({
    *   use: {
-   *     mockingProxy: true
+   *     mockingProxy: 'inject-via-header'
    *   },
    * });
    * ```
    *
    */
-  mockingProxy: boolean | undefined;
+  mockingProxy: MockingProxyMode | undefined;
 }
 
 export type ScreenshotMode = 'off' | 'on' | 'only-on-failure' | 'on-first-failure';
 export type TraceMode = 'off' | 'on' | 'retain-on-failure' | 'on-first-retry' | 'on-all-retries' | 'retain-on-first-failure';
 export type VideoMode = 'off' | 'on' | 'retain-on-failure' | 'on-first-retry';
+export type MockingProxyMode = 'off' | 'inject-via-header';
 
 /**
  * Playwright Test provides many options to configure test environment,
diff --git a/utils/generate_types/overrides-test.d.ts b/utils/generate_types/overrides-test.d.ts
index b9c144a132..10475b5649 100644
--- a/utils/generate_types/overrides-test.d.ts
+++ b/utils/generate_types/overrides-test.d.ts
@@ -236,12 +236,13 @@ export interface PlaywrightWorkerOptions {
   screenshot: ScreenshotMode | { mode: ScreenshotMode } & Pick<PageScreenshotOptions, 'fullPage' | 'omitBackground'>;
   trace: TraceMode | /** deprecated */ 'retry-with-trace' | { mode: TraceMode, snapshots?: boolean, screenshots?: boolean, sources?: boolean, attachments?: boolean };
   video: VideoMode | /** deprecated */ 'retry-with-video' | { mode: VideoMode, size?: ViewportSize };
-  mockingProxy: boolean | undefined;
+  mockingProxy: MockingProxyMode | undefined;
 }
 
 export type ScreenshotMode = 'off' | 'on' | 'only-on-failure' | 'on-first-failure';
 export type TraceMode = 'off' | 'on' | 'retain-on-failure' | 'on-first-retry' | 'on-all-retries' | 'retain-on-first-failure';
 export type VideoMode = 'off' | 'on' | 'retain-on-failure' | 'on-first-retry';
+export type MockingProxyMode = 'off' | 'inject-via-header';
 
 export interface PlaywrightTestOptions {
   acceptDownloads: boolean;