diff --git a/docs/tool-reference.md b/docs/tool-reference.md
index 0e126b8c..64054697 100644
--- a/docs/tool-reference.md
+++ b/docs/tool-reference.md
@@ -149,6 +149,7 @@
 **Parameters:**
 
 - **ignoreCache** (boolean) _(optional)_: Whether to ignore cache on reload.
+- **initScript** (string) _(optional)_: (optional) A JavaScript function to be executed by the tool on new document for every page load before any other scripts.
 - **timeout** (integer) _(optional)_: Maximum wait time in milliseconds. If set to 0, the default timeout will be used.
 - **type** (enum: "url", "back", "forward", "reload") _(optional)_: Navigate the page by URL, back or forward in history, or reload.
 - **url** (string) _(optional)_: Target URL (only type=url)
diff --git a/src/tools/pages.ts b/src/tools/pages.ts
index f4638860..270c08e4 100644
--- a/src/tools/pages.ts
+++ b/src/tools/pages.ts
@@ -116,6 +116,12 @@ export const navigatePage = defineTool({
       .boolean()
       .optional()
       .describe('Whether to ignore cache on reload.'),
+    initScript: zod
+      .string()
+      .optional()
+      .describe(
+        '(optional) A JavaScript function to be executed by the tool on new document for every page load before any other scripts.',
+      ),
     ...timeoutSchema,
   },
   handler: async (request, response, context) => {
@@ -132,6 +138,10 @@ export const navigatePage = defineTool({
       request.params.type = 'url';
     }
 
+    if (request.params.initScript) {
+      await page.evaluateOnNewDocument(request.params.initScript);
+    }
+
     await context.waitForEventsAfterAction(async () => {
       switch (request.params.type) {
         case 'url':
diff --git a/tests/tools/pages.test.ts b/tests/tools/pages.test.ts
index a4a76bcd..6e69de61 100644
--- a/tests/tools/pages.test.ts
+++ b/tests/tools/pages.test.ts
@@ -193,6 +193,28 @@ describe('pages', () => {
         assert.ok(response.includePages);
       });
     });
+    it('navigates to correct page with initScript', async () => {
+      await withBrowser(async (response, context) => {
+        await navigatePage.handler(
+          {
+            params: {
+              url: 'data:text/html,<div>Hello MCP</div>',
+              initScript: 'window.initScript = "completed"',
+            },
+          },
+          response,
+          context,
+        );
+        const page = context.getSelectedPage();
+
+        // wait for up to 1s for the global variable to set by the initScript to exist
+        await page.waitForFunction("window.initScript==='completed'", {
+          timeout: 1000,
+        });
+
+        assert.ok(response.includePages);
+      });
+    });
   });
   describe('resize', () => {
     it('create a page', async () => {