feat: auto handle dialogs during script evaluation (#1839)

Provide a argument to LLM to handle dialogs that come up during code
execution.

---------

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

Author: Lightning00Blade

docs/tool-reference.md

@@ -1,6 +1,6 @@
 <!-- AUTO GENERATED DO NOT EDIT - run 'npm run gen' to update-->
 
-# Chrome DevTools MCP Tool Reference (~6962 cl100k_base tokens)
+# Chrome DevTools MCP Tool Reference (~7005 cl100k_base tokens)
 
 - **[Input automation](#input-automation)** (9 tools)
   - [`click`](#click)
@@ -333,6 +333,7 @@ so returned values have to be JSON-serializable.
 }`
 
 - **args** (array) _(optional)_: An optional list of arguments to pass to the function.
+- **dialogAction** (string) _(optional)_: Handle dialogs while execution. "accept", "dismiss", or string for response of window.prompt. Defaults to accept.
 
 ---
 

src/McpPage.ts

@@ -117,7 +117,7 @@ export class McpPage implements ContextPage {
 
   waitForEventsAfterAction(
     action: () => Promise<unknown>,
-    options?: {timeout?: number},
+    options?: {timeout?: number; handleDialog?: 'accept' | 'dismiss' | string},
   ): Promise<void> {
     const helper = this.createWaitForHelper(
       this.cpuThrottlingRate,

src/WaitForHelper.ts

@@ -5,7 +5,7 @@
  */
 
 import {logger} from './logger.js';
-import type {Page, Protocol, CdpPage} from './third_party/index.js';
+import type {Page, Protocol, CdpPage, Dialog} from './third_party/index.js';
 import type {PredefinedNetworkConditions} from './third_party/index.js';
 
 export class WaitForHelper {
@@ -126,8 +126,24 @@ export class WaitForHelper {
 
   async waitForEventsAfterAction(
     action: () => Promise<unknown>,
-    options?: {timeout?: number},
+    options?: {timeout?: number; handleDialog?: 'accept' | 'dismiss' | string},
   ): Promise<void> {
+    if (options?.handleDialog) {
+      const dialogHandler = (dialog: Pick<Dialog, 'accept' | 'dismiss'>) => {
+        if (options.handleDialog === 'dismiss') {
+          void dialog.dismiss();
+        } else if (options.handleDialog === 'accept') {
+          void dialog.accept();
+        } else {
+          void dialog.accept(options.handleDialog);
+        }
+      };
+      this.#page.on('dialog', dialogHandler);
+      this.#abortController.signal.addEventListener('abort', () => {
+        this.#page.off('dialog', dialogHandler);
+      });
+    }
+
     const navigationFinished = this.waitForNavigationStarted()
       .then(navigationStated => {
         if (navigationStated) {

src/bin/cliDefinitions.ts

@@ -155,6 +155,13 @@ export const commands: Commands = {
         description: 'An optional list of arguments to pass to the function.',
         required: false,
       },
+      dialogAction: {
+        name: 'dialogAction',
+        type: 'string',
+        description:
+          'Handle dialogs while execution. "accept", "dismiss", or string for response of window.prompt. Defaults to accept.',
+        required: false,
+      },
     },
   },
   fill: {

src/telemetry/tool_call_metrics.json

@@ -107,6 +107,10 @@
       {
         "name": "args_count",
         "argType": "number"
+      },
+      {
+        "name": "dialog_action_length",
+        "argType": "number"
       }
     ]
   },

src/tools/ToolDefinition.ts

@@ -247,7 +247,7 @@ export type ContextPage = Readonly<{
   clearDialog(): void;
   waitForEventsAfterAction(
     action: () => Promise<unknown>,
-    options?: {timeout?: number},
+    options?: {timeout?: number; handleDialog?: 'accept' | 'dismiss' | string},
   ): Promise<void>;
   getInPageTools(): ToolGroup<InPageToolDefinition> | undefined;
 }>;

src/tools/script.ts

@@ -46,6 +46,12 @@ Example with arguments: \`(el) => {
         )
         .optional()
         .describe(`An optional list of arguments to pass to the function.`),
+      dialogAction: zod
+        .string()
+        .optional()
+        .describe(
+          'Handle dialogs while execution. "accept", "dismiss", or string for response of window.prompt. Defaults to accept.',
+        ),
       ...(cliArgs?.experimentalPageIdRouting ? pageIdSchema : {}),
       ...(cliArgs?.categoryExtensions
         ? {
@@ -64,6 +70,7 @@ Example with arguments: \`(el) => {
         args: uidArgs,
         function: fnString,
         pageId,
+        dialogAction,
       } = request.params;
 
       if (cliArgs?.categoryExtensions && serviceWorkerId) {
@@ -77,11 +84,12 @@ Example with arguments: \`(el) => {
         }
 
         const worker = await getWebWorker(context, serviceWorkerId);
-        await context
-          .getSelectedMcpPage()
-          .waitForEventsAfterAction(async () => {
+        await context.getSelectedMcpPage().waitForEventsAfterAction(
+          async () => {
             await performEvaluation(worker, fnString, [], response);
-          });
+          },
+          {handleDialog: dialogAction ?? 'accept'},
+        );
         return;
       }
 
@@ -101,9 +109,12 @@ Example with arguments: \`(el) => {
 
         const evaluatable = await getPageOrFrame(page, frames);
 
-        await mcpPage.waitForEventsAfterAction(async () => {
-          await performEvaluation(evaluatable, fnString, args, response);
-        });
+        await mcpPage.waitForEventsAfterAction(
+          async () => {
+            await performEvaluation(evaluatable, fnString, args, response);
+          },
+          {handleDialog: dialogAction ?? 'accept'},
+        );
       } finally {
         void Promise.allSettled(args.map(arg => arg.dispose()));
       }

tests/tools/script.test.ts

@@ -98,6 +98,75 @@ describe('script', () => {
       });
     });
 
+    it('work for scripts that trigger dialogs', async () => {
+      await withMcpContext(async (response, context) => {
+        const page = context.getSelectedPptrPage();
+
+        await page.setContent(html`<button id="test">test</button>`);
+
+        await evaluateScript().handler(
+          {
+            params: {
+              function: String(() => {
+                alert('hello');
+                return 'Works';
+              }),
+            },
+          },
+          response,
+          context,
+        );
+        const lineEvaluation = response.responseLines.at(2)!;
+        assert.strictEqual(JSON.parse(lineEvaluation), 'Works');
+      });
+    });
+
+    it('work for scripts that trigger dialogs and dismiss them', async () => {
+      await withMcpContext(async (response, context) => {
+        const page = context.getSelectedPptrPage();
+
+        await page.setContent(html`<button id="test">test</button>`);
+
+        await evaluateScript().handler(
+          {
+            params: {
+              function: String(() => {
+                return confirm('hello');
+              }),
+              dialogAction: 'dismiss',
+            },
+          },
+          response,
+          context,
+        );
+        const lineEvaluation = response.responseLines.at(2)!;
+        assert.strictEqual(JSON.parse(lineEvaluation), false);
+      });
+    });
+
+    it('work for scripts that trigger prompts and fill them', async () => {
+      await withMcpContext(async (response, context) => {
+        const page = context.getSelectedPptrPage();
+
+        await page.setContent(html`<button id="test">test</button>`);
+
+        await evaluateScript().handler(
+          {
+            params: {
+              function: String(() => {
+                return prompt('Enter your name:');
+              }),
+              dialogAction: 'John Doe',
+            },
+          },
+          response,
+          context,
+        );
+        const lineEvaluation = response.responseLines.at(2)!;
+        assert.strictEqual(JSON.parse(lineEvaluation), 'John Doe');
+      });
+    });
+
     it('work for async functions', async () => {
       await withMcpContext(async (response, context) => {
         const page = context.getSelectedPptrPage();