fix: Handle errors during tool calls and check if a dialog is open

This change also adds a check for existence of open dialogs before trying to detect open devtools

Author: samiyac

src/WaitForHelper.ts

@@ -128,8 +128,10 @@ export class WaitForHelper {
     action: () => Promise<unknown>,
     options?: {timeout?: number; handleDialog?: 'accept' | 'dismiss' | string},
   ): Promise<void> {
+    let dialogOpened = false;
     if (options?.handleDialog) {
       const dialogHandler = (dialog: Pick<Dialog, 'accept' | 'dismiss'>) => {
+        dialogOpened = true;
         if (options.handleDialog === 'dismiss') {
           void dialog.dismiss();
         } else if (options.handleDialog === 'accept') {
@@ -167,6 +169,10 @@ export class WaitForHelper {
     try {
       await navigationFinished;
 
+      if (dialogOpened) {
+        return;
+      }
+
       // Wait for stable dom after navigation so we execute in
       // the correct context
       await this.waitForStableDom();

src/index.ts

@@ -199,19 +199,22 @@ export async function createMcpServer(
           logger(`${tool.name} request: ${JSON.stringify(params, null, '  ')}`);
           const context = await getContext();
           logger(`${tool.name} context: resolved`);
-          await context.detectOpenDevToolsWindows();
+          const page =
+            serverArgs.experimentalPageIdRouting &&
+              params.pageId &&
+              !serverArgs.slim
+              ? context.getPageById(params.pageId)
+              : context.getSelectedMcpPage();
+          // If there is a dialog open, we will skip devtools detection
+          if (!page.getDialog()) {
+            await context.detectOpenDevToolsWindows();
+          }
           const response = serverArgs.slim
             ? new SlimMcpResponse(serverArgs)
             : new McpResponse(serverArgs);
 
           response.setRedactNetworkHeaders(serverArgs.redactNetworkHeaders);
           if ('pageScoped' in tool && tool.pageScoped) {
-            const page =
-              serverArgs.experimentalPageIdRouting &&
-              params.pageId &&
-              !serverArgs.slim
-                ? context.getPageById(params.pageId)
-                : context.getSelectedMcpPage();
             response.setPage(page);
             await tool.handler(
               {

src/tools/ToolDefinition.ts

@@ -336,6 +336,18 @@ export function definePageTool<
   return {
     ...definition,
     pageScoped: true,
+    handler: async (request, response, context) => {
+      try {
+        await definition.handler(request, response, context);
+      } catch (error) {
+        const dialog = request.page.getDialog();
+        if (dialog) {
+          response.appendResponseLine(`[Blocked] Action triggered a dialog.`);
+          return;
+        }
+        throw error;
+      }
+    },
   } as DefinedPageTool<Schema>;
 }