address comments

src/browser.ts

@@ -84,6 +84,7 @@ export class BrowserManager {
   private screencastActive: boolean = false;
   private screencastSessionId: number = 0;
   private frameCallback: ((frame: ScreencastFrame) => void) | null = null;
+  private screencastFrameHandler: ((params: any) => void) | null = null;
 
   /**
    * Check if browser is launched
@@ -952,8 +953,8 @@ export class BrowserManager {
     this.frameCallback = callback;
     this.screencastActive = true;
 
-    // Listen for screencast frames
-    cdp.on('Page.screencastFrame', async (params: any) => {
+    // Create and store the frame handler so we can remove it later
+    this.screencastFrameHandler = async (params: any) => {
       const frame: ScreencastFrame = {
         data: params.data,
         metadata: params.metadata,
@@ -967,7 +968,10 @@ export class BrowserManager {
       if (this.frameCallback) {
         this.frameCallback(frame);
       }
-    });
+    };
+
+    // Listen for screencast frames
+    cdp.on('Page.screencastFrame', this.screencastFrameHandler);
 
     // Start the screencast
     await cdp.send('Page.startScreencast', {
@@ -990,12 +994,18 @@ export class BrowserManager {
     try {
       const cdp = await this.getCDPSession();
       await cdp.send('Page.stopScreencast');
+
+      // Remove the event listener to prevent accumulation
+      if (this.screencastFrameHandler) {
+        cdp.off('Page.screencastFrame', this.screencastFrameHandler);
+      }
     } catch {
       // Ignore errors when stopping
     }
 
     this.screencastActive = false;
     this.frameCallback = null;
+    this.screencastFrameHandler = null;
   }
 
   /**

src/stream-server.ts

@@ -304,8 +304,11 @@ export class StreamServer {
    * Start screencasting
    */
   private async startScreencast(): Promise<void> {
+    // Set flag immediately to prevent race conditions with concurrent calls
     if (this.isScreencasting) return;
+    this.isScreencasting = true;
 
+    try {
       // Check if browser is launched
       if (!this.browser.isLaunched()) {
         throw new Error('Browser not launched');
@@ -319,12 +322,15 @@ export class StreamServer {
         everyNthFrame: 1,
       });
 
-    this.isScreencasting = true;
-
       // Notify all clients
       for (const client of this.clients) {
         this.sendStatus(client);
       }
+    } catch (error) {
+      // Reset flag on failure so caller can retry
+      this.isScreencasting = false;
+      throw error;
+    }
   }
 
   /**