diff --git a/packages/extension/src/agent/MultiPageAgent.ts b/packages/extension/src/agent/MultiPageAgent.ts
index aa768bc..e7a3f4b 100644
--- a/packages/extension/src/agent/MultiPageAgent.ts
+++ b/packages/extension/src/agent/MultiPageAgent.ts
@@ -50,6 +50,8 @@ export class MultiPageAgent extends PageAgentCore {
 
 		super({
 			...config,
+			// Disabled: AbortSignal cannot cross contexts
+			experimentalScriptExecutionTool: false,
 			pageController: pageController as any,
 			customTools: customTools,
 			customSystemPrompt: systemPrompt,
diff --git a/packages/extension/src/agent/RemotePageController.ts b/packages/extension/src/agent/RemotePageController.ts
index aaa8234..580f9c2 100644
--- a/packages/extension/src/agent/RemotePageController.ts
+++ b/packages/extension/src/agent/RemotePageController.ts
@@ -133,11 +133,7 @@ export class RemotePageController {
 		return this.remoteCallDomAction('scroll_horizontally', args)
 	}
 
-	async executeJavascript(script: string, _signal?: AbortSignal): Promise<DomActionReturn> {
-		// `AbortSignal` is not structured-cloneable across the messaging boundary.
-		// The remote script runs without it
-		return this.remoteCallDomAction('execute_javascript', [script])
-	}
+	// `execute_javascript` is intentionally not implemented: AbortSignal cannot cross context
 
 	/** @note Managed by content script via storage polling. */
 	async showMask(): Promise<void> {}