diff --git a/apps/browser-extension/entrypoints/background.ts b/apps/browser-extension/entrypoints/background.ts
index ccf3dce0..39e70752 100644
--- a/apps/browser-extension/entrypoints/background.ts
+++ b/apps/browser-extension/entrypoints/background.ts
@@ -15,6 +15,8 @@ import {
 	type TwitterImportConfig,
 	TwitterImporter,
 } from "../utils/twitter-import"
+import { createTwitterImportController } from "../utils/twitter-import-controller"
+import { createTwitterImportNotifications } from "../utils/twitter-import-notifications"
 import type {
 	ExtensionMessage,
 	MemoryData,
@@ -66,7 +68,9 @@ function inferPlatformFromUrl(url?: string): string | undefined {
 }
 
 export default defineBackground(() => {
-	let twitterImporter: TwitterImporter | null = null
+	const twitterImports = createTwitterImportController(
+		(config: TwitterImportConfig) => new TwitterImporter(config),
+	)
 
 	browser.runtime.onInstalled.addListener(async (details) => {
 		if (details.reason === "install" || details.reason === "update") {
@@ -90,36 +94,6 @@ export default defineBackground(() => {
 		["requestHeaders", "extraHeaders"],
 	)
 
-	// Send message to current active tab.
-	const sendMessageToCurrentTab = async (message: string) => {
-		const tabs = await browser.tabs.query({
-			active: true,
-			currentWindow: true,
-		})
-		if (tabs.length > 0 && tabs[0].id) {
-			await browser.tabs.sendMessage(tabs[0].id, {
-				type: MESSAGE_TYPES.IMPORT_UPDATE,
-				importedMessage: message,
-			})
-		}
-	}
-
-	/**
-	 * Send import completion message
-	 */
-	const sendImportDoneMessage = async (totalImported: number) => {
-		const tabs = await browser.tabs.query({
-			active: true,
-			currentWindow: true,
-		})
-		if (tabs.length > 0 && tabs[0].id) {
-			await browser.tabs.sendMessage(tabs[0].id, {
-				type: MESSAGE_TYPES.IMPORT_DONE,
-				totalImported,
-			})
-		}
-	}
-
 	/**
 	 * Save memory to supermemory API
 	 */
@@ -246,22 +220,35 @@ export default defineBackground(() => {
 	 * Handle extension messages
 	 */
 	browser.runtime.onMessage.addListener(
-		(message: ExtensionMessage, _sender, sendResponse) => {
+		(message: ExtensionMessage, sender, sendResponse) => {
 			// Handle Twitter import request
 			if (message.type === MESSAGE_TYPES.BATCH_IMPORT_ALL) {
+				const notifications = createTwitterImportNotifications(
+					sender.tab?.id,
+					(tabId, notification) =>
+						browser.tabs.sendMessage(tabId, notification),
+				)
 				const importConfig: TwitterImportConfig = {
 					isFolderImport: message.isFolderImport,
 					bookmarkCollectionId: message.bookmarkCollectionId,
 					selectedProject: message.selectedProject,
-					onProgress: sendMessageToCurrentTab,
-					onComplete: sendImportDoneMessage,
-					onError: async (error: Error) => {
-						await sendMessageToCurrentTab(`Error: ${error.message}`)
-					},
+					onProgress: notifications.onProgress,
+					onComplete: notifications.onComplete,
+					onError: notifications.onError,
 				}
 
-				twitterImporter = new TwitterImporter(importConfig)
-				twitterImporter.startImport().catch(console.error)
+				const importTask = twitterImports.start(importConfig)
+				if (!importTask) {
+					const error = "An X bookmark import is already in progress"
+					void notifications.onError(new Error(error))
+					sendResponse({
+						success: false,
+						error,
+					})
+					return true
+				}
+
+				importTask.catch(console.error)
 				sendResponse({ success: true })
 				return true
 			}
diff --git a/apps/browser-extension/entrypoints/content/index.ts b/apps/browser-extension/entrypoints/content/index.ts
index 776d9e9f..4f47b1db 100644
--- a/apps/browser-extension/entrypoints/content/index.ts
+++ b/apps/browser-extension/entrypoints/content/index.ts
@@ -1,4 +1,5 @@
 import { DOMAINS, MESSAGE_TYPES } from "../../utils/constants"
+import { isTwitterImportNotification } from "../../utils/twitter-import-notifications"
 import { DOMUtils } from "../../utils/ui-components"
 import { initializeChatGPT } from "./chatgpt"
 import { initializeClaude } from "./claude"
@@ -28,9 +29,7 @@ export default defineContentScript({
 				return saveMemory(message.actionSource || "content_script")
 			} else if (message.action === MESSAGE_TYPES.TWITTER_IMPORT_OPEN_MODAL) {
 				return openImportModal()
-			} else if (message.type === MESSAGE_TYPES.IMPORT_UPDATE) {
-				updateTwitterImportUI(message)
-			} else if (message.type === MESSAGE_TYPES.IMPORT_DONE) {
+			} else if (isTwitterImportNotification(message)) {
 				updateTwitterImportUI(message)
 			}
 		})
diff --git a/apps/browser-extension/entrypoints/content/twitter.ts b/apps/browser-extension/entrypoints/content/twitter.ts
index 875f4bab..95ae2e60 100644
--- a/apps/browser-extension/entrypoints/content/twitter.ts
+++ b/apps/browser-extension/entrypoints/content/twitter.ts
@@ -135,12 +135,14 @@ export async function openImportModal() {
 		const projects = response.success && response.data ? response.data : []
 
 		if (projects.length === 0) {
-			await browser.runtime.sendMessage({
+			const importResponse = await browser.runtime.sendMessage({
 				type: MESSAGE_TYPES.BATCH_IMPORT_ALL,
 			})
-			await trackEvent(POSTHOG_EVENT_KEY.TWITTER_IMPORT_STARTED, {
-				source: `${POSTHOG_EVENT_KEY.SOURCE}_content_script`,
-			})
+			if (importResponse?.success) {
+				await trackEvent(POSTHOG_EVENT_KEY.TWITTER_IMPORT_STARTED, {
+					source: `${POSTHOG_EVENT_KEY.SOURCE}_content_script`,
+				})
+			}
 		} else {
 			await showAllBookmarksProjectModal(projects)
 		}
@@ -163,14 +165,16 @@ async function showAllBookmarksProjectModal(
 			modal.remove()
 
 			try {
-				await browser.runtime.sendMessage({
+				const importResponse = await browser.runtime.sendMessage({
 					type: MESSAGE_TYPES.BATCH_IMPORT_ALL,
 					selectedProject: selectedProject,
 				})
-				await trackEvent(POSTHOG_EVENT_KEY.TWITTER_IMPORT_STARTED, {
-					source: `${POSTHOG_EVENT_KEY.SOURCE}_content_script`,
-					project_selected: true,
-				})
+				if (importResponse?.success) {
+					await trackEvent(POSTHOG_EVENT_KEY.TWITTER_IMPORT_STARTED, {
+						source: `${POSTHOG_EVENT_KEY.SOURCE}_content_script`,
+						project_selected: true,
+					})
+				}
 			} catch (error) {
 				console.error("Error importing all bookmarks:", error)
 			}
@@ -464,7 +468,17 @@ function removeAllTwitterUI() {
 /**
  * Shows or updates the import progress toast in the bottom-right
  */
-function showOrUpdateImportProgressToast(message: string, isComplete = false) {
+let importToastDismissTimer: ReturnType<typeof setTimeout> | null = null
+
+function showOrUpdateImportProgressToast(
+	message: string,
+	status: "progress" | "success" | "error" = "progress",
+) {
+	if (importToastDismissTimer) {
+		clearTimeout(importToastDismissTimer)
+		importToastDismissTimer = null
+	}
+
 	let toast = document.getElementById(ELEMENT_IDS.TWITTER_IMPORT_PROGRESS_TOAST)
 
 	if (!toast) {
@@ -538,31 +552,36 @@ function showOrUpdateImportProgressToast(message: string, isComplete = false) {
 		}
 	}
 
-	// Style for completion
-	if (isComplete) {
-		const icon = toast.querySelector(
-			"#sm-import-progress-icon",
-		) as HTMLImageElement
+	const icon = toast.querySelector(
+		"#sm-import-progress-icon",
+	) as HTMLImageElement
+	const textSpan = toast.querySelector(
+		"#sm-import-progress-text",
+	) as HTMLSpanElement
+
+	if (status === "progress") {
+		if (icon) {
+			icon.style.animation = "smPulse 1.5s ease-in-out infinite"
+			icon.style.opacity = "1"
+		}
+		if (textSpan) textSpan.style.color = "#374151"
+	} else {
 		if (icon) {
 			icon.style.animation = "none"
 			icon.style.opacity = "1"
 		}
-
-		const textSpan = toast.querySelector(
-			"#sm-import-progress-text",
-		) as HTMLSpanElement
 		if (textSpan) {
-			textSpan.style.color = "#059669"
+			textSpan.style.color = status === "success" ? "#059669" : "#dc2626"
 		}
 
-		// Auto-dismiss after 4 seconds on completion
-		setTimeout(() => {
+		importToastDismissTimer = setTimeout(() => {
 			const existingToast = document.getElementById(
 				ELEMENT_IDS.TWITTER_IMPORT_PROGRESS_TOAST,
 			)
 			if (existingToast) {
 				dismissToast(existingToast)
 			}
+			importToastDismissTimer = null
 		}, 4000)
 	}
 }
@@ -573,15 +592,19 @@ export function updateTwitterImportUI(message: {
 	totalImported?: number
 }) {
 	if (message.type === MESSAGE_TYPES.IMPORT_UPDATE && message.importedMessage) {
-		showOrUpdateImportProgressToast(message.importedMessage, false)
+		showOrUpdateImportProgressToast(message.importedMessage)
 	}
 
 	if (message.type === MESSAGE_TYPES.IMPORT_DONE) {
 		showOrUpdateImportProgressToast(
 			`✓ Imported ${message.totalImported} tweets!`,
-			true,
+			"success",
 		)
 	}
+
+	if (message.type === MESSAGE_TYPES.IMPORT_ERROR && message.importedMessage) {
+		showOrUpdateImportProgressToast(message.importedMessage, "error")
+	}
 }
 
 export async function handleTwitterNavigation() {
diff --git a/apps/browser-extension/utils/constants.ts b/apps/browser-extension/utils/constants.ts
index c5fe8347..0b1cfaf7 100644
--- a/apps/browser-extension/utils/constants.ts
+++ b/apps/browser-extension/utils/constants.ts
@@ -93,6 +93,7 @@ export const MESSAGE_TYPES = {
 	BATCH_IMPORT_ALL: "sm-batch-import-all",
 	IMPORT_UPDATE: "sm-import-update",
 	IMPORT_DONE: "sm-import-done",
+	IMPORT_ERROR: "sm-import-error",
 	GET_RELATED_MEMORIES: "sm-get-related-memories",
 	CAPTURE_PROMPT: "sm-capture-prompt",
 	FETCH_PROJECTS: "sm-fetch-projects",
diff --git a/apps/browser-extension/utils/twitter-import-controller.test.ts b/apps/browser-extension/utils/twitter-import-controller.test.ts
new file mode 100644
index 00000000..1c3e2312
--- /dev/null
+++ b/apps/browser-extension/utils/twitter-import-controller.test.ts
@@ -0,0 +1,66 @@
+import { describe, expect, mock, test } from "bun:test"
+import { createTwitterImportController } from "./twitter-import-controller"
+
+function deferred() {
+	return Promise.withResolvers<void>()
+}
+
+describe("Twitter import controller", () => {
+	test("allows only one import until the active run completes", async () => {
+		const firstRun = deferred()
+		const secondRun = deferred()
+		const startImport = mock()
+			.mockImplementationOnce(() => firstRun.promise)
+			.mockImplementationOnce(() => secondRun.promise)
+		const createImporter = mock(() => ({ startImport }))
+		const controller = createTwitterImportController(createImporter)
+
+		const first = controller.start({ source: "first" })
+		const duplicate = controller.start({ source: "duplicate" })
+
+		expect(first).toBe(firstRun.promise)
+		expect(duplicate).toBeNull()
+		expect(createImporter).toHaveBeenCalledTimes(1)
+		expect(startImport).toHaveBeenCalledTimes(1)
+
+		firstRun.resolve()
+		await first
+
+		const second = controller.start({ source: "second" })
+		expect(second).toBe(secondRun.promise)
+		expect(createImporter).toHaveBeenCalledTimes(2)
+	})
+
+	test("releases the lock when an import rejects", async () => {
+		const failedRun = deferred()
+		const recoveredRun = deferred()
+		const startImport = mock()
+			.mockImplementationOnce(() => failedRun.promise)
+			.mockImplementationOnce(() => recoveredRun.promise)
+		const controller = createTwitterImportController(() => ({ startImport }))
+
+		const failed = controller.start("failed")
+		failedRun.reject(new Error("network failed"))
+		await expect(failed).rejects.toThrow("network failed")
+
+		expect(controller.start("recovered")).toBe(recoveredRun.promise)
+		expect(startImport).toHaveBeenCalledTimes(2)
+	})
+
+	test("releases the lock when importer startup throws", async () => {
+		const recoveredRun = deferred()
+		const createImporter = mock()
+			.mockImplementationOnce(() => {
+				throw new Error("startup failed")
+			})
+			.mockImplementationOnce(() => ({
+				startImport: () => recoveredRun.promise,
+			}))
+		const controller = createTwitterImportController(createImporter)
+
+		await expect(controller.start("failed")).rejects.toThrow("startup failed")
+
+		expect(controller.start("recovered")).toBe(recoveredRun.promise)
+		expect(createImporter).toHaveBeenCalledTimes(2)
+	})
+})
diff --git a/apps/browser-extension/utils/twitter-import-controller.ts b/apps/browser-extension/utils/twitter-import-controller.ts
new file mode 100644
index 00000000..c51263ca
--- /dev/null
+++ b/apps/browser-extension/utils/twitter-import-controller.ts
@@ -0,0 +1,32 @@
+type TwitterImportRunner = {
+	startImport: () => Promise<void>
+}
+
+export function createTwitterImportController<Config>(
+	createImporter: (config: Config) => TwitterImportRunner,
+) {
+	let running: Promise<void> | null = null
+
+	return {
+		start(config: Config): Promise<void> | null {
+			if (running) return null
+
+			const task = (() => {
+				try {
+					return Promise.resolve(createImporter(config).startImport())
+				} catch (error) {
+					return Promise.reject(error)
+				}
+			})()
+
+			running = task
+			void task
+				.finally(() => {
+					if (running === task) running = null
+				})
+				.catch(() => {})
+
+			return task
+		},
+	}
+}
diff --git a/apps/browser-extension/utils/twitter-import-notifications.test.ts b/apps/browser-extension/utils/twitter-import-notifications.test.ts
new file mode 100644
index 00000000..f2840e60
--- /dev/null
+++ b/apps/browser-extension/utils/twitter-import-notifications.test.ts
@@ -0,0 +1,92 @@
+import { describe, expect, mock, test } from "bun:test"
+import { MESSAGE_TYPES } from "./constants"
+import {
+	createTwitterImportNotifications,
+	isTwitterImportNotification,
+} from "./twitter-import-notifications"
+
+describe("Twitter import notifications", () => {
+	test("recognizes every notification routed to the content script", () => {
+		for (const type of [
+			MESSAGE_TYPES.IMPORT_UPDATE,
+			MESSAGE_TYPES.IMPORT_DONE,
+			MESSAGE_TYPES.IMPORT_ERROR,
+		]) {
+			expect(isTwitterImportNotification({ type })).toBe(true)
+		}
+		expect(
+			isTwitterImportNotification({ type: MESSAGE_TYPES.BATCH_IMPORT_ALL }),
+		).toBe(false)
+	})
+
+	test("keeps progress, errors, and completion on the initiating tab", async () => {
+		let activeTabId = 7
+		const sendMessage = mock(async () => {})
+		const notifications = createTwitterImportNotifications(
+			activeTabId,
+			sendMessage,
+		)
+
+		activeTabId = 42
+		await notifications.onProgress("Imported 10 bookmarks")
+		await notifications.onError(new Error("rate limited"))
+		await notifications.onComplete(10)
+
+		expect(activeTabId).toBe(42)
+		expect(sendMessage.mock.calls).toEqual([
+			[
+				7,
+				{
+					type: MESSAGE_TYPES.IMPORT_UPDATE,
+					importedMessage: "Imported 10 bookmarks",
+				},
+			],
+			[
+				7,
+				{
+					type: MESSAGE_TYPES.IMPORT_ERROR,
+					importedMessage: "Error: rate limited",
+				},
+			],
+			[7, { type: MESSAGE_TYPES.IMPORT_DONE, totalImported: 10 }],
+		])
+	})
+
+	test("does not let tab closure interrupt import callbacks", async () => {
+		const sendMessage = mock(async () => {
+			throw new Error("Receiving end does not exist")
+		})
+		const notifications = createTwitterImportNotifications(7, sendMessage)
+
+		await notifications.onProgress("Retrying")
+		await notifications.onError(new Error("failed"))
+		await notifications.onComplete(0)
+
+		expect(sendMessage).toHaveBeenCalledTimes(3)
+	})
+
+	test("accepts tab id zero", async () => {
+		const sendMessage = mock(async () => {})
+		const notifications = createTwitterImportNotifications(0, sendMessage)
+
+		await notifications.onProgress("Starting")
+
+		expect(sendMessage).toHaveBeenCalledWith(0, {
+			type: MESSAGE_TYPES.IMPORT_UPDATE,
+			importedMessage: "Starting",
+		})
+	})
+
+	test("skips notifications when the request has no sender tab", async () => {
+		const sendMessage = mock(async () => {})
+		const notifications = createTwitterImportNotifications(
+			undefined,
+			sendMessage,
+		)
+
+		await notifications.onProgress("Starting")
+		await notifications.onComplete(0)
+
+		expect(sendMessage).not.toHaveBeenCalled()
+	})
+})
diff --git a/apps/browser-extension/utils/twitter-import-notifications.ts b/apps/browser-extension/utils/twitter-import-notifications.ts
new file mode 100644
index 00000000..5e8c4898
--- /dev/null
+++ b/apps/browser-extension/utils/twitter-import-notifications.ts
@@ -0,0 +1,63 @@
+import { MESSAGE_TYPES } from "./constants"
+
+type TwitterImportNotification =
+	| {
+			type: typeof MESSAGE_TYPES.IMPORT_UPDATE
+			importedMessage: string
+	  }
+	| {
+			type: typeof MESSAGE_TYPES.IMPORT_DONE
+			totalImported: number
+	  }
+	| {
+			type: typeof MESSAGE_TYPES.IMPORT_ERROR
+			importedMessage: string
+	  }
+
+type SendTabMessage = (
+	tabId: number,
+	message: TwitterImportNotification,
+) => Promise<unknown>
+
+const TWITTER_IMPORT_NOTIFICATION_TYPES = new Set<string>([
+	MESSAGE_TYPES.IMPORT_UPDATE,
+	MESSAGE_TYPES.IMPORT_DONE,
+	MESSAGE_TYPES.IMPORT_ERROR,
+])
+
+export function isTwitterImportNotification(message: { type?: string }) {
+	return !!message.type && TWITTER_IMPORT_NOTIFICATION_TYPES.has(message.type)
+}
+
+export function createTwitterImportNotifications(
+	tabId: number | undefined,
+	sendMessage: SendTabMessage,
+) {
+	const deliver = async (message: TwitterImportNotification): Promise<void> => {
+		if (tabId === undefined) return
+		try {
+			await sendMessage(tabId, message)
+		} catch {
+			// The initiating tab can be closed or navigated while the import keeps
+			// running. Notification delivery must not cancel the import itself.
+		}
+	}
+
+	return {
+		onProgress: (message: string) =>
+			deliver({
+				type: MESSAGE_TYPES.IMPORT_UPDATE,
+				importedMessage: message,
+			}),
+		onComplete: (totalImported: number) =>
+			deliver({
+				type: MESSAGE_TYPES.IMPORT_DONE,
+				totalImported,
+			}),
+		onError: (error: Error) =>
+			deliver({
+				type: MESSAGE_TYPES.IMPORT_ERROR,
+				importedMessage: `Error: ${error.message}`,
+			}),
+	}
+}