From ac3efc5685fafaf150fc20980198853565a7a61e Mon Sep 17 00:00:00 2001
From: Michael Drury <me@michaeldrury.co.uk>
Date: Thu, 9 Oct 2025 10:53:22 +0100
Subject: [PATCH] fix: Chat side panel open/close behaviour and builder state
 accuracy (no-changelog) (#20525)

---
 .../frontend/@n8n/stores/src/constants.ts     |   2 +
 packages/frontend/editor-ui/src/App.vue       |  13 +-
 .../CredentialEdit/CredentialConfig.vue       |   6 +-
 .../src/components/Error/NodeErrorView.vue    |   8 +-
 .../src/components/Node/NodeCreation.vue      |  10 +-
 .../Node/NodeCreator/NodeCreator.vue          |  13 +-
 .../render-types/CanvasNodeChoicePrompt.vue   |  18 +-
 .../handlers/builderCreditsUpdated.test.ts    |   4 +-
 .../handlers/builderCreditsUpdated.ts         |   2 +-
 .../assistant/assistant.store.test.ts         |  46 ++-
 .../src/features/assistant/assistant.store.ts |  82 +---
 .../assistant}/builder.store.test.ts          |  61 +--
 .../assistant}/builder.store.ts               | 121 ++----
 .../assistant/chatPanel.store.test.ts         | 362 ++++++++++++++++++
 .../src/features/assistant/chatPanel.store.ts | 199 ++++++++++
 .../assistant/chatPanelState.store.ts         |  24 ++
 .../Agent/AskAssistantBuild.test.ts           |   2 +-
 .../components/Agent/AskAssistantBuild.vue    |   2 +-
 .../components/Agent/ExecuteMessage.test.ts   |   2 +-
 .../components/Agent/ExecuteMessage.vue       |   2 +-
 .../assistant/components/AssistantsHub.vue    |  67 ++--
 .../Chat/AskAssistantFloatingButton.vue       |  16 +-
 .../Chat/NewAssistantSessionModal.vue         |   8 +-
 .../src/features/assistant/constants.ts       |  20 +
 .../frontend/editor-ui/src/views/NodeView.vue |   2 +-
 25 files changed, 803 insertions(+), 289 deletions(-)
 rename packages/frontend/editor-ui/src/{stores => features/assistant}/builder.store.test.ts (97%)
 rename packages/frontend/editor-ui/src/{stores => features/assistant}/builder.store.ts (86%)
 create mode 100644 packages/frontend/editor-ui/src/features/assistant/chatPanel.store.test.ts
 create mode 100644 packages/frontend/editor-ui/src/features/assistant/chatPanel.store.ts
 create mode 100644 packages/frontend/editor-ui/src/features/assistant/chatPanelState.store.ts
 create mode 100644 packages/frontend/editor-ui/src/features/assistant/constants.ts

diff --git a/packages/frontend/@n8n/stores/src/constants.ts b/packages/frontend/@n8n/stores/src/constants.ts
index 7cea01c1aa1..a080721495f 100644
--- a/packages/frontend/@n8n/stores/src/constants.ts
+++ b/packages/frontend/@n8n/stores/src/constants.ts
@@ -24,6 +24,8 @@ export const STORES = {
 	COLLABORATION: 'collaboration',
 	ASSISTANT: 'assistant',
 	BUILDER: 'builder',
+	CHAT_PANEL: 'chatPanel',
+	CHAT_PANEL_STATE: 'chatPanelState',
 	BECOME_TEMPLATE_CREATOR: 'becomeTemplateCreator',
 	PROJECTS: 'projects',
 	API_KEYS: 'apiKeys',
diff --git a/packages/frontend/editor-ui/src/App.vue b/packages/frontend/editor-ui/src/App.vue
index 81a825e6e83..d71ac305e87 100644
--- a/packages/frontend/editor-ui/src/App.vue
+++ b/packages/frontend/editor-ui/src/App.vue
@@ -15,8 +15,8 @@ import {
 	HIRING_BANNER,
 	VIEWS,
 } from '@/constants';
+import { useChatPanelStore } from '@/features/assistant/chatPanel.store';
 import { useAssistantStore } from '@/features/assistant/assistant.store';
-import { useBuilderStore } from '@/stores/builder.store';
 import { useNDVStore } from '@/stores/ndv.store';
 import { useSettingsStore } from '@/stores/settings.store';
 import { useUIStore } from '@/stores/ui.store';
@@ -38,7 +38,7 @@ import { hasPermission } from './utils/rbac/permissions';
 const route = useRoute();
 const rootStore = useRootStore();
 const assistantStore = useAssistantStore();
-const builderStore = useBuilderStore();
+const chatPanelStore = useChatPanelStore();
 const uiStore = useUIStore();
 const usersStore = useUsersStore();
 const settingsStore = useSettingsStore();
@@ -71,8 +71,7 @@ const isDemoMode = computed(() => route.name === VIEWS.DEMO);
 const hasContentFooter = ref(false);
 const appGrid = ref<Element | null>(null);
 
-const assistantSidebarWidth = computed(() => assistantStore.chatWidth);
-const builderSidebarWidth = computed(() => builderStore.chatWidth);
+const chatPanelWidth = computed(() => chatPanelStore.width);
 
 useTelemetryContext({ ndv_source: computed(() => ndvStore.lastSetActiveNodeSource) });
 
@@ -107,8 +106,8 @@ const updateGridWidth = async () => {
 		uiStore.appGridDimensions = { width, height };
 	}
 };
-// As assistant sidebar width changes, recalculate the total width regularly
-watch([assistantSidebarWidth, builderSidebarWidth], async () => {
+// As chat panel width changes, recalculate the total width regularly
+watch(chatPanelWidth, async () => {
 	await updateGridWidth();
 });
 
@@ -211,6 +210,7 @@ useExposeCssVar('--ask-assistant-floating-button-bottom-offset', askAiFloatingBu
 	grid-area: banners;
 	z-index: var(--z-index-top-banners);
 }
+
 .content {
 	display: flex;
 	flex-direction: column;
@@ -230,6 +230,7 @@ useExposeCssVar('--ask-assistant-floating-button-bottom-offset', askAiFloatingBu
 		display: block;
 	}
 }
+
 .contentWrapper {
 	display: flex;
 	grid-area: content;
diff --git a/packages/frontend/editor-ui/src/components/CredentialEdit/CredentialConfig.vue b/packages/frontend/editor-ui/src/components/CredentialEdit/CredentialConfig.vue
index 609e25610c7..902a5e32983 100644
--- a/packages/frontend/editor-ui/src/components/CredentialEdit/CredentialConfig.vue
+++ b/packages/frontend/editor-ui/src/components/CredentialEdit/CredentialConfig.vue
@@ -30,6 +30,7 @@ import CopyInput from '../CopyInput.vue';
 import CredentialInputs from './CredentialInputs.vue';
 import GoogleAuthButton from './GoogleAuthButton.vue';
 import OauthButton from './OauthButton.vue';
+import { useChatPanelStore } from '@/features/assistant/chatPanel.store';
 import { useAssistantStore } from '@/features/assistant/assistant.store';
 import FreeAiCreditsCallout from '@/components/FreeAiCreditsCallout.vue';
 
@@ -41,6 +42,7 @@ import {
 	N8nNotice,
 	N8nText,
 } from '@n8n/design-system';
+
 type Props = {
 	mode: string;
 	credentialType: ICredentialType;
@@ -82,6 +84,7 @@ const rootStore = useRootStore();
 const uiStore = useUIStore();
 const workflowsStore = useWorkflowsStore();
 const assistantStore = useAssistantStore();
+const chatPanelStore = useChatPanelStore();
 
 const i18n = useI18n();
 const telemetry = useTelemetry();
@@ -223,7 +226,7 @@ async function onAskAssistantClick() {
 		});
 		return;
 	}
-	await assistantStore.initCredHelp(props.credentialType);
+	await chatPanelStore.openWithCredHelp(props.credentialType);
 }
 
 watch(showOAuthSuccessBanner, (newValue, oldValue) => {
@@ -414,6 +417,7 @@ watch(showOAuthSuccessBanner, (newValue, oldValue) => {
 .askAssistantButton {
 	display: flex;
 	align-items: center;
+
 	> span {
 		margin-left: var(--spacing-3xs);
 		font-size: var(--font-size-s);
diff --git a/packages/frontend/editor-ui/src/components/Error/NodeErrorView.vue b/packages/frontend/editor-ui/src/components/Error/NodeErrorView.vue
index f41433c4c7d..8ce4e15e241 100644
--- a/packages/frontend/editor-ui/src/components/Error/NodeErrorView.vue
+++ b/packages/frontend/editor-ui/src/components/Error/NodeErrorView.vue
@@ -20,6 +20,7 @@ import type {
 import { sanitizeHtml } from '@/utils/htmlUtils';
 import { MAX_DISPLAY_DATA_SIZE, NEW_ASSISTANT_SESSION_MODAL, VIEWS } from '@/constants';
 import type { BaseTextKey } from '@n8n/i18n';
+import { useChatPanelStore } from '@/features/assistant/chatPanel.store';
 import { useAssistantStore } from '@/features/assistant/assistant.store';
 import type { ChatRequest } from '@/features/assistant/assistant.types';
 import { useUIStore } from '@/stores/ui.store';
@@ -32,6 +33,7 @@ import {
 	N8nIconButton,
 	N8nTooltip,
 } from '@n8n/design-system';
+
 type Props = {
 	// TODO: .node can be undefined
 	error: NodeError | NodeApiError | NodeOperationError;
@@ -52,6 +54,7 @@ const ndvStore = useNDVStore();
 const workflowsStore = useWorkflowsStore();
 const rootStore = useRootStore();
 const assistantStore = useAssistantStore();
+const chatPanelStore = useChatPanelStore();
 const uiStore = useUIStore();
 
 const workflowId = computed(() => workflowsStore.workflowId);
@@ -444,7 +447,7 @@ async function onAskAssistantClick() {
 		});
 		return;
 	}
-	await assistantStore.initErrorHelper(errorHelp);
+	await chatPanelStore.openWithErrorHelper(errorHelp);
 	assistantStore.trackUserOpenedAssistant({
 		source: 'error',
 		task: 'error',
@@ -754,6 +757,7 @@ async function onAskAssistantClick() {
 		margin-bottom: var(--spacing-xs);
 		margin-top: var(--spacing-xs);
 		flex-direction: row-reverse;
+
 		span {
 			margin-right: var(--spacing-5xs);
 			margin-left: var(--spacing-5xs);
@@ -776,6 +780,7 @@ async function onAskAssistantClick() {
 			width: 100%;
 			overflow: auto;
 			background: var(--color-background-light);
+
 			code {
 				font-size: var(--font-size-s);
 			}
@@ -797,6 +802,7 @@ async function onAskAssistantClick() {
 		align-items: center;
 		justify-content: center;
 		cursor: pointer;
+
 		&:hover {
 			color: var(--color-primary);
 		}
diff --git a/packages/frontend/editor-ui/src/components/Node/NodeCreation.vue b/packages/frontend/editor-ui/src/components/Node/NodeCreation.vue
index 41ac2032148..55390305184 100644
--- a/packages/frontend/editor-ui/src/components/Node/NodeCreation.vue
+++ b/packages/frontend/editor-ui/src/components/Node/NodeCreation.vue
@@ -20,7 +20,8 @@ import KeyboardShortcutTooltip from '@/components/KeyboardShortcutTooltip.vue';
 import { useI18n } from '@n8n/i18n';
 import { useTelemetry } from '@/composables/useTelemetry';
 import { useAssistantStore } from '@/features/assistant/assistant.store';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '@/features/assistant/builder.store';
+import { useChatPanelStore } from '@/features/assistant/chatPanel.store';
 
 import { N8nAssistantIcon, N8nButton, N8nIconButton, N8nTooltip } from '@n8n/design-system';
 
@@ -51,6 +52,7 @@ const i18n = useI18n();
 const telemetry = useTelemetry();
 const assistantStore = useAssistantStore();
 const builderStore = useBuilderStore();
+const chatPanelStore = useChatPanelStore();
 
 const { getAddedNodesAndConnections } = useActions();
 
@@ -101,11 +103,11 @@ function toggleFocusPanel() {
 
 async function onAskAssistantButtonClick() {
 	if (builderStore.isAIBuilderEnabled) {
-		await builderStore.toggleChat();
+		await chatPanelStore.toggle({ mode: 'builder' });
 	} else {
-		assistantStore.toggleChat();
+		await chatPanelStore.toggle({ mode: 'assistant' });
 	}
-	if (builderStore.isAssistantOpen || assistantStore.isAssistantOpen) {
+	if (chatPanelStore.isOpen) {
 		assistantStore.trackUserOpenedAssistant({
 			source: 'canvas',
 			task: 'placeholder',
diff --git a/packages/frontend/editor-ui/src/components/Node/NodeCreator/NodeCreator.vue b/packages/frontend/editor-ui/src/components/Node/NodeCreator/NodeCreator.vue
index 8d8d5573633..97a05481c96 100644
--- a/packages/frontend/editor-ui/src/components/Node/NodeCreator/NodeCreator.vue
+++ b/packages/frontend/editor-ui/src/components/Node/NodeCreator/NodeCreator.vue
@@ -12,8 +12,7 @@ import NodesListPanel from './Panel/NodesListPanel.vue';
 import { useCredentialsStore } from '@/stores/credentials.store';
 import { useUIStore } from '@/stores/ui.store';
 import { DRAG_EVENT_DATA_KEY } from '@/constants';
-import { useAssistantStore } from '@/features/assistant/assistant.store';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useChatPanelStore } from '@/features/assistant/chatPanel.store';
 import type { NodeTypeSelectedPayload } from '@/Interface';
 import { onClickOutside } from '@vueuse/core';
 
@@ -37,8 +36,7 @@ const emit = defineEmits<{
 	nodeTypeSelected: [value: NodeTypeSelectedPayload[]];
 }>();
 const uiStore = useUIStore();
-const assistantStore = useAssistantStore();
-const builderStore = useBuilderStore();
+const chatPanelStore = useChatPanelStore();
 
 const { setShowScrim, setActions, setMergeNodes } = useNodeCreatorStore();
 const { generateMergedNodesAndActions } = useActionsGenerator();
@@ -58,11 +56,8 @@ const nodeCreatorInlineStyle = computed(() => {
 });
 
 function getRightOffset() {
-	if (assistantStore.isAssistantOpen) {
-		return assistantStore.chatWidth;
-	}
-	if (builderStore.isAssistantOpen) {
-		return builderStore.chatWidth;
+	if (chatPanelStore.isOpen) {
+		return chatPanelStore.width;
 	}
 
 	return 0;
diff --git a/packages/frontend/editor-ui/src/components/canvas/elements/nodes/render-types/CanvasNodeChoicePrompt.vue b/packages/frontend/editor-ui/src/components/canvas/elements/nodes/render-types/CanvasNodeChoicePrompt.vue
index 200748cc938..b3e5308cf89 100644
--- a/packages/frontend/editor-ui/src/components/canvas/elements/nodes/render-types/CanvasNodeChoicePrompt.vue
+++ b/packages/frontend/editor-ui/src/components/canvas/elements/nodes/render-types/CanvasNodeChoicePrompt.vue
@@ -1,15 +1,20 @@
 <script setup lang="ts">
 import { NODE_CREATOR_OPEN_SOURCES } from '@/constants';
 import { useNodeCreatorStore } from '@/stores/nodeCreator.store';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useChatPanelStore } from '@/features/assistant/chatPanel.store';
 import { useI18n } from '@n8n/i18n';
+import { computed } from 'vue';
 
 import { N8nIcon } from '@n8n/design-system';
 
 const nodeCreatorStore = useNodeCreatorStore();
-const builderStore = useBuilderStore();
+const chatPanelStore = useChatPanelStore();
 const i18n = useI18n();
 
+const isChatWindowOpen = computed(
+	() => chatPanelStore.isOpen && chatPanelStore.isBuilderModeActive,
+);
+
 const onAddFirstStepClick = () => {
 	if (nodeCreatorStore.isCreateNodeActive) {
 		nodeCreatorStore.isCreateNodeActive = false;
@@ -21,7 +26,7 @@ const onAddFirstStepClick = () => {
 };
 
 async function onBuildWithAIClick() {
-	await builderStore.toggleChat();
+	await chatPanelStore.toggle({ mode: 'builder' });
 }
 </script>
 
@@ -55,12 +60,7 @@ async function onBuildWithAIClick() {
 
 		<!-- Build with AI Button -->
 		<div :class="$style.option">
-			<div
-				:class="[
-					$style.selectedButtonHighlight,
-					{ [$style.highlighted]: builderStore.isAssistantOpen },
-				]"
-			>
+			<div :class="[$style.selectedButtonHighlight, { [$style.highlighted]: isChatWindowOpen }]">
 				<button
 					:class="[$style.button]"
 					data-test-id="canvas-build-with-ai-button"
diff --git a/packages/frontend/editor-ui/src/composables/usePushConnection/handlers/builderCreditsUpdated.test.ts b/packages/frontend/editor-ui/src/composables/usePushConnection/handlers/builderCreditsUpdated.test.ts
index d667c73b153..ad421bdc204 100644
--- a/packages/frontend/editor-ui/src/composables/usePushConnection/handlers/builderCreditsUpdated.test.ts
+++ b/packages/frontend/editor-ui/src/composables/usePushConnection/handlers/builderCreditsUpdated.test.ts
@@ -1,8 +1,8 @@
 import { builderCreditsUpdated } from './builderCreditsUpdated';
 import type { BuilderCreditsPushMessage } from '@n8n/api-types/push/builder-credits';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '@/features/assistant/builder.store';
 
-vi.mock('@/stores/builder.store', () => ({
+vi.mock('@/features/assistant/builder.store', () => ({
 	useBuilderStore: vi.fn(),
 }));
 
diff --git a/packages/frontend/editor-ui/src/composables/usePushConnection/handlers/builderCreditsUpdated.ts b/packages/frontend/editor-ui/src/composables/usePushConnection/handlers/builderCreditsUpdated.ts
index e29a3cef224..96c7ca06111 100644
--- a/packages/frontend/editor-ui/src/composables/usePushConnection/handlers/builderCreditsUpdated.ts
+++ b/packages/frontend/editor-ui/src/composables/usePushConnection/handlers/builderCreditsUpdated.ts
@@ -1,5 +1,5 @@
 import type { BuilderCreditsPushMessage } from '@n8n/api-types/push/builder-credits';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '@/features/assistant/builder.store';
 
 export async function builderCreditsUpdated(event: BuilderCreditsPushMessage): Promise<void> {
 	const builderStore = useBuilderStore();
diff --git a/packages/frontend/editor-ui/src/features/assistant/assistant.store.test.ts b/packages/frontend/editor-ui/src/features/assistant/assistant.store.test.ts
index 235456ef2c1..f626602edf0 100644
--- a/packages/frontend/editor-ui/src/features/assistant/assistant.store.test.ts
+++ b/packages/frontend/editor-ui/src/features/assistant/assistant.store.test.ts
@@ -1,12 +1,15 @@
 import { describe, it, expect, beforeEach } from 'vitest';
 import { setActivePinia, createPinia } from 'pinia';
 import {
+	useChatPanelStore,
 	DEFAULT_CHAT_WIDTH,
-	ENABLED_VIEWS,
 	MAX_CHAT_WIDTH,
 	MIN_CHAT_WIDTH,
-	useAssistantStore,
-} from '@/features/assistant/assistant.store';
+} from './chatPanel.store';
+import { ASSISTANT_ENABLED_VIEWS } from './constants';
+
+const ENABLED_VIEWS = ASSISTANT_ENABLED_VIEWS;
+import { useAssistantStore } from '@/features/assistant/assistant.store';
 import { useWorkflowsStore } from '@/stores/workflows.store';
 import type { ChatRequest } from '@/features/assistant/assistant.types';
 import { usePostHog } from '@/stores/posthog.store';
@@ -79,46 +82,47 @@ describe('AI Assistant store', () => {
 
 	it('initializes with default values', () => {
 		const assistantStore = useAssistantStore();
+		const chatPanelStore = useChatPanelStore();
 
-		expect(assistantStore.chatWidth).toBe(DEFAULT_CHAT_WIDTH);
+		expect(chatPanelStore.width).toBe(DEFAULT_CHAT_WIDTH);
 		expect(assistantStore.chatMessages).toEqual([]);
-		expect(assistantStore.chatWindowOpen).toBe(false);
+		expect(chatPanelStore.isOpen).toBe(false);
 		expect(assistantStore.streaming).toBeUndefined();
 	});
 
 	it('can change chat width', () => {
-		const assistantStore = useAssistantStore();
+		const chatPanelStore = useChatPanelStore();
 
-		assistantStore.updateWindowWidth(400);
-		expect(assistantStore.chatWidth).toBe(400);
+		chatPanelStore.updateWidth(400);
+		expect(chatPanelStore.width).toBe(400);
 	});
 
 	it('should not allow chat width to be less than the minimal width', () => {
-		const assistantStore = useAssistantStore();
+		const chatPanelStore = useChatPanelStore();
 
-		assistantStore.updateWindowWidth(100);
-		expect(assistantStore.chatWidth).toBe(MIN_CHAT_WIDTH);
+		chatPanelStore.updateWidth(100);
+		expect(chatPanelStore.width).toBe(MIN_CHAT_WIDTH);
 	});
 
 	it('should not allow chat width to be more than the maximal width', () => {
-		const assistantStore = useAssistantStore();
+		const chatPanelStore = useChatPanelStore();
 
-		assistantStore.updateWindowWidth(2000);
-		expect(assistantStore.chatWidth).toBe(MAX_CHAT_WIDTH);
+		chatPanelStore.updateWidth(2000);
+		expect(chatPanelStore.width).toBe(MAX_CHAT_WIDTH);
 	});
 
-	it('should open chat window', () => {
-		const assistantStore = useAssistantStore();
+	it('should open chat window', async () => {
+		const chatPanelStore = useChatPanelStore();
 
-		assistantStore.openChat();
-		expect(assistantStore.chatWindowOpen).toBe(true);
+		await chatPanelStore.open({ mode: 'assistant' });
+		expect(chatPanelStore.isOpen).toBe(true);
 	});
 
 	it('should close chat window', () => {
-		const assistantStore = useAssistantStore();
+		const chatPanelStore = useChatPanelStore();
 
-		assistantStore.closeChat();
-		expect(assistantStore.chatWindowOpen).toBe(false);
+		chatPanelStore.close();
+		expect(chatPanelStore.isOpen).toBe(false);
 	});
 
 	it('can add a simple assistant message', () => {
diff --git a/packages/frontend/editor-ui/src/features/assistant/assistant.store.ts b/packages/frontend/editor-ui/src/features/assistant/assistant.store.ts
index d2a701c8cde..26d2e58f4e8 100644
--- a/packages/frontend/editor-ui/src/features/assistant/assistant.store.ts
+++ b/packages/frontend/editor-ui/src/features/assistant/assistant.store.ts
@@ -1,11 +1,11 @@
 import { chatWithAssistant, replaceCode } from '@/api/ai';
 import {
-	VIEWS,
-	EDITABLE_CANVAS_VIEWS,
+	type VIEWS,
 	PLACEHOLDER_EMPTY_WORKFLOW_ID,
 	CREDENTIAL_EDIT_MODAL_KEY,
-	ASK_AI_SLIDE_OUT_DURATION_MS,
+	EDITABLE_CANVAS_VIEWS,
 } from '@/constants';
+import { ASSISTANT_ENABLED_VIEWS } from './constants';
 import { STORES } from '@n8n/stores';
 import type { ChatRequest } from '@/features/assistant/assistant.types';
 import type { ChatUI } from '@n8n/design-system/types/assistant';
@@ -28,31 +28,18 @@ import { useTelemetry } from '@/composables/useTelemetry';
 import { useToast } from '@/composables/useToast';
 import { useUIStore } from '@/stores/ui.store';
 import AiUpdatedCodeMessage from '@/components/AiUpdatedCodeMessage.vue';
+import { useChatPanelStateStore } from './chatPanelState.store';
 import { useCredentialsStore } from '@/stores/credentials.store';
 import { useAIAssistantHelpers } from '@/features/assistant/composables/useAIAssistantHelpers';
 
-export const MAX_CHAT_WIDTH = 425;
-export const MIN_CHAT_WIDTH = 380;
-export const DEFAULT_CHAT_WIDTH = 400;
-export const ENABLED_VIEWS = [
-	...EDITABLE_CANVAS_VIEWS,
-	VIEWS.EXECUTION_PREVIEW,
-	VIEWS.WORKFLOWS,
-	VIEWS.CREDENTIALS,
-	VIEWS.PROJECTS_CREDENTIALS,
-	VIEWS.PROJECTS_WORKFLOWS,
-	VIEWS.PROJECT_SETTINGS,
-	VIEWS.TEMPLATE_SETUP,
-];
+export const ENABLED_VIEWS = ASSISTANT_ENABLED_VIEWS;
 const READABLE_TYPES = ['code-diff', 'text', 'block'];
 
 export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
-	const chatWidth = ref<number>(DEFAULT_CHAT_WIDTH);
-
 	const settings = useSettingsStore();
 	const rootStore = useRootStore();
+	const chatPanelStateStore = useChatPanelStateStore();
 	const chatMessages = ref<ChatUI.AssistantMessage[]>([]);
-	const chatWindowOpen = ref<boolean>(false);
 	const usersStore = useUsersStore();
 	const uiStore = useUIStore();
 	const workflowsStore = useWorkflowsStore();
@@ -102,7 +89,12 @@ export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
 		return !sessionStarted || sessionExplicitlyEnded;
 	});
 
-	const isAssistantOpen = computed(() => canShowAssistant.value && chatWindowOpen.value);
+	const isAssistantOpen = computed(
+		() =>
+			canShowAssistant.value &&
+			chatPanelStateStore.isOpen &&
+			chatPanelStateStore.activeMode === 'assistant',
+	);
 
 	const isAssistantEnabled = computed(() => settings.isAiAssistantEnabled);
 
@@ -144,43 +136,8 @@ export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
 		currentSessionWorkflowId.value = workflowsStore.workflowId;
 	}
 
-	// As assistant sidebar opens and closes, use window width to calculate the container width
-	// This will prevent animation race conditions from making ndv twitchy
-	function openChat() {
-		chatWindowOpen.value = true;
-		chatMessages.value = chatMessages.value.map((msg) => ({ ...msg, read: true }));
-		uiStore.appGridDimensions = {
-			...uiStore.appGridDimensions,
-			width: window.innerWidth - chatWidth.value,
-		};
-	}
-
-	function closeChat() {
-		chatWindowOpen.value = false;
-		// Looks smoother if we wait for slide animation to finish before updating the grid width
-		// Has to wait for longer than SlideTransition duration
-		setTimeout(() => {
-			uiStore.appGridDimensions = {
-				...uiStore.appGridDimensions,
-				width: window.innerWidth,
-			};
-			// If session has ended, reset the chat
-			if (isSessionEnded.value) {
-				resetAssistantChat();
-			}
-		}, ASK_AI_SLIDE_OUT_DURATION_MS + 50);
-	}
-
-	function toggleChat() {
-		if (isAssistantOpen.value) {
-			closeChat();
-		} else {
-			openChat();
-		}
-	}
-
 	function addAssistantMessages(newMessages: ChatRequest.MessageResponse[], id: string) {
-		const read = chatWindowOpen.value;
+		const read = chatPanelStateStore.isOpen && chatPanelStateStore.activeMode === 'assistant';
 		const messages = [...chatMessages.value].filter(
 			(msg) => !(msg.id === id && msg.role === 'assistant'),
 		);
@@ -242,10 +199,6 @@ export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
 		chatMessages.value = messages;
 	}
 
-	function updateWindowWidth(width: number) {
-		chatWidth.value = Math.min(Math.max(width, MIN_CHAT_WIDTH), MAX_CHAT_WIDTH);
-	}
-
 	function isNodeErrorActive(context: ChatRequest.ErrorContext) {
 		const targetNode = context.node.name;
 
@@ -439,7 +392,6 @@ export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
 		chatSessionCredType.value = credentialType;
 		addUserMessage(userMessage, id);
 		addLoadingAssistantMessage(locale.baseText('aiAssistant.thinkingSteps.thinking'));
-		openChat();
 		streaming.value = true;
 
 		let payload: ChatRequest.InitSupportChat | ChatRequest.InitCredHelp = {
@@ -497,8 +449,6 @@ export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
 		);
 
 		addLoadingAssistantMessage(locale.baseText('aiAssistant.thinkingSteps.analyzingError'));
-		openChat();
-
 		streaming.value = true;
 		const payload: ChatRequest.RequestPayload['payload'] = {
 			role: 'user',
@@ -833,7 +783,6 @@ export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
 		isAssistantEnabled,
 		canShowAssistantButtonsOnCanvas,
 		hideAssistantFloatingButton,
-		chatWidth,
 		chatMessages,
 		unreadCount,
 		streaming,
@@ -845,10 +794,6 @@ export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
 		isFloatingButtonShown,
 		onNodeExecution,
 		trackUserOpenedAssistant,
-		openChat,
-		closeChat,
-		toggleChat,
-		updateWindowWidth,
 		isNodeErrorActive,
 		initErrorHelper,
 		initSupportChat,
@@ -856,7 +801,6 @@ export const useAssistantStore = defineStore(STORES.ASSISTANT, () => {
 		applyCodeDiff,
 		undoCodeDiff,
 		resetAssistantChat,
-		chatWindowOpen,
 		addAssistantMessages,
 		assistantThinkingMessage,
 		chatSessionError,
diff --git a/packages/frontend/editor-ui/src/stores/builder.store.test.ts b/packages/frontend/editor-ui/src/features/assistant/builder.store.test.ts
similarity index 97%
rename from packages/frontend/editor-ui/src/stores/builder.store.test.ts
rename to packages/frontend/editor-ui/src/features/assistant/builder.store.test.ts
index 35af2d7ff0a..d96ed94b3b1 100644
--- a/packages/frontend/editor-ui/src/stores/builder.store.test.ts
+++ b/packages/frontend/editor-ui/src/features/assistant/builder.store.test.ts
@@ -4,12 +4,21 @@
 import { describe, it, expect, beforeEach, vi } from 'vitest';
 import { setActivePinia } from 'pinia';
 import { createTestingPinia } from '@pinia/testing';
-import { ENABLED_VIEWS, useBuilderStore } from '@/stores/builder.store';
-import { usePostHog } from './posthog.store';
+import { useBuilderStore } from './builder.store';
+import {
+	useChatPanelStore,
+	DEFAULT_CHAT_WIDTH,
+	MAX_CHAT_WIDTH,
+	MIN_CHAT_WIDTH,
+} from './chatPanel.store';
+import { BUILDER_ENABLED_VIEWS } from './constants';
+
+const ENABLED_VIEWS = BUILDER_ENABLED_VIEWS;
+import { usePostHog } from '@/stores/posthog.store';
 import { useSettingsStore } from '@/stores/settings.store';
-import { defaultSettings } from '../__tests__/defaults';
+import { defaultSettings } from '@/__tests__/defaults';
 import merge from 'lodash/merge';
-import { DEFAULT_POSTHOG_SETTINGS } from './posthog.store.test';
+import { DEFAULT_POSTHOG_SETTINGS } from '@/stores/posthog.store.test';
 import {
 	WORKFLOW_BUILDER_DEPRECATED_EXPERIMENT,
 	WORKFLOW_BUILDER_RELEASE_EXPERIMENT,
@@ -25,13 +34,7 @@ import {
 } from '@/composables/useWorkflowState';
 import type { Telemetry } from '@/plugins/telemetry';
 import type { ChatUI } from '@n8n/design-system/types/assistant';
-import {
-	DEFAULT_CHAT_WIDTH,
-	MAX_CHAT_WIDTH,
-	MIN_CHAT_WIDTH,
-} from '@/features/assistant/assistant.store';
 import { type INodeTypeDescription } from 'n8n-workflow';
-import type {} from 'n8n-workflow';
 import { mockedStore } from '@/__tests__/utils';
 import { useWorkflowsStore } from '@/stores/workflows.store';
 import { useNodeTypesStore } from '@/stores/nodeTypes.store';
@@ -166,46 +169,47 @@ describe('AI Builder store', () => {
 
 	it('initializes with default values', () => {
 		const builderStore = useBuilderStore();
+		const chatPanelStore = useChatPanelStore();
 
-		expect(builderStore.chatWidth).toBe(DEFAULT_CHAT_WIDTH);
+		expect(chatPanelStore.width).toBe(DEFAULT_CHAT_WIDTH);
 		expect(builderStore.chatMessages).toEqual([]);
-		expect(builderStore.chatWindowOpen).toBe(false);
+		expect(chatPanelStore.isOpen).toBe(false);
 		expect(builderStore.streaming).toBe(false);
 	});
 
 	it('can change chat width', () => {
-		const builderStore = useBuilderStore();
+		const chatPanelStore = useChatPanelStore();
 
-		builderStore.updateWindowWidth(400);
-		expect(builderStore.chatWidth).toBe(400);
+		chatPanelStore.updateWidth(400);
+		expect(chatPanelStore.width).toBe(400);
 	});
 
 	it('should not allow chat width to be less than the minimal width', () => {
-		const builderStore = useBuilderStore();
+		const chatPanelStore = useChatPanelStore();
 
-		builderStore.updateWindowWidth(100);
-		expect(builderStore.chatWidth).toBe(MIN_CHAT_WIDTH);
+		chatPanelStore.updateWidth(100);
+		expect(chatPanelStore.width).toBe(MIN_CHAT_WIDTH);
 	});
 
 	it('should not allow chat width to be more than the maximal width', () => {
-		const builderStore = useBuilderStore();
+		const chatPanelStore = useChatPanelStore();
 
-		builderStore.updateWindowWidth(2000);
-		expect(builderStore.chatWidth).toBe(MAX_CHAT_WIDTH);
+		chatPanelStore.updateWidth(2000);
+		expect(chatPanelStore.width).toBe(MAX_CHAT_WIDTH);
 	});
 
 	it('should open chat window', async () => {
-		const builderStore = useBuilderStore();
+		const chatPanelStore = useChatPanelStore();
 
-		await builderStore.openChat();
-		expect(builderStore.chatWindowOpen).toBe(true);
+		await chatPanelStore.open({ mode: 'builder' });
+		expect(chatPanelStore.isOpen).toBe(true);
 	});
 
 	it('should close chat window', () => {
-		const builderStore = useBuilderStore();
+		const chatPanelStore = useChatPanelStore();
 
-		builderStore.closeChat();
-		expect(builderStore.chatWindowOpen).toBe(false);
+		chatPanelStore.close();
+		expect(chatPanelStore.isOpen).toBe(false);
 	});
 
 	it('can process a simple assistant message through API', async () => {
@@ -1550,6 +1554,7 @@ describe('AI Builder store', () => {
 
 		it('should call fetchBuilderCredits when opening chat', async () => {
 			const builderStore = useBuilderStore();
+			const chatPanelStore = useChatPanelStore();
 
 			// Mock posthog to return variant for release experiment
 			vi.spyOn(posthogStore, 'getVariant').mockImplementation((experimentName) => {
@@ -1568,7 +1573,7 @@ describe('AI Builder store', () => {
 			// Mock loadSessions to prevent actual API call
 			vi.spyOn(chatAPI, 'getAiSessions').mockResolvedValueOnce({ sessions: [] });
 
-			await builderStore.openChat();
+			await chatPanelStore.open({ mode: 'builder' });
 
 			expect(mockGetBuilderCredits).toHaveBeenCalled();
 			expect(builderStore.creditsQuota).toBe(100);
diff --git a/packages/frontend/editor-ui/src/stores/builder.store.ts b/packages/frontend/editor-ui/src/features/assistant/builder.store.ts
similarity index 86%
rename from packages/frontend/editor-ui/src/stores/builder.store.ts
rename to packages/frontend/editor-ui/src/features/assistant/builder.store.ts
index 3af7ddca41a..3dc773312a6 100644
--- a/packages/frontend/editor-ui/src/stores/builder.store.ts
+++ b/packages/frontend/editor-ui/src/features/assistant/builder.store.ts
@@ -1,29 +1,23 @@
 import type { VIEWS } from '@/constants';
 import {
 	DEFAULT_NEW_WORKFLOW_NAME,
-	ASK_AI_SLIDE_OUT_DURATION_MS,
-	EDITABLE_CANVAS_VIEWS,
 	WORKFLOW_BUILDER_DEPRECATED_EXPERIMENT,
 	WORKFLOW_BUILDER_RELEASE_EXPERIMENT,
+	EDITABLE_CANVAS_VIEWS,
 } from '@/constants';
+import { BUILDER_ENABLED_VIEWS } from './constants';
 import { STORES } from '@n8n/stores';
 import type { ChatUI } from '@n8n/design-system/types/assistant';
 import { isToolMessage, isWorkflowUpdatedMessage } from '@n8n/design-system/types/assistant';
 import { defineStore } from 'pinia';
-import { computed, watch, ref } from 'vue';
+import { computed, ref } from 'vue';
 import { useRoute } from 'vue-router';
-import { useSettingsStore } from './settings.store';
+import { useSettingsStore } from '@/stores/settings.store';
 import { assert } from '@n8n/utils/assert';
 import { useI18n } from '@n8n/i18n';
 import { useTelemetry } from '@/composables/useTelemetry';
-import { useUIStore } from './ui.store';
-import { usePostHog } from './posthog.store';
-import {
-	DEFAULT_CHAT_WIDTH,
-	MAX_CHAT_WIDTH,
-	MIN_CHAT_WIDTH,
-} from '@/features/assistant/assistant.store';
-import { useWorkflowsStore } from './workflows.store';
+import { usePostHog } from '@/stores/posthog.store';
+import { useWorkflowsStore } from '@/stores/workflows.store';
 import { useBuilderMessages } from '@/composables/useBuilderMessages';
 import { chatWithBuilder, getAiSessions, getBuilderCredits } from '@/api/ai';
 import { generateMessageId, createBuilderPayload } from '@/helpers/builderHelpers';
@@ -33,19 +27,18 @@ import pick from 'lodash/pick';
 import { jsonParse } from 'n8n-workflow';
 import { useToast } from '@/composables/useToast';
 import { injectWorkflowState } from '@/composables/useWorkflowState';
-import { useNodeTypesStore } from './nodeTypes.store';
-import { useCredentialsStore } from './credentials.store';
+import { useNodeTypesStore } from '@/stores/nodeTypes.store';
+import { useCredentialsStore } from '@/stores/credentials.store';
 import { getAuthTypeForNodeCredential, getMainAuthField } from '@/utils/nodeTypesUtils';
 import { stringSizeInBytes } from '@/utils/typesUtils';
+import { useChatPanelStateStore } from './chatPanelState.store';
 
 const INFINITE_CREDITS = -1;
-export const ENABLED_VIEWS = [...EDITABLE_CANVAS_VIEWS];
+export const ENABLED_VIEWS = BUILDER_ENABLED_VIEWS;
 
 export const useBuilderStore = defineStore(STORES.BUILDER, () => {
 	// Core state
-	const chatWidth = ref<number>(DEFAULT_CHAT_WIDTH);
 	const chatMessages = ref<ChatUI.AssistantMessage[]>([]);
-	const chatWindowOpen = ref<boolean>(false);
 	const streaming = ref<boolean>(false);
 	const assistantThinkingMessage = ref<string | undefined>();
 	const streamingAbortController = ref<AbortController | null>(null);
@@ -54,11 +47,11 @@ export const useBuilderStore = defineStore(STORES.BUILDER, () => {
 	const creditsClaimed = ref<number | undefined>();
 
 	// Store dependencies
+	const chatPanelStateStore = useChatPanelStateStore();
 	const settings = useSettingsStore();
 	const rootStore = useRootStore();
 	const workflowsStore = useWorkflowsStore();
 	const workflowState = injectWorkflowState();
-	const uiStore = useUIStore();
 	const credentialsStore = useCredentialsStore();
 	const nodeTypesStore = useNodeTypesStore();
 
@@ -99,7 +92,12 @@ export const useBuilderStore = defineStore(STORES.BUILDER, () => {
 		() => isAssistantEnabled.value && EDITABLE_CANVAS_VIEWS.includes(route.name as VIEWS),
 	);
 
-	const isAssistantOpen = computed(() => canShowAssistant.value && chatWindowOpen.value);
+	const isAssistantOpen = computed(
+		() =>
+			canShowAssistant.value &&
+			chatPanelStateStore.isOpen &&
+			chatPanelStateStore.activeMode === 'builder',
+	);
 
 	const isAIBuilderEnabled = computed(() => {
 		// Check license first
@@ -160,62 +158,6 @@ export const useBuilderStore = defineStore(STORES.BUILDER, () => {
 		initialGeneration.value = false;
 	}
 
-	/**
-	 * Opens the chat panel and adjusts the canvas viewport to make room.
-	 */
-	async function openChat() {
-		chatMessages.value = [];
-		await fetchBuilderCredits();
-		await loadSessions();
-		uiStore.appGridDimensions = {
-			...uiStore.appGridDimensions,
-			width: window.innerWidth - chatWidth.value,
-		};
-		chatWindowOpen.value = true;
-	}
-
-	/**
-	 * Closes the chat panel with a delayed viewport restoration.
-	 * The delay (ASK_AI_SLIDE_OUT_DURATION_MS + 50ms) ensures the slide-out animation
-	 * completes before expanding the canvas, preventing visual jarring.
-	 * Messages remain in memory.
-	 */
-	function closeChat() {
-		chatWindowOpen.value = false;
-		// Looks smoother if we wait for slide animation to finish before updating the grid width
-		// Has to wait for longer than SlideTransition duration
-		setTimeout(() => {
-			if (!window) {
-				return; // for unit testing
-			}
-
-			uiStore.appGridDimensions = {
-				...uiStore.appGridDimensions,
-				width: window.innerWidth,
-			};
-		}, ASK_AI_SLIDE_OUT_DURATION_MS + 50);
-	}
-
-	/**
-	 * Toggles between open and closed state for the chat panel.
-	 */
-	async function toggleChat() {
-		if (isAssistantOpen.value) {
-			closeChat();
-		} else {
-			await openChat();
-		}
-	}
-
-	/**
-	 * Updates chat panel width with enforced boundaries.
-	 * Width is clamped between MIN_CHAT_WIDTH (330px) and MAX_CHAT_WIDTH (650px)
-	 * to ensure usability on various screen sizes.
-	 */
-	function updateWindowWidth(width: number) {
-		chatWidth.value = Math.min(Math.max(width, MIN_CHAT_WIDTH), MAX_CHAT_WIDTH);
-	}
-
 	// Message handling functions
 	function addLoadingAssistantMessage(message: string) {
 		assistantThinkingMessage.value = message;
@@ -570,6 +512,11 @@ export const useBuilderStore = defineStore(STORES.BUILDER, () => {
 		return JSON.stringify(pick(workflowsStore.workflow, ['nodes', 'connections']));
 	}
 
+	function updateBuilderCredits(quota?: number, claimed?: number) {
+		creditsQuota.value = quota;
+		creditsClaimed.value = claimed;
+	}
+
 	async function fetchBuilderCredits() {
 		const releaseExperimentVariant = posthogStore.getVariant(
 			WORKFLOW_BUILDER_RELEASE_EXPERIMENT.name,
@@ -581,39 +528,21 @@ export const useBuilderStore = defineStore(STORES.BUILDER, () => {
 		try {
 			const response = await getBuilderCredits(rootStore.restApiContext);
 			updateBuilderCredits(response.creditsQuota, response.creditsClaimed);
-		} catch (error) {
+		} catch {
 			// Keep default values on error
 		}
 	}
 
-	function updateBuilderCredits(quota?: number, claimed?: number) {
-		creditsQuota.value = quota;
-		creditsClaimed.value = claimed;
-	}
-
-	// Watch for route changes and close chat when leaving enabled views
-	watch(
-		() => route.name,
-		(newRoute) => {
-			// Close the chat window when navigating away from canvas/enabled views
-			if (!ENABLED_VIEWS.includes(newRoute as VIEWS) && chatWindowOpen.value) {
-				chatWindowOpen.value = false;
-			}
-		},
-	);
-
 	// Public API
 	return {
 		// State
 		isAssistantEnabled,
 		canShowAssistantButtonsOnCanvas,
-		chatWidth,
 		chatMessages,
 		streaming,
 		isAssistantOpen,
 		canShowAssistant,
 		assistantThinkingMessage,
-		chatWindowOpen,
 		isAIBuilderEnabled,
 		workflowPrompt,
 		toolMessages,
@@ -627,11 +556,7 @@ export const useBuilderStore = defineStore(STORES.BUILDER, () => {
 		hasNoCreditsRemaining,
 
 		// Methods
-		updateWindowWidth,
 		stopStreaming,
-		closeChat,
-		openChat,
-		toggleChat,
 		resetBuilderChat,
 		sendChatMessage,
 		loadSessions,
diff --git a/packages/frontend/editor-ui/src/features/assistant/chatPanel.store.test.ts b/packages/frontend/editor-ui/src/features/assistant/chatPanel.store.test.ts
new file mode 100644
index 00000000000..803e0e0a61d
--- /dev/null
+++ b/packages/frontend/editor-ui/src/features/assistant/chatPanel.store.test.ts
@@ -0,0 +1,362 @@
+import { describe, it, expect, beforeEach, vi, afterEach } from 'vitest';
+import { setActivePinia } from 'pinia';
+import { createTestingPinia } from '@pinia/testing';
+import {
+	useChatPanelStore,
+	DEFAULT_CHAT_WIDTH,
+	MIN_CHAT_WIDTH,
+	MAX_CHAT_WIDTH,
+} from './chatPanel.store';
+import { useChatPanelStateStore } from './chatPanelState.store';
+import { useUIStore } from '@/stores/ui.store';
+import { useAssistantStore } from '@/features/assistant/assistant.store';
+import { useBuilderStore } from './builder.store';
+import { ASSISTANT_ENABLED_VIEWS, BUILDER_ENABLED_VIEWS } from './constants';
+import { VIEWS } from '@/constants';
+import { reactive } from 'vue';
+import { mockedStore } from '@/__tests__/utils';
+import type { ICredentialType } from 'n8n-workflow';
+import type { ChatRequest } from '@/features/assistant/assistant.types';
+import type { ChatUI } from '@n8n/design-system/types/assistant';
+
+// Mock vue-router
+const mockRoute = reactive({ name: VIEWS.WORKFLOW });
+vi.mock('vue-router', () => ({
+	useRoute: () => mockRoute,
+}));
+
+// Mock window.innerWidth
+Object.defineProperty(window, 'innerWidth', {
+	writable: true,
+	configurable: true,
+	value: 1920,
+});
+
+describe('chatPanel.store', () => {
+	let chatPanelStore: ReturnType<typeof useChatPanelStore>;
+	let chatPanelStateStore: ReturnType<typeof useChatPanelStateStore>;
+	let uiStore: ReturnType<typeof mockedStore<typeof useUIStore>>;
+	let assistantStore: ReturnType<typeof mockedStore<typeof useAssistantStore>>;
+	let builderStore: ReturnType<typeof mockedStore<typeof useBuilderStore>>;
+
+	beforeEach(() => {
+		vi.clearAllTimers();
+		vi.useFakeTimers();
+
+		setActivePinia(
+			createTestingPinia({
+				createSpy: vi.fn,
+				stubActions: false, // Don't stub actions so actual store logic runs
+			}),
+		);
+
+		chatPanelStateStore = useChatPanelStateStore();
+		uiStore = mockedStore(useUIStore);
+		assistantStore = mockedStore(useAssistantStore);
+		builderStore = mockedStore(useBuilderStore);
+
+		// Reset to default route
+		mockRoute.name = VIEWS.WORKFLOW;
+
+		// Mock store methods
+		assistantStore.initCredHelp = vi.fn().mockResolvedValue(undefined);
+		assistantStore.initErrorHelper = vi.fn().mockResolvedValue(undefined);
+		assistantStore.resetAssistantChat = vi.fn();
+		assistantStore.isSessionEnded = false;
+		assistantStore.chatMessages = [];
+
+		builderStore.fetchBuilderCredits = vi.fn().mockResolvedValue(undefined);
+		builderStore.loadSessions = vi.fn().mockResolvedValue(undefined);
+		builderStore.resetBuilderChat = vi.fn();
+		builderStore.chatMessages = [];
+
+		uiStore.appGridDimensions = { width: 1920, height: 1080 };
+
+		// Initialize chatPanelStore after all mocks are set up
+		chatPanelStore = useChatPanelStore();
+	});
+
+	afterEach(() => {
+		vi.restoreAllMocks();
+		vi.useRealTimers();
+	});
+
+	describe('initialization', () => {
+		it('should initialize with correct default values', () => {
+			expect(chatPanelStore.isOpen).toBe(false);
+			expect(chatPanelStore.width).toBe(DEFAULT_CHAT_WIDTH);
+			expect(chatPanelStore.activeMode).toBe('builder');
+			expect(chatPanelStore.isAssistantModeActive).toBe(false);
+			expect(chatPanelStore.isBuilderModeActive).toBe(true);
+		});
+
+		it('should expose constants', () => {
+			expect(chatPanelStore.DEFAULT_CHAT_WIDTH).toBe(DEFAULT_CHAT_WIDTH);
+			expect(chatPanelStore.MIN_CHAT_WIDTH).toBe(MIN_CHAT_WIDTH);
+			expect(chatPanelStore.MAX_CHAT_WIDTH).toBe(MAX_CHAT_WIDTH);
+		});
+	});
+
+	describe('open', () => {
+		it('should open panel in builder mode', async () => {
+			mockRoute.name = BUILDER_ENABLED_VIEWS[0];
+
+			await chatPanelStore.open({ mode: 'builder' });
+
+			expect(chatPanelStateStore.isOpen).toBe(true);
+			expect(chatPanelStateStore.activeMode).toBe('builder');
+			expect(builderStore.fetchBuilderCredits).toHaveBeenCalled();
+			expect(builderStore.loadSessions).toHaveBeenCalled();
+			expect(uiStore.appGridDimensions.width).toBe(window.innerWidth - DEFAULT_CHAT_WIDTH);
+		});
+
+		it('should open panel in assistant mode', async () => {
+			mockRoute.name = ASSISTANT_ENABLED_VIEWS[0];
+			assistantStore.chatMessages = [
+				{
+					id: '1',
+					role: 'user',
+					type: 'text',
+					content: 'test',
+					read: false,
+				} as ChatUI.AssistantMessage,
+			];
+
+			await chatPanelStore.open({ mode: 'assistant' });
+
+			expect(chatPanelStateStore.isOpen).toBe(true);
+			expect(chatPanelStateStore.activeMode).toBe('assistant');
+			expect(assistantStore.chatMessages[0].read).toBe(true);
+		});
+
+		it('should close panel if mode is not enabled in current view', async () => {
+			mockRoute.name = VIEWS.HOMEPAGE; // Not in BUILDER_ENABLED_VIEWS
+
+			await chatPanelStore.open({ mode: 'builder' });
+
+			expect(chatPanelStateStore.isOpen).toBe(false);
+		});
+
+		it('should not change mode if no mode option provided', async () => {
+			mockRoute.name = BUILDER_ENABLED_VIEWS[0];
+			chatPanelStateStore.activeMode = 'builder';
+
+			await chatPanelStore.open();
+
+			expect(chatPanelStateStore.activeMode).toBe('builder');
+		});
+	});
+
+	describe('close', () => {
+		beforeEach(async () => {
+			mockRoute.name = BUILDER_ENABLED_VIEWS[0];
+			await chatPanelStore.open({ mode: 'builder' });
+		});
+
+		it('should close panel immediately', () => {
+			chatPanelStore.close();
+
+			expect(chatPanelStateStore.isOpen).toBe(false);
+		});
+
+		it('should reset UI grid dimensions after timeout', () => {
+			chatPanelStore.close();
+
+			vi.runAllTimers();
+
+			expect(uiStore.appGridDimensions.width).toBe(window.innerWidth);
+		});
+
+		it('should reset builder chat after timeout', () => {
+			chatPanelStore.close();
+
+			vi.runAllTimers();
+
+			expect(builderStore.resetBuilderChat).toHaveBeenCalled();
+		});
+
+		it('should reset assistant chat only if session ended', () => {
+			assistantStore.isSessionEnded = true;
+
+			chatPanelStore.close();
+			vi.runAllTimers();
+
+			expect(assistantStore.resetAssistantChat).toHaveBeenCalled();
+		});
+
+		it('should not reset assistant chat if session not ended', () => {
+			assistantStore.isSessionEnded = false;
+
+			chatPanelStore.close();
+			vi.runAllTimers();
+
+			expect(assistantStore.resetAssistantChat).not.toHaveBeenCalled();
+		});
+	});
+
+	describe('toggle', () => {
+		it('should open panel when closed', async () => {
+			mockRoute.name = BUILDER_ENABLED_VIEWS[0];
+			expect(chatPanelStateStore.isOpen).toBe(false);
+
+			await chatPanelStore.toggle({ mode: 'builder' });
+
+			expect(chatPanelStateStore.isOpen).toBe(true);
+		});
+
+		it('should close panel when open', async () => {
+			mockRoute.name = BUILDER_ENABLED_VIEWS[0];
+			await chatPanelStore.open({ mode: 'builder' });
+			expect(chatPanelStateStore.isOpen).toBe(true);
+
+			await chatPanelStore.toggle();
+
+			expect(chatPanelStateStore.isOpen).toBe(false);
+		});
+	});
+
+	describe('switchMode', () => {
+		beforeEach(async () => {
+			mockRoute.name = ASSISTANT_ENABLED_VIEWS[0]; // Supports both modes
+			await chatPanelStore.open({ mode: 'builder' });
+		});
+
+		it('should switch from builder to assistant mode', () => {
+			chatPanelStore.switchMode('assistant');
+
+			expect(chatPanelStateStore.activeMode).toBe('assistant');
+			expect(chatPanelStore.isAssistantModeActive).toBe(true);
+			expect(chatPanelStore.isBuilderModeActive).toBe(false);
+		});
+
+		it('should switch from assistant to builder mode', () => {
+			chatPanelStateStore.activeMode = 'assistant';
+
+			chatPanelStore.switchMode('builder');
+
+			expect(chatPanelStateStore.activeMode).toBe('builder');
+			expect(chatPanelStore.isAssistantModeActive).toBe(false);
+			expect(chatPanelStore.isBuilderModeActive).toBe(true);
+		});
+
+		it('should close panel if mode not enabled in current view', () => {
+			mockRoute.name = VIEWS.HOMEPAGE; // Only supports assistant
+
+			chatPanelStore.switchMode('builder');
+
+			expect(chatPanelStateStore.isOpen).toBe(false);
+		});
+	});
+
+	describe('updateWidth', () => {
+		it('should update width within bounds', () => {
+			chatPanelStore.updateWidth(410);
+
+			expect(chatPanelStateStore.width).toBe(410);
+		});
+
+		it('should clamp width to MIN_CHAT_WIDTH', () => {
+			chatPanelStore.updateWidth(200);
+
+			expect(chatPanelStateStore.width).toBe(MIN_CHAT_WIDTH);
+		});
+
+		it('should clamp width to MAX_CHAT_WIDTH', () => {
+			chatPanelStore.updateWidth(500);
+
+			expect(chatPanelStateStore.width).toBe(MAX_CHAT_WIDTH);
+		});
+
+		it('should update UI grid dimensions when panel is open', async () => {
+			mockRoute.name = BUILDER_ENABLED_VIEWS[0];
+			await chatPanelStore.open({ mode: 'builder' });
+
+			chatPanelStore.updateWidth(420);
+
+			expect(uiStore.appGridDimensions.width).toBe(window.innerWidth - 420);
+		});
+
+		it('should not update UI grid dimensions when panel is closed', () => {
+			const initialWidth = uiStore.appGridDimensions.width;
+
+			chatPanelStore.updateWidth(420);
+
+			expect(uiStore.appGridDimensions.width).toBe(initialWidth);
+		});
+	});
+
+	describe('openWithCredHelp', () => {
+		it('should initialize cred help and open in assistant mode', async () => {
+			mockRoute.name = ASSISTANT_ENABLED_VIEWS[0];
+			const credType: ICredentialType = {
+				name: 'googleSheetsOAuth2Api',
+				displayName: 'Google Sheets OAuth2 API',
+				properties: [],
+			};
+
+			await chatPanelStore.openWithCredHelp(credType);
+
+			expect(assistantStore.initCredHelp).toHaveBeenCalledWith(credType);
+			expect(chatPanelStateStore.isOpen).toBe(true);
+			expect(chatPanelStateStore.activeMode).toBe('assistant');
+		});
+	});
+
+	describe('openWithErrorHelper', () => {
+		it('should initialize error helper and open in assistant mode', async () => {
+			mockRoute.name = ASSISTANT_ENABLED_VIEWS[0];
+			const errorContext: ChatRequest.ErrorContext = {
+				error: {
+					name: 'TestError',
+					message: 'test error',
+				},
+				node: {
+					id: 'node-1',
+					name: 'Test Node',
+					type: 'n8n-nodes-base.test',
+					typeVersion: 1,
+					position: [0, 0],
+					parameters: {},
+				},
+			};
+
+			await chatPanelStore.openWithErrorHelper(errorContext);
+
+			expect(assistantStore.initErrorHelper).toHaveBeenCalledWith(errorContext);
+			expect(chatPanelStateStore.isOpen).toBe(true);
+			expect(chatPanelStateStore.activeMode).toBe('assistant');
+		});
+	});
+
+	describe('computed properties', () => {
+		it('should compute isAssistantModeActive correctly', () => {
+			chatPanelStateStore.activeMode = 'assistant';
+			expect(chatPanelStore.isAssistantModeActive).toBe(true);
+			expect(chatPanelStore.isBuilderModeActive).toBe(false);
+		});
+
+		it('should compute isBuilderModeActive correctly', () => {
+			chatPanelStateStore.activeMode = 'builder';
+			expect(chatPanelStore.isBuilderModeActive).toBe(true);
+			expect(chatPanelStore.isAssistantModeActive).toBe(false);
+		});
+
+		it('should expose isOpen as computed', () => {
+			chatPanelStateStore.isOpen = true;
+			expect(chatPanelStore.isOpen).toBe(true);
+
+			chatPanelStateStore.isOpen = false;
+			expect(chatPanelStore.isOpen).toBe(false);
+		});
+
+		it('should expose width as computed', () => {
+			chatPanelStateStore.width = 420;
+			expect(chatPanelStore.width).toBe(420);
+		});
+
+		it('should expose activeMode as computed', () => {
+			chatPanelStateStore.activeMode = 'assistant';
+			expect(chatPanelStore.activeMode).toBe('assistant');
+		});
+	});
+});
diff --git a/packages/frontend/editor-ui/src/features/assistant/chatPanel.store.ts b/packages/frontend/editor-ui/src/features/assistant/chatPanel.store.ts
new file mode 100644
index 00000000000..26a57d7078c
--- /dev/null
+++ b/packages/frontend/editor-ui/src/features/assistant/chatPanel.store.ts
@@ -0,0 +1,199 @@
+import { computed, watch } from 'vue';
+import { defineStore } from 'pinia';
+import { STORES } from '@n8n/stores';
+import { useUIStore } from '@/stores/ui.store';
+import { useRoute } from 'vue-router';
+import { ASK_AI_SLIDE_OUT_DURATION_MS } from '@/constants';
+import type { VIEWS } from '@/constants';
+import { ASSISTANT_ENABLED_VIEWS, BUILDER_ENABLED_VIEWS } from './constants';
+import { useChatPanelStateStore, type ChatPanelMode } from './chatPanelState.store';
+import { useAssistantStore } from './assistant.store';
+import { useBuilderStore } from './builder.store';
+import type { ICredentialType } from 'n8n-workflow';
+import type { ChatRequest } from './assistant.types';
+
+export const MAX_CHAT_WIDTH = 425;
+export const MIN_CHAT_WIDTH = 380;
+export const DEFAULT_CHAT_WIDTH = 400;
+
+/**
+ * Type guard to check if a route name is a valid VIEWS value within the enabled views
+ * Performs runtime validation to safely narrow the type without unsafe assertions
+ */
+function isEnabledView(
+	route: string | symbol | undefined,
+	views: readonly VIEWS[],
+): route is VIEWS {
+	return typeof route === 'string' && (views as readonly string[]).includes(route);
+}
+
+export const useChatPanelStore = defineStore(STORES.CHAT_PANEL, () => {
+	const uiStore = useUIStore();
+	const route = useRoute();
+	const chatPanelStateStore = useChatPanelStateStore();
+
+	// Computed
+	const isAssistantModeActive = computed(() => chatPanelStateStore.activeMode === 'assistant');
+	const isBuilderModeActive = computed(() => chatPanelStateStore.activeMode === 'builder');
+
+	// Actions
+	async function open(options?: { mode?: ChatPanelMode }) {
+		const mode = options?.mode;
+		if (mode) {
+			chatPanelStateStore.activeMode = mode;
+		}
+
+		// Check if the mode is enabled in the current view
+		const enabledViews =
+			chatPanelStateStore.activeMode === 'assistant'
+				? ASSISTANT_ENABLED_VIEWS
+				: BUILDER_ENABLED_VIEWS;
+		const currentRoute = route?.name;
+
+		if (!isEnabledView(currentRoute, enabledViews)) {
+			// Mode is not enabled in current view, close the panel instead
+			close();
+			return;
+		}
+
+		// Handle mode-specific initialization
+		if (chatPanelStateStore.activeMode === 'builder') {
+			const builderStore = useBuilderStore();
+			builderStore.chatMessages = [];
+			await builderStore.fetchBuilderCredits();
+			await builderStore.loadSessions();
+		} else if (chatPanelStateStore.activeMode === 'assistant') {
+			const assistantStore = useAssistantStore();
+			assistantStore.chatMessages = assistantStore.chatMessages.map((msg) => ({
+				...msg,
+				read: true,
+			}));
+		}
+
+		chatPanelStateStore.isOpen = true;
+		// Update UI grid dimensions when opening
+		uiStore.appGridDimensions = {
+			...uiStore.appGridDimensions,
+			width: window.innerWidth - chatPanelStateStore.width,
+		};
+	}
+
+	function close() {
+		chatPanelStateStore.isOpen = false;
+		// Wait for slide animation to finish before updating grid width and resetting
+		setTimeout(() => {
+			uiStore.appGridDimensions = {
+				...uiStore.appGridDimensions,
+				width: window.innerWidth,
+			};
+
+			const assistantStore = useAssistantStore();
+			const builderStore = useBuilderStore();
+
+			// Reset assistant only if session has ended
+			if (assistantStore.isSessionEnded) {
+				assistantStore.resetAssistantChat();
+			}
+
+			// Always reset builder
+			builderStore.resetBuilderChat();
+		}, ASK_AI_SLIDE_OUT_DURATION_MS + 50);
+	}
+
+	async function toggle(options?: { mode?: ChatPanelMode }) {
+		if (chatPanelStateStore.isOpen) {
+			close();
+		} else {
+			await open(options);
+		}
+	}
+
+	function switchMode(mode: ChatPanelMode) {
+		// Check if the mode is enabled in the current view
+		const enabledViews = mode === 'assistant' ? ASSISTANT_ENABLED_VIEWS : BUILDER_ENABLED_VIEWS;
+		const currentRoute = route?.name;
+
+		if (!isEnabledView(currentRoute, enabledViews)) {
+			// Mode is not enabled in current view, close the panel
+			close();
+			return;
+		}
+
+		// Switch the mode without re-initialization
+		chatPanelStateStore.activeMode = mode;
+	}
+
+	function updateWidth(newWidth: number) {
+		const clampedWidth = Math.min(Math.max(newWidth, MIN_CHAT_WIDTH), MAX_CHAT_WIDTH);
+		chatPanelStateStore.width = clampedWidth;
+		if (chatPanelStateStore.isOpen) {
+			uiStore.appGridDimensions = {
+				...uiStore.appGridDimensions,
+				width: window.innerWidth - clampedWidth,
+			};
+		}
+	}
+
+	/**
+	 * Opens assistant with credential help context
+	 */
+	async function openWithCredHelp(credentialType: ICredentialType) {
+		const assistantStore = useAssistantStore();
+		await assistantStore.initCredHelp(credentialType);
+		await open({ mode: 'assistant' });
+	}
+
+	/**
+	 * Opens assistant with error helper context
+	 */
+	async function openWithErrorHelper(context: ChatRequest.ErrorContext) {
+		const assistantStore = useAssistantStore();
+		await assistantStore.initErrorHelper(context);
+		await open({ mode: 'assistant' });
+	}
+
+	// Watch route changes and close if panel can't be shown in current view
+	watch(
+		() => route?.name,
+		(newRoute) => {
+			if (!chatPanelStateStore.isOpen || !newRoute) {
+				return;
+			}
+			const builderStore = useBuilderStore();
+
+			const enabledViews =
+				chatPanelStateStore.activeMode === 'assistant'
+					? ASSISTANT_ENABLED_VIEWS
+					: BUILDER_ENABLED_VIEWS;
+
+			if (!isEnabledView(newRoute, enabledViews)) {
+				close();
+			} else if (isEnabledView(newRoute, BUILDER_ENABLED_VIEWS)) {
+				// If entering an editable canvas view with builder mode active, refresh state
+				builderStore.resetBuilderChat();
+			}
+		},
+	);
+
+	return {
+		// State - expose from chatPanelStateStore
+		isOpen: computed(() => chatPanelStateStore.isOpen),
+		width: computed(() => chatPanelStateStore.width),
+		activeMode: computed(() => chatPanelStateStore.activeMode),
+		// Computed
+		isAssistantModeActive,
+		isBuilderModeActive,
+		// Actions
+		open,
+		close,
+		toggle,
+		switchMode,
+		updateWidth,
+		openWithCredHelp,
+		openWithErrorHelper,
+		// Constants
+		DEFAULT_CHAT_WIDTH,
+		MIN_CHAT_WIDTH,
+		MAX_CHAT_WIDTH,
+	};
+});
diff --git a/packages/frontend/editor-ui/src/features/assistant/chatPanelState.store.ts b/packages/frontend/editor-ui/src/features/assistant/chatPanelState.store.ts
new file mode 100644
index 00000000000..8171beb8991
--- /dev/null
+++ b/packages/frontend/editor-ui/src/features/assistant/chatPanelState.store.ts
@@ -0,0 +1,24 @@
+import { ref } from 'vue';
+import { defineStore } from 'pinia';
+import { STORES } from '@n8n/stores';
+
+export type ChatPanelMode = 'assistant' | 'builder';
+
+export const DEFAULT_CHAT_WIDTH = 400;
+
+/**
+ * Shared reactive state for chat panel that can be imported without circular dependencies.
+ * This is a simple store that only holds state, no actions.
+ * Updated by chatPanel.store.ts, read by assistant/builder stores.
+ */
+export const useChatPanelStateStore = defineStore(STORES.CHAT_PANEL_STATE, () => {
+	const isOpen = ref(false);
+	const width = ref(DEFAULT_CHAT_WIDTH);
+	const activeMode = ref<ChatPanelMode>('builder');
+
+	return {
+		isOpen,
+		width,
+		activeMode,
+	};
+});
diff --git a/packages/frontend/editor-ui/src/features/assistant/components/Agent/AskAssistantBuild.test.ts b/packages/frontend/editor-ui/src/features/assistant/components/Agent/AskAssistantBuild.test.ts
index 6fc8259fb7d..da671c265d4 100644
--- a/packages/frontend/editor-ui/src/features/assistant/components/Agent/AskAssistantBuild.test.ts
+++ b/packages/frontend/editor-ui/src/features/assistant/components/Agent/AskAssistantBuild.test.ts
@@ -89,7 +89,7 @@ import { fireEvent } from '@testing-library/vue';
 import { faker } from '@faker-js/faker';
 
 import AskAssistantBuild from './AskAssistantBuild.vue';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '../../builder.store';
 import { mockedStore } from '@/__tests__/utils';
 import { STORES } from '@n8n/stores';
 import { useWorkflowsStore } from '@/stores/workflows.store';
diff --git a/packages/frontend/editor-ui/src/features/assistant/components/Agent/AskAssistantBuild.vue b/packages/frontend/editor-ui/src/features/assistant/components/Agent/AskAssistantBuild.vue
index f56fd0481ce..16f3af159ca 100644
--- a/packages/frontend/editor-ui/src/features/assistant/components/Agent/AskAssistantBuild.vue
+++ b/packages/frontend/editor-ui/src/features/assistant/components/Agent/AskAssistantBuild.vue
@@ -1,5 +1,5 @@
 <script lang="ts" setup>
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '../../builder.store';
 import { useUsersStore } from '@/stores/users.store';
 import { computed, watch, ref } from 'vue';
 import { useTelemetry } from '@/composables/useTelemetry';
diff --git a/packages/frontend/editor-ui/src/features/assistant/components/Agent/ExecuteMessage.test.ts b/packages/frontend/editor-ui/src/features/assistant/components/Agent/ExecuteMessage.test.ts
index 4e7d5241597..bd20efa2009 100644
--- a/packages/frontend/editor-ui/src/features/assistant/components/Agent/ExecuteMessage.test.ts
+++ b/packages/frontend/editor-ui/src/features/assistant/components/Agent/ExecuteMessage.test.ts
@@ -13,7 +13,7 @@ import { CHAT_TRIGGER_NODE_TYPE } from '@/constants';
 import { useWorkflowsStore } from '@/stores/workflows.store';
 import { useNodeTypesStore } from '@/stores/nodeTypes.store';
 import { useLogsStore } from '@/stores/logs.store';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '../../builder.store';
 
 const workflowValidationIssuesRef = ref<
 	Array<{ node: string; type: string; value: string | string[] }>
diff --git a/packages/frontend/editor-ui/src/features/assistant/components/Agent/ExecuteMessage.vue b/packages/frontend/editor-ui/src/features/assistant/components/Agent/ExecuteMessage.vue
index 1b694b1f588..2e127a35071 100644
--- a/packages/frontend/editor-ui/src/features/assistant/components/Agent/ExecuteMessage.vue
+++ b/packages/frontend/editor-ui/src/features/assistant/components/Agent/ExecuteMessage.vue
@@ -15,7 +15,7 @@ import { isChatNode } from '@/utils/aiUtils';
 import { useToast } from '@/composables/useToast';
 import { N8nTooltip } from '@n8n/design-system';
 import { nextTick } from 'vue';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '../../builder.store';
 
 interface Emits {
 	/** Emitted when workflow execution completes */
diff --git a/packages/frontend/editor-ui/src/features/assistant/components/AssistantsHub.vue b/packages/frontend/editor-ui/src/features/assistant/components/AssistantsHub.vue
index a73628d5bba..eda84270c4b 100644
--- a/packages/frontend/editor-ui/src/features/assistant/components/AssistantsHub.vue
+++ b/packages/frontend/editor-ui/src/features/assistant/components/AssistantsHub.vue
@@ -1,30 +1,42 @@
 <script lang="ts" setup>
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '@/features/assistant/builder.store';
+import { useChatPanelStore } from '@/features/assistant/chatPanel.store';
 import { useAssistantStore } from '@/features/assistant/assistant.store';
 import { useDebounce } from '@/composables/useDebounce';
 import { computed, onBeforeUnmount, ref } from 'vue';
 import SlideTransition from '@/components/transitions/SlideTransition.vue';
 import AskAssistantBuild from './Agent/AskAssistantBuild.vue';
 import AskAssistantChat from './Chat/AskAssistantChat.vue';
+import { useRoute } from 'vue-router';
+import { BUILDER_ENABLED_VIEWS } from '../constants';
+import type { VIEWS } from '@/constants';
 
 import { N8nResizeWrapper } from '@n8n/design-system';
 import HubSwitcher from '@/features/assistant/components/HubSwitcher.vue';
 
 const builderStore = useBuilderStore();
 const assistantStore = useAssistantStore();
+const chatPanelStore = useChatPanelStore();
+const route = useRoute();
 
 const askAssistantBuildRef = ref<InstanceType<typeof AskAssistantBuild>>();
 const askAssistantChatRef = ref<InstanceType<typeof AskAssistantChat>>();
 
-const isBuildMode = ref(builderStore.isAIBuilderEnabled);
+const isBuildMode = computed(() => chatPanelStore.isBuilderModeActive);
+const chatWidth = computed(() => chatPanelStore.width);
 
-const chatWidth = computed(() => {
-	return isBuildMode.value ? builderStore.chatWidth : assistantStore.chatWidth;
+// Show toggle only when both modes are available in current view
+const canToggleModes = computed(() => {
+	const currentRoute = route?.name;
+	return (
+		builderStore.isAIBuilderEnabled &&
+		currentRoute &&
+		BUILDER_ENABLED_VIEWS.includes(currentRoute as VIEWS)
+	);
 });
 
 function onResize(data: { direction: string; x: number; width: number }) {
-	builderStore.updateWindowWidth(data.width);
-	assistantStore.updateWindowWidth(data.width);
+	chatPanelStore.updateWidth(data.width);
 }
 
 function onResizeDebounced(data: { direction: string; x: number; width: number }) {
@@ -32,38 +44,33 @@ function onResizeDebounced(data: { direction: string; x: number; width: number }
 }
 
 async function toggleAssistantMode() {
-	const wasOpen = builderStore.isAssistantOpen || assistantStore.isAssistantOpen;
+	const wasOpen = chatPanelStore.isOpen;
 	const switchingToBuild = !isBuildMode.value;
-
-	isBuildMode.value = !isBuildMode.value;
+	const newMode = switchingToBuild ? 'builder' : 'assistant';
 
 	if (wasOpen) {
-		// If chat is already open, just toggle the window flags without reloading
 		if (switchingToBuild) {
-			// Load sessions first if builder has no messages
+			// Load sessions before switching mode if builder has no messages
 			if (builderStore.chatMessages.length === 0) {
 				await builderStore.fetchBuilderCredits();
 				await builderStore.loadSessions();
 			}
-			builderStore.chatWindowOpen = true;
-			assistantStore.chatWindowOpen = false;
-		} else {
-			assistantStore.chatWindowOpen = true;
-			builderStore.chatWindowOpen = false;
 		}
+
+		// Now switch the mode - data is already loaded
+		chatPanelStore.switchMode(newMode);
 	} else {
 		// Opening from closed state - use full open logic
-		if (isBuildMode.value) {
-			await builderStore.openChat();
+		if (switchingToBuild) {
+			await chatPanelStore.open({ mode: 'builder' });
 		} else {
-			assistantStore.openChat();
+			await chatPanelStore.open({ mode: 'assistant' });
 		}
 	}
 }
 
 function onClose() {
-	builderStore.closeChat();
-	assistantStore.closeChat();
+	chatPanelStore.close();
 }
 
 function onSlideEnterComplete() {
@@ -77,14 +84,14 @@ function onSlideEnterComplete() {
 const unsubscribeAssistantStore = assistantStore.$onAction(({ name }) => {
 	// When assistant is opened from error or credentials help
 	// switch from build mode to chat mode
-	if (['toggleChat', 'openChat', 'initErrorHelper', 'initCredHelp'].includes(name)) {
-		isBuildMode.value = false;
+	if (['initErrorHelper', 'initCredHelp'].includes(name)) {
+		chatPanelStore.switchMode('assistant');
 	}
 });
 
 const unsubscribeBuilderStore = builderStore.$onAction(({ name }) => {
-	if (['toggleChat', 'openChat', 'sendChatMessage'].includes(name)) {
-		isBuildMode.value = true;
+	if (['sendChatMessage'].includes(name)) {
+		chatPanelStore.switchMode('builder');
 	}
 });
 
@@ -97,9 +104,11 @@ onBeforeUnmount(() => {
 <template>
 	<SlideTransition @after-enter="onSlideEnterComplete">
 		<N8nResizeWrapper
-			v-show="builderStore.isAssistantOpen || assistantStore.isAssistantOpen"
+			v-show="chatPanelStore.isOpen"
 			:supported-directions="['left']"
 			:width="chatWidth"
+			:min-width="chatPanelStore.MIN_CHAT_WIDTH"
+			:max-width="chatPanelStore.MAX_CHAT_WIDTH"
 			:class="$style.resizeWrapper"
 			data-test-id="ask-assistant-sidebar"
 			@resize="onResizeDebounced"
@@ -107,13 +116,13 @@ onBeforeUnmount(() => {
 			<div :style="{ width: `${chatWidth}px` }" :class="$style.wrapper">
 				<div :class="$style.assistantContent">
 					<AskAssistantBuild v-if="isBuildMode" ref="askAssistantBuildRef" @close="onClose">
-						<template #header>
+						<template v-if="canToggleModes" #header>
 							<HubSwitcher :is-build-mode="isBuildMode" @toggle="toggleAssistantMode" />
 						</template>
 					</AskAssistantBuild>
 					<AskAssistantChat v-else ref="askAssistantChatRef" @close="onClose">
-						<!-- Header switcher is only visible when AIBuilder is enabled -->
-						<template v-if="builderStore.isAIBuilderEnabled" #header>
+						<!-- Header switcher is only visible when both modes are available in current view -->
+						<template v-if="canToggleModes" #header>
 							<HubSwitcher :is-build-mode="isBuildMode" @toggle="toggleAssistantMode" />
 						</template>
 					</AskAssistantChat>
diff --git a/packages/frontend/editor-ui/src/features/assistant/components/Chat/AskAssistantFloatingButton.vue b/packages/frontend/editor-ui/src/features/assistant/components/Chat/AskAssistantFloatingButton.vue
index 89a319ba478..ba337117fee 100644
--- a/packages/frontend/editor-ui/src/features/assistant/components/Chat/AskAssistantFloatingButton.vue
+++ b/packages/frontend/editor-ui/src/features/assistant/components/Chat/AskAssistantFloatingButton.vue
@@ -2,13 +2,15 @@
 import { useI18n } from '@n8n/i18n';
 import { useStyles } from '@/composables/useStyles';
 import { useAssistantStore } from '@/features/assistant/assistant.store';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '../../builder.store';
+import { useChatPanelStore } from '../../chatPanel.store';
 import { computed } from 'vue';
 
 import { N8nAskAssistantButton, N8nAssistantAvatar, N8nTooltip } from '@n8n/design-system';
 
 const assistantStore = useAssistantStore();
 const builderStore = useBuilderStore();
+const chatPanelStore = useChatPanelStore();
 const i18n = useI18n();
 const { APP_Z_INDEXES } = useStyles();
 
@@ -28,11 +30,17 @@ const lastUnread = computed(() => {
 
 const onClick = async () => {
 	if (builderStore.isAIBuilderEnabled) {
-		await builderStore.toggleChat();
+		// Toggle with appropriate mode based on current state
+		if (chatPanelStore.isOpen && chatPanelStore.isBuilderModeActive) {
+			chatPanelStore.close();
+		} else {
+			await chatPanelStore.open({ mode: 'builder' });
+		}
 	} else {
-		assistantStore.toggleChat();
+		// For assistant-only mode
+		await chatPanelStore.toggle({ mode: 'assistant' });
 	}
-	if (builderStore.isAssistantOpen || assistantStore.isAssistantOpen) {
+	if (chatPanelStore.isOpen) {
 		assistantStore.trackUserOpenedAssistant({
 			source: 'canvas',
 			task: 'placeholder',
diff --git a/packages/frontend/editor-ui/src/features/assistant/components/Chat/NewAssistantSessionModal.vue b/packages/frontend/editor-ui/src/features/assistant/components/Chat/NewAssistantSessionModal.vue
index 05a27402d59..05bd8f279b4 100644
--- a/packages/frontend/editor-ui/src/features/assistant/components/Chat/NewAssistantSessionModal.vue
+++ b/packages/frontend/editor-ui/src/features/assistant/components/Chat/NewAssistantSessionModal.vue
@@ -3,14 +3,17 @@ import { NEW_ASSISTANT_SESSION_MODAL } from '@/constants';
 import Modal from '@/components/Modal.vue';
 import { useI18n } from '@n8n/i18n';
 import { useUIStore } from '@/stores/ui.store';
+import { useChatPanelStore } from '../../chatPanel.store';
 import type { ChatRequest } from '@/features/assistant/assistant.types';
 import { useAssistantStore } from '@/features/assistant/assistant.store';
 import type { ICredentialType } from 'n8n-workflow';
 
 import { N8nAssistantIcon, N8nAssistantText, N8nButton, N8nText } from '@n8n/design-system';
+
 const i18n = useI18n();
 const uiStore = useUIStore();
 const assistantStore = useAssistantStore();
+const chatPanelStore = useChatPanelStore();
 
 const props = defineProps<{
 	name: string;
@@ -25,14 +28,14 @@ const close = () => {
 
 const startNewSession = async () => {
 	if ('errorHelp' in props.data.context) {
-		await assistantStore.initErrorHelper(props.data.context.errorHelp);
+		await chatPanelStore.openWithErrorHelper(props.data.context.errorHelp);
 		assistantStore.trackUserOpenedAssistant({
 			source: 'error',
 			task: 'error',
 			has_existing_session: true,
 		});
 	} else if ('credHelp' in props.data.context) {
-		await assistantStore.initCredHelp(props.data.context.credHelp.credType);
+		await chatPanelStore.openWithCredHelp(props.data.context.credHelp.credType);
 	}
 	close();
 };
@@ -80,6 +83,7 @@ const startNewSession = async () => {
 	p {
 		line-height: normal;
 	}
+
 	p + p {
 		margin-top: 10px;
 	}
diff --git a/packages/frontend/editor-ui/src/features/assistant/constants.ts b/packages/frontend/editor-ui/src/features/assistant/constants.ts
new file mode 100644
index 00000000000..3a7d101e928
--- /dev/null
+++ b/packages/frontend/editor-ui/src/features/assistant/constants.ts
@@ -0,0 +1,20 @@
+import { EDITABLE_CANVAS_VIEWS, VIEWS } from '@/constants';
+
+/**
+ * Views where the Assistant chat panel can be shown
+ */
+export const ASSISTANT_ENABLED_VIEWS = [
+	...EDITABLE_CANVAS_VIEWS,
+	VIEWS.EXECUTION_PREVIEW,
+	VIEWS.WORKFLOWS,
+	VIEWS.CREDENTIALS,
+	VIEWS.PROJECTS_CREDENTIALS,
+	VIEWS.PROJECTS_WORKFLOWS,
+	VIEWS.PROJECT_SETTINGS,
+	VIEWS.TEMPLATE_SETUP,
+];
+
+/**
+ * Views where the Builder chat panel can be shown
+ */
+export const BUILDER_ENABLED_VIEWS = [...EDITABLE_CANVAS_VIEWS];
diff --git a/packages/frontend/editor-ui/src/views/NodeView.vue b/packages/frontend/editor-ui/src/views/NodeView.vue
index c432a804781..21f61e3af78 100644
--- a/packages/frontend/editor-ui/src/views/NodeView.vue
+++ b/packages/frontend/editor-ui/src/views/NodeView.vue
@@ -122,7 +122,7 @@ import { shouldIgnoreCanvasShortcut } from '@/utils/canvasUtils';
 import { getSampleWorkflowByTemplateId } from '@/features/templates/utils/workflowSamples';
 import type { CanvasLayoutEvent } from '@/composables/useCanvasLayout';
 import { useWorkflowSaving } from '@/composables/useWorkflowSaving';
-import { useBuilderStore } from '@/stores/builder.store';
+import { useBuilderStore } from '@/features/assistant/builder.store';
 import { usePostHog } from '@/stores/posthog.store';
 import KeyboardShortcutTooltip from '@/components/KeyboardShortcutTooltip.vue';
 import { useWorkflowExtraction } from '@/composables/useWorkflowExtraction';