diff --git a/apps/server-e2e/src/ai_settings.spec.ts b/apps/server-e2e/src/ai_settings.spec.ts
new file mode 100644
index 000000000..bd3df1c8b
--- /dev/null
+++ b/apps/server-e2e/src/ai_settings.spec.ts
@@ -0,0 +1,251 @@
+import { test, expect } from "@playwright/test";
+import App from "./support/app";
+
+test.describe("AI Settings", () => {
+    test("Should access AI settings page", async ({ page, context }) => {
+        page.setDefaultTimeout(15_000);
+
+        const app = new App(page, context);
+        await app.goto();
+
+        // Go to settings
+        await app.goToSettings();
+        
+        // Navigate to AI settings
+        await app.clickNoteOnNoteTreeByTitle("AI Settings");
+        
+        // Verify we're on the AI settings page
+        await expect(app.currentNoteSplitTitle).toHaveValue("AI Settings");
+        
+        // Check that AI settings content is visible
+        const aiSettingsContent = app.currentNoteSplitContent;
+        await aiSettingsContent.waitFor({ state: "visible" });
+        
+        // Verify basic AI settings elements are present
+        await expect(aiSettingsContent).toBeVisible();
+    });
+
+    test("Should toggle AI features", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Go to AI settings
+        await app.goToSettings();
+        await app.clickNoteOnNoteTreeByTitle("AI Settings");
+        
+        // Look for AI enable/disable toggle
+        const aiToggle = app.currentNoteSplitContent.locator('input[type="checkbox"]').first();
+        
+        if (await aiToggle.isVisible()) {
+            // Get initial state
+            const initialState = await aiToggle.isChecked();
+            
+            // Toggle the setting
+            await aiToggle.click();
+            
+            // Wait for the change to be saved
+            await page.waitForTimeout(1000);
+            
+            // Verify the state changed
+            const newState = await aiToggle.isChecked();
+            expect(newState).toBe(!initialState);
+            
+            // Toggle back to original state
+            await aiToggle.click();
+            await page.waitForTimeout(1000);
+            
+            // Verify we're back to the original state
+            const finalState = await aiToggle.isChecked();
+            expect(finalState).toBe(initialState);
+        }
+    });
+
+    test("Should configure AI provider settings", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Go to AI settings
+        await app.goToSettings();
+        await app.clickNoteOnNoteTreeByTitle("AI Settings");
+        
+        // Look for provider configuration elements
+        const settingsContent = app.currentNoteSplitContent;
+        
+        // Check for common AI provider setting elements
+        const providerSelects = settingsContent.locator('select');
+        const apiKeyInputs = settingsContent.locator('input[type="password"], input[type="text"]');
+        
+        if (await providerSelects.count() > 0) {
+            // Test provider selection
+            const firstSelect = providerSelects.first();
+            await firstSelect.click();
+            
+            // Verify options are available
+            const options = firstSelect.locator('option');
+            const optionCount = await options.count();
+            expect(optionCount).toBeGreaterThan(0);
+        }
+        
+        if (await apiKeyInputs.count() > 0) {
+            // Test API key field interaction (without actually setting a key)
+            const firstInput = apiKeyInputs.first();
+            await firstInput.click();
+            
+            // Verify the field is interactive
+            await expect(firstInput).toBeFocused();
+        }
+    });
+
+    test("Should display AI model options", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Go to AI settings
+        await app.goToSettings();
+        await app.clickNoteOnNoteTreeByTitle("AI Settings");
+        
+        const settingsContent = app.currentNoteSplitContent;
+        
+        // Look for model selection elements
+        const modelSelects = settingsContent.locator('select').filter({ hasText: /model|gpt|claude|llama/i });
+        
+        if (await modelSelects.count() > 0) {
+            const modelSelect = modelSelects.first();
+            await modelSelect.click();
+            
+            // Verify model options are present
+            const options = modelSelect.locator('option');
+            const optionCount = await options.count();
+            expect(optionCount).toBeGreaterThanOrEqual(1);
+        }
+    });
+
+    test("Should save AI settings changes", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Go to AI settings
+        await app.goToSettings();
+        await app.clickNoteOnNoteTreeByTitle("AI Settings");
+        
+        const settingsContent = app.currentNoteSplitContent;
+        
+        // Look for save button or auto-save indication
+        const saveButton = settingsContent.locator('button').filter({ hasText: /save|apply/i });
+        
+        if (await saveButton.count() > 0) {
+            // Test save functionality
+            await saveButton.first().click();
+            
+            // Wait for save to complete
+            await page.waitForTimeout(1000);
+            
+            // Look for success indication (toast, message, etc.)
+            const successMessage = page.locator('.toast, .notification, .success-message');
+            if (await successMessage.count() > 0) {
+                await expect(successMessage.first()).toBeVisible();
+            }
+        }
+    });
+
+    test("Should handle invalid AI configuration", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Go to AI settings
+        await app.goToSettings();
+        await app.clickNoteOnNoteTreeByTitle("AI Settings");
+        
+        const settingsContent = app.currentNoteSplitContent;
+        
+        // Look for API key input to test invalid configuration
+        const apiKeyInput = settingsContent.locator('input[type="password"], input[type="text"]').first();
+        
+        if (await apiKeyInput.isVisible()) {
+            // Enter invalid API key
+            await apiKeyInput.fill("invalid-api-key-test");
+            
+            // Look for test/validate button
+            const testButton = settingsContent.locator('button').filter({ hasText: /test|validate|check/i });
+            
+            if (await testButton.count() > 0) {
+                await testButton.first().click();
+                
+                // Wait for validation
+                await page.waitForTimeout(2000);
+                
+                // Look for error message
+                const errorMessage = page.locator('.error, .alert-danger, .text-danger');
+                if (await errorMessage.count() > 0) {
+                    await expect(errorMessage.first()).toBeVisible();
+                }
+            }
+            
+            // Clear the invalid input
+            await apiKeyInput.fill("");
+        }
+    });
+
+    test("Should navigate between AI setting sections", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Go to AI settings
+        await app.goToSettings();
+        await app.clickNoteOnNoteTreeByTitle("AI Settings");
+        
+        // Look for sub-sections or tabs in AI settings
+        const tabs = app.currentNoteSplitContent.locator('.nav-tabs a, .tab-header, .section-header');
+        
+        if (await tabs.count() > 1) {
+            // Test navigation between sections
+            const firstTab = tabs.first();
+            const secondTab = tabs.nth(1);
+            
+            await firstTab.click();
+            await page.waitForTimeout(500);
+            
+            await secondTab.click();
+            await page.waitForTimeout(500);
+            
+            // Verify navigation worked by checking if content changed
+            await expect(app.currentNoteSplitContent).toBeVisible();
+        }
+    });
+
+    test("Should display AI feature documentation", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Go to AI settings
+        await app.goToSettings();
+        await app.clickNoteOnNoteTreeByTitle("AI Settings");
+        
+        const settingsContent = app.currentNoteSplitContent;
+        
+        // Look for help or documentation links
+        const helpLinks = settingsContent.locator('a').filter({ hasText: /help|documentation|learn more|guide/i });
+        const helpButtons = settingsContent.locator('button, .help-icon, .info-icon').filter({ hasText: /\?|help|info/i });
+        
+        if (await helpLinks.count() > 0) {
+            // Test help link accessibility
+            const firstHelpLink = helpLinks.first();
+            await expect(firstHelpLink).toBeVisible();
+        }
+        
+        if (await helpButtons.count() > 0) {
+            // Test help button functionality
+            const helpButton = helpButtons.first();
+            await helpButton.click();
+            
+            // Wait for help content to appear
+            await page.waitForTimeout(1000);
+            
+            // Look for help modal or tooltip
+            const helpContent = page.locator('.modal, .tooltip, .popover, .help-content');
+            if (await helpContent.count() > 0) {
+                await expect(helpContent.first()).toBeVisible();
+            }
+        }
+    });
+});
\ No newline at end of file
diff --git a/apps/server-e2e/src/llm_chat.spec.ts b/apps/server-e2e/src/llm_chat.spec.ts
new file mode 100644
index 000000000..73c5ed86c
--- /dev/null
+++ b/apps/server-e2e/src/llm_chat.spec.ts
@@ -0,0 +1,377 @@
+import { test, expect } from "@playwright/test";
+import App from "./support/app";
+
+test.describe("LLM Chat Features", () => {
+    test("Should access LLM chat interface", async ({ page, context }) => {
+        page.setDefaultTimeout(15_000);
+
+        const app = new App(page, context);
+        await app.goto();
+
+        // Look for AI/LLM chat access points in the interface
+        // This could be a launcher button, menu item, or widget
+        const aiButtons = page.locator('[data-trigger-command*="ai"], [data-trigger-command*="llm"], [data-trigger-command*="chat"]');
+        const aiMenuItems = page.locator('a, button').filter({ hasText: /ai chat|llm|assistant|chat/i });
+        
+        // Try the launcher bar first
+        const launcherAiButton = app.launcherBar.locator('.launcher-button').filter({ hasText: /ai|chat|assistant/i });
+        
+        if (await launcherAiButton.count() > 0) {
+            await launcherAiButton.first().click();
+            
+            // Wait for chat interface to load
+            await page.waitForTimeout(1000);
+            
+            // Look for chat interface elements
+            const chatInterface = page.locator('.llm-chat, .ai-chat, .chat-widget, .chat-panel');
+            if (await chatInterface.count() > 0) {
+                await expect(chatInterface.first()).toBeVisible();
+            }
+        } else if (await aiButtons.count() > 0) {
+            await aiButtons.first().click();
+            await page.waitForTimeout(1000);
+        } else if (await aiMenuItems.count() > 0) {
+            await aiMenuItems.first().click();
+            await page.waitForTimeout(1000);
+        }
+        
+        // Verify some form of AI/chat interface is accessible
+        const possibleChatElements = page.locator('.chat, .llm, .ai, [class*="chat"], [class*="llm"], [class*="ai"]');
+        const elementCount = await possibleChatElements.count();
+        
+        // If no specific chat elements found, at least verify the page is responsive
+        if (elementCount === 0) {
+            await expect(app.currentNoteSplit).toBeVisible();
+        }
+    });
+
+    test("Should create new LLM chat session", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Try to trigger new chat creation
+        await app.triggerCommand("openLlmChat");
+        await page.waitForTimeout(1000);
+        
+        // Alternative: Look for chat creation buttons
+        const newChatButtons = page.locator('button, a').filter({ hasText: /new chat|create chat|start chat/i });
+        
+        if (await newChatButtons.count() > 0) {
+            await newChatButtons.first().click();
+            await page.waitForTimeout(1000);
+        }
+        
+        // Look for chat input elements
+        const chatInputs = page.locator('textarea, input[type="text"]').filter({ hasText: /message|chat|type/i });
+        const possibleChatInputs = page.locator('textarea[placeholder*="message"], textarea[placeholder*="chat"], input[placeholder*="message"]');
+        
+        if (await chatInputs.count() > 0) {
+            await expect(chatInputs.first()).toBeVisible();
+        } else if (await possibleChatInputs.count() > 0) {
+            await expect(possibleChatInputs.first()).toBeVisible();
+        }
+    });
+
+    test("Should handle chat message input", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Try to access chat interface
+        try {
+            await app.triggerCommand("openLlmChat");
+            await page.waitForTimeout(1000);
+        } catch (error) {
+            // If command doesn't exist, continue with alternative methods
+        }
+        
+        // Look for message input areas
+        const messageInputs = page.locator('textarea, input[type="text"]');
+        const chatAreas = page.locator('[contenteditable="true"]');
+        
+        // Try to find and interact with chat input
+        for (let i = 0; i < await messageInputs.count(); i++) {
+            const input = messageInputs.nth(i);
+            const placeholder = await input.getAttribute('placeholder') || '';
+            
+            if (placeholder.toLowerCase().includes('message') || 
+                placeholder.toLowerCase().includes('chat') ||
+                placeholder.toLowerCase().includes('type')) {
+                
+                // Test message input
+                await input.click();
+                await input.fill("Hello, this is a test message for the LLM chat.");
+                
+                // Look for send button
+                const sendButtons = page.locator('button').filter({ hasText: /send|submit/i });
+                const enterHint = page.locator('.hint, .help-text').filter({ hasText: /enter|send/i });
+                
+                if (await sendButtons.count() > 0) {
+                    // Don't actually send to avoid API calls in tests
+                    await expect(sendButtons.first()).toBeVisible();
+                } else if (await enterHint.count() > 0) {
+                    // Test Enter key functionality indication
+                    await expect(enterHint.first()).toBeVisible();
+                }
+                
+                // Clear the input
+                await input.fill("");
+                break;
+            }
+        }
+    });
+
+    test("Should display chat history", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Try to access chat interface
+        try {
+            await app.triggerCommand("openLlmChat");
+            await page.waitForTimeout(1000);
+        } catch (error) {
+            // Continue with alternative access methods
+        }
+        
+        // Look for chat history or previous conversations
+        const chatHistory = page.locator('.chat-history, .conversation-list, .message-list');
+        const previousChats = page.locator('.chat-item, .conversation-item');
+        
+        if (await chatHistory.count() > 0) {
+            await expect(chatHistory.first()).toBeVisible();
+        }
+        
+        if (await previousChats.count() > 0) {
+            // Test clicking on a previous chat
+            await previousChats.first().click();
+            await page.waitForTimeout(500);
+            
+            // Look for loaded conversation
+            const messages = page.locator('.message, .chat-message');
+            if (await messages.count() > 0) {
+                await expect(messages.first()).toBeVisible();
+            }
+        }
+    });
+
+    test("Should handle chat settings and configuration", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Try to access chat interface
+        try {
+            await app.triggerCommand("openLlmChat");
+            await page.waitForTimeout(1000);
+        } catch (error) {
+            // Continue
+        }
+        
+        // Look for chat settings or configuration options
+        const settingsButtons = page.locator('button, a').filter({ hasText: /settings|config|options|preferences/i });
+        const gearIcons = page.locator('.fa-cog, .fa-gear, .bx-cog, .settings-icon');
+        
+        if (await settingsButtons.count() > 0) {
+            await settingsButtons.first().click();
+            await page.waitForTimeout(1000);
+            
+            // Look for settings panel
+            const settingsPanel = page.locator('.settings-panel, .config-panel, .options-panel');
+            if (await settingsPanel.count() > 0) {
+                await expect(settingsPanel.first()).toBeVisible();
+            }
+        } else if (await gearIcons.count() > 0) {
+            await gearIcons.first().click();
+            await page.waitForTimeout(1000);
+        }
+        
+        // Look for common chat settings
+        const temperatureSliders = page.locator('input[type="range"]');
+        const modelSelects = page.locator('select');
+        
+        if (await temperatureSliders.count() > 0) {
+            // Test temperature adjustment
+            const slider = temperatureSliders.first();
+            await slider.click();
+            await expect(slider).toBeVisible();
+        }
+        
+        if (await modelSelects.count() > 0) {
+            // Test model selection
+            const select = modelSelects.first();
+            await select.click();
+            
+            const options = select.locator('option');
+            if (await options.count() > 1) {
+                await expect(options.nth(1)).toBeVisible();
+            }
+        }
+    });
+
+    test("Should handle context and note integration", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Create or select a note first
+        await app.addNewTab();
+        
+        // Try to access chat with note context
+        try {
+            await app.triggerCommand("openLlmChatWithContext");
+            await page.waitForTimeout(1000);
+        } catch (error) {
+            // Try alternative method
+            try {
+                await app.triggerCommand("openLlmChat");
+                await page.waitForTimeout(1000);
+            } catch (error2) {
+                // Continue with UI-based approach
+            }
+        }
+        
+        // Look for context integration features
+        const contextButtons = page.locator('button, a').filter({ hasText: /context|include note|add note/i });
+        const atMentions = page.locator('[data-mention], .mention-button');
+        
+        if (await contextButtons.count() > 0) {
+            await contextButtons.first().click();
+            await page.waitForTimeout(1000);
+            
+            // Look for note selection interface
+            const noteSelector = page.locator('.note-selector, .note-picker');
+            if (await noteSelector.count() > 0) {
+                await expect(noteSelector.first()).toBeVisible();
+            }
+        }
+        
+        if (await atMentions.count() > 0) {
+            await atMentions.first().click();
+            await page.waitForTimeout(1000);
+        }
+    });
+
+    test("Should display AI provider status", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Try to access chat interface
+        try {
+            await app.triggerCommand("openLlmChat");
+            await page.waitForTimeout(1000);
+        } catch (error) {
+            // Continue
+        }
+        
+        // Look for AI provider status indicators
+        const statusIndicators = page.locator('.status-indicator, .connection-status, .provider-status');
+        const providerLabels = page.locator('.provider-name, .model-name');
+        const errorMessages = page.locator('.error-message, .alert').filter({ hasText: /api|provider|connection/i });
+        
+        if (await statusIndicators.count() > 0) {
+            await expect(statusIndicators.first()).toBeVisible();
+        }
+        
+        if (await providerLabels.count() > 0) {
+            const label = providerLabels.first();
+            await expect(label).toBeVisible();
+            
+            // Verify it contains a known provider name
+            const text = await label.textContent();
+            const knownProviders = ['openai', 'anthropic', 'claude', 'gpt', 'ollama'];
+            const hasKnownProvider = knownProviders.some(provider => 
+                text?.toLowerCase().includes(provider)
+            );
+            
+            // Either has a known provider or at least some text
+            expect(text?.length).toBeGreaterThan(0);
+        }
+        
+        if (await errorMessages.count() > 0) {
+            // If there are error messages, they should be visible
+            await expect(errorMessages.first()).toBeVisible();
+        }
+    });
+
+    test("Should handle chat export and sharing", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Try to access chat interface
+        try {
+            await app.triggerCommand("openLlmChat");
+            await page.waitForTimeout(1000);
+        } catch (error) {
+            // Continue
+        }
+        
+        // Look for export or sharing features
+        const exportButtons = page.locator('button, a').filter({ hasText: /export|download|save|share/i });
+        const menuButtons = page.locator('.menu-button, .dropdown-toggle');
+        
+        if (await exportButtons.count() > 0) {
+            await exportButtons.first().click();
+            await page.waitForTimeout(1000);
+            
+            // Look for export options
+            const exportOptions = page.locator('.export-options, .download-options');
+            if (await exportOptions.count() > 0) {
+                await expect(exportOptions.first()).toBeVisible();
+            }
+        }
+        
+        if (await menuButtons.count() > 0) {
+            await menuButtons.first().click();
+            await page.waitForTimeout(500);
+            
+            // Look for menu items
+            const menuItems = page.locator('.dropdown-menu a, .menu-item');
+            if (await menuItems.count() > 0) {
+                const exportMenuItem = menuItems.filter({ hasText: /export|download|save/i });
+                if (await exportMenuItem.count() > 0) {
+                    await expect(exportMenuItem.first()).toBeVisible();
+                }
+            }
+        }
+    });
+
+    test("Should handle keyboard shortcuts in chat", async ({ page, context }) => {
+        const app = new App(page, context);
+        await app.goto();
+
+        // Try to access chat interface
+        try {
+            await app.triggerCommand("openLlmChat");
+            await page.waitForTimeout(1000);
+        } catch (error) {
+            // Continue
+        }
+        
+        // Look for message input to test keyboard shortcuts
+        const messageInputs = page.locator('textarea');
+        
+        if (await messageInputs.count() > 0) {
+            const input = messageInputs.first();
+            await input.click();
+            
+            // Test common keyboard shortcuts
+            // Ctrl+Enter or Enter for sending
+            await input.fill("Test message for keyboard shortcuts");
+            
+            // Test Ctrl+A for select all
+            await input.press('Control+a');
+            
+            // Test Escape for clearing/canceling
+            await input.press('Escape');
+            
+            // Verify input is still functional
+            await expect(input).toBeVisible();
+            await expect(input).toBeFocused();
+        }
+        
+        // Test global chat shortcuts
+        try {
+            await page.press('body', 'Control+Shift+l'); // Common LLM chat shortcut
+            await page.waitForTimeout(500);
+        } catch (error) {
+            // Shortcut might not exist, that's fine
+        }
+    });
+});
\ No newline at end of file
diff --git a/apps/server/src/routes/api/llm.spec.ts b/apps/server/src/routes/api/llm.spec.ts
new file mode 100644
index 000000000..76da95f13
--- /dev/null
+++ b/apps/server/src/routes/api/llm.spec.ts
@@ -0,0 +1,355 @@
+import { Application } from "express";
+import { beforeAll, describe, expect, it, vi, beforeEach } from "vitest";
+import supertest from "supertest";
+import config from "../../services/config.js";
+
+// Import the login utility from ETAPI tests
+async function login(app: Application) {
+    // Obtain auth token.
+    const response = await supertest(app)
+        .post("/etapi/auth/login")
+        .send({
+            "password": "demo1234"
+        })
+        .expect(201);
+    const token = response.body.authToken;
+    expect(token).toBeTruthy();
+    return token;
+}
+
+let app: Application;
+
+describe("LLM API Tests", () => {
+    let token: string;
+    let createdChatId: string;
+
+    beforeAll(async () => {
+        // Enable authentication and use ETAPI auth (bypasses CSRF)
+        config.General.noAuthentication = false;
+        const buildApp = (await import("../../app.js")).default;
+        app = await buildApp();
+        token = await login(app);
+    });
+
+    beforeEach(() => {
+        vi.clearAllMocks();
+    });
+
+    describe("Chat Session Management", () => {
+        it("should create a new chat session", async () => {
+            const response = await supertest(app)
+                .post("/api/llm/chat")
+                .send({
+                    title: "Test Chat Session",
+                    systemPrompt: "You are a helpful assistant for testing.",
+                    temperature: 0.7,
+                    maxTokens: 1000,
+                    model: "gpt-3.5-turbo",
+                    provider: "openai"
+                })
+                .expect(200);
+
+            expect(response.body).toMatchObject({
+                sessionId: expect.any(String),
+                title: "Test Chat Session",
+                createdAt: expect.any(String)
+            });
+
+            createdChatId = response.body.sessionId;
+        });
+
+        it("should list all chat sessions", async () => {
+            const response = await supertest(app)
+                .get("/api/llm/chat")
+                .expect(200);
+
+            expect(response.body).toHaveProperty('sessions');
+            expect(Array.isArray(response.body.sessions)).toBe(true);
+            
+            if (response.body.sessions.length > 0) {
+                expect(response.body.sessions[0]).toMatchObject({
+                    id: expect.any(String),
+                    title: expect.any(String),
+                    createdAt: expect.any(String),
+                    lastActive: expect.any(String),
+                    messageCount: expect.any(Number)
+                });
+            }
+        });
+
+        it("should retrieve a specific chat session", async () => {
+            if (!createdChatId) {
+                // Create a chat first if we don't have one
+                const createResponse = await supertest(app)
+                    .post("/api/llm/chat")
+                    .send({
+                        title: "Test Retrieval Chat"
+                    })
+                    .expect(200);
+                
+                createdChatId = createResponse.body.sessionId;
+            }
+
+            const response = await supertest(app)
+                .get(`/api/llm/chat/${createdChatId}`)
+                .expect(200);
+
+            expect(response.body).toMatchObject({
+                id: createdChatId,
+                title: expect.any(String),
+                messages: expect.any(Array),
+                createdAt: expect.any(String)
+            });
+        });
+
+        it("should update a chat session", async () => {
+            if (!createdChatId) {
+                // Create a chat first if we don't have one
+                const createResponse = await supertest(app)
+                    .post("/api/llm/chat")
+                    .send({
+                        title: "Test Update Chat"
+                    })
+                    .expect(200);
+                
+                createdChatId = createResponse.body.sessionId;
+            }
+
+            const response = await supertest(app)
+                .patch(`/api/llm/chat/${createdChatId}`)
+                .send({
+                    title: "Updated Chat Title",
+                    temperature: 0.8
+                })
+                .expect(200);
+
+            expect(response.body).toMatchObject({
+                id: createdChatId,
+                title: "Updated Chat Title",
+                updatedAt: expect.any(String)
+            });
+        });
+
+        it("should return 404 for non-existent chat session", async () => {
+            await supertest(app)
+                .get("/api/llm/chat/nonexistent-chat-id")
+                .expect(404);
+        });
+    });
+
+    describe("Chat Messaging", () => {
+        let testChatId: string;
+
+        beforeEach(async () => {
+            // Create a fresh chat for each test
+            const createResponse = await supertest(app)
+                .post("/api/llm/chat")
+                .send({
+                    title: "Message Test Chat"
+                })
+                .expect(200);
+            
+            testChatId = createResponse.body.sessionId;
+        });
+
+        it("should handle sending a message to a chat", async () => {
+            const response = await supertest(app)
+                .post(`/api/llm/chat/${testChatId}/messages`)
+                .send({
+                    message: "Hello, how are you?",
+                    options: {
+                        temperature: 0.7,
+                        maxTokens: 100
+                    },
+                    includeContext: false,
+                    useNoteContext: false
+                });
+
+            // The response depends on whether AI is actually configured
+            // We should get either a successful response or an error about AI not being configured
+            expect([200, 400, 500]).toContain(response.status);
+            
+            if (response.status === 200) {
+                expect(response.body).toMatchObject({
+                    response: expect.any(String),
+                    sessionId: testChatId
+                });
+            } else {
+                // AI not configured is expected in test environment
+                expect(response.body).toHaveProperty('error');
+            }
+        });
+
+        it("should handle empty message content", async () => {
+            const response = await supertest(app)
+                .post(`/api/llm/chat/${testChatId}/messages`)
+                .send({
+                    message: "",
+                    options: {}
+                });
+
+            expect([400, 500]).toContain(response.status);
+            expect(response.body).toHaveProperty('error');
+        });
+
+        it("should handle invalid chat ID for messaging", async () => {
+            const response = await supertest(app)
+                .post("/api/llm/chat/invalid-chat-id/messages")
+                .send({
+                    message: "Hello",
+                    options: {}
+                });
+
+            expect([404, 500]).toContain(response.status);
+        });
+    });
+
+    describe("Chat Streaming", () => {
+        let testChatId: string;
+
+        beforeEach(async () => {
+            // Create a fresh chat for each test
+            const createResponse = await supertest(app)
+                .post("/api/llm/chat")
+                .send({
+                    title: "Streaming Test Chat"
+                })
+                .expect(200);
+            
+            testChatId = createResponse.body.sessionId;
+        });
+
+        it("should initiate streaming for a chat message", async () => {
+            const response = await supertest(app)
+                .post(`/api/llm/chat/${testChatId}/messages/stream`)
+                .send({
+                    content: "Tell me a short story",
+                    useAdvancedContext: false,
+                    showThinking: false
+                });
+
+            // The streaming endpoint should immediately return success
+            // indicating that streaming has been initiated
+            expect(response.status).toBe(200);
+            expect(response.body).toMatchObject({
+                success: true,
+                message: "Streaming initiated successfully"
+            });
+        });
+
+        it("should handle empty content for streaming", async () => {
+            const response = await supertest(app)
+                .post(`/api/llm/chat/${testChatId}/messages/stream`)
+                .send({
+                    content: "",
+                    useAdvancedContext: false,
+                    showThinking: false
+                });
+
+            expect(response.status).toBe(400);
+            expect(response.body).toMatchObject({
+                success: false,
+                error: "Content cannot be empty"
+            });
+        });
+
+        it("should handle whitespace-only content for streaming", async () => {
+            const response = await supertest(app)
+                .post(`/api/llm/chat/${testChatId}/messages/stream`)
+                .send({
+                    content: "   \n\t   ",
+                    useAdvancedContext: false,
+                    showThinking: false
+                });
+
+            expect(response.status).toBe(400);
+            expect(response.body).toMatchObject({
+                success: false,
+                error: "Content cannot be empty"
+            });
+        });
+
+        it("should handle invalid chat ID for streaming", async () => {
+            const response = await supertest(app)
+                .post("/api/llm/chat/invalid-chat-id/messages/stream")
+                .send({
+                    content: "Hello",
+                    useAdvancedContext: false,
+                    showThinking: false
+                });
+
+            // Should still return 200 for streaming initiation
+            // Errors would be communicated via WebSocket
+            expect(response.status).toBe(200);
+        });
+
+        it("should handle streaming with note mentions", async () => {
+            const response = await supertest(app)
+                .post(`/api/llm/chat/${testChatId}/messages/stream`)
+                .send({
+                    content: "Tell me about this note",
+                    useAdvancedContext: true,
+                    showThinking: true,
+                    mentions: [
+                        {
+                            noteId: "root",
+                            title: "Root Note"
+                        }
+                    ]
+                });
+
+            expect(response.status).toBe(200);
+            expect(response.body).toMatchObject({
+                success: true,
+                message: "Streaming initiated successfully"
+            });
+        });
+    });
+
+    describe("Error Handling", () => {
+        it("should handle malformed JSON in request body", async () => {
+            const response = await supertest(app)
+                .post("/api/llm/chat")
+                .set('Content-Type', 'application/json')
+                .send('{ invalid json }');
+
+            expect([400, 500]).toContain(response.status);
+        });
+
+        it("should handle missing required fields", async () => {
+            const response = await supertest(app)
+                .post("/api/llm/chat")
+                .send({
+                    // Missing required fields
+                });
+
+            // Should still work as title can be auto-generated
+            expect([200, 400, 500]).toContain(response.status);
+        });
+
+        it("should handle invalid parameter types", async () => {
+            const response = await supertest(app)
+                .post("/api/llm/chat")
+                .send({
+                    title: "Test Chat",
+                    temperature: "invalid", // Should be number
+                    maxTokens: "also-invalid" // Should be number
+                });
+
+            // API should handle type conversion or validation
+            expect([200, 400, 500]).toContain(response.status);
+        });
+    });
+
+    afterAll(async () => {
+        // Clean up: delete any created chats
+        if (createdChatId) {
+            try {
+                await supertest(app)
+                    .delete(`/api/llm/chat/${createdChatId}`);
+            } catch (error) {
+                // Ignore cleanup errors
+            }
+        }
+    });
+});
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