feat: added a welcome msg for local LLM users

public/chat/welcome_local_llm.md

@@ -0,0 +1,21 @@
+## Local LLM Mode
+
+Welcome to **K.G.Studio Musician Assistant** in local LLM mode.
+
+- No external API calls are required. Everything runs directly in your browser, with no extra API cost.
+- This mode uses **Gemma 4 E4B** through **LiteRT-LM** with **WebGPU** acceleration.
+- Recommended hardware: a GPU with at least **8 GB VRAM** or a system with at least **16 GB unified RAM**.
+- Performance is more limited than larger cloud-hosted models, especially on harder planning, editing, and multi-step tasks.
+
+### Recommended Workflow
+- Keep requests small and focused.
+- Guide the model step by step toward the final goal.
+- Work on smaller music regions instead of large full-song edits.
+- Prefer simpler music arrangements when possible.
+- Start a new conversation for each standalone task.
+
+### Use an External LLM Instead
+- If you want a larger cloud or self-hosted model, open **Settings -> General -> LLM Provider** and switch away from **Local LLM (Browser)**.
+- For a cloud model, you can use **OpenAI**, or choose **OpenAI Compatible** and enter a provider such as OpenRouter.
+- For a self-hosted model, choose **OpenAI Compatible** and enter your server's **Base URL** and **Model**.
+- After switching providers, start a new conversation so the chat uses the new model cleanly.

src/util/messageFilter/UserMessageFilter.test.ts

@@ -0,0 +1,109 @@
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+import { processUserMessage } from './UserMessageFilter';
+import { addWelcomeMessage } from '../../utils/chatMessageUtils';
+
+const configState = new Map<string, unknown>();
+
+const configManagerMock = {
+  getIsInitialized: vi.fn(() => true),
+  initialize: vi.fn().mockResolvedValue(undefined),
+  get: vi.fn((key: string) => configState.get(key)),
+};
+
+vi.mock('../../core/config/ConfigManager', () => ({
+  ConfigManager: {
+    instance: () => configManagerMock,
+  },
+}));
+
+vi.mock('../chatUtil', () => ({
+  clearChatHistoryAndUI: vi.fn(),
+}));
+
+vi.mock('../../stores/projectStore', () => ({
+  useProjectStore: {
+    getState: () => ({
+      setStatus: vi.fn(),
+      activeRegionId: null,
+      selectedRegionIds: [],
+    }),
+  },
+}));
+
+vi.mock('../../agent/core/SystemPrompts', () => ({
+  SystemPrompts: {
+    getPromptWithContext: vi.fn(async (value: string) => value),
+  },
+}));
+
+describe('processUserMessage /welcome', () => {
+  beforeEach(() => {
+    configState.clear();
+    configState.set('general.llm_provider', 'local_browser');
+    configState.set('general.openai.api_key', '');
+    configState.set('general.gemini.api_key', '');
+    configState.set('general.claude.api_key', '');
+    configState.set('general.claude_openrouter.api_key', '');
+    configState.set('general.openai_compatible.base_url', '');
+    configState.set('general.openai_compatible.model', '');
+
+    configManagerMock.getIsInitialized.mockReturnValue(true);
+    configManagerMock.initialize.mockClear();
+    configManagerMock.get.mockClear();
+
+    vi.stubGlobal('fetch', vi.fn(async (input: string | URL | Request) => {
+      const url = String(input);
+      return {
+        ok: true,
+        status: 200,
+        text: async () => `content:${url}`,
+      };
+    }));
+  });
+
+  it('uses the local welcome for the local browser provider', async () => {
+    configState.set('general.llm_provider', 'local_browser');
+    configState.set('general.openai.api_key', '');
+    configState.set('general.openai_compatible.base_url', '');
+    configState.set('general.openai_compatible.model', '');
+
+    const result = await processUserMessage('/welcome');
+
+    expect(fetch).toHaveBeenCalledWith(expect.stringContaining('chat/welcome_local_llm.md'));
+    expect(result.metadata).toMatchObject({ command: 'welcome', variant: 'local' });
+    expect(result.pseudoAssistantResponse).toContain('welcome_local_llm.md');
+  });
+
+  it('uses the new-user welcome for non-local providers without required config', async () => {
+    configState.set('general.llm_provider', 'openai');
+    configState.set('general.openai.api_key', '');
+
+    const result = await processUserMessage('/welcome');
+
+    expect(fetch).toHaveBeenCalledWith(expect.stringContaining('chat/welcome_new.md'));
+    expect(result.metadata).toMatchObject({ command: 'welcome', variant: 'new' });
+    expect(result.pseudoAssistantResponse).toContain('welcome_new.md');
+  });
+
+  it('uses the returning-user welcome for configured non-local providers', async () => {
+    configState.set('general.llm_provider', 'openai_compatible');
+    configState.set('general.openai_compatible.base_url', 'https://openrouter.ai/api/v1');
+    configState.set('general.openai_compatible.model', 'qwen/qwen3-30b-a3b:free');
+
+    const result = await processUserMessage('/welcome');
+
+    expect(fetch).toHaveBeenCalledWith(expect.stringContaining('chat/welcome_again.md'));
+    expect(result.metadata).toMatchObject({ command: 'welcome', variant: 'again' });
+    expect(result.pseudoAssistantResponse).toContain('welcome_again.md');
+  });
+
+  it('reuses the same welcome routing through addWelcomeMessage', async () => {
+    configState.set('general.llm_provider', 'local_browser');
+
+    const message = await addWelcomeMessage();
+
+    expect(fetch).toHaveBeenCalledWith(expect.stringContaining('chat/welcome_local_llm.md'));
+    expect(message?.role).toBe('assistant');
+    expect(message?.content).toContain('welcome_local_llm.md');
+  });
+});

src/util/messageFilter/UserMessageFilter.ts

@@ -17,6 +17,48 @@ export interface UserMessageFilterResult {
   metadata?: Record<string, unknown>;
 }
 
+function hasText(value: unknown): boolean {
+  return typeof value === 'string' && value.trim() !== '';
+}
+
+function getWelcomeVariant(configManager: ConfigManager): 'local' | 'new' | 'again' {
+  const provider = (configManager.get('general.llm_provider') as string) || LOCAL_LLM_PROVIDER_KEY;
+
+  if (provider === LOCAL_LLM_PROVIDER_KEY) {
+    return 'local';
+  }
+
+  switch (provider) {
+    case 'openai':
+      return hasText(configManager.get('general.openai.api_key')) ? 'again' : 'new';
+    case 'gemini':
+      return hasText(configManager.get('general.gemini.api_key')) ? 'again' : 'new';
+    case 'claude':
+      return hasText(configManager.get('general.claude.api_key')) ? 'again' : 'new';
+    case 'claude_openrouter':
+      return hasText(configManager.get('general.claude_openrouter.api_key')) ? 'again' : 'new';
+    case 'openai_compatible':
+      return hasText(configManager.get('general.openai_compatible.base_url'))
+        && hasText(configManager.get('general.openai_compatible.model'))
+        ? 'again'
+        : 'new';
+    default:
+      return 'new';
+  }
+}
+
+function getWelcomeUrl(variant: 'local' | 'new' | 'again'): string {
+  switch (variant) {
+    case 'local':
+      return `${import.meta.env.BASE_URL}chat/welcome_local_llm.md`;
+    case 'again':
+      return `${import.meta.env.BASE_URL}chat/welcome_again.md`;
+    case 'new':
+    default:
+      return `${import.meta.env.BASE_URL}chat/welcome_new.md`;
+  }
+}
+
 /**
  * Process a user message before it is displayed or sent to the LLM.
  * Handles slash-commands and returns a structured decision.
@@ -53,12 +95,8 @@ export async function processUserMessage(originalMessage: string): Promise<UserM
             await configManager.initialize();
           }
 
-          const openaiKey = (configManager.get('general.openai.api_key') as string) || '';
-          const oaiCompatKey = (configManager.get('general.openai_compatible.api_key') as string) || '';
-          const oaiCompatBaseUrl = (configManager.get('general.openai_compatible.base_url') as string) || '';
-          const isNew = openaiKey.trim() === '' && oaiCompatKey.trim() === '' && oaiCompatBaseUrl.trim() === '';
-
-          const url = isNew ? `${import.meta.env.BASE_URL}chat/welcome_new.md` : `${import.meta.env.BASE_URL}chat/welcome_again.md`;
+          const variant = getWelcomeVariant(configManager);
+          const url = getWelcomeUrl(variant);
           const resp = await fetch(url);
           if (!resp.ok) {
             throw new Error(`Failed to fetch ${url}: ${resp.status}`);
@@ -69,7 +107,7 @@ export async function processUserMessage(originalMessage: string): Promise<UserM
             sendToLLM: false,
             finalMessageForLLM: null,
             pseudoAssistantResponse: md,
-            metadata: { command: 'welcome', variant: isNew ? 'new' : 'again' }
+            metadata: { command: 'welcome', variant }
           };
         } catch (err) {
           const fallback = 'Welcome to K.G.Studio Musician Assistant.';
@@ -267,4 +305,3 @@ export async function processUserMessage(originalMessage: string): Promise<UserM
     };
   }
 }
-