feat: allow user to config Gemma 4 E4B and MDX-NET model download URL

public/config.json

@@ -27,7 +27,11 @@
             "model": ""
         },
         "local_browser": {
-            "context_length": 32768
+            "context_length": 32768,
+            "model_url": "https://huggingface.co/notabilia/gemma-4-E4B-it-litert-lm/resolve/main/gemma-4-E4B-it-web.task"
+        }, 
+        "uvr5_web_runtime": {
+            "mdx_net_model_url": "https://huggingface.co/notabilia/uvr5-models/resolve/main/UVR-MDX-NET-Inst_HQ_3.onnx"
         },
         "soundfont": {
             "base_url": "https://cdn.jsdelivr.net/npm/soundfont-for-samplers/FluidR3_GM/"

src/agent/llm/LocalBrowserLLMProvider.ts

@@ -12,7 +12,7 @@ import {
 import {
   LOCAL_LLM_DEFAULT_CONTEXT_LENGTH,
   LOCAL_LLM_MODEL_FILENAME,
-  LOCAL_LLM_MODEL_URL,
+  LOCAL_LLM_DEFAULT_MODEL_URL,
   normalizeLocalLLMContextLength,
 } from '../../util/localLLMConfig';
 import { LocalLLMModelCache } from '../../util/localLLMModelCache';
@@ -67,12 +67,13 @@ export class LocalBrowserLLMProvider implements LLMProvider {
     }
 
     const maxTokens = this.getConfiguredContextLength();
+    const modelUrl = this.getConfiguredModelUrl();
     console.log(`[localLLM] Initializing with max context length: ${maxTokens} tokens`);
 
     const [{ FilesetResolver, LlmInference }, modelLoad] = await Promise.all([
       this.getMediaPipeModule(),
       LocalLLMModelCache.loadModelReaderWithCache(
-        LOCAL_LLM_MODEL_URL,
+        modelUrl,
         LOCAL_LLM_MODEL_FILENAME,
         progress => {
           LocalLLMModelManager.notifyLoadProgress(progress.receivedBytes, progress.totalBytes, progress.fromCache);
@@ -132,6 +133,16 @@ export class LocalBrowserLLMProvider implements LLMProvider {
     }
   }
 
+  private getConfiguredModelUrl(): string {
+    try {
+      const configManager = ConfigManager.instance();
+      const configured = configManager.get('general.local_browser.model_url');
+      return typeof configured === 'string' && configured.trim() ? configured : LOCAL_LLM_DEFAULT_MODEL_URL;
+    } catch {
+      return LOCAL_LLM_DEFAULT_MODEL_URL;
+    }
+  }
+
   private applyTemplate(message: { role: 'user' | 'model'; text: string }): string {
     const template = PROMPT_TEMPLATE[message.role];
     return `${template.pre}${message.text}${template.post}`;

src/components/KGOnePanel.test.tsx

@@ -5,6 +5,10 @@ import KGOnePanel from './KGOnePanel';
 import { KGAudioRegion } from '../core/region/KGAudioRegion';
 import { KGAudioTrack } from '../core/track/KGAudioTrack';
 
+const { mockLocalSeparatorDownload } = vi.hoisted(() => ({
+  mockLocalSeparatorDownload: vi.fn(async (_url?: string, _filename?: string, _onProgress?: unknown) => undefined),
+}));
+
 let kgoneEnabled = false;
 let selectedRegionIds: string[] = [];
 let localModelCached = false;
@@ -31,6 +35,7 @@ vi.mock('../core/config/ConfigManager', () => ({
       get: (key: string) => {
         if (key === 'general.kgone.enabled') return kgoneEnabled;
         if (key === 'general.kgone.base_url') return 'http://127.0.0.1:8000';
+        if (key === 'general.uvr5_web_runtime.mdx_net_model_url') return 'https://example.com/custom-uvr5.onnx';
         return undefined;
       },
     }),
@@ -79,8 +84,9 @@ vi.mock('../util/audioUtil', () => ({
 vi.mock('../util/localSeparatorModelCache', () => ({
   LocalSeparatorModelCache: {
     exists: vi.fn(async () => localModelCached),
-    download: vi.fn(async () => {
+    download: vi.fn(async (url: string, filename: string, onProgress: (progress: unknown) => void) => {
       localModelCached = true;
+      return mockLocalSeparatorDownload(url, filename, onProgress);
     }),
     delete: vi.fn(async () => {
       localModelCached = false;
@@ -124,6 +130,7 @@ describe('KGOnePanel local separator mode', () => {
       { name: 'Instrumental', blob: new Blob(['instrumental'], { type: 'audio/wav' }) },
       { name: 'Vocals', blob: new Blob(['vocals'], { type: 'audio/wav' }) },
     ];
+    mockLocalSeparatorDownload.mockClear();
     mockRefreshProjectState.mockReset();
     mockExecuteCommand.mockReset();
   });
@@ -155,6 +162,20 @@ describe('KGOnePanel local separator mode', () => {
     expect(screen.getByLabelText('MDX overlap')).toBeInTheDocument();
   });
 
+  it('uses the configured UVR5 model URL when downloading the local model', async () => {
+    render(<KGOnePanel isVisible={true} />);
+
+    fireEvent.click(await screen.findByRole('button', { name: 'Download Model' }));
+
+    await waitFor(() => {
+      expect(mockLocalSeparatorDownload).toHaveBeenCalledWith(
+        'https://example.com/custom-uvr5.onnx',
+        'UVR-MDX-NET-Inst_HQ_3.onnx',
+        expect.any(Function),
+      );
+    });
+  });
+
   it('prompts for an audio region when the model is cached but nothing is selected', async () => {
     localModelCached = true;
 

src/components/KGOnePanel.tsx

@@ -18,7 +18,7 @@ import { showAlert } from '../util/dialogUtil';
 import {
   LOCAL_SEPARATOR_MODEL_CONFIG,
   LOCAL_SEPARATOR_MODEL_FILENAME,
-  LOCAL_SEPARATOR_MODEL_URL,
+  LOCAL_SEPARATOR_DEFAULT_MODEL_URL,
 } from '../util/localSeparatorConfig';
 import { LocalSeparatorModelCache } from '../util/localSeparatorModelCache';
 import { runLocalSeparator } from '../util/localSeparatorRunner';
@@ -959,6 +959,13 @@ const SeparatorTab: React.FC<{ mode: KGOneMode }> = ({ mode }) => {
     return null;
   }, [selectedRegionIds]);
 
+  const getConfiguredLocalSeparatorModelUrl = useCallback(() => {
+    const configured = ConfigManager.instance().get('general.uvr5_web_runtime.mdx_net_model_url');
+    return typeof configured === 'string' && configured.trim()
+      ? configured
+      : LOCAL_SEPARATOR_DEFAULT_MODEL_URL;
+  }, []);
+
   const isGenerating = genStatus !== 'idle' && genStatus !== 'done' && genStatus !== 'error';
 
   const handleDownloadLocalModel = useCallback(async () => {
@@ -969,7 +976,7 @@ const SeparatorTab: React.FC<{ mode: KGOneMode }> = ({ mode }) => {
 
     try {
       await LocalSeparatorModelCache.download(
-        LOCAL_SEPARATOR_MODEL_URL,
+        getConfiguredLocalSeparatorModelUrl(),
         LOCAL_SEPARATOR_MODEL_FILENAME,
         progress => {
           const receivedMb = (progress.receivedBytes / (1024 * 1024)).toFixed(1);
@@ -992,7 +999,7 @@ const SeparatorTab: React.FC<{ mode: KGOneMode }> = ({ mode }) => {
     } finally {
       setIsDownloadingLocalModel(false);
     }
-  }, [refreshLocalModelCacheState]);
+  }, [getConfiguredLocalSeparatorModelUrl, refreshLocalModelCacheState]);
 
   const handleDeleteLocalModel = useCallback(async () => {
     setIsDeletingLocalModel(true);

src/components/settings/sections/GeneralSettings.test.tsx

@@ -3,6 +3,13 @@ import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { fireEvent, render, screen, waitFor } from '@testing-library/react';
 import GeneralSettings from './GeneralSettings';
 
+const { localSeparatorModelCacheMock } = vi.hoisted(() => ({
+  localSeparatorModelCacheMock: {
+    delete: vi.fn().mockResolvedValue(undefined),
+    exists: vi.fn().mockResolvedValue(true),
+  },
+}));
+
 const configState = new Map<string, unknown>([
   ['general.llm_provider', 'local_browser'],
   ['general.persist_api_keys_non_localhost', false],
@@ -20,6 +27,8 @@ const configState = new Map<string, unknown>([
   ['general.openai_compatible.base_url', ''],
   ['general.openai_compatible.model', ''],
   ['general.local_browser.context_length', 65536],
+  ['general.local_browser.model_url', 'https://huggingface.co/notabilia/gemma-4-E4B-it-litert-lm/resolve/main/gemma-4-E4B-it-web.task'],
+  ['general.uvr5_web_runtime.mdx_net_model_url', 'https://huggingface.co/notabilia/uvr5-models/resolve/main/UVR-MDX-NET-Inst_HQ_3.onnx'],
   ['general.soundfont.base_url', 'https://cdn.jsdelivr.net/npm/soundfont-for-samplers/FluidR3_GM/'],
   ['general.kgone.enabled', false],
   ['general.kgone.base_url', 'http://127.0.0.1:8000'],
@@ -71,6 +80,10 @@ vi.mock('../../../util/localLLMModelManager', () => ({
   },
 }));
 
+vi.mock('../../../util/localSeparatorModelCache', () => ({
+  LocalSeparatorModelCache: localSeparatorModelCacheMock,
+}));
+
 describe('GeneralSettings', () => {
   beforeEach(() => {
     configState.set('general.local_browser.context_length', 65536);
@@ -91,6 +104,9 @@ describe('GeneralSettings', () => {
       secureContext: true,
       reason: null,
     };
+    localSeparatorModelCacheMock.delete.mockClear();
+    localSeparatorModelCacheMock.exists.mockClear();
+    localSeparatorModelCacheMock.exists.mockResolvedValue(true);
   });
 
   it('renders the local context length selector and VRAM hint', async () => {
@@ -119,6 +135,65 @@ describe('GeneralSettings', () => {
     });
   });
 
+  it('renders and persists local runtime download URLs', async () => {
+    render(<GeneralSettings />);
+
+    expect(await screen.findByDisplayValue('https://huggingface.co/notabilia/gemma-4-E4B-it-litert-lm/resolve/main/gemma-4-E4B-it-web.task')).toBeTruthy();
+    expect(screen.getByDisplayValue('https://huggingface.co/notabilia/uvr5-models/resolve/main/UVR-MDX-NET-Inst_HQ_3.onnx')).toBeTruthy();
+
+    const inputs = screen.getAllByRole('textbox');
+    const gemmaUrlInput = inputs.find(input =>
+      (input as HTMLInputElement).value.includes('gemma-4-E4B-it-web.task'),
+    ) as HTMLInputElement | undefined;
+    const uvr5UrlInput = inputs.find(input =>
+      (input as HTMLInputElement).value.includes('UVR-MDX-NET-Inst_HQ_3.onnx'),
+    ) as HTMLInputElement | undefined;
+
+    expect(gemmaUrlInput).toBeTruthy();
+    expect(uvr5UrlInput).toBeTruthy();
+
+    fireEvent.change(gemmaUrlInput!, { target: { value: 'https://example.com/gemma.task' } });
+    fireEvent.change(uvr5UrlInput!, { target: { value: 'https://example.com/uvr5.onnx' } });
+
+    await waitFor(() => {
+      expect(configManagerMock.set).toHaveBeenCalledWith('general.local_browser.model_url', 'https://example.com/gemma.task');
+      expect(configManagerMock.set).toHaveBeenCalledWith('general.uvr5_web_runtime.mdx_net_model_url', 'https://example.com/uvr5.onnx');
+    });
+  });
+
+  it('restores default download URLs and deletes the UVR5 model cache', async () => {
+    localSeparatorModelCacheMock.exists
+      .mockResolvedValueOnce(true)
+      .mockResolvedValueOnce(false);
+
+    render(<GeneralSettings />);
+
+    expect(await screen.findByText('UVR5 Web Runtime')).toBeTruthy();
+
+    const restoreLinks = screen.getAllByText('Restore default');
+    fireEvent.click(restoreLinks[0]);
+    fireEvent.click(restoreLinks[1]);
+    const uvr5DeleteButton = screen.getAllByRole('button', { name: 'Delete Cached Model' })[1];
+    expect(uvr5DeleteButton).not.toBeDisabled();
+    fireEvent.click(uvr5DeleteButton);
+
+    await waitFor(() => {
+      expect(configManagerMock.set).toHaveBeenCalledWith(
+        'general.local_browser.model_url',
+        'https://huggingface.co/notabilia/gemma-4-E4B-it-litert-lm/resolve/main/gemma-4-E4B-it-web.task',
+      );
+      expect(configManagerMock.set).toHaveBeenCalledWith(
+        'general.uvr5_web_runtime.mdx_net_model_url',
+        'https://huggingface.co/notabilia/uvr5-models/resolve/main/UVR-MDX-NET-Inst_HQ_3.onnx',
+      );
+      expect(localSeparatorModelCacheMock.delete).toHaveBeenCalled();
+    });
+
+    await waitFor(() => {
+      expect(screen.getAllByRole('button', { name: 'Delete Cached Model' })[1]).toBeDisabled();
+    });
+  });
+
   it('keeps local runtime available when runtime may fail on this host', async () => {
     localModelState.runtimeSupport = {
       supported: true,

src/components/settings/sections/GeneralSettings.tsx

@@ -1,15 +1,18 @@
 import React, { useState, useEffect, useCallback, useMemo } from 'react';
 import { ConfigManager } from '../../../core/config/ConfigManager';
 import { LocalLLMModelManager, type LocalLLMModelState } from '../../../util/localLLMModelManager';
+import { LocalSeparatorModelCache } from '../../../util/localSeparatorModelCache';
 import {
   formatLocalLLMContextLength,
   LOCAL_LLM_CONTEXT_LENGTH_OPTIONS,
+  LOCAL_LLM_DEFAULT_MODEL_URL,
   LOCAL_LLM_DEFAULT_CONTEXT_LENGTH,
   LOCAL_LLM_DISPLAY_NAME,
   LOCAL_LLM_PROVIDER_KEY,
   normalizeLocalLLMContextLength,
   type LocalLLMContextLength,
 } from '../../../util/localLLMConfig';
+import { LOCAL_SEPARATOR_DEFAULT_MODEL_URL } from '../../../util/localSeparatorConfig';
 
 const GeneralSettings: React.FC = () => {
   const [llmProvider, setLlmProvider] = useState<string>(LOCAL_LLM_PROVIDER_KEY);
@@ -34,6 +37,11 @@ const GeneralSettings: React.FC = () => {
   const [soundfontServerManaged, setSoundfontServerManaged] = useState<boolean>(false);
   const [localContextLength, setLocalContextLength] = useState<LocalLLMContextLength>(LOCAL_LLM_DEFAULT_CONTEXT_LENGTH);
   const [localModelState, setLocalModelState] = useState<LocalLLMModelState>(LocalLLMModelManager.getState());
+  const [localModelUrl, setLocalModelUrl] = useState<string>('');
+  const [uvr5ModelUrl, setUvr5ModelUrl] = useState<string>('');
+  const [isUvr5ModelCached, setIsUvr5ModelCached] = useState<boolean>(false);
+  const [isCheckingUvr5ModelCache, setIsCheckingUvr5ModelCache] = useState<boolean>(false);
+  const [isDeletingUvr5Model, setIsDeletingUvr5Model] = useState<boolean>(false);
 
   const configManager = ConfigManager.instance();
 
@@ -51,6 +59,18 @@ const GeneralSettings: React.FC = () => {
     }
   }, []);
 
+  const refreshUvr5ModelCacheState = useCallback(async () => {
+    setIsCheckingUvr5ModelCache(true);
+    try {
+      setIsUvr5ModelCached(await LocalSeparatorModelCache.exists());
+    } catch (error) {
+      console.error('Failed to check UVR5 cached model state:', error);
+      setIsUvr5ModelCached(false);
+    } finally {
+      setIsCheckingUvr5ModelCache(false);
+    }
+  }, []);
+
   // Load configuration values on component mount
   useEffect(() => {
     const loadConfig = async () => {
@@ -74,6 +94,8 @@ const GeneralSettings: React.FC = () => {
       setCompatibleBaseUrl((configManager.get('general.openai_compatible.base_url') as string) || '');
       setCompatibleModel((configManager.get('general.openai_compatible.model') as string) || '');
       setLocalContextLength(normalizeLocalLLMContextLength(configManager.get('general.local_browser.context_length')));
+      setLocalModelUrl((configManager.get('general.local_browser.model_url') as string) || LOCAL_LLM_DEFAULT_MODEL_URL);
+      setUvr5ModelUrl((configManager.get('general.uvr5_web_runtime.mdx_net_model_url') as string) || LOCAL_SEPARATOR_DEFAULT_MODEL_URL);
       setSoundfontBaseUrl((configManager.get('general.soundfont.base_url') as string) || '');
       setKgoneEnabled((configManager.get('general.kgone.enabled') as boolean) ?? false);
       setKgoneBaseUrl((configManager.get('general.kgone.base_url') as string) || '');
@@ -83,8 +105,9 @@ const GeneralSettings: React.FC = () => {
 
     loadConfig();
     const unsubscribe = LocalLLMModelManager.subscribe(setLocalModelState);
+    void refreshUvr5ModelCacheState();
     return unsubscribe;
-  }, [configManager]);
+  }, [configManager, refreshUvr5ModelCacheState]);
 
   // Debounced save function for text inputs
   const debouncedSave = useCallback((key: string, value: string) => {
@@ -212,6 +235,16 @@ const GeneralSettings: React.FC = () => {
     debouncedSave('general.kgone.base_url', value);
   };
 
+  const handleLocalModelUrlChange = (value: string) => {
+    setLocalModelUrl(value);
+    debouncedSave('general.local_browser.model_url', value);
+  };
+
+  const handleUvr5ModelUrlChange = (value: string) => {
+    setUvr5ModelUrl(value);
+    debouncedSave('general.uvr5_web_runtime.mdx_net_model_url', value);
+  };
+
   const handleDeleteLocalModel = async () => {
     try {
       await LocalLLMModelManager.deleteCachedModel();
@@ -220,6 +253,19 @@ const GeneralSettings: React.FC = () => {
     }
   };
 
+  const handleDeleteUvr5Model = async () => {
+    setIsDeletingUvr5Model(true);
+    try {
+      await LocalSeparatorModelCache.delete();
+      setIsUvr5ModelCached(false);
+    } catch (error) {
+      console.error('Failed to delete UVR5 cached model:', error);
+    } finally {
+      setIsDeletingUvr5Model(false);
+      await refreshUvr5ModelCacheState();
+    }
+  };
+
   const handleLocalContextLengthChange = async (value: string) => {
     const parsed = Number(value);
     const normalized = normalizeLocalLLMContextLength(parsed);
@@ -325,6 +371,32 @@ const GeneralSettings: React.FC = () => {
             </div>
           </div>
 
+          <div className="settings-item">
+            <label className="settings-label">
+              Download URL
+            </label>
+            <input
+              type="text"
+              className="settings-input"
+              placeholder={`e.g. ${LOCAL_LLM_DEFAULT_MODEL_URL}`}
+              value={localModelUrl}
+              onChange={(e) => handleLocalModelUrlChange(e.target.value)}
+            />
+            <div className="settings-help" style={{ fontSize: '12px', color: '#888', marginTop: '4px' }}>
+              Changing this URL may break downloads or point to an incompatible model file.{' '}
+              <a
+                href="#"
+                onClick={(e) => {
+                  e.preventDefault();
+                  handleLocalModelUrlChange(LOCAL_LLM_DEFAULT_MODEL_URL);
+                }}
+                style={{ color: '#5a9fd4', textDecoration: 'underline', cursor: 'pointer' }}
+              >
+                Restore default
+              </a>
+            </div>
+          </div>
+
           {!localModelState.isCached && !localModelState.isDownloading && localModelState.runtimeSupport.supported && (
             <div className="settings-help" style={{ fontSize: '12px', color: '#888', marginTop: '4px', marginBottom: '8px' }}>
               The local model downloads automatically the next time you chat with `Local LLM (Browser)`.
@@ -366,6 +438,47 @@ const GeneralSettings: React.FC = () => {
           </div>
         </div>
 
+        <div className="settings-group">
+          <h4>UVR5 Web Runtime</h4>
+
+          <div className="settings-item">
+            <label className="settings-label">
+              UVR-MDX-NET-Inst_HQ_3 Download URL
+            </label>
+            <input
+              type="text"
+              className="settings-input"
+              placeholder={`e.g. ${LOCAL_SEPARATOR_DEFAULT_MODEL_URL}`}
+              value={uvr5ModelUrl}
+              onChange={(e) => handleUvr5ModelUrlChange(e.target.value)}
+            />
+            <div className="settings-help" style={{ fontSize: '12px', color: '#888', marginTop: '4px' }}>
+              Changing this URL may break downloads or point to an incompatible model file.{' '}
+              <a
+                href="#"
+                onClick={(e) => {
+                  e.preventDefault();
+                  handleUvr5ModelUrlChange(LOCAL_SEPARATOR_DEFAULT_MODEL_URL);
+                }}
+                style={{ color: '#5a9fd4', textDecoration: 'underline', cursor: 'pointer' }}
+              >
+                Restore default
+              </a>
+            </div>
+          </div>
+
+          <div className="settings-item" style={{ marginTop: '12px' }}>
+            <button
+              type="button"
+              className="settings-btn settings-btn-danger"
+              onClick={() => void handleDeleteUvr5Model()}
+              disabled={isCheckingUvr5ModelCache || isDeletingUvr5Model || !isUvr5ModelCached}
+            >
+              {isDeletingUvr5Model ? 'Deleting...' : 'Delete Cached Model'}
+            </button>
+          </div>
+        </div>
+
         <div className="settings-group">
           <h4>OpenAI</h4>
 

src/core/config/ConfigManager.ts

@@ -10,6 +10,10 @@ interface AppConfig {
     persist_api_keys_non_localhost: boolean;
     local_browser: {
       context_length: 32768 | 65536 | 131072;
+      model_url: string;
+    };
+    uvr5_web_runtime: {
+      mdx_net_model_url: string;
     };
     openai: {
       api_key: string;
@@ -216,7 +220,11 @@ export class ConfigManager {
             model: ''
           },
           local_browser: {
-            context_length: 32768
+            context_length: 32768,
+            model_url: 'https://huggingface.co/notabilia/gemma-4-E4B-it-litert-lm/resolve/main/gemma-4-E4B-it-web.task'
+          },
+          uvr5_web_runtime: {
+            mdx_net_model_url: 'https://huggingface.co/notabilia/uvr5-models/resolve/main/UVR-MDX-NET-Inst_HQ_3.onnx'
           },
           soundfont: {
             base_url: 'https://cdn.jsdelivr.net/npm/soundfont-for-samplers/FluidR3_GM/'

src/core/io/LocalSeparatorModelCache.test.ts

@@ -1,5 +1,9 @@
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { LocalSeparatorModelCache } from '../../util/localSeparatorModelCache';
+import {
+  LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES,
+  LOCAL_SEPARATOR_MODEL_FILENAME,
+} from '../../util/localSeparatorConfig';
 
 class MockWritableFileStream {
   private readonly handle: MockFileSystemFileHandle;
@@ -109,47 +113,81 @@ vi.stubGlobal('navigator', {
 });
 
 describe('LocalSeparatorModelCache', () => {
+  const makeModelBytes = (fill: number): Uint8Array => new Uint8Array(LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES).fill(fill);
+
   beforeEach(() => {
     mockRoot.clear();
     vi.restoreAllMocks();
   });
 
   it('downloads and stores a model in OPFS cache', async () => {
+    const bytes = makeModelBytes(1);
+    vi.stubGlobal('fetch', vi.fn(async () => new Response(bytes, {
+      status: 200,
+      headers: { 'Content-Length': String(LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES) },
+    })));
+
+    await LocalSeparatorModelCache.download('https://example.com/model.onnx');
+
+    expect(await LocalSeparatorModelCache.exists()).toBe(true);
+    const buffer = await LocalSeparatorModelCache.getArrayBuffer();
+    expect(buffer.byteLength).toBe(LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES);
+    expect(new Uint8Array(buffer)[0]).toBe(1);
+  });
+
+  it('replaces a broken cached file on redownload', async () => {
+    vi.stubGlobal('fetch', vi.fn(async () => new Response(makeModelBytes(1), {
+      status: 200,
+      headers: { 'Content-Length': String(LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES) },
+    })));
+    await LocalSeparatorModelCache.download('https://example.com/model.onnx');
+
+    vi.stubGlobal('fetch', vi.fn(async () => new Response(makeModelBytes(9), {
+      status: 200,
+      headers: { 'Content-Length': String(LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES) },
+    })));
+    await LocalSeparatorModelCache.download('https://example.com/model.onnx');
+
+    const buffer = await LocalSeparatorModelCache.getArrayBuffer();
+    expect(buffer.byteLength).toBe(LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES);
+    expect(new Uint8Array(buffer)[0]).toBe(9);
+  });
+
+  it('deletes the cached model file', async () => {
+    vi.stubGlobal('fetch', vi.fn(async () => new Response(makeModelBytes(2), {
+      status: 200,
+      headers: { 'Content-Length': String(LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES) },
+    })));
+    await LocalSeparatorModelCache.download('https://example.com/model.onnx');
+
+    await LocalSeparatorModelCache.delete();
+
+    expect(await LocalSeparatorModelCache.exists()).toBe(false);
+  });
+
+  it('rejects and deletes a cached file when the size is wrong', async () => {
+    const dir = await navigator.storage.getDirectory();
+    const modelsDir = await dir.getDirectoryHandle('models', { create: true });
+    const fileHandle = await modelsDir.getFileHandle(LOCAL_SEPARATOR_MODEL_FILENAME, { create: true });
+    const fileWritable = await fileHandle.createWritable();
+    await fileWritable.write(new Uint8Array([1, 2, 3]));
+    await fileWritable.close();
+
+    const sizeHandle = await modelsDir.getFileHandle(`${LOCAL_SEPARATOR_MODEL_FILENAME}.size`, { create: true });
+    const sizeWritable = await sizeHandle.createWritable();
+    await sizeWritable.write(String(3));
+    await sizeWritable.close();
+
+    expect(await LocalSeparatorModelCache.exists()).toBe(false);
+  });
+
+  it('fails a download when the final size does not match the expected model size', async () => {
     vi.stubGlobal('fetch', vi.fn(async () => new Response(new Uint8Array([1, 2, 3]), {
       status: 200,
       headers: { 'Content-Length': '3' },
     })));
 
-    await LocalSeparatorModelCache.download('https://example.com/model.onnx', 'model.onnx');
-
-    expect(await LocalSeparatorModelCache.exists('model.onnx')).toBe(true);
-    const buffer = await LocalSeparatorModelCache.getArrayBuffer('model.onnx');
-    expect(Array.from(new Uint8Array(buffer))).toEqual([1, 2, 3]);
-  });
-
-  it('replaces a broken cached file on redownload', async () => {
-    vi.stubGlobal('fetch', vi.fn(async () => new Response(new Uint8Array([1]), {
-      status: 200,
-      headers: { 'Content-Length': '1' },
-    })));
-    await LocalSeparatorModelCache.download('https://example.com/model.onnx', 'model.onnx');
-
-    vi.stubGlobal('fetch', vi.fn(async () => new Response(new Uint8Array([9, 8, 7, 6]), {
-      status: 200,
-      headers: { 'Content-Length': '4' },
-    })));
-    await LocalSeparatorModelCache.download('https://example.com/model.onnx', 'model.onnx');
-
-    const buffer = await LocalSeparatorModelCache.getArrayBuffer('model.onnx');
-    expect(Array.from(new Uint8Array(buffer))).toEqual([9, 8, 7, 6]);
-  });
-
-  it('deletes the cached model file', async () => {
-    vi.stubGlobal('fetch', vi.fn(async () => new Response(new Uint8Array([1, 2]), { status: 200 })));
-    await LocalSeparatorModelCache.download('https://example.com/model.onnx', 'model.onnx');
-
-    await LocalSeparatorModelCache.delete('model.onnx');
-
-    expect(await LocalSeparatorModelCache.exists('model.onnx')).toBe(false);
+    await expect(LocalSeparatorModelCache.download('https://example.com/model.onnx')).rejects.toThrow(/size mismatch/i);
+    expect(await LocalSeparatorModelCache.exists()).toBe(false);
   });
 });

src/util/localLLMConfig.ts

@@ -1,7 +1,8 @@
 export const LOCAL_LLM_PROVIDER_KEY = 'local_browser';
-export const LOCAL_LLM_MODEL_URL =
+export const LOCAL_LLM_DEFAULT_MODEL_URL =
   'https://huggingface.co/notabilia/gemma-4-E4B-it-litert-lm/resolve/main/gemma-4-E4B-it-web.task';
 export const LOCAL_LLM_MODEL_FILENAME = 'gemma-4-E4B-it-web.task';
+export const LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES = 2964324352;
 export const LOCAL_LLM_DISPLAY_NAME = 'Gemma 4 E4B';
 export const LOCAL_LLM_LEGACY_FILENAMES = [
   'gemma-3n-E4B-it-int4-Web.litertlm',

src/util/localLLMModelCache.ts

@@ -1,5 +1,5 @@
 import { OpfsModelCache, type ModelDownloadProgress } from './opfsModelCache';
-import { LOCAL_LLM_MODEL_FILENAME } from './localLLMConfig';
+import { LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES, LOCAL_LLM_MODEL_FILENAME } from './localLLMConfig';
 
 const cache = new OpfsModelCache({ directoryName: 'models' });
 let writingToCachePromise: Promise<void> | null = null;
@@ -51,7 +51,9 @@ const createProgressReader = (
 
 export class LocalLLMModelCache {
   public static async exists(filename: string = LOCAL_LLM_MODEL_FILENAME): Promise<boolean> {
-    return cache.exists(filename);
+    return cache.exists(filename, {
+      expectedSizeBytes: LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES,
+    });
   }
 
   public static async getFile(filename: string = LOCAL_LLM_MODEL_FILENAME): Promise<File> {
@@ -98,6 +100,9 @@ export class LocalLLMModelCache {
       streamForCache,
       filename,
       totalBytes > 0 ? totalBytes : null,
+      {
+        expectedSizeBytes: LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES,
+      },
       progress => onProgress?.({ ...progress, fromCache: false }),
     );
     writingToCachePromise = writingToCachePromise.finally(() => {
@@ -117,6 +122,13 @@ export class LocalLLMModelCache {
     filename: string = LOCAL_LLM_MODEL_FILENAME,
     onProgress?: (progress: ModelDownloadProgress) => void,
   ): Promise<void> {
-    await cache.download(sourceUrl, filename, onProgress);
+    await cache.download(
+      sourceUrl,
+      filename,
+      {
+        expectedSizeBytes: LOCAL_LLM_MODEL_EXPECTED_SIZE_BYTES,
+      },
+      onProgress,
+    );
   }
 }

src/util/localLLMModelManager.ts

@@ -2,7 +2,6 @@ import {
   detectLocalLLMRuntimeSupport,
   LOCAL_LLM_LEGACY_FILENAMES,
   LOCAL_LLM_MODEL_FILENAME,
-  LOCAL_LLM_MODEL_URL,
   type LocalLLMRuntimeSupport,
 } from './localLLMConfig';
 import { LocalLLMModelCache } from './localLLMModelCache';

src/util/localSeparatorConfig.ts

@@ -1,9 +1,10 @@
 import type { LocalSeparatorModelConfig } from './localSeparatorTypes';
 
-export const LOCAL_SEPARATOR_MODEL_URL =
+export const LOCAL_SEPARATOR_DEFAULT_MODEL_URL =
   'https://huggingface.co/notabilia/uvr5-models/resolve/main/UVR-MDX-NET-Inst_HQ_3.onnx';
 
 export const LOCAL_SEPARATOR_MODEL_FILENAME = 'UVR-MDX-NET-Inst_HQ_3.onnx';
+export const LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES = 66759214;
 
 export const LOCAL_SEPARATOR_MODEL_CONFIG: LocalSeparatorModelConfig = {
   filename: LOCAL_SEPARATOR_MODEL_FILENAME,

src/util/localSeparatorModelCache.ts

@@ -1,4 +1,7 @@
-import { LOCAL_SEPARATOR_MODEL_FILENAME } from './localSeparatorConfig';
+import {
+  LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES,
+  LOCAL_SEPARATOR_MODEL_FILENAME,
+} from './localSeparatorConfig';
 import { OpfsModelCache, type ModelDownloadProgress } from './opfsModelCache';
 
 const cache = new OpfsModelCache({ directoryName: 'models' });
@@ -7,7 +10,9 @@ export { type ModelDownloadProgress };
 
 export class LocalSeparatorModelCache {
   public static async exists(filename: string = LOCAL_SEPARATOR_MODEL_FILENAME): Promise<boolean> {
-    return cache.exists(filename);
+    return cache.exists(filename, {
+      expectedSizeBytes: LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES,
+    });
   }
 
   public static async getFile(filename: string = LOCAL_SEPARATOR_MODEL_FILENAME): Promise<File> {
@@ -27,6 +32,13 @@ export class LocalSeparatorModelCache {
     filename: string = LOCAL_SEPARATOR_MODEL_FILENAME,
     onProgress?: (progress: ModelDownloadProgress) => void,
   ): Promise<void> {
-    await cache.download(sourceUrl, filename, onProgress);
+    await cache.download(
+      sourceUrl,
+      filename,
+      {
+        expectedSizeBytes: LOCAL_SEPARATOR_MODEL_EXPECTED_SIZE_BYTES,
+      },
+      onProgress,
+    );
   }
 }

src/util/opfsModelCache.ts

@@ -9,6 +9,10 @@ interface OpfsModelCacheOptions {
   sizeSuffix?: string;
 }
 
+interface ModelCacheValidationOptions {
+  expectedSizeBytes?: number | null;
+}
+
 export class OpfsModelCache {
   private readonly directoryName: string;
   private readonly sizeSuffix: string;
@@ -18,7 +22,7 @@ export class OpfsModelCache {
     this.sizeSuffix = options.sizeSuffix ?? '.size';
   }
 
-  public async exists(filename: string): Promise<boolean> {
+  public async exists(filename: string, options: ModelCacheValidationOptions = {}): Promise<boolean> {
     try {
       const dir = await this.getDir();
       const fileHandle = await dir.getFileHandle(filename);
@@ -29,6 +33,10 @@ export class OpfsModelCache {
         await this.delete(filename);
         return false;
       }
+      if (options.expectedSizeBytes != null && expectedSize !== options.expectedSizeBytes) {
+        await this.delete(filename);
+        return false;
+      }
       if (file.size !== expectedSize) {
         await this.delete(filename);
         return false;
@@ -64,6 +72,7 @@ export class OpfsModelCache {
   public async download(
     sourceUrl: string,
     filename: string,
+    options: ModelCacheValidationOptions = {},
     onProgress?: (progress: ModelDownloadProgress) => void,
   ): Promise<void> {
     const response = await fetch(sourceUrl);
@@ -75,13 +84,14 @@ export class OpfsModelCache {
     if (!response.body) {
       throw new Error('Model download response did not include a readable body.');
     }
-    await this.downloadStream(response.body, filename, totalBytes, onProgress);
+    await this.downloadStream(response.body, filename, totalBytes, options, onProgress);
   }
 
   public async downloadStream(
     stream: ReadableStream<Uint8Array>,
     filename: string,
     totalBytes: number | null,
+    options: ModelCacheValidationOptions = {},
     onProgress?: (progress: ModelDownloadProgress) => void,
   ): Promise<void> {
     const dir = await this.getDir();
@@ -111,6 +121,9 @@ export class OpfsModelCache {
       if (!Number.isFinite(sizeValue) || sizeValue <= 0) {
         throw new Error('Model download did not provide a valid size.');
       }
+      if (options.expectedSizeBytes != null && receivedBytes !== options.expectedSizeBytes) {
+        throw new Error(`Model download size mismatch for ${filename}: expected ${options.expectedSizeBytes} bytes, got ${receivedBytes}.`);
+      }
 
       const sizeHandle = await dir.getFileHandle(this.getSizeFilename(filename), { create: true });
       const sizeWritable = await sizeHandle.createWritable();