fix(llm): normalize multimodal image paths to file:// URIs

packages/react-native-executorch/src/controllers/LLMController.ts

@@ -254,7 +254,7 @@ export class LLMController {
         imagePaths && imagePaths.length > 0
           ? await this.nativeModule.generateMultimodal(
               input,
-              imagePaths,
+              imagePaths.map(normalizeImagePath),
               this.getImageToken(),
               this.onToken
             )
@@ -456,3 +456,15 @@ export class LLMController {
     return result;
   }
 }
+
+/**
+ * The native multimodal pipeline expects image paths to be `file://` URIs.
+ * `ResourceFetcher.fetch` and most platform file APIs return raw filesystem
+ * paths without that prefix, so callers routinely pass either form. Accept
+ * both and normalize to the prefixed form here.
+ * @param path - Local image path, either with or without the `file://` prefix.
+ * @returns The same path with a `file://` prefix.
+ */
+function normalizeImagePath(path: string): string {
+  return path.startsWith('file://') ? path : `file://${path}`;
+}

packages/react-native-executorch/src/modules/natural_language_processing/LLMModule.ts

@@ -139,7 +139,7 @@ export class LLMModule {
    * It doesn't manage conversation context. It is intended for users that need access to the model itself without any wrapper.
    * If you want a simple chat with model the consider using `sendMessage`
    * @param input - Raw input string containing the prompt and conversation history.
-   * @param imagePaths - Optional array of local image paths for multimodal inference.
+   * @param imagePaths - Optional array of local image paths for multimodal inference. Each entry may be either `file:///absolute/path` or `/absolute/path` — the controller normalizes the path before passing it to native code.
    * @returns The generated response as a string.
    */
   async forward(input: string, imagePaths?: string[]): Promise<string> {

packages/react-native-executorch/src/types/llm.ts

@@ -270,6 +270,8 @@ export interface Message {
   /**
    * Optional local file path to media (image, audio, etc.).
    * Only valid on `user` messages.
+   * Either `file:///absolute/path` or `/absolute/path` is accepted; the
+   * controller normalizes the path before passing it to native code.
    */
   mediaPath?: string;
 }