feat: Distinguish and preserve embedding model sessions

This commit introduces a new field, `is_embedding`, to the `SessionInfo` structure to clearly mark sessions running dedicated embedding models.

Key changes:
- Adds `is_embedding` to the `SessionInfo` interface in `AIEngine.ts` and the Rust backend.
- Updates the `loadLlamaModel` command signatures to pass this new flag.
- Modifies the llama.cpp extension's **auto-unload logic** to explicitly **filter out** and **not unload** any currently loaded embedding models when a new text generation model is loaded. This is a critical performance fix to prevent the embedding model (e.g., used for RAG) from being repeatedly reloaded.

Also includes minor code style cleanup/reformatting in `jan-provider-web/provider.ts` for improved readability.

core/src/browser/extensions/engines/AIEngine.ts

@@ -182,6 +182,7 @@ export interface SessionInfo {
   port: number // llama-server output port (corrected from portid)
   model_id: string //name of the model
   model_path: string // path of the loaded model
+  is_embedding: boolean
   api_key: string
   mmproj_path?: string
 }

extensions-web/src/jan-provider-web/provider.ts

@@ -45,7 +45,7 @@ export default class JanProviderWeb extends AIEngine {
   // Verify Jan models capabilities in localStorage
   private validateJanModelsLocalStorage() {
     try {
-      console.log("Validating Jan models in localStorage...")
+      console.log('Validating Jan models in localStorage...')
       const storageKey = 'model-provider'
       const data = localStorage.getItem(storageKey)
       if (!data) return
@@ -60,9 +60,14 @@ export default class JanProviderWeb extends AIEngine {
         if (provider.provider === 'jan' && provider.models) {
           for (const model of provider.models) {
             console.log(`Checking Jan model: ${model.id}`, model.capabilities)
-            if (JSON.stringify(model.capabilities) !== JSON.stringify(JAN_MODEL_CAPABILITIES)) {
+            if (
+              JSON.stringify(model.capabilities) !==
+              JSON.stringify(JAN_MODEL_CAPABILITIES)
+            ) {
               hasInvalidModel = true
-              console.log(`Found invalid Jan model: ${model.id}, clearing localStorage`)
+              console.log(
+                `Found invalid Jan model: ${model.id}, clearing localStorage`
+              )
               break
             }
           }
@@ -79,9 +84,17 @@ export default class JanProviderWeb extends AIEngine {
         // If still present, try setting to empty state
         if (afterRemoval) {
           // Try alternative clearing method
-          localStorage.setItem(storageKey, JSON.stringify({ state: { providers: [] }, version: parsed.version || 3 }))
+          localStorage.setItem(
+            storageKey,
+            JSON.stringify({
+              state: { providers: [] },
+              version: parsed.version || 3,
+            })
+          )
         }
-        console.log('Cleared model-provider from localStorage due to invalid Jan capabilities')
+        console.log(
+          'Cleared model-provider from localStorage due to invalid Jan capabilities'
+        )
         // Force a page reload to ensure clean state
         window.location.reload()
       }
@@ -159,6 +172,7 @@ export default class JanProviderWeb extends AIEngine {
         port: 443, // HTTPS port
         model_id: modelId,
         model_path: `remote:${modelId}`, // Indicate this is a remote model
+        is_embedding: false, // assume false here, TODO: might need further implementation
         api_key: '', // API key handled by auth service
       }
 
@@ -193,8 +207,12 @@ export default class JanProviderWeb extends AIEngine {
       console.error(`Failed to unload Jan session ${sessionId}:`, error)
       return {
         success: false,
-        error: error instanceof ApiError ? error.message :
+        error:
-               error instanceof Error ? error.message : 'Unknown error',
+          error instanceof ApiError
+            ? error.message
+            : error instanceof Error
+              ? error.message
+              : 'Unknown error',
       }
     }
   }

extensions/llamacpp-extension/src/index.ts

@@ -333,14 +333,12 @@ export default class llamacpp_extension extends AIEngine {
           )
           // Clear the invalid stored preference
           this.clearStoredBackendType()
-          bestAvailableBackendString = await this.determineBestBackend(
+          bestAvailableBackendString =
-            version_backends
+            await this.determineBestBackend(version_backends)
-          )
         }
       } else {
-        bestAvailableBackendString = await this.determineBestBackend(
+        bestAvailableBackendString =
-          version_backends
+          await this.determineBestBackend(version_backends)
-        )
       }
 
       let settings = structuredClone(SETTINGS)
@@ -1530,6 +1528,7 @@ export default class llamacpp_extension extends AIEngine {
 
     if (
       this.autoUnload &&
+      !isEmbedding &&
       (loadedModels.length > 0 || otherLoadingPromises.length > 0)
     ) {
       // Wait for OTHER loading models to finish, then unload everything
@@ -1537,10 +1536,33 @@ export default class llamacpp_extension extends AIEngine {
         await Promise.all(otherLoadingPromises)
       }
 
-      // Now unload all loaded models
+      // Now unload all loaded Text models excluding embedding models
       const allLoadedModels = await this.getLoadedModels()
       if (allLoadedModels.length > 0) {
-        await Promise.all(allLoadedModels.map((model) => this.unload(model)))
+        const sessionInfos: (SessionInfo | null)[] = await Promise.all(
+          allLoadedModels.map(async (modelId) => {
+            try {
+              return await this.findSessionByModel(modelId)
+            } catch (e) {
+              logger.warn(`Unable to find session for model "${modelId}": ${e}`)
+              return null // treat as “not‑eligible for unload”
+            }
+          })
+        )
+
+        logger.info(JSON.stringify(sessionInfos))
+
+        const nonEmbeddingModels: string[] = sessionInfos
+          .filter(
+            (s): s is SessionInfo => s !== null && s.is_embedding === false
+          )
+          .map((s) => s.model_id)
+
+        if (nonEmbeddingModels.length > 0) {
+          await Promise.all(
+            nonEmbeddingModels.map((modelId) => this.unload(modelId))
+          )
+        }
       }
     }
     const args: string[] = []
@@ -1677,6 +1699,7 @@ export default class llamacpp_extension extends AIEngine {
           libraryPath,
           args,
           envs,
+          isEmbedding,
         }
       )
       return sInfo
@@ -2024,7 +2047,11 @@ export default class llamacpp_extension extends AIEngine {
     let sInfo = await this.findSessionByModel('sentence-transformer-mini')
     if (!sInfo) {
       const downloadedModelList = await this.list()
-      if (!downloadedModelList.some((model) => model.id === 'sentence-transformer-mini')) {
+      if (
+        !downloadedModelList.some(
+          (model) => model.id === 'sentence-transformer-mini'
+        )
+      ) {
         await this.import('sentence-transformer-mini', {
           modelPath:
             'https://huggingface.co/second-state/All-MiniLM-L6-v2-Embedding-GGUF/resolve/main/all-MiniLM-L6-v2-ggml-model-f16.gguf?download=true',

src-tauri/plugins/tauri-plugin-llamacpp/guest-js/index.ts

@@ -30,12 +30,14 @@ export async function cleanupLlamaProcesses(): Promise<void> {
 export async function loadLlamaModel(
   backendPath: string,
   libraryPath?: string,
-  args: string[] = []
+  args: string[] = [],
+  isEmbedding: boolean = false
 ): Promise<SessionInfo> {
   return await invoke('plugin:llamacpp|load_llama_model', {
     backendPath,
     libraryPath,
     args,
+    isEmbedding,
   })
 }
 

src-tauri/plugins/tauri-plugin-llamacpp/src/commands.rs

@@ -44,6 +44,7 @@ pub async fn load_llama_model<R: Runtime>(
     library_path: Option<&str>,
     mut args: Vec<String>,
     envs: HashMap<String, String>,
+    is_embedding: bool,
 ) -> ServerResult<SessionInfo> {
     let state: State<LlamacppState> = app_handle.state();
     let mut process_map = state.llama_server_process.lock().await;
@@ -223,6 +224,7 @@ pub async fn load_llama_model<R: Runtime>(
         port: port,
         model_id: model_id,
         model_path: model_path_pb.display().to_string(),
+        is_embedding: is_embedding,
         api_key: api_key,
         mmproj_path: mmproj_path_string,
     };

src-tauri/plugins/tauri-plugin-llamacpp/src/state.rs

@@ -10,6 +10,7 @@ pub struct SessionInfo {
     pub port: i32, // llama-server output port
     pub model_id: String,
     pub model_path: String, // path of the loaded model
+    pub is_embedding: bool,
     pub api_key: String,
     #[serde(default)]
     pub mmproj_path: Option<String>,