feat: persist model selection

.living_spec/stories/09_system_prompt_persona.md

@@ -1,18 +0,0 @@
-# Story: System Prompt & Persona
-
-## User Story
-**As a** User
-**I want** the Agent to behave like a Senior Engineer and know exactly how to use its tools
-**So that** it writes high-quality code and doesn't hallucinate capabilities or refuse to edit files.
-
-## Acceptance Criteria
-*   [ ] Backend: Define a robust System Prompt constant (likely in `src-tauri/src/llm/prompts.rs`).
-*   [ ] Content: The prompt should define:
-    *   Role: "Senior Software Engineer / Agent".
-    *   Tone: Professional, direct, no fluff.
-    *   Tool usage instructions: "You have access to the local filesystem. Use `read_file` to inspect context before editing."
-    *   Workflow: "When asked to implement a feature, read relevant files first, then write."
-*   [ ] Backend: Inject this system message at the *start* of every `chat` session sent to the Provider.
-
-## Out of Scope
-*   User-editable system prompts (future story).

src-tauri/src/commands/fs.rs

@@ -8,6 +8,7 @@ use tauri_plugin_store::StoreExt;
 
 const STORE_PATH: &str = "store.json";
 const KEY_LAST_PROJECT: &str = "last_project_path";
+const KEY_SELECTED_MODEL: &str = "selected_model";
 
 // -----------------------------------------------------------------------------
 // Helper Functions
@@ -125,6 +126,31 @@ pub async fn get_current_project(
     Ok(None)
 }
 
+#[tauri::command]
+pub async fn get_model_preference(app: AppHandle) -> Result<Option<String>, String> {
+    let store = app
+        .store(STORE_PATH)
+        .map_err(|e| format!("Failed to access store: {}", e))?;
+
+    if let Some(val) = store.get(KEY_SELECTED_MODEL) {
+        if let Some(model) = val.as_str() {
+            return Ok(Some(model.to_string()));
+        }
+    }
+    Ok(None)
+}
+
+#[tauri::command]
+pub async fn set_model_preference(app: AppHandle, model: String) -> Result<(), String> {
+    let store = app
+        .store(STORE_PATH)
+        .map_err(|e| format!("Failed to access store: {}", e))?;
+
+    store.set(KEY_SELECTED_MODEL, json!(model));
+    let _ = store.save();
+    Ok(())
+}
+
 #[tauri::command]
 pub async fn read_file(path: String, state: State<'_, SessionState>) -> Result<String, String> {
     let full_path = resolve_path(&state, &path)?;

src-tauri/src/lib.rs

@@ -15,6 +15,8 @@ pub fn run() {
             commands::fs::open_project,
             commands::fs::close_project,
             commands::fs::get_current_project,
+            commands::fs::get_model_preference,
+            commands::fs::set_model_preference,
             commands::fs::read_file,
             commands::fs::write_file,
             commands::fs::list_directory,

src/components/Chat.tsx

@@ -20,12 +20,22 @@ export function Chat({ projectPath, onCloseProject }: ChatProps) {
 
   useEffect(() => {
     invoke<string[]>("get_ollama_models")
-      .then((models) => {
+      .then(async (models) => {
         if (models.length > 0) {
           setAvailableModels(models);
-          // If we have models and current one isn't valid, switch to first
-          if (!models.includes(model)) {
-            setModel(models[0]);
+
+          // Check backend store for saved model
+          try {
+            const savedModel = await invoke<string | null>(
+              "get_model_preference",
+            );
+            if (savedModel && models.includes(savedModel)) {
+              setModel(savedModel);
+            } else if (!models.includes(model)) {
+              setModel(models[0]);
+            }
+          } catch (e) {
+            console.error(e);
           }
         }
       })
@@ -161,7 +171,13 @@ export function Chat({ projectPath, onCloseProject }: ChatProps) {
           {availableModels.length > 0 ? (
             <select
               value={model}
-              onChange={(e) => setModel(e.target.value)}
+              onChange={(e) => {
+                const newModel = e.target.value;
+                setModel(newModel);
+                invoke("set_model_preference", { model: newModel }).catch(
+                  console.error,
+                );
+              }}
               style={{
                 padding: "6px 32px 6px 16px",
                 borderRadius: "99px",
@@ -188,7 +204,13 @@ export function Chat({ projectPath, onCloseProject }: ChatProps) {
           ) : (
             <input
               value={model}
-              onChange={(e) => setModel(e.target.value)}
+              onChange={(e) => {
+                const newModel = e.target.value;
+                setModel(newModel);
+                invoke("set_model_preference", { model: newModel }).catch(
+                  console.error,
+                );
+              }}
               placeholder="Model"
               style={{
                 padding: "6px 12px",