fix(desktop): preselect model in onboarding so first chat doesn't 400 (#427)

frontend/src/components/Chat/InputArea.tsx

@@ -1,5 +1,6 @@
 import { useState, useRef, useCallback, useEffect } from 'react';
 import { Send, Square, Paperclip, Search } from 'lucide-react';
+import { toast } from 'sonner';
 import { useAppStore, generateId } from '../../lib/store';
 import { streamChat, streamResearch } from '../../lib/sse';
 import { fetchSavings, getBase } from '../../lib/api';
@@ -155,6 +156,10 @@ export function InputArea() {
   const sendMessage = useCallback(async () => {
     const content = input.trim();
     if (!content || streamState.isStreaming) return;
+    if (!selectedModel) {
+      toast.error('Pick a model first (⌘K)');
+      return;
+    }
 
     setInput('');
 
@@ -555,7 +560,7 @@ export function InputArea() {
           value={input}
           onChange={(e) => setInput(e.target.value)}
           onKeyDown={handleKeyDown}
-          placeholder="Message OpenJarvis..."
+          placeholder={selectedModel ? 'Message OpenJarvis...' : 'Pick a model first (⌘K)...'}
           rows={1}
           className="flex-1 bg-transparent outline-none resize-none text-sm leading-relaxed"
           style={{ color: 'var(--color-text)', maxHeight: '200px' }}
@@ -580,13 +585,13 @@ export function InputArea() {
             />
             <button
               onClick={sendMessage}
-              disabled={!input.trim() || modelLoading}
+              disabled={!input.trim() || modelLoading || !selectedModel}
+              title={selectedModel ? 'Send message' : 'Pick a model first (⌘K)'}
               className="p-2 rounded-xl transition-colors shrink-0 cursor-pointer disabled:opacity-30 disabled:cursor-default"
               style={{
                 background: input.trim() ? 'var(--color-accent)' : 'var(--color-bg-tertiary)',
                 color: input.trim() ? 'white' : 'var(--color-text-tertiary)',
               }}
-              title="Send message"
             >
               <Send size={16} />
             </button>

frontend/src/components/SetupScreen.tsx

@@ -1,6 +1,12 @@
-import { useState, useEffect, useCallback } from 'react';
+import { useState, useEffect, useCallback, useRef } from 'react';
 import { Loader2, CheckCircle2, XCircle, Cpu, Server, Database } from 'lucide-react';
-import { getSetupStatus, type SetupStatus } from '../lib/api';
+import {
+  getSetupStatus,
+  fetchModels,
+  fetchRecommendedModel,
+  type SetupStatus,
+} from '../lib/api';
+import { useAppStore } from '../lib/store';
 
 const STEPS = [
   { key: 'ollama_ready', label: 'Inference Engine', icon: Cpu, detail: 'Starting Ollama...' },
@@ -70,10 +76,33 @@ function StepRow({
 
 export function SetupScreen({ onReady }: { onReady: () => void }) {
   const [status, setStatus] = useState<SetupStatus | null>(null);
+  const handedOffRef = useRef(false);
   const poll = useCallback(async () => {
     const s = await getSetupStatus();
     if (s) setStatus(s);
-    if (s?.phase === 'ready') {
+    if (s?.phase === 'ready' && !handedOffRef.current) {
+      handedOffRef.current = true;
+      // Pre-select a model BEFORE handing off so the chat is usable on
+      // first send. Without this, the main app's post-mount fetch can
+      // lose a race to a fast first message and Ollama 400s.
+      try {
+        const [models, rec] = await Promise.all([
+          fetchModels().catch(() => []),
+          fetchRecommendedModel().catch(() => ({ model: '', reason: '' })),
+        ]);
+        const store = useAppStore.getState();
+        store.setModels(models);
+        store.setModelsLoading(false);
+        const recommended = rec.model && models.some((m) => m.id === rec.model)
+          ? rec.model
+          : models[0]?.id || '';
+        if (recommended && !store.selectedModel) {
+          store.setSelectedModel(recommended);
+        }
+      } catch {
+        // Non-fatal: store.setModels auto-selects on later fetch, and
+        // the InputArea guards the empty-model case with a toast.
+      }
       setTimeout(() => onReady(), 600);
     }
   }, [onReady]);

frontend/src/lib/store.ts

@@ -438,7 +438,12 @@ export const useAppStore = create<AppState>((set, get) => {
 
     // ── Models & server ────────────────────────────────────────────
 
-    setModels: (models: ModelInfo[]) => set({ models }),
+    setModels: (models: ModelInfo[]) =>
+      set((state) =>
+        !state.selectedModel && models.length > 0
+          ? { models, selectedModel: models[0].id }
+          : { models },
+      ),
     setModelsLoading: (loading: boolean) => set({ modelsLoading: loading }),
     setSelectedModel: (model: string) => set({ selectedModel: model }),
     setServerInfo: (info: ServerInfo | null) => set({ serverInfo: info }),