feat: Add optional system prompt variable to Helix app

packages/backend/src/apps/helix/actions/new-chat/index.js

@@ -5,14 +5,6 @@ export default defineAction({
   key: 'newChat',
   description: 'Create a new chat session for Helix AI.',
   arguments: [
-    {
-      label: 'Input',
-      key: 'input',
-      type: 'string',
-      required: true,
-      description: 'Prompt to start the chat with.',
-      variables: true,
-    },
     {
       label: 'Session ID',
       key: 'sessionId',
@@ -22,11 +14,29 @@ export default defineAction({
         'ID of the chat session to continue. Leave empty to start a new chat.',
       variables: true,
     },
+    {
+      label: 'System Prompt',
+      key: 'systemPrompt',
+      type: 'string',
+      required: false,
+      description:
+        'Optional system prompt to start the chat with. It will be used only for new chat sessions.',
+      variables: true,
+    },
+    {
+      label: 'Input',
+      key: 'input',
+      type: 'string',
+      required: true,
+      description: 'User input to start the chat with.',
+      variables: true,
+    },
   ],
 
   async run($) {
     const response = await $.http.post('/api/v1/sessions/chat', {
       session_id: $.step.parameters.sessionId,
+      system: $.step.parameters.systemPrompt,
       messages: [
         {
           role: 'user',