Add anvanced mode to messages

apps/sim/blocks/blocks/agent.ts

@@ -85,7 +85,9 @@ export const AgentBlock: BlockConfig<AgentResponse> = {
       id: 'messages',
       title: 'Messages',
       type: 'messages-input',
+      canonicalParamId: 'messages',
       placeholder: 'Enter messages...',
+      mode: 'basic',
       wandConfig: {
         enabled: true,
         maintainHistory: true,
@@ -122,6 +124,15 @@ Return ONLY the JSON array.`,
         generationType: 'json-object',
       },
     },
+    {
+      id: 'messagesRaw',
+      title: 'Messages',
+      type: 'code',
+      canonicalParamId: 'messages',
+      placeholder: '[{"role": "system", "content": "..."}, {"role": "user", "content": "..."}]',
+      language: 'json',
+      mode: 'advanced',
+    },
     {
       id: 'model',
       title: 'Model',