Set Hermes default model to GPT 5.5

hosts/m3-ares/services/hermes-agent.nix

@@ -17,10 +17,21 @@ in {
     settings = {
       # ── Model ──────────────────────────────────────────────────────────
       model = {
-        default = "glm-5.1";
-        provider = "zai";
+        default = "gpt-5.5";
+        provider = "openai-codex";
       };
 
+      fallback_providers = [
+        {
+          provider = "zai";
+          model = "glm-5.1";
+        }
+        {
+          provider = "minimax";
+          model = "MiniMax-M2.7";
+        }
+      ];
+
       credential_pool_strategies = {
         zai = "fill_first";
       };

hosts/m3-hermes/services/hermes-agent.nix

@@ -121,10 +121,21 @@ in {
     settings = {
       # ── Model ──────────────────────────────────────────────────────────
       model = {
-        default = "glm-5.1";
-        provider = "zai";
+        default = "gpt-5.5";
+        provider = "openai-codex";
       };
 
+      fallback_providers = [
+        {
+          provider = "zai";
+          model = "glm-5.1";
+        }
+        {
+          provider = "minimax";
+          model = "MiniMax-M2.7";
+        }
+      ];
+
       credential_pool_strategies = {
         zai = "fill_first";
       };