diff --git a/cli/src/infragpt/llm/providers/openai_provider.py b/cli/src/infragpt/llm/providers/openai_provider.py
index 9fb92be..da19701 100644
--- a/cli/src/infragpt/llm/providers/openai_provider.py
+++ b/cli/src/infragpt/llm/providers/openai_provider.py
@@ -36,7 +36,7 @@ def validate_api_key(self) -> bool:
             }
             
             # Newer models like o4-mini use max_completion_tokens
-            if self.model.startswith("o4") or self.model.startswith("o1"):
+            if self.model.startswith("o4") or self.model.startswith("o1") or self.model.startswith("gpt-5"):
                 params["max_completion_tokens"] = 10
             else:
                 params["max_tokens"] = 10
@@ -113,7 +113,7 @@ def _build_request(self, messages: List[Dict[str, Any]], tools: Optional[List[Di
         }
         
         # Handle temperature - o4 models only support default temperature of 1.0
-        if self.model.startswith("o4") or self.model.startswith("o1"):
+        if self.model.startswith("o4") or self.model.startswith("o1") or self.model.startswith("gpt-5"):
             # Don't set temperature for o4/o1 models (uses default 1.0)
             pass
         else:
@@ -121,7 +121,7 @@ def _build_request(self, messages: List[Dict[str, Any]], tools: Optional[List[Di
         
         if kwargs.get("max_tokens"):
             # Use appropriate parameter based on model
-            if self.model.startswith("o4") or self.model.startswith("o1"):
+            if self.model.startswith("o4") or self.model.startswith("o1") or self.model.startswith("gpt-5"):
                 request["max_completion_tokens"] = kwargs["max_tokens"]
             else:
                 request["max_tokens"] = kwargs["max_tokens"]
diff --git a/cli/src/infragpt/main.py b/cli/src/infragpt/main.py
index 43e649a..b508676 100644
--- a/cli/src/infragpt/main.py
+++ b/cli/src/infragpt/main.py
@@ -82,11 +82,11 @@ def get_credentials_v2(model_string: Optional[str] = None, api_key: Optional[str
             anthropic_key = os.getenv("ANTHROPIC_API_KEY")
             
             if openai_key and not model_string:
-                model_string = "openai:gpt-4o"
+                model_string = "openai:gpt-5"
                 api_key = openai_key
                 provider_name = "openai"
             elif anthropic_key and not model_string:
-                model_string = "anthropic:claude-3-5-sonnet-20241022"
+                model_string = "anthropic:claude-sonnet-4-20250514"
                 api_key = anthropic_key
                 provider_name = "anthropic"