AIML-244 Update agent model defaults and config logging if using Contrast LLM

Author: Jacob Mages-Haskins

src/config.py

@@ -70,7 +70,7 @@ def __init__(self, env: Dict[str, str] = os.environ, testing: bool = False):
 
         default_agent_model = ""
         if is_smartfix_coding_agent:
-            default_agent_model = "bedrock/us.anthropic.claude-3-7-sonnet-20250219-v1:0"
+            default_agent_model = "bedrock/us.anthropic.claude-sonnet-4-5-20250929-v1:0"
         self.AGENT_MODEL = self._get_env_var("AGENT_MODEL", required=False, default=default_agent_model)
 
         # --- Build and Formatting Configuration ---
@@ -120,6 +120,12 @@ def __init__(self, env: Dict[str, str] = os.environ, testing: bool = False):
         self.ENABLE_FULL_TELEMETRY = self._get_bool_env("ENABLE_FULL_TELEMETRY", default=True)
         self.USE_CONTRAST_LLM = self._get_bool_env("USE_CONTRAST_LLM", default=True)
 
+        # Update agent model for Contrast LLM if no explicit model was set
+        if (is_smartfix_coding_agent
+                and self.USE_CONTRAST_LLM
+                and self._get_env_var("AGENT_MODEL", required=False) is None):
+            self.AGENT_MODEL = "contrast/claude-sonnet-4-5"
+
         # --- Vulnerability Configuration ---
         self.VULNERABILITY_SEVERITIES = self._parse_and_validate_severities(
             self._get_env_var("VULNERABILITY_SEVERITIES", required=False, default='["CRITICAL", "HIGH"]')
@@ -213,7 +219,8 @@ def _log_initial_settings(self):
         _log_config_message(f"Debug Mode: {self.DEBUG_MODE}")
         _log_config_message(f"Base Branch: {self.BASE_BRANCH}")
         _log_config_message(f"Run Task: {self.RUN_TASK}")
-        _log_config_message(f"Agent Model: {self.AGENT_MODEL}")
+        if not self.USE_CONTRAST_LLM:
+            _log_config_message(f"Agent Model: {self.AGENT_MODEL}")
         _log_config_message(f"Coding Agent: {self.CODING_AGENT}")
         _log_config_message(f"Skip Writing Security Test: {self.SKIP_WRITING_SECURITY_TEST}")
         _log_config_message(f"Skip QA Review: {self.SKIP_QA_REVIEW}")

test/test_config_integration.py

@@ -74,8 +74,8 @@ def test_coding_agent_smartfix_with_contrast_llm(self):
         # Should have SMARTFIX agent with Contrast LLM enabled
         self.assertEqual(config.CODING_AGENT, 'SMARTFIX')
         self.assertTrue(config.USE_CONTRAST_LLM)
-        # Default agent model should still be set for fallback
-        self.assertEqual(config.AGENT_MODEL, 'bedrock/us.anthropic.claude-3-7-sonnet-20250219-v1:0')
+        # Default agent model should use Contrast LLM constant
+        self.assertEqual(config.AGENT_MODEL, 'contrast/claude-sonnet-4-5')
 
     def test_coding_agent_smartfix_with_byollm(self):
         """Test that SMARTFIX coding agent works with USE_CONTRAST_LLM=False (BYOLLM)."""