fix(config): update default LLM models to stable Nov 2025 versions

docs/bugs/INVESTIGATION_INVALID_MODELS.md

@@ -0,0 +1,30 @@
+# Bug Investigation: Invalid Default LLM Models
+
+## Status
+- **Date:** 2025-11-29
+- **Reporter:** CLI User
+- **Component:** `src/utils/config.py`
+- **Priority:** High (Magentic Mode Blocker)
+- **Resolution:** FIXED
+
+## Issue Description
+The user encountered a 403 error when running in Magentic mode:
+`Error code: 403 - {'error': {'message': 'Project ... does not have access to model gpt-5.1', ... 'code': 'model_not_found'}}`
+
+This indicates the application is trying to use `gpt-5.1`, which the user's API key did not have access to (likely a beta/gated model).
+
+## Root Cause Analysis
+The default config used `gpt-5.1` (beta/preview) and `claude-sonnet-4-5-20250929`.
+Initial remediation mistakenly downgraded these to 2024 models (`gpt-4o`).
+Web search confirmed that in November 2025:
+- `claude-sonnet-4-5-20250929` IS valid.
+- `gpt-5.1` exists but access is restricted (leading to 403).
+- `gpt-5` (August 2025) is the stable flagship.
+
+## Solution Implemented
+Updated `src/utils/config.py` to use:
+- `anthropic_model`: `claude-sonnet-4-5-20250929` (Restored correct Nov 2025 model)
+- `openai_model`: `gpt-5` (Changed from 5.1 to 5 to ensure stability/access).
+
+## Verification
+- `tests/unit/agent_factory/test_judges_factory.py` updated and passed.

src/utils/config.py

@@ -26,7 +26,7 @@ class Settings(BaseSettings):
     llm_provider: Literal["openai", "anthropic", "huggingface"] = Field(
         default="openai", description="Which LLM provider to use"
     )
-    openai_model: str = Field(default="gpt-5.1", description="OpenAI model name")
+    openai_model: str = Field(default="gpt-5", description="OpenAI model name")
     anthropic_model: str = Field(
         default="claude-sonnet-4-5-20250929", description="Anthropic model"
     )

tests/unit/agent_factory/test_judges_factory.py

@@ -25,11 +25,11 @@ def test_get_model_openai(mock_settings):
     """Test that OpenAI model is returned when provider is openai."""
     mock_settings.llm_provider = "openai"
     mock_settings.openai_api_key = "sk-test"
-    mock_settings.openai_model = "gpt-5.1"
+    mock_settings.openai_model = "gpt-5"
 
     model = get_model()
     assert isinstance(model, OpenAIChatModel)
-    assert model.model_name == "gpt-5.1"
+    assert model.model_name == "gpt-5"
 
 
 def test_get_model_anthropic(mock_settings):
@@ -58,7 +58,7 @@ def test_get_model_default_fallback(mock_settings):
     """Test fallback to OpenAI if provider is unknown."""
     mock_settings.llm_provider = "unknown_provider"
     mock_settings.openai_api_key = "sk-test"
-    mock_settings.openai_model = "gpt-5.1"
+    mock_settings.openai_model = "gpt-5"
 
     model = get_model()
     assert isinstance(model, OpenAIChatModel)