Categorize tools into 'model capabilities categories' to help determine which type of model to pick when in auto mode

Encourage Claude to pick the best model for the job automatically in auto mode
Lots of new tests to ensure automatic model picking works reliably based on user preference or when a matching model is not found or ambiguous
Improved error reporting when bogus model is requested and is not configured or available

tests/test_auto_mode.py

@@ -75,7 +75,7 @@ class TestAutoMode:
             model_schema = schema["properties"]["model"]
             assert "enum" in model_schema
             assert "flash" in model_schema["enum"]
-            assert "Choose the best model" in model_schema["description"]
+            assert "select the most suitable model" in model_schema["description"]
 
         finally:
             # Restore
@@ -134,6 +134,58 @@ class TestAutoMode:
                 os.environ.pop("DEFAULT_MODEL", None)
             importlib.reload(config)
 
+    @pytest.mark.asyncio
+    async def test_unavailable_model_error_message(self):
+        """Test that unavailable model shows helpful error with available models"""
+        # Save original
+        original = os.environ.get("DEFAULT_MODEL", "")
+
+        try:
+            # Enable auto mode
+            os.environ["DEFAULT_MODEL"] = "auto"
+            import config
+
+            importlib.reload(config)
+
+            tool = AnalyzeTool()
+
+            # Mock the provider to simulate o3 not being available
+            with patch("providers.registry.ModelProviderRegistry.get_provider_for_model") as mock_provider:
+                # Mock that o3 is not available but flash/pro are
+                def mock_get_provider(model_name):
+                    if model_name in ["flash", "pro", "gemini-2.5-flash-preview-05-20", "gemini-2.5-pro-preview-06-05"]:
+                        # Return a mock provider for available models
+                        from unittest.mock import MagicMock
+
+                        return MagicMock()
+                    else:
+                        # o3 and others are not available
+                        return None
+
+                mock_provider.side_effect = mock_get_provider
+
+                # Execute with unavailable model
+                result = await tool.execute(
+                    {"files": ["/tmp/test.py"], "prompt": "Analyze this", "model": "o3"}  # This model is not available
+                )
+
+            # Should get error with helpful message
+            assert len(result) == 1
+            response = result[0].text
+            assert "error" in response
+            assert "Model 'o3' is not available" in response
+            assert "Available models:" in response
+            # Should list the available models
+            assert "flash" in response or "pro" in response
+
+        finally:
+            # Restore
+            if original:
+                os.environ["DEFAULT_MODEL"] = original
+            else:
+                os.environ.pop("DEFAULT_MODEL", None)
+            importlib.reload(config)
+
     def test_model_field_schema_generation(self):
         """Test the get_model_field_schema method"""
         from tools.base import BaseTool
@@ -173,7 +225,7 @@ class TestAutoMode:
             schema = tool.get_model_field_schema()
             assert "enum" in schema
             assert all(model in schema["enum"] for model in ["flash", "pro", "o3"])
-            assert "Choose the best model" in schema["description"]
+            assert "select the most suitable model" in schema["description"]
 
             # Test normal mode
             os.environ["DEFAULT_MODEL"] = "pro"