fix(providers): omit store parameter for OpenRouter responses endpoint

OpenRouter's /responses endpoint rejects store:true via Zod validation.
This is an endpoint-level limitation, not model-specific. The fix
conditionally omits the store parameter for OpenRouter while maintaining
it for direct OpenAI and Azure OpenAI providers.

- Add provider type check in _generate_with_responses_endpoint
- Include debug logging when store parameter is omitted
- Add regression tests for both OpenRouter and OpenAI behavior

Fixes #348

providers/openai_compatible.py

@@ -421,9 +421,17 @@ class OpenAICompatibleProvider(ModelProvider):
             "model": model_name,
             "input": input_messages,
             "reasoning": {"effort": effort},
-            "store": True,
         }
 
+        # Only include store parameter for providers that support it.
+        # OpenRouter's /responses endpoint rejects store:true via Zod validation (Issue #348).
+        # This is an endpoint-level limitation, not model-specific, so we omit for all
+        # OpenRouter /responses calls. If OpenRouter later supports store, revisit this logic.
+        if self.get_provider_type() != ProviderType.OPENROUTER:
+            completion_params["store"] = True
+        else:
+            logging.debug(f"Omitting 'store' parameter for OpenRouter provider (model: {model_name})")
+
         # Add max tokens if specified (using max_completion_tokens for responses endpoint)
         if max_output_tokens:
             completion_params["max_completion_tokens"] = max_output_tokens

tests/test_openrouter_store_parameter.py

@@ -0,0 +1,158 @@
+"""Tests for OpenRouter store parameter handling in responses endpoint.
+
+Regression tests for GitHub Issue #348: OpenAI "store" parameter validation error
+for certain models via OpenRouter.
+
+OpenRouter's /responses endpoint rejects store:true via Zod validation. This is an
+endpoint-level limitation, not model-specific. These tests verify that:
+- OpenRouter provider omits the store parameter
+- Direct OpenAI provider includes store: true
+"""
+
+import unittest
+from unittest.mock import Mock, patch
+
+from providers.openai_compatible import OpenAICompatibleProvider
+from providers.shared import ProviderType
+
+
+class MockOpenRouterProvider(OpenAICompatibleProvider):
+    """Mock provider that simulates OpenRouter behavior."""
+
+    FRIENDLY_NAME = "OpenRouter Test"
+
+    def get_provider_type(self):
+        return ProviderType.OPENROUTER
+
+    def get_capabilities(self, model_name):
+        mock_caps = Mock()
+        mock_caps.default_reasoning_effort = "high"
+        return mock_caps
+
+    def validate_model_name(self, model_name):
+        return True
+
+    def list_models(self, **kwargs):
+        return ["openai/gpt-5-pro", "openai/gpt-5.1-codex"]
+
+
+class MockOpenAIProvider(OpenAICompatibleProvider):
+    """Mock provider that simulates direct OpenAI behavior."""
+
+    FRIENDLY_NAME = "OpenAI Test"
+
+    def get_provider_type(self):
+        return ProviderType.OPENAI
+
+    def get_capabilities(self, model_name):
+        mock_caps = Mock()
+        mock_caps.default_reasoning_effort = "high"
+        return mock_caps
+
+    def validate_model_name(self, model_name):
+        return True
+
+    def list_models(self, **kwargs):
+        return ["gpt-5-pro", "gpt-5.1-codex"]
+
+
+class TestStoreParameterHandling(unittest.TestCase):
+    """Test store parameter is conditionally included based on provider type.
+
+    **Feature: openrouter-store-parameter-fix, Property 1: OpenRouter requests omit store parameter**
+    **Feature: openrouter-store-parameter-fix, Property 2: Direct OpenAI requests include store parameter**
+    """
+
+    def setUp(self):
+        """Set up test fixtures."""
+        self.openrouter_provider = MockOpenRouterProvider("test-key")
+        self.openai_provider = MockOpenAIProvider("test-key")
+
+    @patch.object(OpenAICompatibleProvider, "client", new_callable=lambda: property(lambda self: Mock()))
+    def test_openrouter_responses_omits_store_parameter(self, mock_client):
+        """Test that OpenRouter provider omits store parameter from responses endpoint.
+
+        **Feature: openrouter-store-parameter-fix, Property 1: OpenRouter requests omit store parameter**
+        **Validates: Requirements 1.1, 2.1**
+
+        OpenRouter's /responses endpoint rejects store:true via Zod validation (Issue #348).
+        The store parameter should be omitted entirely for OpenRouter requests.
+        """
+        # Capture the completion_params passed to the API
+        captured_params = {}
+
+        def capture_create(**kwargs):
+            captured_params.update(kwargs)
+            # Return a mock response
+            mock_response = Mock()
+            mock_response.output_text = "Test response"
+            mock_response.usage = None
+            return mock_response
+
+        mock_client_instance = Mock()
+        mock_client_instance.responses.create = capture_create
+
+        with patch.object(
+            MockOpenRouterProvider, "client", new_callable=lambda: property(lambda self: mock_client_instance)
+        ):
+            provider = MockOpenRouterProvider("test-key")
+
+            # Call the method that builds completion_params
+            try:
+                provider._generate_with_responses_endpoint(
+                    model_name="openai/gpt-5-pro",
+                    messages=[{"role": "user", "content": "test"}],
+                    temperature=0.7,
+                )
+            except Exception:
+                pass  # We only care about the captured params
+
+        # Verify store parameter is NOT in the request
+        self.assertNotIn("store", captured_params, "OpenRouter requests should NOT include 'store' parameter")
+
+    @patch.object(OpenAICompatibleProvider, "client", new_callable=lambda: property(lambda self: Mock()))
+    def test_openai_responses_includes_store_parameter(self, mock_client):
+        """Test that direct OpenAI provider includes store parameter in responses endpoint.
+
+        **Feature: openrouter-store-parameter-fix, Property 2: Direct OpenAI requests include store parameter**
+        **Validates: Requirements 1.2, 2.2**
+
+        Direct OpenAI API supports the store parameter for stored completions.
+        The store parameter should be included with value True for OpenAI requests.
+        """
+        # Capture the completion_params passed to the API
+        captured_params = {}
+
+        def capture_create(**kwargs):
+            captured_params.update(kwargs)
+            # Return a mock response
+            mock_response = Mock()
+            mock_response.output_text = "Test response"
+            mock_response.usage = None
+            return mock_response
+
+        mock_client_instance = Mock()
+        mock_client_instance.responses.create = capture_create
+
+        with patch.object(
+            MockOpenAIProvider, "client", new_callable=lambda: property(lambda self: mock_client_instance)
+        ):
+            provider = MockOpenAIProvider("test-key")
+
+            # Call the method that builds completion_params
+            try:
+                provider._generate_with_responses_endpoint(
+                    model_name="gpt-5-pro",
+                    messages=[{"role": "user", "content": "test"}],
+                    temperature=0.7,
+                )
+            except Exception:
+                pass  # We only care about the captured params
+
+        # Verify store parameter IS in the request with value True
+        self.assertIn("store", captured_params, "OpenAI requests should include 'store' parameter")
+        self.assertTrue(captured_params["store"], "OpenAI requests should have store=True")
+
+
+if __name__ == "__main__":
+    unittest.main()