fix: harden tool-call protocol and fallback handling

tests/test_error_normalization_middleware.py

@@ -15,7 +15,11 @@ from types import SimpleNamespace
 
 import pytest
 
-from EvoScientist.llm.errors import ProviderStreamError
+from EvoScientist.llm.errors import (
+    AgentControlError,
+    ModelToolProtocolError,
+    ProviderStreamError,
+)
 from EvoScientist.middleware.error_normalization import (
     ErrorNormalizationMiddleware,
     _normalize,
@@ -148,6 +152,23 @@ class TestNormalize:
         )
         assert _normalize(req, pre_wrapped) is None
 
+    @pytest.mark.parametrize(
+        "error",
+        [
+            AgentControlError("MODEL_TOOL_LOOP_DETECTED", "loop stopped"),
+            ModelToolProtocolError(
+                "missing_name",
+                provider="openai",
+                model="gpt-example",
+                route_key="route-1",
+            ),
+        ],
+    )
+    def test_platform_control_error_passes_through(self, error):
+        req = _request(_openai_model())
+
+        assert _normalize(req, error) is None
+
 
 # ---------------------------------------------------------------------------
 # _is_provider_error — used by tool selector to distinguish provider
@@ -355,6 +376,25 @@ class TestMiddleware:
             self._run_awrap(mw, req, handler)
         assert excinfo.value is raised
 
+    def test_awrap_preserves_model_tool_protocol_error_identity(self):
+        raised = ModelToolProtocolError(
+            "missing_name",
+            provider="openai",
+            model="gpt-example",
+            route_key="route-1",
+        )
+
+        async def handler(_req):
+            raise raised
+
+        req = _request(_openai_model())
+        with pytest.raises(ModelToolProtocolError) as excinfo:
+            self._run_awrap(ErrorNormalizationMiddleware(), req, handler)
+
+        assert excinfo.value is raised
+        assert excinfo.value.code == "MODEL_TOOL_PROTOCOL_INVALID"
+        assert excinfo.value.fallbackable is True
+
     def test_awrap_wraps_any_exception_from_recognized_model(self):
         """Any exception raised inside a call to a provider-recognized
         model gets wrapped — including builtins like ``RuntimeError``.