diff --git a/google/genai/_gaos/resources/interactions/__init__.py b/google/genai/_gaos/resources/interactions/__init__.py
index 1a58f6bca..728ff78ca 100644
--- a/google/genai/_gaos/resources/interactions/__init__.py
+++ b/google/genai/_gaos/resources/interactions/__init__.py
@@ -112,7 +112,7 @@
 from ...types.interactions.mediaresolution import MediaResolution
 from ...types.interactions.modalitytokens import ModalityTokens
 from ...types.interactions.model import Model
-from ...types.interactions.modeloutputstep import ModelOutputStep
+from ...types.interactions.modeloutputstep import ModelOutputStep, ModelOutputStepError
 from ...types.interactions.parallelaisearchconfig import ParallelAISearchConfig
 from ...types.interactions.placecitation import PlaceCitation
 from ...types.interactions.ragresource import RagResource
@@ -270,6 +270,7 @@
     "ModalityTokens",
     "Model",
     "ModelOutputStep",
+    "ModelOutputStepError",
     "ModelParam",
     "ParallelAISearchConfig",
     "PlaceCitation",
diff --git a/google/genai/_gaos/types/interactions/__init__.py b/google/genai/_gaos/types/interactions/__init__.py
index f4a711f23..2640ae402 100644
--- a/google/genai/_gaos/types/interactions/__init__.py
+++ b/google/genai/_gaos/types/interactions/__init__.py
@@ -274,7 +274,12 @@
     from .mediaresolution import MediaResolution
     from .modalitytokens import ModalityTokens, ModalityTokensParam
     from .model import Model
-    from .modeloutputstep import ModelOutputStep, ModelOutputStepParam
+    from .modeloutputstep import (
+        ModelOutputStep,
+        ModelOutputStepError,
+        ModelOutputStepErrorParam,
+        ModelOutputStepParam,
+    )
     from .parallelaisearchconfig import (
         ParallelAISearchConfig,
         ParallelAISearchConfigParam,
@@ -573,6 +578,8 @@
     "ModalityTokensParam",
     "Model",
     "ModelOutputStep",
+    "ModelOutputStepError",
+    "ModelOutputStepErrorParam",
     "ModelOutputStepParam",
     "Network",
     "NetworkEnum",
@@ -915,6 +922,8 @@
     "ModalityTokensParam": ".modalitytokens",
     "Model": ".model",
     "ModelOutputStep": ".modeloutputstep",
+    "ModelOutputStepError": ".modeloutputstep",
+    "ModelOutputStepErrorParam": ".modeloutputstep",
     "ModelOutputStepParam": ".modeloutputstep",
     "ParallelAISearchConfig": ".parallelaisearchconfig",
     "ParallelAISearchConfigParam": ".parallelaisearchconfig",
diff --git a/google/genai/_gaos/types/interactions/modeloutputstep.py b/google/genai/_gaos/types/interactions/modeloutputstep.py
index 80e04566b..e2dde0aca 100644
--- a/google/genai/_gaos/types/interactions/modeloutputstep.py
+++ b/google/genai/_gaos/types/interactions/modeloutputstep.py
@@ -23,15 +23,67 @@
 import pydantic
 from pydantic import model_serializer
 from pydantic.functional_validators import AfterValidator
-from typing import List, Literal, Optional
+from typing import Any, Dict, List, Literal, Optional
 from typing_extensions import Annotated, NotRequired, TypedDict
 
 
+class ModelOutputStepErrorParam(TypedDict):
+    r"""The error result of the operation in case of failure or cancellation."""
+
+    code: NotRequired[int]
+    r"""The status code, which should be an enum value of google.rpc.Code."""
+    message: NotRequired[str]
+    r"""A developer-facing error message, which should be in English. Any
+    user-facing error message should be localized and sent in the
+    google.rpc.Status.details field, or localized by the client.
+    """
+    details: NotRequired[List[Dict[str, Any]]]
+    r"""A list of messages that carry the error details.  There is a common set of
+    message types for APIs to use.
+    """
+
+
+class ModelOutputStepError(BaseModel):
+    r"""The error result of the operation in case of failure or cancellation."""
+
+    code: Optional[int] = None
+    r"""The status code, which should be an enum value of google.rpc.Code."""
+
+    message: Optional[str] = None
+    r"""A developer-facing error message, which should be in English. Any
+    user-facing error message should be localized and sent in the
+    google.rpc.Status.details field, or localized by the client.
+    """
+
+    details: Optional[List[Dict[str, Any]]] = None
+    r"""A list of messages that carry the error details.  There is a common set of
+    message types for APIs to use.
+    """
+
+    @model_serializer(mode="wrap")
+    def serialize_model(self, handler):
+        optional_fields = set(["code", "message", "details"])
+        serialized = handler(self)
+        m = {}
+
+        for n, f in type(self).model_fields.items():
+            k = f.alias or n
+            val = serialized.get(k, serialized.get(n))
+
+            if val != UNSET_SENTINEL:
+                if val is not None or k not in optional_fields:
+                    m[k] = val
+
+        return m
+
+
 class ModelOutputStepParam(TypedDict):
     r"""Output generated by the model."""
 
     type: Literal["model_output"]
     content: NotRequired[List[ContentParam]]
+    error: NotRequired[ModelOutputStepErrorParam]
+    r"""The error result of the operation in case of failure or cancellation."""
 
 
 class ModelOutputStep(BaseModel):
@@ -46,9 +98,12 @@ class ModelOutputStep(BaseModel):
 
     content: Optional[List[Content]] = None
 
+    error: Optional[ModelOutputStepError] = None
+    r"""The error result of the operation in case of failure or cancellation."""
+
     @model_serializer(mode="wrap")
     def serialize_model(self, handler):
-        optional_fields = set(["content"])
+        optional_fields = set(["content", "error"])
         serialized = handler(self)
         m = {}
 
diff --git a/google/genai/_gaos/types/interactions/step.py b/google/genai/_gaos/types/interactions/step.py
index d8b1bf02e..4cb637747 100644
--- a/google/genai/_gaos/types/interactions/step.py
+++ b/google/genai/_gaos/types/interactions/step.py
@@ -52,9 +52,9 @@
 StepParam = TypeAliasType(
     "StepParam",
     Union[
-        ModelOutputStepParam,
         UserInputStepParam,
         FileSearchCallStepParam,
+        ModelOutputStepParam,
         ThoughtStepParam,
         FileSearchResultStepParam,
         CodeExecutionCallStepParam,