Fixes #3008 Responses API: multi-turn conversations 400 on turn 2 when passing response.output back as input

src/openai/types/responses/response.py

@@ -1,6 +1,6 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
-from typing import List, Union, Optional
+from typing import Any, Dict, List, Union, Optional
 from typing_extensions import Literal, TypeAlias
 
 from .tool import Tool
@@ -319,3 +319,31 @@ def output_text(self) -> str:
                         texts.append(content.text)
 
         return "".join(texts)
+
+    def output_as_input(self) -> List[Dict[str, Any]]:
+        """Return the response output items as a list of input-ready dicts for use in a subsequent turn.
+
+        This is the recommended way to build multi-turn conversations manually.
+        It calls ``as_input()`` on items that have that method (e.g.
+        :class:`ResponseOutputMessage`, :class:`ResponseReasoningItem`,
+        :class:`ResponseFunctionToolCall`), stripping output-only fields like
+        ``status`` and ``encrypted_content`` that the API rejects as input.
+        For all other output item types, ``to_dict()`` is used as a fallback.
+
+        Example::
+
+            conversation: list[dict] = []
+            for msg in ["What is the capital of France?", "And Germany?"]:
+                conversation.append({"role": "user", "content": msg})
+                response = client.responses.create(
+                    model="o4-mini", input=conversation, max_output_tokens=200,
+                )
+                conversation.extend(response.output_as_input())
+        """
+        result: List[Dict[str, Any]] = []
+        for item in self.output:
+            if hasattr(item, "as_input"):
+                result.append(item.as_input())
+            else:
+                result.append(item.to_dict())
+        return result

src/openai/types/responses/response_function_tool_call.py

@@ -1,6 +1,6 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
-from typing import Optional
+from typing import Any, Dict, Optional
 from typing_extensions import Literal
 
 from ..._models import BaseModel
@@ -39,3 +39,12 @@ class ResponseFunctionToolCall(BaseModel):
     One of `in_progress`, `completed`, or `incomplete`. Populated when items are
     returned via API.
     """
+
+    def as_input(self) -> Dict[str, Any]:
+        """Return a dict representation of this item suitable for use as input in a subsequent response.
+
+        This strips output-only fields (``status``) that the API does not accept as input.
+        """
+        data = self.to_dict()
+        data.pop("status", None)
+        return data

src/openai/types/responses/response_output_message.py

@@ -1,6 +1,6 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
-from typing import List, Union, Optional
+from typing import Any, Dict, List, Union, Optional
 from typing_extensions import Literal, Annotated, TypeAlias
 
 from ..._utils import PropertyInfo
@@ -42,3 +42,12 @@ class ResponseOutputMessage(BaseModel):
     sending follow-up requests, preserve and resend phase on all assistant messages
     — dropping it can degrade performance. Not used for user messages.
     """
+
+    def as_input(self) -> Dict[str, Any]:
+        """Return a dict representation of this item suitable for use as input in a subsequent response.
+
+        This strips output-only fields that the API does not accept as input.
+        """
+        data = self.to_dict()
+        data.pop("status", None)
+        return data

src/openai/types/responses/response_reasoning_item.py

@@ -1,6 +1,6 @@
 # File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.
 
-from typing import List, Optional
+from typing import Any, Dict, List, Optional
 from typing_extensions import Literal
 
 from ..._models import BaseModel
@@ -60,3 +60,14 @@ class ResponseReasoningItem(BaseModel):
     One of `in_progress`, `completed`, or `incomplete`. Populated when items are
     returned via API.
     """
+
+    def as_input(self) -> Dict[str, Any]:
+        """Return a dict representation of this item suitable for use as input in a subsequent response.
+
+        This strips output-only fields (``status``, ``encrypted_content``) that the
+        API does not accept as input.
+        """
+        data = self.to_dict()
+        data.pop("status", None)
+        data.pop("encrypted_content", None)
+        return data