Stub in an initial OpenAI Responses API

Signed-off-by: Ben Browning <bbrownin@redhat.com>

llama_stack/apis/datatypes.py

@@ -24,6 +24,7 @@ class Api(Enum):
     eval = "eval"
     post_training = "post_training"
     tool_runtime = "tool_runtime"
+    openai_responses = "openai_responses"
 
     telemetry = "telemetry"
 

llama_stack/apis/openai_responses/__init__.py

@@ -0,0 +1,7 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from .openai_responses import *  # noqa: F401 F403

llama_stack/apis/openai_responses/openai_responses.py

@@ -0,0 +1,91 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+# All rights reserved.
+#
+# This source code is licensed under the terms described in the LICENSE file in
+# the root directory of this source tree.
+
+from typing import AsyncIterator, List, Literal, Optional, Protocol, Union, runtime_checkable
+
+from pydantic import BaseModel, Field
+from typing_extensions import Annotated
+
+from llama_stack.schema_utils import json_schema_type, webmethod
+
+
+@json_schema_type
+class OpenAIResponseError(BaseModel):
+    code: str
+    message: str
+
+
+@json_schema_type
+class OpenAIResponseOutputMessageContentOutputText(BaseModel):
+    text: str
+    type: Literal["output_text"] = "output_text"
+
+
+OpenAIResponseOutputMessageContent = Annotated[
+    Union[OpenAIResponseOutputMessageContentOutputText,],
+    Field(discriminator="type"),
+]
+
+
+@json_schema_type
+class OpenAIResponseOutputMessage(BaseModel):
+    id: str
+    content: List[OpenAIResponseOutputMessageContent]
+    role: Literal["assistant"] = "assistant"
+    status: str
+    type: Literal["message"] = "message"
+
+
+OpenAIResponseOutput = Annotated[
+    Union[OpenAIResponseOutputMessage,],
+    Field(discriminator="type"),
+]
+
+
+@json_schema_type
+class OpenAIResponseObject(BaseModel):
+    created_at: int
+    error: Optional[OpenAIResponseError] = None
+    id: str
+    model: str
+    object: Literal["response"] = "response"
+    output: List[OpenAIResponseOutput]
+    parallel_tool_calls: bool = False
+    previous_response_id: Optional[str] = None
+    status: str
+    temperature: Optional[float] = None
+    top_p: Optional[float] = None
+    truncation: Optional[str] = None
+    user: Optional[str] = None
+
+
+@json_schema_type
+class OpenAIResponseObjectStream(BaseModel):
+    response: OpenAIResponseObject
+    type: Literal["response.created"] = "response.created"
+
+
+@runtime_checkable
+class OpenAIResponses(Protocol):
+    """
+    OpenAI Responses API implementation.
+    """
+
+    @webmethod(route="/openai/v1/responses/{id}", method="GET")
+    async def get_openai_response(
+        self,
+        id: str,
+    ) -> OpenAIResponseObject: ...
+
+    @webmethod(route="/openai/v1/responses", method="POST")
+    async def create_openai_response(
+        self,
+        input: str,
+        model: str,
+        previous_response_id: Optional[str] = None,
+        store: Optional[bool] = True,
+        stream: Optional[bool] = False,
+    ) -> Union[OpenAIResponseObject, AsyncIterator[OpenAIResponseObjectStream]]: ...