docs: Standardize OpenAI Docs (#25280)

- **Description:** Standardize OpenAI Docs
- **Issue:** the issue #24803

---------

Co-authored-by: Chester Curme <chester.curme@gmail.com>

libs/partners/openai/langchain_openai/llms/base.py

@@ -605,21 +605,105 @@ def max_tokens_for_prompt(self, prompt: str) -> int:
 
 
 class OpenAI(BaseOpenAI):
-    """OpenAI large language models.
+    """OpenAI completion model integration.
+
+    Setup:
+        Install ``langchain-openai`` and set environment variable ``OPENAI_API_KEY``.
+
+        .. code-block:: bash
+
+            pip install -U langchain-openai
+            export OPENAI_API_KEY="your-api-key"
+
+    Key init args — completion params:
+        model: str
+            Name of OpenAI model to use.
+        temperature: float
+            Sampling temperature.
+        max_tokens: Optional[int]
+            Max number of tokens to generate.
+        logprobs: Optional[bool]
+            Whether to return logprobs.
+        stream_options: Dict
+            Configure streaming outputs, like whether to return token usage when
+            streaming (``{"include_usage": True}``).
+
+    Key init args — client params:
+        timeout: Union[float, Tuple[float, float], Any, None]
+            Timeout for requests.
+        max_retries: int
+            Max number of retries.
+        api_key: Optional[str]
+            OpenAI API key. If not passed in will be read from env var OPENAI_API_KEY.
+        base_url: Optional[str]
+            Base URL for API requests. Only specify if using a proxy or service
+            emulator.
+        organization: Optional[str]
+            OpenAI organization ID. If not passed in will be read from env
+            var OPENAI_ORG_ID.
+
+    See full list of supported init args and their descriptions in the params section.
+
+    Instantiate:
+        .. code-block:: python
 
-    To use, you should have the environment variable ``OPENAI_API_KEY``
-    set with your API key, or pass it as a named parameter to the constructor.
+            from langchain_openai import OpenAI
 
-    Any parameters that are valid to be passed to the openai.create call can be passed
-    in, even if not explicitly saved on this class.
+            llm = OpenAI(
+                model="gpt-3.5-turbo-instruct",
+                temperature=0,
+                max_retries=2,
+                # api_key="...",
+                # base_url="...",
+                # organization="...",
+                # other params...
+            )
 
-    Example:
+    Invoke:
         .. code-block:: python
 
-            from langchain_openai import OpenAI
+            input_text = "The meaning of life is "
+            llm.invoke(input_text)
 
-            model = OpenAI(model_name="gpt-3.5-turbo-instruct")
-    """
+        .. code-block:: none
+
+            "a philosophical question that has been debated by thinkers and scholars for centuries."
+
+    Stream:
+        .. code-block:: python
+
+            for chunk in llm.stream(input_text):
+                print(chunk, end="|")
+
+        .. code-block:: none
+
+            a| philosophical| question| that| has| been| debated| by| thinkers| and| scholars| for| centuries|.
+
+        .. code-block:: python
+
+            "".join(llm.stream(input_text))
+
+        .. code-block:: none
+
+            "a philosophical question that has been debated by thinkers and scholars for centuries."
+
+    Async:
+        .. code-block:: python
+
+            await llm.ainvoke(input_text)
+
+            # stream:
+            # async for chunk in (await llm.astream(input_text)):
+            #    print(chunk)
+
+            # batch:
+            # await llm.abatch([input_text])
+
+        .. code-block:: none
+
+            "a philosophical question that has been debated by thinkers and scholars for centuries."
+
+    """  # noqa: E501
 
     @classmethod
     def get_lc_namespace(cls) -> List[str]: