From 64ff4e4f186eb7cd6384c8810330b4924c0f7e8d Mon Sep 17 00:00:00 2001
From: Eugene Yurtsev <eyurtsev@gmail.com>
Date: Wed, 15 May 2024 13:29:38 -0400
Subject: [PATCH] x

---
 docs/docs/versions/overview.mdx               |   4 +
 docs/docs/versions/v_02/astream_events.mdx    | 124 ++++++++++++++++++
 .../versions/{v0_2.mdx => v_02/index.mdx}     |   5 +-
 3 files changed, 132 insertions(+), 1 deletion(-)
 create mode 100644 docs/docs/versions/v_02/astream_events.mdx
 rename docs/docs/versions/{v0_2.mdx => v_02/index.mdx} (99%)

diff --git a/docs/docs/versions/overview.mdx b/docs/docs/versions/overview.mdx
index d6786e02514..f4544bbac22 100644
--- a/docs/docs/versions/overview.mdx
+++ b/docs/docs/versions/overview.mdx
@@ -7,6 +7,10 @@ sidebar_label: Overview
 
 ## What’s new in LangChain?
 
+The following features have been added during the development of 0.2.x:
+
+- Rolled out `v2` of the [Event Streaming API](https://python.langchain.com/docs/expression_language/streaming/#using-stream-events)
+
 The following features have been added during the development of 0.1.x:
 
 - Better streaming support via the [Event Streaming API](https://python.langchain.com/docs/expression_language/streaming/#using-stream-events)
diff --git a/docs/docs/versions/v_02/astream_events.mdx b/docs/docs/versions/v_02/astream_events.mdx
new file mode 100644
index 00000000000..f299c11a4fb
--- /dev/null
+++ b/docs/docs/versions/v_02/astream_events.mdx
@@ -0,0 +1,124 @@
+---
+sidebar_position: 1
+sidebar_label: astream_events
+---
+
+# astream_events V2
+
+We've added a `v2` of the astream_events API with the release of `0.2.0`.
+
+You can see this [PR](https://github.com/langchain-ai/langchain/pull/21638) for more details.
+
+The `v2` version is a re-write of the `v1` version, and should be more efficient, with more consistent output for the events.
+
+The `v1` version of the API will be deprecated in favor of the `v2` version. `v1` is deprecated as of `0.2.0` and removed in `0.4.0`.
+
+## Changes
+
+Below is a list of changes between the `v1` and `v2` versions of the API.
+
+### on_chat_model_end `output`
+
+In `v1`, the outputs associated with `on_chat_model_end` changed depending on whether the
+chat model was run as a root level runnable or as part of a chain.
+
+As a root level runnable the output was:
+
+```python
+"data": {"output": AIMessageChunk(content="hello world!", id='some id')}
+```
+
+As part of a chain the output was:
+
+```
+            "data": {
+                "output": {
+                    "generations": [
+                        [
+                            {
+                                "generation_info": None,
+                                "message": AIMessageChunk(
+                                    content="hello world!", id=AnyStr()
+                                ),
+                                "text": "hello world!",
+                                "type": "ChatGenerationChunk",
+                            }
+                        ]
+                    ],
+                    "llm_output": None,
+                }
+            },
+```
+
+
+As of `v2`, the output will always be the simpler representation:
+
+```python
+"data": {"output": AIMessageChunk(content="hello world!", id='some id')}
+```
+
+:::note
+Non chat models (i.e., regular LLMs) are will be consistently associated with the more verbose format for now.
+:::
+
+### Removed `on_retriever_stream`
+
+The `on_retriever_stream` event was an artifact of the implementation and has been removed.
+
+Full information associated with the event is already available in the `on_retriever_end` event.
+
+Please use `on_retriever_end` instead.
+
+### Removed `on_tool_stream`
+
+The `on_tool_stream` event was an artifact of the implementation and has been removed.
+
+Full information associated with the event is already available in the `on_tool_end` event.
+
+Please use `on_tool_end` instead.
+
+### Update output for `on_retriever_end`
+
+`on_retriever_end` output will always return a list of `Documents`.
+
+Before:
+```python
+{
+    "data": {
+        "output": [
+            Document(...),
+            Document(...),
+            ...
+        ]
+    }
+}
+```
+
+
+### Propagating Names
+
+Names of runnables have been updated to be more consistent.
+
+```python
+model = GenericFakeChatModel(messages=infinite_cycle).configurable_fields(
+    messages=ConfigurableField(
+        id="messages",
+        name="Messages",
+        description="Messages return by the LLM",
+    )
+)
+```
+
+In `v1`, the event name was `RunnableConfigurableFields`.
+
+In `v2`, the event name is `GenericFakeChatModel`.
+
+If you're filtering by event names, check if you need to update your filters.
+
+### RunnableRetry
+
+Usage of [RunnableRetry](https://api.python.langchain.com/en/latest/runnables/langchain_core.runnables.retry.RunnableRetry.html)
+within an LCEL chain being streamed generated an incorrect `on_chain_end` event in `v1` corresponding
+to the failed runnable invocation that was being retried.
+
+This event has been removed in `v2`.
\ No newline at end of file
diff --git a/docs/docs/versions/v0_2.mdx b/docs/docs/versions/v_02/index.mdx
similarity index 99%
rename from docs/docs/versions/v0_2.mdx
rename to docs/docs/versions/v_02/index.mdx
index ef06512cf82..34eacbee606 100644
--- a/docs/docs/versions/v0_2.mdx
+++ b/docs/docs/versions/v_02/index.mdx
@@ -172,4 +172,7 @@ We have two main types of deprecations:
 
 2. Code that has better alternatives available and will eventually be removed, so there’s only a single way to do things. (e.g., `predict_messages` method in ChatModels has been deprecated in favor of `invoke`).
 
-    Many of these were marked for removal in 0.2. We have bumped the removal to 0.3.
\ No newline at end of file
+    Many of these were marked for removal in 0.2. We have bumped the removal to 0.3.
+
+### Notable Deprecations
+