CONTRIBUTING.md

@@ -25,7 +25,11 @@ LangChain supports several different types of integrations with third-party prov
 
 We welcome such contributions, but ask that you read our dedicated [integration contribution guide](https://github.com/langchain-ai/langchainjs/blob/main/.github/contributing/INTEGRATIONS.md) for specific details and patterns to consider before opening a pull request.
 
-These should generally reside in the `libs/langchain-community` workspace and be imported as `@langchain/community/module/name`, but more in-depth integrations or suites of integrations may also reside in separate packages that depend on and extend `@langchain/core`. See [`@langchain/google-genai`](https://github.com/langchain-ai/langchainjs/blob/main/libs/langchain-google-genai) for an example.
+You can also check out the [guide on extending LangChain.js](https://js.langchain.com/docs/guides/extending_langchain/) in our docs.
+
+#### Integration packages
+
+Integrations should generally reside in the `libs/langchain-community` workspace and be imported as `@langchain/community/module/name`. More in-depth integrations or suites of integrations may also reside in separate packages that depend on and extend `@langchain/core`. See [`@langchain/google-genai`](https://github.com/langchain-ai/langchainjs/blob/main/libs/langchain-google-genai) for an example.
 
 To make creating packages like this easier, we offer the [`create-langchain-integration`](https://github.com/langchain-ai/langchainjs/blob/main/libs/create-langchain-integration/) utility that will automatically scaffold a repo with support for both ESM + CJS entrypoints. You can run it like this:
 

deno.json

@@ -4,13 +4,15 @@
     "@langchain/community/": "npm:/@langchain/community/",
     "@langchain/openai": "npm:@langchain/openai",
     "@langchain/core/": "npm:/@langchain/core/",
+    "dotenv/": "npm:/dotenv/",
     "cheerio": "npm:/cheerio",
     "@langchain/pinecone": "npm:@langchain/pinecone",
     "@pinecone-database/pinecone": "npm:@pinecone-database/pinecone",
     "zod": "npm:/zod",
     "zod-to-json-schema": "npm:/zod-to-json-schema",
     "@langchain/anthropic": "npm:@langchain/anthropic",
     "node-llama-cpp": "npm:/node-llama-cpp",
-    "readline": "https://deno.land/x/readline@v1.1.0/mod.ts"
+    "readline": "https://deno.land/x/readline@v1.1.0/mod.ts",
+    "ml-distance": "npm:/ml-distance"
   }
 }

docs/core_docs/docs/ecosystem/langserve.mdx

@@ -1,15 +1,15 @@
-# LangServe
+# Integrating with LangServe
 
 [LangServe](https://python.langchain.com/docs/langserve) is a Python framework that helps developers deploy LangChain [runnables and chains](/docs/expression_language/)
 as REST APIs.
 
 If you have a deployed LangServe route, you can use the [RemoteRunnable](https://api.js.langchain.com/classes/langchain_runnables_remote.RemoteRunnable.html) class to interact
 with it as if it were a local chain. This allows you to more easily call hosted LangServe instances from JavaScript environments (like in the browser on the frontend).
 
-You'll need to install or package LangChain into your frontend:
+You'll need to install or package LangChain core into your frontend:
 
 ```bash npm2yarn
-npm install langchain
+npm install @langchain/core
 ```
 
 ## Usage
@@ -23,9 +23,7 @@ import Example from "@examples/ecosystem/langsmith.ts";
 <CodeBlock language="typescript">{Example}</CodeBlock>
 
 [`streamLog`](/docs/expression_language/interface) is a lower level method for streaming chain intermediate steps as partial JSONPatch chunks.
-This method allows for a few extra options as well to only include or exclude certain named steps.
-
-`@langchain/core` also provides an `applyPatch` utility for aggregating these chunks into a full output:
+This method allows for a few extra options as well to only include or exclude certain named steps:
 
 import StreamLogExample from "@examples/ecosystem/langsmith_stream_log.ts";
 

docs/core_docs/docs/expression_language/cookbook/_category_.yml

@@ -1,2 +1,2 @@
 label: "Cookbook"
-position: 2
+position: 5

docs/core_docs/docs/expression_language/how_to/_category_.yml

@@ -1,2 +1,2 @@
 label: "How to"
-position: 1
+position: 4

docs/core_docs/docs/expression_language/interface.mdx

@@ -1,5 +1,5 @@
 ---
-sidebar_position: 0
+sidebar_position: 2
 ---
 
 import CodeBlock from "@theme/CodeBlock";
@@ -13,6 +13,7 @@ This is a standard interface with a few different methods, which make it easy to
 - [`invoke`](/docs/expression_language/interface#invoke): call the chain on an input
 - [`batch`](/docs/expression_language/interface#batch): call the chain on a list of inputs
 - [`streamLog`](/docs/expression_language/interface#stream-log): stream back intermediate steps as they happen, in addition to the final response
+- [`streamEvents`](/docs/expression_language/interface#stream-events): **beta** stream events as they happen in the chain (introduced in `@langchain/core` 0.1.27)
 
 The **input type** varies by component :
 
@@ -96,3 +97,138 @@ npm install @langchain/community @langchain/openai
 ```
 
 <CodeBlock language="typescript">{StreamLogExample}</CodeBlock>
+
+## Stream events
+
+Event Streaming is a **beta** API, and may change a bit based on feedback. It provides a way to stream both intermediate steps and final output from the chain.
+
+Note: Introduced in `@langchain/core` 0.1.27
+
+For now, when using the `streamEvents` API, for everything to work properly please:
+
+- Any custom functions / runnables must propragate callbacks
+- Set proper parameters on models to force the LLM to stream tokens.
+
+### Event Reference
+
+Here is a reference table that shows some events that might be emitted by the various Runnable objects.
+Definitions for some of the Runnable are included after the table.
+
+⚠️ When streaming the inputs for the runnable will not be available until the input stream has been entirely consumed This means that the inputs will be available at for the corresponding `end` hook rather than `start` event.
+
+| event                | name             | chunk                           | input                                         | output                                          |
+| -------------------- | ---------------- | ------------------------------- | --------------------------------------------- | ----------------------------------------------- |
+| on_chat_model_start  | [model name]     |                                 | {"messages": [[SystemMessage, HumanMessage]]} |                                                 |
+| on_chat_model_stream | [model name]     | AIMessageChunk(content="hello") |                                               |                                                 |
+| on_chat_model_end    | [model name]     |                                 | {"messages": [[SystemMessage, HumanMessage]]} | {"generations": [...], "llm_output": None, ...} |
+| on_llm_start         | [model name]     |                                 | {'input': 'hello'}                            |                                                 |
+| on_llm_stream        | [model name]     | 'Hello'                         |                                               |                                                 |
+| on_llm_end           | [model name]     |                                 | 'Hello human!'                                |
+| on_chain_start       | format_docs      |                                 |                                               |                                                 |
+| on_chain_stream      | format_docs      | "hello world!, goodbye world!"  |                                               |                                                 |
+| on_chain_end         | format_docs      |                                 | [Document(...)]                               | "hello world!, goodbye world!"                  |
+| on_tool_start        | some_tool        |                                 | {"x": 1, "y": "2"}                            |                                                 |
+| on_tool_stream       | some_tool        | {"x": 1, "y": "2"}              |                                               |                                                 |
+| on_tool_end          | some_tool        |                                 |                                               | {"x": 1, "y": "2"}                              |
+| on_retriever_start   | [retriever name] |                                 | {"query": "hello"}                            |                                                 |
+| on_retriever_chunk   | [retriever name] | {documents: [...]}              |                                               |                                                 |
+| on_retriever_end     | [retriever name] |                                 | {"query": "hello"}                            | {documents: [...]}                              |
+| on_prompt_start      | [template_name]  |                                 | {"question": "hello"}                         |                                                 |
+| on_prompt_end        | [template_name]  |                                 | {"question": "hello"}                         | ChatPromptValue(messages: [SystemMessage, ...]) |
+
+import StreamEventsExample from "@examples/agents/stream_events.ts";
+
+<CodeBlock language="typescript">{StreamEventsExample}</CodeBlock>
+
+```
+-----
+Starting agent: Agent with input: {"input":"what is the weather in SF"}
+
+-----
+Starting tool: TavilySearchResults with inputs: weather in San Francisco
+
+-----
+Finished tool: TavilySearchResults
+
+Tool output was: [{"title":"Weather in San Francisco","url":"https://www.weatherapi.com/","content":"Weather in San Francisco is {'location': {'name': 'San Francisco', 'region': 'California', 'country': 'United States of America', 'lat': 37.78, 'lon': -122.42, 'tz_id': 'America/Los_Angeles', 'localtime_epoch': 1707638479, 'localtime': '2024-02-11 0:01'}, 'current': {'last_updated_epoch': 1707638400, 'last_updated': '2024-02-11 00:00', 'temp_c': 11.1, 'temp_f': 52.0, 'is_day': 0, 'condition': {'text': 'Partly cloudy', 'icon': '//cdn.weatherapi.com/weather/64x64/night/116.png', 'code': 1003}, 'wind_mph': 9.4, 'wind_kph': 15.1, 'wind_degree': 270, 'wind_dir': 'W', 'pressure_mb': 1022.0, 'pressure_in': 30.18, 'precip_mm': 0.0, 'precip_in': 0.0, 'humidity': 83, 'cloud': 25, 'feelslike_c': 11.5, 'feelslike_f': 52.6, 'vis_km': 16.0, 'vis_miles': 9.0, 'uv': 1.0, 'gust_mph': 13.9, 'gust_kph': 22.3}}","score":0.98371,"raw_content":null},{"title":"San Francisco, California November 2024 Weather Forecast","url":"https://www.weathertab.com/en/c/e/11/united-states/california/san-francisco/","content":"Temperature Forecast Temperature Forecast Normal Avg High Temps 60 to 70 °F Avg Low Temps 45 to 55 °F Weather Forecast Legend WeatherTAB helps you plan activities on days with the least risk of rain. Our forecasts are not direct predictions of rain/snow. Not all risky days will have rain/snow.","score":0.9517,"raw_content":null},{"title":"Past Weather in San Francisco, California, USA — Yesterday or Further Back","url":"https://www.timeanddate.com/weather/usa/san-francisco/historic","content":"Past Weather in San Francisco, California, USA — Yesterday and Last 2 Weeks. Weather. Time Zone. DST Changes. Sun & Moon. Weather Today Weather Hourly 14 Day Forecast Yesterday/Past Weather Climate (Averages) Currently: 52 °F. Light rain. Overcast.","score":0.945,"raw_content":null},{"title":"San Francisco, California February 2024 Weather Forecast - detailed","url":"https://www.weathertab.com/en/g/e/02/united-states/california/san-francisco/","content":"Free Long Range Weather Forecast for San Francisco, California February 2024. Detailed graphs of monthly weather forecast, temperatures, and degree days.","score":0.92177,"raw_content":null},{"title":"San Francisco Weather in 2024 - extremeweatherwatch.com","url":"https://www.extremeweatherwatch.com/cities/san-francisco/year-2024","content":"Year: What's the hottest temperature in San Francisco so far this year? As of February 2, the highest temperature recorded in San Francisco, California in 2024 is 73 °F which happened on January 29. Highest Temperatures: All-Time By Year Highest Temperatures in San Francisco in 2024 What's the coldest temperature in San Francisco so far this year?","score":0.91598,"raw_content":null}]
+
+-----
+| The
+|  current
+|  weather
+|  in
+|  San
+|  Francisco
+|  is
+|  partly
+|  cloudy
+|  with
+|  a
+|  temperature
+|  of
+|
+| 52
+| .
+| 0
+| °F
+|  (
+| 11
+| .
+| 1
+| °C
+| ).
+|  The
+|  wind
+|  speed
+|  is
+|
+| 15
+| .
+| 1
+|  k
+| ph
+|  coming
+|  from
+|  the
+|  west
+| ,
+|  and
+|  the
+|  humidity
+|  is
+|  at
+|
+| 83
+| %.
+|  If
+|  you
+|  need
+|  more
+|  detailed
+|  information
+| ,
+|  you
+|  can
+|  visit
+|  [
+| Weather
+|  in
+|  San
+|  Francisco
+| ](
+| https
+| ://
+| www
+| .weather
+| api
+| .com
+| /
+| ).
+
+-----
+Finished agent: Agent
+
+Agent output was: The current weather in San Francisco is partly cloudy with a temperature of 52.0°F (11.1°C). The wind speed is 15.1 kph coming from the west, and the humidity is at 83%. If you need more detailed information, you can visit [Weather in San Francisco](https://www.weatherapi.com/).
+
+-----
+```