Readme rewrite (#12615)

Co-authored-by: Lance Martin <lance@langchain.dev>
Co-authored-by: Harrison Chase <hw.chase.17@gmail.com>

templates/openai-functions-agent/README.md

@@ -1,16 +1,72 @@
-# OpenAI Functions Agent
 
-This template creates an agent that uses OpenAI function calling to communicate its decisions of what actions to take.
-This example creates an agent that can optionally look up things on the internet using Tavily's search engine.
+# openai-functions-agent
 
-##  LLM
+This template creates an agent that uses OpenAI function calling to communicate its decisions on what actions to take. 
 
-This template will use `OpenAI` by default. 
+This example creates an agent that can optionally look up information on the internet using Tavily's search engine.
 
-Be sure that `OPENAI_API_KEY` is set in your environment.
+## Environment Setup
 
-##  Tools
+The following environment variables need to be set:
 
-This template will use `Tavily` by default. 
+Set the `OPENAI_API_KEY` environment variable to access the OpenAI models.
 
-Be sure that `TAVILY_API_KEY` is set in your environment.
+Set the `TAVILY_API_KEY` environment variable to access Tavily.
+
+## Usage
+
+To use this package, you should first have the LangChain CLI installed:
+
+```shell
+pip install -U "langchain-cli[serve]"
+```
+
+To create a new LangChain project and install this as the only package, you can do:
+
+```shell
+langchain app new my-app --package openai-functions-agent
+```
+
+If you want to add this to an existing project, you can just run:
+
+```shell
+langchain app add openai-functions-agent
+```
+
+And add the following code to your `server.py` file:
+```python
+from openai_functions_agent import chain as openai_functions_agent_chain
+
+add_routes(app, openai_functions_agent_chain, path="/openai-functions-agent")
+```
+
+(Optional) Let's now configure LangSmith. 
+LangSmith will help us trace, monitor and debug LangChain applications. 
+LangSmith is currently in private beta, you can sign up [here](https://smith.langchain.com/). 
+If you don't have access, you can skip this section
+
+```shell
+export LANGCHAIN_TRACING_V2=true
+export LANGCHAIN_API_KEY=<your-api-key>
+export LANGCHAIN_PROJECT=<your-project>  # if not specified, defaults to "default"
+```
+
+If you are inside this directory, then you can spin up a LangServe instance directly by:
+
+```shell
+langchain serve
+```
+
+This will start the FastAPI app with a server is running locally at 
+[http://localhost:8000](http://localhost:8000)
+
+We can see all templates at [http://127.0.0.1:8000/docs](http://127.0.0.1:8000/docs)
+We can access the playground at [http://127.0.0.1:8000/openai-functions-agent/playground](http://127.0.0.1:8000/openai-functions-agent/playground)  
+
+We can access the template from code with:
+
+```python
+from langserve.client import RemoteRunnable
+
+runnable = RemoteRunnable("http://localhost:8000/openai-functions-agent")
+```