docs: Add how-to page for LangGraph Studio (#802)

* Add how-to page for LangGraph Studio.

* Fix spelling error.

* Fix grammar typo.

docs/docs/cloud/deployment/studio.md

@@ -0,0 +1,44 @@
+# How to Test with LangGraph Studio
+
+LangGraph applications can be tested with LangGraph Studio. LangGraph Studio is a robust UI for testing and exercising functionality of the graphs in a LangGraph application. The LangGraph Studio UI connects directly to a LangGraph Cloud deployments or to a local LangGraph API instance.
+
+The LangGraph Studio UI is available within <a href="https://www.langchain.com/langsmith" target="_blank">LangSmith</a>. To test a LangGraph application, navigate to the <a href="https://smith.langchain.com/" target="_blank">LangSmith UI</a>.
+
+## Test Cloud Deployment
+
+The LangGraph Studio UI connects directly to LangGraph Cloud deployments.
+
+Starting from the <a href="https://smith.langchain.com/" target="_blank">LangSmith UI</a>...
+
+1. In the left-hand navigation panel, select `Deployments`. The `Deployments` view contains a list of existing LangGraph Cloud deployments.
+1. Select an existing deployment to test with LangGraph Studio.
+1. In the top-right corner, select `Open LangGraph Studio`.
+1. [Invoke an assistant](#invoke-assistant) or [view an existing thread](#view-thread).
+
+## Test Local Instance
+
+The LangGraph Studio UI connects directly to local LangGraph API instances. This is helpful for quickly iterating and testing during the development process.
+
+Starting from the <a href="https://smith.langchain.com/" target="_blank">LangSmith UI</a>...
+
+1. Find the hostname of the local LangGraph API instance. For example, `http://localhost:9123`.
+1. Navigate to the URL `/studio/thread/` and set the `baseUrl` query parameter to the hostname. For example, `https://smith.langchain.com/studio/thread?baseUrl=http://localhost:9123`.
+1. [Invoke an assistant](#invoke-assistant) or [view an existing thread](#view-thread).
+
+## Invoke Assistant
+
+1. The LangGraph Studio UI displays a visualization of the selected assistant.
+    1. In the top-right dropdown menu of the left-hand pane, select an assistant.
+    1. In the bottom of the left-hand pane, edit the `Input` and `Configure` the assistant.
+    1. Select `Submit` to invoke the selected assistant.
+1. View output of the invocation in the right-hand pane.
+
+## View Thread
+
+1. In the top of the right-hand pane, select the `New Thread` dropdown menu to view existing threads.
+1. View the state of the thread (i.e. the output) in the right-hand pane.
+1. To create a new thread, select `+ New Thread`.
+
+## Edit Thread State
+
+The LangGraph Studio UI contains features for editing thread state. Explore these features in the right-hand pane. Select the `Edit` icon, modify the desired state, and then select `Fork` to invoke the assistant with the updated state.

docs/mkdocs.yml

@@ -175,6 +175,7 @@ nav:
           - Deployment:
               - Setup App: 'cloud/deployment/setup.md'
               - Deploy to Cloud: 'cloud/deployment/cloud.md'
+              - Test with Studio: 'cloud/deployment/studio.md'
               - Self-Host: 'cloud/deployment/self_hosted.md'
           - Streaming:
               - Stream Values: 'cloud/how-tos/cloud_examples/stream_values.ipynb'