Update docs

Author: fujita-h

README.md

@@ -71,6 +71,7 @@ However, you can try the [Azure pricing calculator](https://azure.com/e/a87a169b
 - Azure AI Document Intelligence: SO (Standard) tier using pre-built layout. Pricing per document page, sample documents have 261 pages total. [Pricing](https://azure.microsoft.com/pricing/details/form-recognizer/)
 - Azure AI Search: Basic tier, 1 replica, free level of semantic search. Pricing per hour. [Pricing](https://azure.microsoft.com/pricing/details/search/)
 - Azure Blob Storage: Standard tier with ZRS (Zone-redundant storage). Pricing per storage and read operations. [Pricing](https://azure.microsoft.com/pricing/details/storage/blobs/)
+- Azure Cosmos DB: Serverless tier. Pricing per request unit and storage. [Pricing](https://azure.microsoft.com/pricing/details/cosmos-db/)
 - Azure Monitor: Pay-as-you-go tier. Costs based on data ingested. [Pricing](https://azure.microsoft.com/pricing/details/monitor/)
 
 To reduce costs, you can switch to free SKUs for various services, but those SKUs have limitations.

docs/deploy_features.md

@@ -8,6 +8,7 @@ You should typically enable these features before running `azd up`. Once you've
 * [Using text-embedding-3 models](#using-text-embedding-3-models)
 * [Enabling GPT-4 Turbo with Vision](#enabling-gpt-4-turbo-with-vision)
 * [Enabling chat history](#enabling-chat-history)
+* [Enabling persistent chat history with Azure Cosmos DB](#enabling-persistent-chat-history-with-azure-cosmos-db)
 * [Enabling language picker](#enabling-language-picker)
 * [Enabling speech input/output](#enabling-speech-inputoutput)
 * [Enabling Integrated Vectorization](#enabling-integrated-vectorization)
@@ -158,7 +159,15 @@ This feature allows users to view the chat history of their conversation, stored
 azd env set USE_CHAT_HISTORY_BROWSER true
 ```
 
-In the future, we plan to add support for optionally storing chat history in a server-side storage such as Cosmos DB.
+## Enabling persistent chat history with Azure Cosmos DB
+
+This feature allows authenticated users to view the chat history of their conversations, stored in the server-side storage using [Azure Cosmos DB](https://learn.microsoft.com/azure/cosmos-db/).This option requires that authentication be enabled. The chat history will be persistent and accessible from any device where the user logs in with the same account. To enable server-stored chat history, run:
+
+```shell
+azd env set USE_CHAT_HISTORY_COSMOS true
+```
+
+When both the browser-stored and Cosmos DB options are enabled, Cosmos DB will take precedence over browser-stored chat history.
 
 ## Enabling language picker
 

docs/deploy_lowcost.md

@@ -71,6 +71,14 @@ However, if your goal is to minimize costs while prototyping your application, f
       azd env set USE_LOCAL_HTML_PARSER true
       ```
 
+1. Use the free tier of Azure Cosmos DB:
+
+    ```shell
+    azd env set AZURE_COSMOSDB_SKU free
+    ```
+
+    Limitation: You can have only one free Cosmos DB account. To keep your account free of charge, ensure that you do not exceed the free tier limits. For more information, see the [Azure Cosmos DB lifetime free tier](https://learn.microsoft.com/azure/cosmos-db/free-tier).
+
 1. Turn off Azure Monitor (Application Insights):
 
     ```shell

docs/other_samples.md

@@ -31,7 +31,7 @@ Feature comparison:
 | RAG approach | Multiple approaches | Only via ChatCompletion API data_sources |
 | Vector support | ✅ Yes | ✅ Yes |
 | Data ingestion | ✅ Yes ([Many formats](data_ingestion.md#supported-document-formats)) | ✅ Yes ([Many formats](https://learn.microsoft.com/azure/ai-services/openai/concepts/use-your-data?tabs=ai-search#data-formats-and-file-types)) |
-| Persistent chat history | ❌ No (browser tab only) | ✅ Yes, in CosmosDB |
+| Persistent chat history | ✅ Yes | ✅ Yes |
 | User feedback | ❌ No | ✅ Yes |
 | GPT-4-vision |  ✅ Yes | ❌ No |
 | Auth + ACL |  ✅ Yes | ✅ Yes |