How to use ChatMessageStore

[verdie-g]

I'm kind of confused about ChatMessageStore

• what is the purpose of SerializedState and JsonSerializerOptions?
• why CosmosChatMessageStore don't use those?
• Is CosmosChatMessageStore.ConversationId the same thing as ChatResponse.ConversationId?
• CosmosChatMessageStore takes an optional userId which sounds great to prevent another user to hijack a conversation but when can it be passed? The ChatClientAgentOptions.ChatMessageStoreFactory doesn't give the opportunity to grab the current user of the request.
• How can I pass additional metadata to the saved messages (e.g. conversation title)?

[eavanvalkenburg]

@westey-m @rogerbarreto @SergeyMenshykh can one of you take a look here!

[westey-m]

• what is the purpose of SerializedState and JsonSerializerOptions?

When an AgentThread is serialized for storage, the state of the ChatMessageStore is also serialized with it. In the case of CosmosChatMessageStore the state contains various ids/settings associated with that store instance. See

agent-framework/dotnet/src/Microsoft.Agents.AI.CosmosNoSql/CosmosChatMessageStore.cs

Line 632 in 8b4f7d5

private sealed class StoreState

Taking the JsonSerializerOptions parameter provides support for NativeAOT by allowing source generated serialization configuration.

• why CosmosChatMessageStore don't use those?

Since the CosmosDB SDK doesn't support native AOT, there is no value in supporting it on CosmosChatMessageStore either.

• Is CosmosChatMessageStore.ConversationId the same thing as ChatResponse.ConversationId?

Not exactly. They are typically mutually exclusive. ChatResponse.ConverationId is returned if the service requires/supports storing chat history in the AI service. It returns null if not.

If the AI service does not support storing chat history in the service, an Agent will use a ChatMessageStore. Either the default InMemoryChatMessageStore (in which case there is no conversation id) or a custom one provided via a factory, and then it is up to that implementation to decide what id(s) it would use to store the chat history under.
For more info see: https://learn.microsoft.com/en-us/agent-framework/user-guide/agents/agent-memory?pivots=programming-language-csharp#chat-history

• CosmosChatMessageStore takes an optional userId which sounds great to prevent another user to hijack a conversation but when can it be passed? The ChatClientAgentOptions.ChatMessageStoreFactory doesn't give the opportunity to grab the current user of the request.

What is preventing you from for example reading the user token from the HttpContext in the factory, assuming you are using asp.net?

• How can I pass additional metadata to the saved messages (e.g. conversation title)?

Can you explain more about your scenario? E.g. is this for filtering or categorization in the DB, or do you want to use this data again with the agent in some way?

[ouvreboite]

What is preventing you from for example reading the user token from the HttpContext in the factory, assuming you are using asp.net?

How would you do that? The ctx provided in ChatMessageStoreFactory is a ChatMessageStoreFactoryContext. I don't see a way to access the HttpContext from it.

Or do you mean that the whole AIAgent should be instanciated in an ASP's AddScoped() to access the HttpContext from here?

[westey-m]

Or do you mean that the whole AIAgent should be instanciated in an ASP's AddScoped() to access the HttpContext from here?

It should be fine to register the AIAgent and its associated ChatMessageStoreFactory as a singleton. If you are using HttpContextAccessor, this should work fine, since it is itself registered as a singleton.

It uses AsyncLocal to propagate the HttpContext, so the HttpContext should always be the correct "local" one even if the same instance of the accessor is used everywhere.