Chat Service - Basics¶

The chat service is responsible for all interactions with the Unique chat frontend as seen below

alt text

The following elements are directly influenced by it.

Element	Description
User Message	The request as entered by the user
Assistant Message	The answer of the agent/workflow or LLM
Json Value	The final request sent to the LLM that creates the assistant message
Debug Info	Debug information generated during the processing of the request

The ChatService from the unique_toolkit is used to communicate to these elments. Please see Event Driven Applications on how to initialize services and setup a development setup. The service itself can be imported as

1	`from unique_toolkit import ChatService`

Chat State¶

The ChatService is a stateful service and therefore should be freshly instantiated for each request sent by a user from the frontend.

Basics¶

The below sequence diagram shows the dataflow on user input.

sequenceDiagram
    participant FE as Frontend
    participant B as Backend
    participant W as LLM Workflow/Agent
    participant DB as Database

    FE->>B: Send user input

    B->>DB: Create User Message
    B->>DB: Create Assistant Message (placeholder)
    B-->>W: Emit `ChatEvent`

    W->>B: Update Assistant  Message 
    B-->>FE: Return Assistant Message
    B->>DB: Update Assistant Message

The Chat Event¶

For each input of the user the application obtains a ChatEvent, this objects contains the id's of the user message in the database as well as the following assistant message entry. We can use these entries to return the final as well as intermediate results to the user using

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chat_service.modify_assistant_message(
        content="Intermediate assistant message",
    )

The functionality automatically uses the last assistant message within the chat.

The message can be updated as many times as desired to display intermediate results but it is important to ensure that the user has time to read it between the updates. Especially, when using the async version modify_assistant_message_async a short async sleep after modification can be helpful.

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chat_service.modify_assistant_message(
        content="Final assistant message",
    )