Hybrid Search(enhaced chat)Field Mapping, Semantic Index configuration & Knowledge Graph Dependency

[SheljaS]

Hi Everyone

We are using Enhanced Chat in Patch 7 and I would like clarity on Index Source configuration, especially around Field Mapping, Semantic Index configuration, and Related List settings.

Context

We are on Enhanced Chat
Index Source is already configured
Patch version is Patch 7
Users run natural language searches such as
How many incidents were raised last month

Observations

In the Index Source configuration, the following options are available
Field Mapping
Semantic Index configuration
Related List configuration

After reviewing the documentation, the purpose of these configurations is still not very clear, especially in the context of Enhanced Chat.

Current Behavior

When Knowledge Graph is not configured, Enhanced Chat does not return incident data for prompts like
How many incidents were raised last month

After configuring Knowledge Graph, the same prompt returns correct incident information.

Clarifications Needed

I would like to understand the following points

The role of Field Mapping in Enhanced Chat in Patch 7
The role of Semantic Index configuration in Enhanced Chat
Whether Field Mapping and Semantic Index are mandatory or optional
Whether these configurations have a direct dependency on Knowledge Graph
Whether Enhanced Chat requires Knowledge Graph to return structured or analytical data such as incident counts
Whether there is any supported way to get these results without configuring Knowledge Graph
If yes, what is the minimum required configuration
If no, whether Knowledge Graph is mandatory for such use cases

I have already gone through the official documentation but could not find clear explanations or examples that cover this behavior.

Any clarification, documentation references, or real world implementation experiences would be very helpful.

Thank you