[pilotneko]

Keyword alone sucks for negation. Searching a set of patient documents for “Which of my patients has COPD?” to get a set of responses that states “COPD not indicated” will not endear you to the physician using your tool. Hybrid (keyword + semantic) is much more all-encompassing.

[bob1029]

Forwarding the users query directly to the document store seems ridiculous to me. The whole point is for the LLM to interpret the context and issue multiple targeted queries based upon the interpretation(s) arrived at.

The LLM is the semantic part. FTS is the keyword part. This is the hybrid you're looking for.

[pilotneko]

Sometimes you are searching for supporting evidence that is semantically related. COPD was just an example, you won’t get a direct keyword match if the Physician is searching for lung disease.