> ## Documentation Index
> Fetch the complete documentation index at: https://docs.contextual.ai/llms.txt
> Use this file to discover all available pages before exploring further.

# Semantic Search Weight

> `(semantic_alpha)`

## Description

When chunks are scored during retrieval (based on their relevance to the user query), this controls how much weight the scoring gives to semantic similarity. Semantic searching looks for text that conveys similar meaning and concepts, rather than just matching exact keywords or phrases.

The value ranges from `0` to `1`, and Contextual AI defaults to `0.9`. The value of the semantic search weight and lexical search weight must sum to `1`.