---
title: "Lucent Concepts"
description: "Core concepts behind XI Lucent's ingestion pipeline, chunking strategies, hybrid search, and XRAG."
published: 2026-05-14T12:11:18.485234+00:00
updated: 2026-05-14T12:11:18.485234+00:00
tags: ["concepts", "lucent"]
url: https://xiobjects.com/docs/xio/lucent/concepts
source: XI Objects
---

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# Lucent Concepts

These docs explain how Lucent works under the hood. If you want to tune behavior, pick the right chunking strategy, or understand why a query returns what it returns, this is where to start.

- [Ingestion & Retrieval Pipeline](/docs/xio/lucent/concepts/pipeline) — the full sequence from raw bytes to ranked results, including atomicity, re-ingestion behavior, and content hash short-circuiting
- [Chunking Strategies](/docs/xio/lucent/concepts/chunking) — how `SemanticChunker`, `StructuralChunker`, `SentenceChunker`, and `FixedSizeChunker` differ, and when to use each
- [Hybrid Search](/docs/xio/lucent/concepts/hybrid-search) — how vector cosine similarity and BM25 full-text search are fused with Reciprocal Rank Fusion, how filters work, and how scoring is composed
- [XRAG: Verified-Provenance RAG](/docs/xio/lucent/concepts/xrag) — how XION cryptographic trust verification integrates into ingestion, what attribution metadata looks like on chunks, and how signed sources are preserved for re-verification
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