RAG

Sefism.

A to Z

Glossary

Every concept in this sheet, plus the smaller terms it uses. Select a concept to open its card.

C
Choosing chunk size
Small chunks match questions precisely but lose surrounding context; large chunks keep context but dilute the embedding and waste prompt space.
Chunk metadata
Fields stored with each chunk such as source URL, title, section heading, date, language, product version and access group.
Chunking
Splitting documents into passages small enough to embed and retrieve precisely, but large enough to make sense alone.
D
Document parsing
Extracting clean text from PDFs, HTML, slides and docs while keeping structure such as headings, tables and lists.
F
Fixed-size chunks with overlap
Cutting text every N tokens or characters, with each chunk repeating the last part of the previous one.
I
Indexing and query pipelines
Indexing runs ahead of time: load, clean, chunk, embed and store documents.
K
Knowledge base
The collection of documents the system can retrieve from: docs, tickets, PDFs, wiki pages or database rows.
R
RAG vs fine-tuning
RAG adds knowledge at question time; fine-tuning changes model weights to learn a style, format or narrow skill.
RAG vs long context
If all your content fits comfortably in the model context window, you can sometimes paste it in instead of retrieving.
Retrieval augmented generation
A pattern where your code first searches your own documents for passages relevant to a question, then gives those passages to an LLM to answer from.
S
Semantic chunking
Placing chunk boundaries where the meaning shifts, detected by comparing embeddings of neighbouring sentences.
Small-to-big retrieval
Embed small chunks for precise matching, but hand the model the larger parent section they came from.
Start with a naive baseline
Fixed-size chunks, one embedding model, top 5 by vector similarity and a simple grounded prompt.
Structure-aware chunking
Splitting on natural boundaries first, such as headings, then paragraphs, then sentences, and only cutting mid-sentence as a last resort.
09 · Glossary, A to Z9 / 9