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

# Overview

Explore the key concepts of the document processing pipeline.

<Card title="How It Works" icon="gears" href="/key-concepts/how-it-works">
  A deeper dive on the end-to-end pipeline
</Card>

<CardGroup cols={2}>
  <Card title="Metadata" icon="tag" href="/key-concepts/metadata">
    The fields extracted, modified and written
  </Card>

  <Card title="Matter Pages" icon="book-open" href="/key-concepts/matter-pages">
    The page sets containing key information
  </Card>

  <Card title="Token Costs" icon="calculator" href="/key-concepts/token-costs">
    How we estimate the cost of each run
  </Card>

  <Card title="Duplicate Detection" icon="fingerprint" href="/key-concepts/duplicate-detection">
    Document identification and change tracking through CRC32 hashing.
  </Card>

  <Card title="Annotation Handling" icon="pencil" href="/key-concepts/annotation-handling">
    Organization of document markups, highlights, and reader notes.
  </Card>
</CardGroup>