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

# SCV Source-Knowledge Engines: Provider Reality for Symphony

> Eight independently packaged SCV, hyperscaler, edge, and provider engines preserve exact source revisions and produce reproducible graph and query evidence.

The SCV source-knowledge engines are eight independently packaged C++26 processes that hold private semantic knowledge about offsite provider resources, offerings, regions, constraints, and hybrid possibilities. They preserve exact source revisions and bounded captures so downstream tools can reproduce results.

## Engines

<CardGroup cols={2}>
  <Card title="scv-engine" icon="cloud">
    Umbrella SCV source engine for the shared cloud vocabulary.
  </Card>

  <Card title="scev-engine" icon="server">
    Symphony Cloud Edge Vector source engine.
  </Card>

  <Card title="scev-cf-engine" icon="cloud-bolt">
    Cloudflare-specific edge source engine.
  </Card>

  <Card title="schv-aws-engine" icon="aws">
    Amazon Web Services source engine.
  </Card>

  <Card title="schv-azure-engine" icon="microsoft">
    Microsoft Azure source engine.
  </Card>

  <Card title="schv-do-engine" icon="digital-ocean">
    DigitalOcean source engine.
  </Card>

  <Card title="schv-gcp-engine" icon="google">
    Google Cloud Platform source engine.
  </Card>

  <Card title="scv-graph-duckdb-connector" icon="database">
    Optional DuckDB connector for retained relational graph indexing.
  </Card>
</CardGroup>

## What the SCV engines do

* Preserve explicit source revisions and bounded captures
* Retain qualified claims and native document structure
* Produce reproducible graph and query evidence
* Feed portable provider packages and finite caller-directed composition

## What they do not do

<Warning>
  Provider operations and complete cloud catalogs remain outside this increment. The SCV engines describe what is known; they do not act on providers.
</Warning>

qxctl separately administers audited local source changes and coherent graph selection through retained workflows and protected graph selection. Dedicated graph traversal and operational adapters remain separate work.

## Related surfaces

<CardGroup cols={2}>
  <Card title="SCV vector" icon="cloud" href="/symphony/symphony/vectors/scv">
    Cloud Vector contract that these engines implement.
  </Card>

  <Card title="SOV vector" icon="terminal" href="/symphony/symphony/vectors/sov">
    Ops Vector that acts on SCV evidence via qxctl.
  </Card>

  <Card title="qxctl vector commands" icon="terminal" href="/symphony/symphony/qxctl/vector-commands">
    Graph selection, source workflows, and DuckDB connector administration.
  </Card>
</CardGroup>


## Related topics

- [Symphony Cloud Vector: Provider Resource Knowledge](/symphony/symphony/vectors/scv.md)
- [Symphony Vector Engines: Independent Installation Overview](/symphony/symphony/engines/overview.md)
- [Symphony Ops Vector: qxctl Operations Control](/symphony/symphony/vectors/sov.md)
- [SSFV: Symphony Semantic Feature Vector and Registry](/symphony/symphony/skv/ssfv.md)
- [Symphony Vectors and Delivery Phases](/symphony/symphony/concepts/vectors.md)