> ## 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.

# SACV: API Contract Governance for QuanuX Symphony

> SACV governs versioned API contracts through bounded OpenAPI 3.2.0 checks, deterministic compatibility diffs, and caller-declared registry proposals across vectors.

The Symphony API Contract Vector (SACV) governs versioned API contracts across the platform. Its engine is an independently installable C++ process that performs bounded OpenAPI 3.2.0 JSON validation, deterministic compatibility diffs, and disposable inventories. Endpoint semantics remain with the domain-owning vector or module; SACV governs contract shape and compatibility.

## Operations

* **Inspect and check**: validate that an OpenAPI 3.2.0 JSON document conforms to the bounded profile.
* **Diff**: compute deterministic compatibility diffs between contract versions.
* **Propose**: accept caller-declared registry proposals for new or changed contracts.
* **Project**: emit disposable inventories for reviewers and downstream tools.

## What SACV governs

SACV bounds:

* The contract shape (OpenAPI 3.2.0 with the SACV profile)
* Compatibility classification between versions
* Registry membership for accepted contracts

It does not:

* Own endpoint semantics (each vector or module keeps those)
* Generate SDKs, publish artifacts, or issue tokens
* Imply a live network surface exists (mention of a future private API does not create one)

<Note>
  SACV is read, query, validate, and propose only. Programmatic canonical apply is disabled across the SKV engines.
</Note>

## Related surfaces

<CardGroup cols={2}>
  <Card title="SKV overview" icon="book-open" href="/symphony/symphony/skv/overview">
    The umbrella framework and Contract Quad model.
  </Card>

  <Card title="SODV" icon="scroll" href="/symphony/symphony/skv/sodv">
    Governs any official publication of a SACV-registered contract.
  </Card>

  <Card title="SAV" icon="scale-balanced" href="/symphony/symphony/skv/sav">
    Evaluates composition and compatibility across declared components.
  </Card>

  <Card title="qxctl vector commands" icon="terminal" href="/symphony/symphony/qxctl/vector-commands">
    Run `qxctl sacv ...` to inspect, check, diff, and propose.
  </Card>
</CardGroup>


## Related topics

- [Symphony Knowledge Vector: SKV Framework Overview](/symphony/symphony/skv/overview.md)
- [SODV: Official Documentation and Release Governance](/symphony/symphony/skv/sodv.md)
- [QuanuX Symphony Platform Doctrine](/symphony/symphony/doctrine.md)
- [QuanuX Symphony Documentation](/symphony/symphony/index.md)
- [Quickstart: Explore QuanuX Symphony](/symphony/symphony/quickstart.md)