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

# Capabilities

> How headgate keeps backend and feature claims honest.

Headgate maintains a capability register alongside its conformance suite. A completed or
partial capability must cite a named assertion, test, or executed scenario in the evidence
ledger. The validation gate rejects claims whose evidence no longer resolves.

<Card title="Browse implemented features" icon="list-tree" href="/docs/reference/feature-index">
  Use the public feature index to find the guide for each implemented capability area.
</Card>

| Status   | Meaning                                                                       |
| -------- | ----------------------------------------------------------------------------- |
| Complete | The capability is implemented and its cited conformance evidence passes.      |
| Partial  | A documented subset is implemented and the evidence identifies that boundary. |
| Missing  | The capability is not implemented and must not be advertised at runtime.      |
| Deferred | The capability was deliberately postponed with its rationale recorded.        |

## Runtime capabilities

Backends also advertise optional runtime capabilities explicitly:

* inspection and operator control;
* application transactions;
* push notifications;
* result, output, and progress storage.

A missing capability produces an explicit unsupported error or absent upcast. It is never
a public method that silently does nothing.

## Mechanical checks

* `scripts/check-evidence.py` resolves every completed and partial claim.
* `scripts/check-inventory.py` fails when a tracked test disappears.
* `scripts/run-scenarios.py` executes YAML scenarios against live stores.
* `scripts/test-admission.sh` compares backend and language behavior.

<Card title="Verification commands" icon="terminal" href="/docs/reference/verification">
  Run the same evidence and conformance gates used for feature claims.
</Card>