# Capabilities (/docs/reference/capabilities)



Capability declarations distinguish unsupported behavior from supported behavior with meaningful modes.

```ts title="capabilities.ts"
import { capabilityMode, requireCapability, supports } from "@opencoredev/sandbox-sdk";

if (supports(sandbox, "ports.expose")) {
  console.log(capabilityMode(sandbox, "ports.expose"));
}

requireCapability(sandbox, "snapshot.create");
```

| Helper                | Result                                                             |
| --------------------- | ------------------------------------------------------------------ |
| `supports()`          | Returns a boolean and narrows intent before an optional operation. |
| `capabilityMode()`    | Returns the provider's mode or `false`.                            |
| `requireCapability()` | Returns the mode or throws an `unsupported` `SandboxError`.        |

Modes describe real differences such as `public` versus `authenticated` ports, `filesystem` versus `template` snapshots, and `combined-stream` versus `separate-streams` command output.

## Read next [#read-next]

Compare provider declarations in [Compatibility](/docs/reference/compatibility).