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

# Runtime API

> Work with execution context, control flow, utilities, libraries, and Agents.

Use the smallest namespace that fits the operation. Platform state and external I/O belong to `api` or `storage`; pure transformation belongs to `util`; reusable domain behavior is addressed through `lib.Category.Name.ElementKey.X`.

<Tip>
  Use the generated [Low-code runtime reference](/low-code/reference/index) when you need an exact signature or editor-provided example. It is organized by `api`, `storage`, `agent`, and `util`, and is synchronized from the declaration source that feeds Monaco.
</Tip>

## Context and control

```js theme={null}
const input = api.input();
const executionId = api.getExecutionId();
const operationId = api.getOperationId();

if (!input?.customerId) {
  api.throw(400, { message: 'customerId is required' });
}

api.log({ message: 'Started', args: { executionId, operationId } });
```

Use `api.getExecutionId()` to correlate the current execution with traces, logs, and operations history.

## Nested execution

```js theme={null}
const result = await api.executeComponent({
  componentId: api.input('componentId'),
  input: { customerId: api.input('customerId') },
});

return result;
```

Nested calls are bounded and inherit the caller's execution deadline. Use a library rather than a nested component when you only need shared in-process business logic.

## Utilities

```js theme={null}
const id = util.randomUUID();
const encoded = util.encodeBase64(JSON.stringify(api.input()));
const signature = util.hmac(encoded, await api.getSecret('SIGNING_SECRET'));

return { id, encoded, signature };
```

## Agents

The `agent` namespace exposes Agent, run, inbox, plugin, and Assistant-thread operations to approved runtime code. Exact operations and authorization are shown in the generated editor declarations and Platform API reference.

<Warning>
  A runtime method appearing in editor types does not bypass role, instance, approval, or policy enforcement. Treat generated types as a callable contract, not a permission grant.
</Warning>