---
url: 'https://adk.nht.io/api/@nhtio/adk/batteries/sandbox/interfaces/GuestGlobal.md'
description: A declared capability kept in the host runner.
---

# Interface: GuestGlobal

Defined in: [src/batteries/sandbox/js/ses\_contracts.ts:4](https://github.com/NHTIO/ADK/blob/v1.20260824.1/src/src/batteries/sandbox/js/ses_contracts.ts#L4)

A declared capability kept in the host runner.

## Properties

| Property                                          | Modifier   | Type                                                        | Description                                                                                                                                                                                                                                                                                                                     | Defined in                                                                                                                                        |
| ------------------------------------------------- | ---------- | ----------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------- |
|  `cancellation` | `readonly` | `"killable"` | `"cooperative"` | `"atomic"`               | Completion policy for an in-flight capability call. **Remarks** This is required with no default. `killable` kills its child, `cooperative` is best-effort, and `atomic` must finish before recycling; guessing `cooperative` for a capability that spawns a child is unsafe.                                                   | [src/batteries/sandbox/js/ses\_contracts.ts:22](https://github.com/NHTIO/ADK/blob/v1.20260824.1/src/src/batteries/sandbox/js/ses_contracts.ts#L22) |
|  `fn`                     | `readonly` | (`args`: `unknown`\[], `signal`: `AbortSignal`) => `unknown` | Host implementation invoked by the guest-facing capability stub. **Remarks** The signal is lifecycle-scoped, not per call: expiry of `hostcallTimeoutMs` does not fire it. Arguments and results must be structured-clone/codec serialisable, and every guest call is asynchronous even when this host function is synchronous. | [src/batteries/sandbox/js/ses\_contracts.ts:13](https://github.com/NHTIO/ADK/blob/v1.20260824.1/src/src/batteries/sandbox/js/ses_contracts.ts#L13) |