> For the complete documentation index, see [llms.txt](https://docs.computesdk.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.computesdk.com/providers/brezel.md).

# Brezel

Brezel provider for ComputeSDK — self-hosted Firecracker sandboxes backed by operator-qualified immutable environments.

[Brezel](https://github.com/infercrane/brezel) is an open-source, self-hosted Firecracker sandbox runtime for autonomous agents.

## Installation

```bash
npm install computesdk @computesdk/brezel
```

Configure a project-scoped service token, the public HTTPS endpoint, and a prequalified immutable environment revision:

```bash
BREZEL_API_KEY=your_project_scoped_token
BREZEL_API_URL=https://brezel.example.com
BREZEL_PROJECT_ID=agents
BREZEL_ENVIRONMENT_REVISION=envr_qualified
BREZEL_ALLOW_INTERNET=false
```

## Usage

```typescript
import { brezel } from '@computesdk/brezel';

const compute = brezel({
  apiKey: process.env.BREZEL_API_KEY,
  baseUrl: process.env.BREZEL_API_URL,
  project: process.env.BREZEL_PROJECT_ID,
  environmentRevision: process.env.BREZEL_ENVIRONMENT_REVISION,
  allowInternet: false,
});

const sandbox = await compute.instances.create();
const result = await sandbox.runCommand('node --version');
console.log(result.stdout);
await sandbox.destroy();
```

## Configuration options

| Option                | Environment variable          | Description                                                               |
| --------------------- | ----------------------------- | ------------------------------------------------------------------------- |
| `apiKey`              | `BREZEL_API_KEY`              | Project-scoped Brezel service token.                                      |
| `baseUrl`             | `BREZEL_API_URL`              | Public HTTPS endpoint for the Brezel deployment.                          |
| `project`             | `BREZEL_PROJECT_ID`           | Project boundary used for sandbox operations.                             |
| `environmentRevision` | `BREZEL_ENVIRONMENT_REVISION` | Prequalified immutable environment revision used by default.              |
| `allowInternet`       | `BREZEL_ALLOW_INTERNET`       | Allows outbound internet access when exactly `true`; defaults to `false`. |
| `apiTimeoutMs`        | —                             | Timeout for Brezel management API operations, in milliseconds.            |

## Supported operations

| Method       | Supported | Notes                                                              |
| ------------ | --------- | ------------------------------------------------------------------ |
| `create`     | ✅         | Uses a prequalified immutable environment revision.                |
| `getById`    | ✅         | Returns `null` for absent or terminal sandboxes.                   |
| `list`       | ✅         | Lists active sandboxes in the configured project.                  |
| `destroy`    | ✅         | Waits for a confirmed terminal state or resource absence.          |
| `runCommand` | ✅         | Supports `env`, `cwd`, background execution, and output callbacks. |
| `getInfo`    | ✅         | Includes the environment revision and Brezel resource revision.    |
| `getUrl`     | ✅         | Creates a time-limited preview lease for a guest port.             |
| `filesystem` | ✅         | Native file reads/writes plus directory operations.                |
| `snapshot`   | ❌         | Not exposed through ComputeSDK yet.                                |

`templateId` may override the configured immutable environment revision for a single create call. Arbitrary image builds are intentionally outside the request path.

Create-time environment variables are not exposed because Brezel cannot yet restore them durably after reconnection. Pass environment variables to `runCommand` instead.


---

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