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

# Agent Options

> Configure the Magnitude agent and browser

Magnitude can be customized by passing in options when you start a browser agent:

```ts theme={null}
await startBrowserAgent({
    // Starting URL for agent
    url: "https://google.com", 
    // Show thoughts and actions
    narrate: true,
    // LLM configuration
    llm: {
        provider: 'anthropic',
        options: {
            model: 'claude-sonnet-4-20250514',
            apiKey: process.env.ANTHROPIC_API_KEY
        }
    },
    // Any system instructions specific to your agent or website
    prompt: 'Prefer mouse to keyboard when filling out form fields'
});
```

<Warning>Only some LLMs are compatible with Magnitude - see [compatible LLMs](/core-concepts/compatible-llms) for details.</Warning>

<Info>For information on configuring the test runner instead see [Configure Test Runner](/testing/test-configuration)</Info>

## Browser Options

Various browser options can also be passed, such as browser launch options or context options:

```ts theme={null}
const agent = await startBrowserAgent({
    url: "https://google.com", 
    browser: {
        // Configured launched browser:
        launchOptions: {
            // chromium launch options, for example enabling CDP
            args: ["--remote-debugging-port=9222"]
        },
        contextOptions: {
            // see https://playwright.dev/docs/api/class-browser#browser-new-context
            // for comprehensive list of options
            viewport: {
                width: 1280,
                height: 720
            }
        }
    }
});
```

See Playwright's docs on [Launch Options](https://playwright.dev/docs/api/class-browsertype#browser-type-launch) and [Browser Context](https://playwright.dev/docs/api/class-browsercontext) for more details on what can be configured.

You can also connect via CDP to an open CDP-enabled browser:

```ts theme={null}
const agent = await startBrowserAgent({
    url: "https://google.com", 
    browser: {
        cdp: "http://localhost:9222"
    }
});
```