> ## Documentation Index
> Fetch the complete documentation index at: https://kernel.sh/docs/llms.txt
> Use this file to discover all available pages before exploring further.
# Telemetry Categories
> The categories a browser session can capture, what each contains, and their cost
A category groups related telemetry events and is the unit you enable or disable. Selection is opt-in: a session captures a category only when you turn it on.
For the full payload schema of any event type, see the [Stream telemetry events](https://kernel.sh/docs/api-reference/browser-telemetry/stream-telemetry-events-via-sse) endpoint in the API reference.
## Operational
These categories report on the session itself rather than page content.
| Category | Captures | Event types |
| ------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------- |
| `control` | Actions that drive the browser: computer-control calls, Playwright code execution, screenshots and clipboard access, plus browser-control commands sent over the CDP proxy | `api_call`, `cdp_command` |
| `platform` | Calls that manage the VM rather than drive the browser: recording lifecycle, filesystem, process execution, log streaming, scale-to-zero, telemetry, display and browser configuration, and extension uploads | `platform_api_call` |
| `connection` | CDP and live view connect/disconnect activity | `cdp_connect`, `cdp_disconnect`, `live_view_connect`, `live_view_disconnect` |
| `system` | VM-level failures | `system_oom_kill`, `service_crashed` |
| `captcha` | Results of automated captcha solves | `captcha_solve_result` |
`control` answers "what did my agent do." `platform` is mostly Kernel acting on the VM on your behalf - saving a profile, capturing a replay, polling a recorder - so it is off by default even though the rest of this group is on. Enable it when you are debugging a profile save, a replay, or a session-setup step rather than the agent itself.
`control` reports one `cdp_command` for each supported browser-control command it can classify from the CDP proxy - input gestures, navigation, dialogs, file selection, screenshots, and every command phase, including `mouseMoved`, `keyUp`, and `char`. It doesn't report arbitrary CDP traffic; general inspection traffic such as most DOM and Runtime commands isn't classified as browser control. The command stream isn't sampled, coalesced, or reordered.
### Reduce CDP command volume
Use `control.cdp.excluded_methods` to omit high-volume methods such as `Input.dispatchMouseEvent` during a humanized cursor path or `Page.captureScreenshot` during a screencast:
```typescript Typescript/Javascript theme={null}
import Kernel from '@onkernel/sdk';
const kernel = new Kernel();
const browser = await kernel.browsers.create({
telemetry: {
browser: {
control: {
enabled: true,
cdp: {
excluded_methods: ['Input.dispatchMouseEvent', 'Page.captureScreenshot'],
},
},
},
},
});
```
```python Python theme={null}
from kernel import Kernel
kernel = Kernel()
browser = kernel.browsers.create(
telemetry={
"browser": {
"control": {
"enabled": True,
"cdp": {
"excluded_methods": [
"Input.dispatchMouseEvent",
"Page.captureScreenshot",
],
},
},
},
},
)
```
Exclusion affects telemetry only; the commands still reach the browser. On `cdp_disconnect`, `telemetry_excluded` counts configured exclusions. Treat a nonzero `telemetry_dropped` as a telemetry-loss signal rather than using it to reconstruct the missing command sequence; the browser commands themselves still reach the browser.
## Browser activity
These categories report what's happening in the page. Capturing any of them attaches a Chrome DevTools Protocol (CDP) collector to the session and produces highly granular page-level events. Capturing them adds overhead, so enable only the ones you need.
| Category | Captures | Event types |
| ------------- | --------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| `console` | Console output from the page | `console_log`, `console_error` |
| `network` | Network requests, responses, and failures | `network_request`, `network_response`, `network_loading_failed`, `network_idle`, `proxy_error` |
| `page` | Navigation and page lifecycle, including performance signals and renderer crashes | `page_navigation`, `page_dom_content_loaded`, `page_load`, `page_tab_opened`, `page_crashed`, `page_layout_shift`, `page_lcp`, `page_layout_settled`, `page_navigation_settled` |
| `interaction` | Browser-native input in the page (clicks, keys, scroll) | `interaction_click`, `interaction_key`, `interaction_scroll_settled` |
| `screenshot` | Periodic screenshots of the session | `monitor_screenshot` |
`interaction` events are browser-native DOM events observed in the page, not calls to the [computer-control](/docs/browsers/computer-controls) API (those are reported by the `control` category).
### The monitor category
`monitor` reports the health of the CDP collector itself: `monitor_disconnected`, `monitor_reconnected`, `monitor_reconnect_failed`, and `monitor_init_failed`.
It isn't directly settable. It flows automatically whenever any of the browser-activity categories are captured. You can still [filter the stream](/docs/browsers/telemetry/streaming) by `monitor` to isolate these events.
## Data sensitivity
Telemetry is off by default. The default set isn't limited to session metadata: `control` records the source you submit for Playwright execution and sanitized arguments for supported browser-control commands, while `captcha` can record the host and path of the page where a solve ran. The browser-activity categories capture what flows through the page, which is your own browser's data and can include credentials and personal information.
| Category | Can contain sensitive data |
| --------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ |
| `network` | Request and response headers (including `Authorization` and `Cookie`), request bodies, and truncated response bodies, plus full URLs. A common place for session tokens, credentials, and personal data. |
| `console` | Anything the page logs. Applications often log access tokens, request or response bodies, and personal data through `console.log`. |
| `page` | Page URLs and titles, which can embed tokens or identifiers in query strings or fragments. |
| `interaction` | Text of clicked elements and typed keys, which can include personal data entered into forms. |
| `screenshot` | A full rendered image of the page - the broadest exposure, capturing anything visible on screen. |
| `control` | The source you submit to the Playwright code-execution endpoint, on the `code` field of `api_call`, capped at 8 KB and marked with `...[truncated]` when cut. Whatever your script embeds is captured with it, so a literal password or token in the snippet is captured too. `cdp_command` carries sanitized arguments such as the method and phase, coordinates, counts, flags, and named keys such as `Enter` and `Tab`. Typed text, file paths, scripts, templates, dialog input, and autofill values aren't captured; navigation commands retain only the URL scheme, not the host, path, query, or fragment. |
| `captcha` | Captcha type, solve outcome and duration. It can include the host and path of the page where the captcha was solved; the query string is excluded. Failed solves can include a solver-specific error code. |
| `platform`, `connection`, `system`, `monitor` | Session and VM metadata only (VM-management calls, connection and health events). No page content. |
Captured events are persisted and can be replayed by [resuming the stream](/docs/browsers/telemetry/streaming#resuming-after-a-disconnect), so this sensitivity applies to the data at rest, not just the live stream. Events are retained for 30 days, then expired (see [Retention](/docs/browsers/telemetry/overview#retention)). Treat captured telemetry - and anywhere you forward or store it - with the same care as the underlying content. For how Kernel encrypts, retains, and processes data overall, see [Security](/docs/security) and the [Data Processing Addendum](/docs/dpa).
Some exposure is reduced for you automatically: input into sensitive fields such as passwords is suppressed (`interaction_key` isn't emitted for them, and `interaction_click` omits the element text), and `cdp_command` reports text lengths rather than the text itself. Beyond that, because selection is opt-in, the most effective control is to capture only the categories you need - enable `network`, `console`, `page`, `interaction`, or `screenshot` deliberately, and prefer the operational categories when you only need session health.
If you capture `control` and run Playwright code, pass credentials in through variables your snippet reads rather than as literals in the submitted source, so the captured `code` doesn't carry them.
If you operate under HIPAA, GDPR, or similar obligations, be deliberate about the browser-activity categories: pointing them at a site that handles regulated data captures that data into storage. If your organization has a BAA with Kernel, the `network`, `console`, and `screenshot` categories are disabled and can't be captured. `control` and `captcha` stay available; keep regulated values out of the Playwright source you submit, and disable `captcha` if the page host or path identifies regulated data.
If you have compliance requirements around what Kernel may process, [contact us](mailto:security@kernel.sh) before enabling them.