Kernel browser provider for Hermes Agent

Use Kernel cloud browsers with the browser_* tools in Hermes Agent. The plugin creates a Kernel browser, gives Hermes its CDP endpoint, and deletes the browser when the Hermes session ends or becomes inactive.

Requirements

• A current Hermes Agent installation with the BrowserProvider plugin API
• A Kernel API key
• Node.js 20 or newer for Hermes's agent-browser dependency

Install

hermes plugins install kernel/hermes-browser-plugin --enable

The installer prompts for KERNEL_API_KEY and saves it to the active Hermes profile's .env file. Then select Kernel as the browser provider:

hermes config set browser.cloud_provider kernel

Alternatively, run hermes setup tools and choose Browser Automation → Kernel. Restart a running Hermes CLI or gateway after changing the provider.

Verify the plugin and configuration:

hermes plugins list
hermes config show
hermes doctor

Configuration

Kernel settings are read from the active Hermes profile's .env file.

Variable	Default	Purpose
KERNEL_API_KEY	required	Authenticates requests to Kernel
KERNEL_STEALTH	true	Enables Kernel's stealth browser mode
KERNEL_HEADLESS	true	Set to false for a visible browser and live view
KERNEL_TIMEOUT_SECONDS	Kernel default	Browser inactivity timeout in seconds
KERNEL_PROXY_ID	unset	Attaches an existing Kernel proxy by ID
KERNEL_PROFILE	unset	Loads this profile and saves changes when the browser closes
KERNEL_BASE_URL	https://api.onkernel.com	Overrides the Kernel API URL

Boolean variables accept 0, false, no, and off as false values.

QA smoke test

Run Hermes interactively so the browser remains available while you inspect it in the Kernel dashboard:

hermes chat --verbose --toolsets browser

Then ask:

Use browser_navigate, not web search, to open https://example.com. Call browser_snapshot, report the exact title and stealth_features, and tell me whether any cloud fallback warning occurred.

A passing run has all of these properties:

1. The title is Example Domain.
2. stealth_features includes stealth.
3. There is no fallback_warning.
4. A matching browser appears in the Kernel dashboard.
5. Exiting Hermes or waiting for inactivity cleanup removes the browser.

Hermes can fall back to local Chromium when a cloud provider fails. A successful navigation alone does not prove Kernel was used; check both the tool result and the Kernel dashboard.

Development

Install uv, then run:

uv run pytest -q
uv run ruff check .

To check registration against a Hermes source checkout:

scripts/check-hermes-integration.sh /path/to/hermes-agent

The integration check installs a temporary copy of the plugin, enables it, and verifies that Hermes registers kernel alongside its bundled browser providers. It does not create a live Kernel browser.

Uninstall

hermes plugins remove browser-kernel

If Kernel was the active browser provider, select another provider with hermes setup tools or set local mode:

hermes config set browser.cloud_provider local

License

MIT