Deprecated: This reference supports the stable browser implementation.
hatch. Prefer the unified browser tool when experimental mode is enabled.

Browser Launch Modes

browser.start launch modes:

• Default: Playwright-managed, no debugging port
• cdp_port=N: managed CDP, opens a local debugging port so other local tools can attach (see the browser_cdp skill)
• private_mode=true: same as the default, kept for backward compatibility

Parameter meanings:

• headed: whether to display the browser window
• private_mode: kept for backward compatibility; it no longer changes the launch mode

The two parameters are independent and can be freely combined.

Common Usage

Default launch:

{"action": "start"}

Open a visible window:

{"action": "start", "headed": true}

private_mode

Already the default behavior — do not set it. The parameter is kept only so that older calls keep working, and passing it together with cdp_port is rejected.

Notes

• The default is Playwright-managed with no debugging port
• The launch mode is entirely determined by the call parameters
• Managed CDP requires Chrome / Chromium / Edge to be installed locally
• When the user manually operates the visible browser, the idle timer may not be refreshed
• private_mode is an explicit parameter for each start call and is not persisted
• If a browser is already running, you must stop it and then start again to switch launch modes or window visibility
• Visible mode occupies the desktop and requires a graphical environment; it may not work on servers or headless environments