What policies are available?
off disables sizing and is the default. initial allows one stabilized
sizing attempt near startup. continuous keeps authenticated sizing authority
for meaningful later content growth and shrink until the runtime stops.
Which policy should I use?
Use initial when the application layout settles once. Use continuous for
apps with route changes, expandable tools, or other trusted content that can
change height after launch.
How do I enable it?
Set host_sizing = "initial" or host_sizing = "continuous" in a profile, or
pass the matching --host-sizing value. Omission means off.
Why is it off by default?
The app must deliberately provide a complete desired host viewport height, and the feature changes native window geometry. Default-off behavior avoids guessing about product-owned layout.
Does continuous resize on every frontend update?
No. Reports must be authenticated, launch-bound, source-bound, and monotonically sequenced. LitLaunch ignores duplicates, stale reports, and target jitter at or below one CSS pixel, then stabilizes meaningful changes before a native attempt.
Does it resize width or move the window?
No. Both policies are height-only and preserve width and position. Host sizing is not general window management.
What happens if fitting is unavailable?
The app remains open and usable, and the window stays unchanged. Unsupported launches, missing reports, unsafe window states, user geometry changes, authority loss, timeouts, and native refusal all fail safely.
Which launches are supported?
Current scope is Windows webapp mode with an explicit Edge or Chrome selection, a LitLaunch-managed browser profile, a loopback app host, and one trusted frontend adapter. Browser tabs, unmanaged profiles, network-exposed apps, and width fitting are outside the feature.
Why is it Experimental?
Current evidence covers Edge and Chrome, direct and shortcut launches, and 100% and 150% mixed-DPI Windows 11 displays. Windows 10, 125% scaling, alternate taskbar layouts, and independent Windows hosts remain unproven.
Does it require a specific frontend framework?
No. Any trusted frontend that can report a complete host-relative content measurement can use the documented report contract. LitLaunch does not import, detect, or require any particular frontend library.
How should the handoff be handled?
Forward it only to the trusted frontend surface for the current launch. Do not log, persist, cache, place it in a URL, or embed it into static frontend assets. See the host-sizing guide for the audited adapter pattern.