Smart default snapshot scoping to main content area #45
Description
Problem
A goto to a typical website returns the full accessibility tree including sidebars, navigation, footers, banners, and other chrome. For dev.to's homepage, this produced 40KB of output when the relevant content (article feed) was roughly 30% of that.
The --snapshot-selector flag exists but requires foreknowledge of the DOM structure, which the agent doesn't have on first visit.
Proposal
When no --snapshot-selector is provided, auto-detect and prefer the <main> element if one exists. Most modern websites use semantic HTML with a <main> element containing the primary content. This would cut output size significantly without requiring the agent to know the page structure upfront.
Fallback chain:
<main>element (if exists and is non-empty)[role="main"](ARIA equivalent)- Full page (current behavior)
This could be a default that users override with --snapshot-selector or disable with --snapshot-full.
Impact
On the dev.to test case, scoping to <main> would have reduced output from ~40KB to ~15KB - keeping it under the 30K tool output limit and saving significant context tokens.