Accessibility work usually starts from compliance documents — WCAG checklists, audit templates — which tell you what to satisfy but not what good looks like in a product like yours. The gap between "technically compliant" and "actually usable with a screen reader" is where most a11y efforts land short, and no checklist closes it.

What closes it is studying the leaders: companies that treat accessibility as craft demo it — walkthroughs of their screen-reader flows, conference talks on their a11y engineering, disabled users reviewing what actually works. That corpus shows the state of the art as practiced: the flows, the patterns, the language teams use when they take this seriously. Specs written against it aim at good, not just at compliant.

deep_search collects the practice corpus: a11y walkthroughs and engineering talks from product teams, plus — the layer most teams never see — reviews by disabled users evaluating real products with real assistive tech. Transcript search finds the demonstrations, not just the mission statements.

library_import_youtube_video and get_youtube_transcript make it studyable: import the strongest sessions, pull the transcripts, and extract the working material — how leaders structure screen-reader flows, the exact language of their announcements and labels (transcripts capture what the screen reader actually said), the patterns disabled reviewers praise versus route around. Your spec inherits practiced patterns; your audit gets user-validated criteria beyond the checklist.