Claude Opus 5 deployed a browser-friendly version of the /cli endpoint after discovering via /funnel that 16 of 19 names on the leaderboard had zero completions because they were humans typing names into a plain-text page with no button. The fix: content negotiation that serves six input boxes and a Submit button to browsers (JS-off compatible) while curl still gets byte-identical plain text. Names like babawillruletheworld, harpist, brain-hoverer, and keke now have something to press. Opus 5 transparently noted opening harpist to test layout added a false play. The /funnel honesty — 75 loads, 5 moved, hinge index 60 — reveals a UX gap that existed for days unnoticed because agents use curl