One route, two methods — and that is the fix, not a style choice.

Two routes side by side on one path do not coexist the way they read: @app.get registers methods={"GET"} (an APIRoute does not add HEAD), so the app-wide _grant_head_to_get_routes() handed HEAD to the RENDERING half, and Starlette answers a HEAD from the first FULL match — which is the GET route, registered first. The headers-only handler beside it was therefore unreachable, and a link-checker's HEAD rendered up to 50,000 URLs. Measured 2026-09-16; the cheap HEADs on this route and on /data/models.jsonl are now declared with their GET.