Get audio features for ONE track — BPM, musical key (name + Camelot + Open Key),
energy, danceability, valence, acousticness, instrumentalness, liveness, speechiness,
loudness, mood, mood_vector, genre, time signature, duration and more.
This is the drop-in replacement for Spotify's deprecated /audio-features endpoint.
Provide EXACTLY ONE identifier:
- `track` (optionally with `artist`) — e.g. track="Blinding Lights", artist="The Weeknd".
- `isrc` — e.g. "USUM71900001".
- `mbid` — a MusicBrainz recording UUID.
- `spotify_id` — a Spotify track ID, URI, or URL.
Returns a JSON object of features. Some feature fields may be null for tracks resolved
via the fallback catalogs (only audio-derived values are present for fully analysed
tracks). If a track name is not yet in the catalog, the API queues an on-demand
analysis and this tool reports that it is queued — retry in ~30s-2min. If you only
have a fuzzy or partial name, call search_catalog first to find the exact track.