Selection starts with the active source catalog and the room's hard filters: game mode, key count where applicable, difficulty, playable length, pass-count policy, age policy when enabled, and availability. .pool gives the current room settings.

The bot avoids recent played or skipped maps, excludes maps already reserved in the visible playlist, and spaces songs. Player feedback affects weighting. Mania also has structural preferences and experimental farm evidence. Preference cannot make an ineligible map pass the hard filters.

Unavailable maps are temporarily quarantined so the bot can rotate past repeated failures. Expiry allows later rechecks rather than permanently declaring the map unavailable. An empty source switch preserves the previous working pool.

The catalog, active difficulty range, and filters all influence eligible counts. Research coverage grows over time; experimental classifications can change after validation. See fallback and repeated maps.