שולחן ערוך · אורח חיים

Concise summary:

ג׳ seifim: the siman governs conduct toward the שמש (the attendant who serves the diners without eating with them). One gives him at once from any fragrant dish he craves, מפני עגמת נפש (to spare him distress of soul) — and there is even an issue of danger (סכנה, כתובות ס״א ע״א); it is מדת חסידות to give him from every kind. Nothing is handed to him while the cup is in the blesser's hand, and bread is given him only if one knows he washed his hands and will bless (מוראת שמים). The שמש blesses בורא פרי הגפן over every cup, since he is כנמלך (without continuous intent); and the Rama: two who eat together, the שמש eats with them without permission, so they join for the zimoun.