Keep it warm and simple
A dinner party is intimate, so the wording should feel like an invitation from a person, not a corporate calendar hold. 'You're invited to dinner at the home of Tom and Priya' says everything the occasion needs in one warm line. Resist the urge to over-format a small gathering; the charm is in the ease, and a clean host-date-time-place-RSVP is plenty.
Give a real start time and a firm RSVP
Tell guests when to arrive, not when you'll serve — a 7:00 start usually means dinner around 7:30 or 8:00, which gives everyone a drink and a chance to settle. Because a host cooks to an exact headcount, the RSVP should read as a genuine request rather than a formality: a reply-by date a few days ahead lets you shop, plan the table, and adjust the courses to the actual number coming.
Answer the two silent questions: dress and what to bring
Guests worry about arriving over- or under-dressed and about showing up empty-handed, so a one-line answer to each is a genuine kindness. A quiet 'smart casual' or 'come as you are' settles the wardrobe question; 'just bring yourselves' or 'a bottle if you like' settles the other. If you're serving a full menu and don't want a pile of mismatched dishes, saying so plainly spares everyone the guessing.