The best shapes for broth
Pasta served in clear meat broth rather than dressed with a sauce. The broth is not poured over the top, it is the dish, and the pasta is sized so a spoon can carry both at once. This is the winter register of Italian cooking and mostly the register of filled pasta.
Pasta served in the liquid itself. Small absorbent shapes and filled parcels are the only correct answers, the broth is the sauce and the spoon is the fork.
Canonical: tortellini, cappelletti, pastina family, orzo.

Each piece is smaller than a peppercorn, so sauce never coats individual beads the way it coats a noodle.

This is pastina scale, so the cooking liquid is the dish.

The rings are a binding shape, not a plating shape.

Anolini are tiny and made to be cooked and served in broth, not coated.

A short small tube reads as a soup and braise pasta first.

A strand under a millimeter wide is nearly all surface.

This is a filled hat, so the sauce works from the inside out.

This is a spoon shape.

Scale every pairing to a soup spoon.

Fideos are most often dry-toasted or browned in oil first, then simmered directly in stock or sauce so they absorb liquid rather than being boiled and drained.

Toasting changes how fregula behaves.

Because the pieces are flat, thin, and uneven, they cook fast and behave differently across their varied thicknesses, which suits them to broths and brothy bean or chickpea soups where the pasta thickens the liquid.

Marubini are a brodo pasta before they are anything else.

Treat orzo as a grain that happens to be pasta.

Quadrucci are built for broth, not for a clinging sauce.

The filling carries the flavor, so the sauce's job is to coat, not compete.

Stelline are soup physics in miniature.

This is a thin, delicate egg ribbon, so it wants light dressings that cling without weighing it down.

This is a very thin, yolk-rich flat ribbon, so it wants light fat-based dressings that cling to the fine strands without burying them.

Tortellini are built for broth.
What we would not put it on
Any full-size shape. A rigatoni sitting in broth makes two foods in one bowl rather than one dish, and it cannot be eaten with the spoon the broth requires.
Want it the other way around? Start from a shape in the Pairing Finder.
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