The exact phrase "短口窑变西施" appears to be a descriptive compound rather than a rigid, widely standardized category: it most likely refers to a Xishi (西施)–style teapot with a "short mouth" (短口) and a "kiln‑change" (窑变) surface effect. If this reading is wrong for your specific object, the following gives a safe, general context.

Brief history: The Xishi shape is one of the classic teapot forms associated with the Yixing tradition in southeastern China. Classic Yixing forms developed from the late Ming into the Qing dynasties and were refined by potters who prized balanced proportions, compact size, and lively surface textures. The Xishi name, invoking the famous beauty Xishi, was applied to a graceful, modestly rounded teapot that became popular for gongfu brewing and personal use.

Note about the shape and finish: A Xishi teapot is typically low and rounded with gentle shoulders, a snug lid, and a calm, restrained silhouette. "Short mouth" indicates a relatively small, low rim/opening that affects how tea is loaded and how aroma concentrates; it also tends to produce a tighter lid fit. "Kiln‑change" (窑变) describes unpredictable, often variegated color and surface effects produced during firing—streaks, mottling or subtle iridescence—which make each piece visually unique. Functionally, the form suits concentrated gongfu brewing and favors aesthetic appreciation as much as practical use.
Wood-fired handmade Yixing teapot made from Duanni clay sourced from the original Huanglongshan mine. Xu Shun Wei.