  AdS supergravity admits supersymmetric solutions that describe BPS defects.
Here, we investigate such solutions in AdS$_3$ supergravity, which is
formulated as a Chern-Simons theory on $\mathrm{OSp}(2|1)\,\times\,
\mathrm{OSp}(2|1)$. We compute the Killing spinor equation on the BTZ geometry
in different ways, looking for BPS solutions on the entire space of parameters.
We focus our attention on defects that represent geometries with integer
angular excesses; these correspond to specific negative values of the BTZ mass.
We compare our solutions with other results in the literature, finding exact
agreement. We argue that, in the semiclassical limit, the BPS defects can be
associated to degenerate representations of the Virasoro symmetry at the
boundary. The case of non-diagonal representations, describing stationary,
non-static defects, is also discussed.
