  We study D-brane moduli spaces and tachyon condensation in B-type topological
minimal models and their massive deformations. We show that any B-type brane is
isomorphic with a direct sum of `minimal' branes, and that its moduli space is
stratified according to the type of such decompositions. Using the
Landau-Ginzburg formulation, we propose a closed formula for the effective
deformation potential, defined as the generating function of tree-level open
string amplitudes in the presence of D-branes. This provides a direct link to
the categorical description, and can be formulated in terms of holomorphic
matrix models. We also check that the critical locus of this potential
reproduces the D-branes' moduli space as expected from general considerations.
Using these tools, we perform a detailed analysis of a few examples, for which
we obtain a complete algebro-geometric description of moduli spaces and strata.
