  We characterize four types of agentive knowledge using a stit semantics over
branching discrete-time structures. These are \emph{ex ante} knowledge,
\emph{ex interim} knowledge, \emph{ex post} knowledge, and know-how. The first
three are notions that arose from game-theoretical analyses on the stages of
information disclosure across the decision making process, and the fourth has
gained prominence both in logics of action and in deontic logic as a means to
formalize ability. In recent years, logicians in AI have argued that any
comprehensive study of responsibility attribution and blameworthiness should
include proper treatment of these kinds of knowledge. This paper intends to
clarify previous attempts to formalize them in stit logic and to propose
alternative interpretations that in our opinion are more akin to the study of
responsibility in the stit tradition. The logic we present uses an extension
with knowledge operators of the Xstit language, and formulas are evaluated with
respect to branching discrete-time models. We also present an axiomatic system
for this logic, and address its soundness and completeness.
