Two short lines carry a lot here. The speaker is standing at the point where day turns into night, the moment of dusk, and that boundary becomes a kind of inheritance. What gets handed over isn't money or land but "a legacy of oughts": all the things one ought to do, ought to have done, ought to be.
The word "oughts" is the key. It sounds like "noughts" or zeroes too, so the legacy might also be a pile of nothings, or a set of duties that add up to emptiness. That double sense is my reading, but it fits the quiet, slightly wry tone.
The speaker doesn't seem angry. The verb "receive" is calm, almost passive, as if they accept the weight without arguing. The mood is hushed and reflective, with a faint sadness. Dusk is a time of in-between feelings, and the poem leaves us there, thinking about what we've been told to carry and whether we ever chose it.