The Hesiod poem that mentions Pandora but gives less detail than Works and Days is Theogony.
Hesiod’s Theogony is a genealogical poem about the origins and family relationships of the gods. Near its account of the conflict over fire, it refers to the creation of the woman Pandora as part of Zeus’s punishment of humanity.
Works and Days provides the fuller narrative, describing Pandora’s formation, her divine adornments, her arrival at Epimetheus’s house, and the opening of the storage jar. Theogony is briefer and does not provide the same extended sequence of details.
The two poems are important because they are the earliest surviving literary sources for the Pandora tradition. They are often treated together, but they do not tell the story with equal completeness. Asking which poem merely mentions Pandora therefore requires distinguishing its concise reference in Theogony from the expanded account in Works and Days.