The document discusses several tools for determining glycosylation sites and glycan structures from mass spectrometry data, including GlycoMod and Glyco-search-MS. GlycoMod allows users to input protein sequences, digestion data, and MS data to identify potential glycopeptides and glycosylation positions. Glyco-search-MS uses a database of calculated MS fragments to aid in determining oligosaccharide structures, but has limited structures in its database. Many of the tools have poor interfaces or lack documentation, and may not provide answers due to technical or experimental limitations, so they should be used carefully.