As far as I know, there are no official tools for creating mods, just custom, why does no one want to do their mods for their servers? For example, new weapons, animations, objects, maybe in the future developers will make tools, but I do not understand why ordinary people do not do it. Maybe someone can explain it to me.
uMod (formally known as OxideMod) has developer documentation for their platform:
You can’t implement custom weapons, only skinned items for preexisting entities.
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