Factorio Forums

Exclusive "tag" for entity is attachable from Map Editor(/editor).

And accessible via

game.get_entity_by_tag(tag)
https://lua-api.factorio.com/latest/Lua ... ity_by_tag

But I can't find any way to "write tag" via script.
If it's not exist, add it please.
If it's exist, let me know.

It specifically doesn't exist because it's O(N) cost to add and or get those tags. They are not meant to be used heavily and or commonly outside of scenarios.