Hydra Docs
Exports

Safe zones

Tell Hydra when a player enters or leaves a safe zone your script manages.

SetPlayerSafeZone (server)

lua
exports.HydraAC:SetPlayerSafeZone(source, true)   -- entered
exports.HydraAC:SetPlayerSafeZone(source, false)  -- left

SetSafeZone(source, inside) is the same export under a shorter name.

SetSafeZone (client)

For zone scripts that run on the client. Hydra forwards it to the server.

lua
pcall(function() exports.HydraAC:SetSafeZone(true) end)

While a player is in a safe zone, godmode and invincibility are not flagged.

Most servers need neither: Hydra learns your green zones by itself, and you can draw your own in Zones & spots › Safe zones. See Zones and spots.