diff --git a/builtin/client/register.lua b/builtin/client/register.lua
index acd36ab36..27a6b02d9 100644
--- a/builtin/client/register.lua
+++ b/builtin/client/register.lua
@@ -4,6 +4,13 @@ core.callback_origins = {}
 local getinfo = debug.getinfo
 debug.getinfo = nil
 
+--- Runs given callbacks.
+--
+-- Note: this function is also called from C++
+-- @tparam table  callbacks a table with registered callbacks, like `core.registered_on_*`
+-- @tparam number mode      a RunCallbacksMode, as defined in src/script/common/c_internal.h
+-- @param         ...       arguments for the callback
+-- @return depends on mode
 function core.run_callbacks(callbacks, mode, ...)
 	assert(type(callbacks) == "table")
 	local cb_len = #callbacks