The International Holocaust Remembrance Allowance definition of Anti-Semitism is:
// Antisemitism is a certain perception of Jews, which may be expressed as hatred toward Jews. Rhetorical and physical manifestations of antisemitism are directed toward Jewish or non-Jewish individuals and/or their property, toward Jewish community institutions and religious facilities. //
https://www.holocaustremembrance.com/working-definition-antisemitism
Labour signed up to the definition two years ago when it was first published. The Conservatives also adopted the definition at the same time.
Not part of the definition, but for guidance are 11 examples. The Labour Party HAS adpoted the definition, but only cite 7 of the examples. The 4 missing examples are mainly about criticism of Israel the country, not of Jewish people.