The instruction said an emoji "is fine where it carries something the words do
not, and wrong as a status marker at the head of every line", and what came
back was a tick at the head of every line: the one thing that sentence named.
A rule with an exception in it is a rule the model satisfies by finding the
exception. It is a flat prohibition now.
The gate had the same shape. It asserted the word emoji appeared in the
prompt, which the sentence licensing emoji satisfied perfectly - the
comment-versus-code defect committed by the very test whose docstring names it
for markdown. It now asserts that the sentence mentioning emoji forbids them,
and refuses ten ways of writing the exception back in. Three known-bad
mutations, all killed.