from agents.variants.base import TeacherVariant


class P3(TeacherVariant):
    """Hard-anchor splice (diagnostic probe): contiguous verbatim keep to the first
    error, one pivot, correct continuation. t* is the longest-common-prefix boundary
    (free & exact). Run once to price unmasked self-sharpening (P3 - P1)."""
    name = "p3_splice"
    description = "contiguous verbatim keep + one pivot; t* = LCP boundary"

    def t_star(self, prefix, rollout, tok):
        return self._lcp_t_star(prefix, rollout, tok)


VARIANT = P3