read_full_data_domain deep-copied the shared worksheets on every call; a long report reads five domains twice, so ten copies for read-only use. The shared part is now copied once (full_data_domain_base) and reused for every domain's facts and their leaf check; each domain's facts are still copied out so domains share no objects. Long reports byte-identical on four fictional charts; with #121, -24–29% end to end. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01DbBXoz1Qk3y9buDv1mkmTu