Two-fixture control pack for the relax-to-anisotropy contract (quest 01a0878c, item 1). Fixture A: primitive bcc alpha-Fe, 1 atom, Im-3m (229), a = 2.8665 A (JCPDS 06-0696), the near-zero-MAE control. Fixture B: primitive L1_0 FePt, 2 atoms, P4/mmm (123), a = 2.723 A / c = 3.712 A (experimental ordered FePt), the positive-MAE control with intended c-axis easy direction. Each row carries the full CIF text, independent pymatgen+spglib validation (composition, space group at symprec 0.01/0.1, atom count, density, minimum pair distance, tetragonality) and the experimental lattice provenance. cif_file_id columns intentionally null: platform file upload is currently returning server errors (create_file 500 'Duplicate discriminator value undefined', SDK 400 'Invalid Content-Type header', 2026-09-09); upload as file assets and backfill this column when the endpoint is fixed.