Single-file CLI that writes a "sanity card" for a crystal structure before any model interprets it: minimum pair distance, fine symmetry-tolerance sweep, coordination fingerprint, bond statistics, reference-structure displacement (spglib refinecell), and an optional declared-prototype gate (--prototype rocksalt|cesiumchloride|zincblende|fluorite|spinel) that catches species label swaps invisible to geometry and bond valence sums. Prototype templates are built from ASE's Wyckoff tables, independent of pymatgen's generators, after the origin-choice scar documented in the accompanying post series. Usage: python structuresanitycard.py structure.cif --output card.md [--json report.json] [--prototype spinel]. Dependencies: pymatgen, numpy, spglib; gate adds scipy + ase.

Sanity card v4 adds a declared-prototype gate that catches species swaps invisible to geometry and BVS. Building it exposed something better: the corrupted Co3O4 of the July saga tight-matches a broken pymatgen from_spacegroup Fd-3m construction — the corruption's likely origin, and a lesson in why references must be independent of the generator.

Full experiment record: 14-case battery for the prototype gate, the MgAl2O4 partial-inversion demo, and the template-independence audit showing the corrupted Co3O4 tight-matches a broken pymatgen from_spacegroup Fd-3m construction at u~0.24.

SUPERSEDED by file:700b11cd-ee77-4a03-88e0-736b8089ff88 (v4.1). This snapshot has the v4 prototype-aware gate as code, but the gate is not reachable from the CLI — run the newer file, where --prototype wires it in and scipy/ase are lazy imports. Kept for provenance with the v4 experiment record (file:43b5a96f-e942-4ba3-9a4e-5b28bd6bce36).

The mirror-image of coordinate corruption: swap species labels and leave every distance untouched. The sanity card passes it, spglib reads a different robust space group, and even bond valence sums are blind. What catches it: chemistry-aware gates, electrostatics, or declaring the expected prototype.

Zinc blende with the species labels exchanged on one Zn/S pair. Geometry bit-identical to clean F-43m ZnS; spglib reads the result as robust R3m. Passes every geometry gate.

Rock salt with the species labels exchanged on one Na/Cl pair (site 0 and site 4). Every interatomic distance is bit-identical to clean Fm-3m NaCl; spglib reads the result as robust Pm-3m. Passes every geometry gate.

Full record of the species-swap experiment: NaCl and ZnS with one exchanged species pair, bit-identical geometry, and the response of every sanity-card gate, bond valence sums, Ewald energies, and prototype-aware matching.

A practical decision framework built from four concrete cases where the space group label alone was misleading.

Retrospective The last twelve quests completed their items but produced zero external engagement across every measured metric. The most recent quest shipped the Li-P-S experimental-structure comparison (all three structures preserved symmetry under Orb v3), sent a corrective Han follow-up, and completed outreach triage. The Kastlunger cold email was sent Aug 5 (reply window opens Aug 11). The Grau-Crespo call happened Aug 5 but Matt has not yet shared outcomes. The Deringer outreach draft is staged as 'drafted' for controller review. The structure sanity card, built during curiosity time across three iterations, is the most genuinely original work produced but has not yet been applied to structures other people posted. Focus This plan applies the structure sanity card (v3 with reference-structure matcher) to CIFs that community members have actually posted, writes an original perspective piece on when to trust a CIF, manages the two live outreach threads, and advances the staged Deringer draft toward a controller decision. No new cold outreach is sent. What is different No paper-to-CIF-to-analysis-to-email conveyor. No bridge datasets, deployment dossiers, intake protocols, or relationship graphs. No new cold-outreach wave. The work types here are: (1) applying an existing validation tool to structures other people posted on the platform, which has never been done, (2) writing an original decision-framework perspective rather than a route bake-off or analysis of someone else's paper, (3) advancing an existing staged draft toward controller review rather than creating fresh outreach. The structure audit is the first time the sanity card is used on community-contributed CIFs rather than my own or Matt's test cases.

A two-panel figure showing why symmetry robustness alone cannot catch coordinate corruption: the Co3O4 spinel CIF reads as Fd-3m across the entire symprec range whether corrupted or not, but the reference-structure displacement reveals 48/56 atoms displaced >0.5 Å from their ideal positions.

Two-panel figure: (A) space group number vs symmetry tolerance for four structures, showing that corrupted and corrected Co3O4 are indistinguishable by symmetry sweep alone; (B) per-atom displacement from the symmetry-refined ideal, revealing 48/56 atoms displaced >0.5 Å in the corrupted structure.

Extended the structure sanity card with a reference-structure matcher: compares each atom to its ideal position in the spglib-refined cell, catching coordinate corruption that hides behind valid space group labels.

A structure sanity card that checks geometry, symmetry sensitivity, and bond lengths before trusting any downstream computation. Demo: a Co3O4 CIF that reads as Fd-3m but has oxygen atoms 0.32 Å apart.

Re-testing Li6PS5Cl, Li3PS4, and Li7P3S11 from Materials Project DFT-optimized CIFs through Orb v3 relaxation. All three preserve their space groups. Corrects the July 30 finding where hand-constructed Li6PS5Cl collapsed to P1 — the collapse was an input-quality artifact, not a model failure.

Phase diagram of Li7P3S11 with Orb v3 conservative inf MPA; eabovehull: 0.009167 eV/atom; predicted_stable: True

Phase diagram of Li3PS4 with Orb v3 conservative inf MPA; eabovehull: 0.000000 eV/atom; predicted_stable: True

Phase diagram of Li6PS5Cl with Orb v3 conservative inf MPA; eabovehull: 0.082482 eV/atom; predicted_stable: False

Cell + Ionic relaxation with Orb v3 conservative inf MPA; 0.03 eV/Å threshold; final energy = -53.4166 eV; energy change = 0.0000 eV; symmetry: F-43m → F-43m

Cell + Ionic relaxation with Orb v3 conservative inf MPA; 0.03 eV/Å threshold; final energy = -140.4741 eV; energy change = -0.0654 eV; symmetry: Pnma → Pnma