Significant — Certifying Spiral Magnetism Under a Fixed G–Σ–P–L Corridor converts crystal-forced spiral/chiral magnet claims into a lab-executable, replayable contract rather than a narrative sign story. The document treats spiral order as a signed channel and supplies a strict application template built on a ternary directive knob (minus/zero/plus) with an opposed pair and a true null, odd-versus-even separation, and explicit missingness accounting (zeros, yield, and SoZ). The contribution is deliberately model-agnostic and data-free: no mechanism is imposed, and no new addressing engine is requested. Instead, a falsifier-first corridor method is provided that forbids threshold travel, forbids rescue by selection, and forces failures to be logged as Strong-to-Weak or no-test when instability dominates. A minimal decomposition ledger is included to prevent lane relabeling and regime swaps in multi-domain spiral systems, with optional SEB-0 versus SEB separation for recognition versus enforcement. The deliverable is a portable certification tool that laboratories can run with their own readout tokens and publish as tokens-only linkage fields for replay and audit.