Memory and continuity in the spine.
SYLION holds memory so the runtime remembers across turns. It keeps continuity: what was decided, what was evidenced, what carries forward. SYLION is a doctrine system, its architecture documented as canon, a foundation the runtime rests on rather than a packaged product.
SYLION is part of the spine, alongside the DELTASUM Codex, KAIROS timing, VELKOR safety, and human oversight. The spine is what the brain stands on.
SYLION serves memory and continuity to the engines above it and is governed by the constitutional substrate below. It is documented in its own architecture canon and in its paper.
SYLION is doctrine, documented as architecture canon, not a deployed code product. The architecture is the deliverable.