# Deterministic order is a cross-cutting v1 invariant

_2026-09-21 · booth_

**Deterministic order is a cross-cutting v1 invariant** —
operator directive, mid-implementation. Every ordered collection the Booth
renders must have a *stated* rule producing the same sequence on every render
of the same state; the rule can be anything defensible (byte order, time, an
explicit number, an arbitrary-but-recorded sequence), but no rule at all is
forbidden. It binds harder here than elsewhere because the Booth's job is
**comparison** — the operator judges tile 47 against tile 47 and refers to
artifacts positionally, so an order that moves between renders misfiles a flag
or a note rather than crashing. Recorded as `ROADMAP.md` § "Cross-cutting
invariant" (with the per-collection table) and `CLAUDE.md` invariant 6, and
tested. Still undecided and must be settled before those units ship: **U7's
section ordering and compare pairing**, and **U6's bench listing**.