Out of scope (v0)

Deliberately deferred:

• Set/map literal syntax ({1, 2, 3}, {"a": 1}).
• Registry and VCS dependencies. ox build resolves [dependencies] path dependencies only (Build pipeline); a bare version requirement (ufo = "1.0"), the version/git/branch/tag/rev/registry keys, and the ox.lock lockfile refuse with OE1240.
• Federated service <endpoint> { … } external-store calls.
• Managed bridge rules — the #[add] / #[delete] / #[revise] / #[override] operators (Brewka et al. 2011) that withdraw or rewrite target-standpoint conclusions, and the #[managed] escape from the bridge-graph acyclicity requirement (Bridge rules).
• MLT* orderless types.
• #[brave] / stable-model semantics — multiple two-valued models with credulous and skeptical readings, as an alternative to the default well-founded semantics (derive).
• User-defined operators.
• Async / await.
• Const generics.
• Higher-kinded types.
• Runtime trait objects (dyn Trait).
• Topology declarations inside metarel bodies.
• Refinement-driven width-selection on primitive types (current behavior: arbitrary-precision; explicit i32 etc. for fixed-width).
• Raw-identifier escape for hard-reserved keywords (e.g., a Rust-style r# prefix). Today, vocabulary authors may freely use contextual identifiers (type, rel, kind, role, …) because they are not lexer-level reserved — see reserved keywords. Hard-reserved keywords (derive, query, mutate, check, fn, …) cannot currently be used as identifiers. If demand surfaces from vocabulary authors, an r# escape is the obvious extension.
• Hypergraph path traversal. v0 Path<NodeT, EdgeT> (The Path type) is over binary relations only; n-ary relations (pub rel Transaction(seller, buyer, item)) are queryable as predicates but not path-traversable. A principled hypergraph traversal semantics — specifying which endpoint the path enters and exits through — is deferred.
• Temporal proof tags — the 4-slot Governatori-Rotolo schema $\pm\partial^{t_d}@{t_r}, l_{t_l}$ over the bitemporal substrate (Temporal substrate, Defeasibility).
• Alternative defeasibility strategy vocabularies — ambiguity propagation, stricter team-defeat variants, dynamic preferences, MKNF hybrid knowledge bases, rational closure / KLM typicality. These arrive as use-imported strategy packages, not switches on the Governatori strategy (Defeasibility).

These may land in later language versions.