zu-patterns 0.2.2

Zu pattern library: the policy-prior / move-ordering layer over the Action Surface (§5)

zu-patterns — the policy-prior / move-ordering layer (§5)

A UI is a state space; the Action Surface is the move generator (affordances = legal moves). This package is the policy prior + guided search layer over that surface — the AlphaZero shape, not Deep Blue. It does not brute-force a live space (visiting a node might charge a card). It proposes the promising interaction without exploring, and the rail (§1) verifies the prediction.

The new port — Pattern (group zu.patterns)

The Pattern Protocol lives in zu-core (zu_core.ports.Pattern), like the other ports. A pattern is read-only: it recognizes a situation over a core SurfaceView (zu_core.surface) and emits success_invariants / failure_invariants (declarative zu_core.invariants.Invariants the rail verifies). It never calls a tool and never decides the task action — that is the policy's job. A recognized pattern is a prior to be confirmed by observation, never ground truth (ZU-RAIL-9): its success criteria compile (via compile_spec) to Monitors, and a behaviour mismatch fires a detector.

The boundary that makes this clean: recognize takes the core SurfaceView, never zu-tools' Surface. zu-tools projects its Surface onto SurfaceView through a one-way adapter (zu_tools.surface_adapter.to_surface_view), so zu-patterns depends only on zu-core.

The pieces

• recognizer.py — a pure pass over a SurfaceView: classify → archetype + confidence. Low confidence ⇒ no hint (fall through to the model).
• reversibility.py — a principled, default-to-committing classifier of an action as reversible (read-only/idempotent, safe to explore live) vs committing (side-effecting — the live-search/rail commit boundary). No site-specific keyword blocklist: HTTP-method/idempotency, affordance semantics, an extensible prior set, default-to-committing on uncertainty.
• rail.py — the success/failure → Invariant helpers shared by the patterns.
• search.py — an offline best-first planner over the Phase-1 zu_core.reachability.Fsm with the recognizer as the move-ordering prior, plus an event-log → Fsm transition-model builder. Pure, offline, $0. The live guided-MPC loop and the Shadow-sourced transition model are deferred seams (stubbed/documented).

The 8 starter archetypes

cookie_banner, login_form, search_box, modal_dialog, paginated_list, sortable_table, autocomplete, cart_checkout — the last is the canonical irreversible-boundary pattern (its place-order/pay step is classified COMMITTING; the script stops before it).

All recognition is deterministic structural matching over roles/labels/states (no model), so every pattern is tested at $0 with hand-built SurfaceViews. A small-model recognizer is a future plugin behind the same Protocol.