diff --git a/crates/surreal_container/tests/scheduler_seam.rs b/crates/surreal_container/tests/scheduler_seam.rs
new file mode 100644
index 00000000..b1b2c208
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+++ b/crates/surreal_container/tests/scheduler_seam.rs
@@ -0,0 +1,125 @@
+//! Seam falsifier: `SurrealMailboxView` → `VersionScheduler::on_version` → `KanbanMove`.
+//!
+//! ADDITIVE. Asserts the IN-direction wiring the module doc-comments *claim*
+//! ("a version tick, fed to `VersionScheduler::on_version`, lowers to the next
+//! legal Rubicon move over a `MailboxSoaView`") actually holds end-to-end —
+//! driven by the REAL `SurrealMailboxView` read-glove, not a hand-rolled fake,
+//! across the FULL Rubicon lifecycle (the in-crate unit test covers one tick).
+//!
+//! Each test states its kill-condition: the observation that would prove the
+//! seam WRONG. None of these pin "current behaviour" — they pin the contract
+//! the doc-comments assert.
+
+use lance_graph_contract::kanban::{ExecTarget, KanbanColumn};
+use lance_graph_contract::scheduler::{DatasetVersion, NextPhaseScheduler, VersionScheduler};
+use lance_graph_contract::soa_view::MailboxSoaView;
+use surreal_container::view::SurrealMailboxView;
+
+/// One empty-column view at `phase` (the scheduler reads only `phase()` +
+/// `mailbox_id()` + `current_cycle()`; row columns are irrelevant to lowering).
+fn view_at(phase: KanbanColumn) -> SurrealMailboxView<'static> {
+    SurrealMailboxView::from_columns(7, 5, 13, phase, &[], &[], &[], &[])
+}
+
+/// KILL-CONDITION: if any forward tick lowers to a column the Rubicon DAG does
+/// not sanction (`can_transition_to` == false), the scheduler is mis-wired.
+/// Walks the whole canonical arc through the real view.
+#[test]
+fn full_rubicon_arc_lowers_to_legal_successors() {
+    let scheduler = NextPhaseScheduler;
+    // The canonical forward arc the doc-comment names.
+    let arc = [
+        (KanbanColumn::Planning, KanbanColumn::CognitiveWork),
+        (KanbanColumn::CognitiveWork, KanbanColumn::Evaluation),
+        (KanbanColumn::Evaluation, KanbanColumn::Commit),
+        (KanbanColumn::Plan, KanbanColumn::Planning), // re-deliberate
+    ];
+    for (i, (from, want_to)) in arc.iter().enumerate() {
+        let mv = scheduler
+            .on_version(&view_at(*from), DatasetVersion(i as u64 + 1), ExecTarget::Native)
+            .unwrap_or_else(|| panic!("{from:?} must schedule a forward move"));
+        assert_eq!(mv.from, *from, "move.from must echo the observed phase");
+        assert_eq!(mv.to, *want_to, "{from:?} must lower to {want_to:?}");
+        // The DAG itself must sanction the emitted edge — the falsifier.
+        assert!(
+            from.can_transition_to(mv.to),
+            "scheduler emitted an illegal Rubicon edge {from:?}->{:?}",
+            mv.to
+        );
+    }
+}
+
+/// KILL-CONDITION: an absorbing column (`Commit`/`Prune`) is cycle-end — it must
+/// schedule NOTHING. If `on_version` returns `Some` here, the lifecycle would
+/// never terminate (a mailbox past Commit would keep being advanced).
+#[test]
+fn absorbing_columns_schedule_no_move() {
+    let scheduler = NextPhaseScheduler;
+    for phase in [KanbanColumn::Commit, KanbanColumn::Prune] {
+        assert!(phase.is_absorbing(), "{phase:?} must be absorbing (precondition)");
+        assert!(
+            scheduler
+                .on_version(&view_at(phase), DatasetVersion(99), ExecTarget::Native)
+                .is_none(),
+            "{phase:?} is absorbing — it must schedule no advance"
+        );
+    }
+}
+
+/// KILL-CONDITION: the Libet `-550_000 µs` readiness-potential anchor is stamped
+/// ONLY on the Planning→CognitiveWork Σ-commit crossing. If any other tick
+/// carries a non-zero offset (or that crossing carries zero), the Libet anchor
+/// is mis-placed.
+#[test]
+fn libet_anchor_only_on_sigma_commit_crossing() {
+    let scheduler = NextPhaseScheduler;
+
+    let crossing = scheduler
+        .on_version(&view_at(KanbanColumn::Planning), DatasetVersion(1), ExecTarget::Native)
+        .expect("Planning advances");
+    assert_eq!(crossing.to, KanbanColumn::CognitiveWork);
+    assert_eq!(
+        crossing.libet_offset_us, -550_000,
+        "the Σ-commit crossing must carry the -550ms Libet anchor"
+    );
+
+    for from in [KanbanColumn::CognitiveWork, KanbanColumn::Evaluation, KanbanColumn::Plan] {
+        let mv = scheduler
+            .on_version(&view_at(from), DatasetVersion(2), ExecTarget::Native)
+            .expect("non-absorbing column advances");
+        assert_eq!(
+            mv.libet_offset_us, 0,
+            "{from:?} is not the Σ-commit crossing — Libet offset must be 0"
+        );
+    }
+}
+
+/// KILL-CONDITION: the scheduler is a pure function of (view, version, exec).
+/// Same inputs MUST yield the same move — the determinism the whole
+/// version-tick → lifecycle mechanism stands on. A difference proves hidden
+/// state leaked in.
+#[test]
+fn lowering_is_deterministic() {
+    let scheduler = NextPhaseScheduler;
+    let a = scheduler
+        .on_version(&view_at(KanbanColumn::CognitiveWork), DatasetVersion(7), ExecTarget::Jit)
+        .expect("advances");
+    let b = scheduler
+        .on_version(&view_at(KanbanColumn::CognitiveWork), DatasetVersion(7), ExecTarget::Jit)
+        .expect("advances");
+    assert_eq!(a, b, "same (view, version, exec) must lower to the same move");
+}
+
+/// KILL-CONDITION: the `exec` backend selector must ride through the lowering
+/// onto the emitted move unchanged (it names where the precipitated plan runs).
+/// If it is dropped or rewritten, the planner's execution-target choice is lost.
+#[test]
+fn exec_target_rides_onto_the_move() {
+    let scheduler = NextPhaseScheduler;
+    for exec in [ExecTarget::Native, ExecTarget::Jit, ExecTarget::SurrealQl, ExecTarget::Elixir] {
+        let mv = scheduler
+            .on_version(&view_at(KanbanColumn::Planning), DatasetVersion(3), exec)
+            .expect("advances");
+        assert_eq!(mv.exec, exec, "exec target must survive the lowering");
+    }
+}