kernels: shared block-window to global coordinate helper

BlockStep (slot-reservoir wall rows) and BlockChannelStep computed the
global cell of a block-window cell with the same four lines.
block_global_xy (core/layout.cuh, 2D, __forceinline__) now holds them;
both kernels call it with their own domain width. Same integer
operations: no numerical, ABI or scheduling change. The slot-reservoir
kernel layout is unchanged (no split).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/compatibility.md

@@ -0,0 +1,35 @@
+# Compatibility and API changes
+
+Changes that can make a previously accepted setup or call behave differently.
+Each entry names the commit, the affected entry points and the observable result.
+
+## 87c3a31: cut-link ownership is validated for every body
+
+`validate_cut_link_ownership` (`body/preprocess/flag_overlay.py`) now runs for
+passive bodies as well as Jet/aperture bodies. Every cut link must have an
+active fluid receiver (FLUID set, SOLID clear), and each `(receiver, direction)`
+population may have only one writer.
+
+Rejected with `ValueError`, before flags, populations or device buffers change:
+
+1. Overlapping or touching passive solids whose cut links write the same
+   population ("Boundary requires unique cut-link writers").
+2. A body whose cut-link receiver is a non-fluid cell, e.g. a channel wall row
+   or the inlet/outlet column ("Cut links must have active fluid receivers").
+
+Both were previously accepted silently for passive bodies; the interpolated
+boundary then had undefined results. The rules apply to the cut links of all
+bodies together, so a passive body overlapping a Jet body is rejected as well.
+The check runs in `Simulation.initialize`, runtime body sync (`sync_bodies`),
+checkpoint save and checkpoint load (`common/checkpoint.py`). Load validates
+before restoring anything, so a checkpoint whose saved geometry violates either
+rule no longer restores; rebuild the geometry with separated bodies.
+
+## 87c3a31: `Simulation.read_surface_exchange` accepts Jet-driven bodies
+
+`read_surface_exchange(id)` previously required `SurfaceActuation` on the body.
+It now also accepts bodies that own Jet aperture links, including Jets with zero
+or negative amplitude (the aperture test is geometric). Bodies with neither
+`SurfaceActuation` nor aperture links still raise
+`ValueError("Body has no surface actuation")`. The value is unchanged: the latest
+step's wall/aperture exchange, not total nozzle force.

docs/validation/dfg_re20.md

@@ -0,0 +1,49 @@
+# DFG 2D-1 (Re 20) against the official reference intervals
+
+`tests/validation/run_dfg_re20.py` runs the steady DFG 2D-1 case on the refined
+channel root (D40 root, D80 wide fine patch) and on the uniform D80 grid. Geometry,
+inflow, initial state, layout and observation are those of the pinned Re100 runner
+(`run_refined_dfg.py`, `re100_helpers.py`, both unchanged); only the lattice
+viscosity is set for Re 20 (root tau 0.56, fine 0.62, uniform 0.62, lattice speed 0.01).
+
+Label: "compared against the official reference bands", not a full benchmark
+certification: the outlet is pressure-NEQ (`neq_extrap`), not do-nothing, and the
+inlet is local Zou-He.
+
+## Quantities
+
+- Cd = 2 Fx / (rho U^2 D), Cl = 2 Fy / (rho U^2 D), interval means over each sample.
+- p_diff = p(0.15, 0.2) - p(0.25, 0.2), linear extrapolation to the exact surface
+  points (`re100_helpers.pressure_probes`). The helper returns dp / (rho U^2) in
+  scaled units; p_diff = dp * 0.04 for U = 0.2 m/s, rho = 1. Both are reported.
+- Official intervals (Schaefer & Turek 1996): Cd [5.57, 5.59], Cl [0.0104, 0.0110],
+  p_diff [0.1172, 0.1176].
+
+## Bounds and steady rule (frozen before any run)
+
+- End time t* = 60 (30 s physical): 240,000 refined root steps, 480,000 uniform steps.
+- One sample every t* = 0.5 (0.25 s) at the end of a synchronized root step; Cd and
+  Cl are interval means. Trailing window t* 50..60 inclusive (21 samples).
+- Steady rule (our engineering choice, not official): in the window, for each of Cd,
+  Cl, p_diff, max - min <= 10 % and |least-squares slope x window| <= 2 % of its
+  official interval width (range 2e-3 / 6e-5 / 4e-5; slope 4e-4 / 1.2e-5 / 8e-6).
+  Absolute limits, so the small Cl is never a divisor. Never relaxed after a run.
+- The verdict uses the window mean; the distance to the nearest interval edge is
+  reported for each quantity (negative outside).
+- Force sign: fluid on cylinder, x along the inflow, y up from the bottom wall; Cd > 0
+  and the official Cl > 0 (`cd_positive` is reported).
+- Not steady at t* = 60: status `NOT_STEADY`, no interval verdict. Health limits
+  (Mach <= 0.2, rho in [0.5, 1.5]) stop the run with `UNHEALTHY`.
+- Steady: `WITHIN_INTERVALS` or `OUTSIDE_INTERVALS`, with the per-quantity verdict.
+
+## Run
+
+```
+python tests/validation/run_dfg_re20.py --output <new-dir> --plan
+CUDA_VISIBLE_DEVICES=<n> python tests/validation/run_dfg_re20.py --case both \
+    --collision SRT --output <new-dir> --max-wall-seconds <cap>
+```
+
+The uniform D80 control separates method error from refinement error. `--plan` writes `plan.json` only. A GPU run writes `plan.json` and `result.json`
+(per case: lattice parameters, every sample, window ranges, status, verdict).
+Host contract tests: `tests/unit/test_dfg_re20.py`.

docs/validation/refined_dfg_window.md

@@ -56,3 +56,62 @@ Root must independently review and admit any execution. An admitted paired pilot
 the existing watchdog, device selection, `--gpu-gates-approved`, positive
 `--max-wall-seconds` and a new output directory, adding only `--exchange-window` to the
 selected collision's pilot command. No GPU or remote action was performed for this patch.
+
+## Public Jet diagnostic option
+
+`--collision MRT --exchange-window --jet-scenario zero|fixed|reverse` selects
+unshifted FP32, no LES, constant transfer on both existing public backends. Default
+`none` and the historical manifests remain unchanged. `zero` registers both Jets at
+zero amplitude and retains every existing DFG verdict, including pressure. `fixed`
+uses outward radial parabolic sectors at pi/2 and 3pi/2, half-width pi/12, peaks
+(+.001,-.001). Both use the existing D40/D80 geometry and U=.01. Sector origins are
+(80.5,81) in root edge coordinates and (160,160.5) in uniform node coordinates;
+radial extent is [0,1.005R]. `reverse` keeps those peaks through t*=300, updates both
+public setters at that completed boundary, and continues to 305 with opposite signs.
+
+Fixed diagnostic windows are 250–260, 260–270, 270–280, 280–290 and 290–300; reversal
+adds 300–305. Histories retain exact interval endpoints and root/uniform lattice
+impulses. The refined window uses total exchange; uniform uses public `read_force`
+batch averages. Driven windows report mean/min/max/RMS Cd/Cl without applying DFG
+reference or periodicity gates. Exit zero means healthy execution, not qualification;
+`matched_case_pass` remains false. No independent CV or stress-load claim is made.
+
+This opt-in records current source/helper hashes with the existing manifest format,
+checkout revision/dirty state and runner hash. Pilot/full must match that snapshot
+and the exact scenario. It does not relabel current source as historical evidence.
+Use the existing bounded plan/pilot/full commands with the three option flags above;
+full requires the matching completed t*=5 paired pilot. `step_seconds` includes force
+readback; observation/overhead and total wall time are separate, not kernel throughput.
+
+Add `--observe-cv` to record independent scalar control-volume samples from the
+already downloaded public macros. The pilot exercises this path at t*=.02..5;
+full records 501 endpoints at 290..300. Each `cv_history.jsonl` row contains actual
+root time, preceding interval start/duration/impulse, and two inventories/outward
+fluxes ordered [mass,Px,Py]. Exclude the first row's preceding impulse: that row
+supplies the initial inventory. Uniform native impulse converts by .5² to root
+units; refined ledger impulse is already in root units. Explicit native-aligned
+contours differ by .25 root cells in x and are recorded in the plan. Cropping
+retains the two-cell face-gradient stencils. No fields or per-link arrays are saved.
+`cv_observation_seconds` is the CV portion of observation/overhead time. Helper hash
+and the observation flag must match pilot/full. Time integration, temporal
+coarsening and any physical assessment remain separate offline work.
+
+## Bounded resolution and placement controls
+
+Defaults remain `--case both --uniform-diameter 80 --placement wide`. Single-case
+runs use `--case uniform` or `--case refined` and never report a matched-case pass.
+Their own reference/periodicity or driven-diagnostic results remain available.
+A single zero-Jet full run exits successfully only when its periodicity and the
+unchanged complete DFG reference verdict pass; driven completion is not qualification.
+
+The D160 option requires `--case uniform --uniform-diameter 160` and an explicit
+public Jet scenario. U and Jet speeds stay .01 and ±.001; viscosity is .016,
+grid 3521×658, center (320,320.5), radius80. CV uses root spacing/time factor .25,
+origin (.375,.75), impulse factor .0625, root viscosity .004, and x-face shift .125.
+
+`--case refined --placement compact` selects root bounds (48,48,128,128), fine
+168×168 and origin (46,46), with the same D40/fineD80 body/Jet resolution. Its CV
+contours are (52,52,112,112) and (50,50,120,120); complete face-gradient stencils
+are clear of both solids and the transfer footprint. Compact is refined-only.
+CV metadata gives each grid's spacing/origin/contours explicitly. Case, uniform
+diameter and placement must match the newly completed pilot in every receipt.

src/CelerisLab/body/jets.py

@@ -216,11 +216,8 @@ def surface_link_velocity(objects, cfg, flags, fluid_idx, dir, body_id, rx, ry,
     enabled = [obj for obj in objects if obj.surface_actuation is not None]
     if not enabled and not jets:
         return None, None
-    from ..lbm.descriptors import FLUID, SOLID
-    if np.any((flags[fluid_idx] & FLUID) == 0) or np.any(flags[fluid_idx] & SOLID):
-        raise ValueError("Surface cut links must have active fluid receivers")
-    if len(np.unique(fluid_idx.astype(np.uint64)*cfg.nq+dir)) != len(dir):
-        raise ValueError("Surface boundary requires unique cut-link writers")
+    from .preprocess.flag_overlay import validate_cut_link_ownership
+    validate_cut_link_ownership(flags, fluid_idx, dir, cfg.nq)
     surface_velocity = np.zeros((len(dir), 2), np.float32)
     surface_aperture = np.zeros(len(dir), bool)
     for obj in enabled:

src/CelerisLab/body/manager.py

@@ -27,7 +27,7 @@ import pycuda.driver as cuda
 
 from .objects import SimObject
 from .registry import BodyRegistry
-from .preprocess.flag_overlay import merge_flag_masks
+from .preprocess.flag_overlay import merge_flag_masks, validate_cut_link_ownership
 from ..cuda.compiler_v2 import obs_layout
 from ..cuda.obs_layout import ObsLayout
 from ..lbm.descriptors import (
@@ -369,9 +369,9 @@ class ObjectManager:
 
         Args:
             objects: List of SimObject instances to process.
-            domain_flags: Optional uint16 flags for donor-cell classification.
+            domain_flags: Optional uint16 flags for receiver/donor classification.
             sensor_cell_counts_out: Int array to fill with per-object sensor
-                cell counts.  If provided, ``fill(0)`` is called first.
+                cell counts after the full geometry has passed validation.
             hits_out: List that receives one FP64 (n, 2) array of true hit
                 points row-aligned with the cut-link columns (for Jets).
 
@@ -394,8 +394,8 @@ class ObjectManager:
         active_fluid = ((domain_flags & FLUID) != 0) & ((domain_flags & SOLID) == 0)
         force_owners: set[int] = set()
 
-        if sensor_cell_counts_out is not None:
-            sensor_cell_counts_out.fill(0)
+        sensor_counts = (np.zeros_like(sensor_cell_counts_out)
+                         if sensor_cell_counts_out is not None else None)
 
         ez = None
         if self.cfg and self.cfg.is_d3q19:
@@ -430,9 +430,9 @@ class ObjectManager:
                 if len(cells) > 0:
                     s_cells.append(cells)
                     s_ids.append(ids)
-                    if (sensor_cell_counts_out is not None
-                            and 0 <= obj.obj_id < sensor_cell_counts_out.size):
-                        sensor_cell_counts_out[obj.obj_id] = int(len(cells))
+                    if (sensor_counts is not None
+                            and 0 <= obj.obj_id < sensor_counts.size):
+                        sensor_counts[obj.obj_id] = int(len(cells))
             if obj.is_force_region and hasattr(obj, 'get_sensor_list'):
                 cells, ids = obj.get_sensor_list(self.nx, self.ny, self.nz)
                 keep = active_fluid[cells]
@@ -461,8 +461,9 @@ class ObjectManager:
         r_fr_ids = np.concatenate(fr_ids) if fr_ids else np.zeros(0, dtype=np.int32)
 
         r_hit = np.concatenate(cl_hit) if cl_hit else np.zeros((0, 2))
-        if hits_out is not None:
-            hits_out.append(r_hit)
+        # Passive walls need the same ownership guarantees as driven walls.
+        # Overlapping solids are not a supported union-boundary operation.
+        validate_cut_link_ownership(domain_flags, r_idx, r_dir, self.nq)
         if self.jets or any(obj.surface_actuation is not None for obj in objects):
             # Reject unresolved apertures/ownership before sync or restart mutates state.
             from ..lbm.curved_links import CurvedLinkSoA
@@ -470,6 +471,11 @@ class ObjectManager:
             links.assign_host(r_idx, r_dir, r_q, r_bid, r_rx, r_ry, r_rz, r_fallback)
             links.assign_surface(objects, self.cfg, domain_flags, jets=self.jets, hits=r_hit)
 
+        if sensor_cell_counts_out is not None:
+            sensor_cell_counts_out[:] = sensor_counts
+        if hits_out is not None:
+            hits_out.append(r_hit)
+
         return (
             r_idx, r_dir, r_q, r_bid,
             r_rx, r_ry, r_rz, r_fallback,
@@ -487,8 +493,6 @@ class ObjectManager:
                 the caller has already prepared and uploaded the final flag field
                 for this geometry, such as during initialization.
         """
-        self._telemetry_field = field
-
         next_flags = self.build_flags(field.build_channel_flags()) if rebuild_flags else field.flag
         hits = []
 
@@ -499,6 +503,7 @@ class ObjectManager:
             fr_cells, fr_obj_id,
         ) = self.build_compact_lists(domain_flags=next_flags, hits_out=hits)
 
+        self._telemetry_field = field
         if rebuild_flags:
             field.flag = next_flags
             field.upload_flags()

src/CelerisLab/body/preprocess/flag_overlay.py

@@ -1,6 +1,6 @@
 # CelerisLab/body/preprocess/flag_overlay.py
 """
-Flag overlay: merge per-object flag masks onto a clean domain base.
+Flag overlay and cut-link ownership checks against the merged domain.
 """
 
 from __future__ import annotations
@@ -12,6 +12,15 @@ import numpy as np
 from ...lbm.descriptors import FLUID, SOLID, SENSOR_FLAG, FRC_REGION
 
 
+def validate_cut_link_ownership(flags, fluid_idx, directions, nq):
+    """Reject solid receivers and multiple writers to one population."""
+    if np.any((flags[fluid_idx] & FLUID) == 0) or np.any(flags[fluid_idx] & SOLID):
+        raise ValueError("Cut links must have active fluid receivers")
+    writers = fluid_idx.astype(np.uint64) * nq + directions
+    if len(np.unique(writers)) != len(directions):
+        raise ValueError("Boundary requires unique cut-link writers")
+
+
 def merge_flag_masks(
     base: np.ndarray,
     masks: List[np.ndarray],

src/CelerisLab/lbm/kernels/blocks.cu

@@ -168,21 +168,15 @@ extern "C" __global__ void BlockStep(const fpxx* in, fpxx* out, unsigned int hal
         stream_pull_load(k, f, in + base, j);
         if (cell_kind == KIND_ACTIVE) {
             if (d_block_wall.nx != 0) {
-                const unsigned int bx = NX - 2 * halo, by = NY - 2 * halo;
-                const unsigned int nbx = d_block_wall.nx / bx;
-                const unsigned int gx = (blockIdx.z % nbx) * bx + x - halo;
-                const unsigned int gy = (blockIdx.z / nbx) * by + y - halo;
+                unsigned int gx, gy;
+                block_global_xy(x, y, halo, d_block_wall.nx, gx, gy);
                 if (gy == 1)
                     reconstruct_bottom_velocity(f, 0.0f, bottom_wall_normal_velocity(
                         gx, d_block_wall.nx, d_block_wall.slot_width, d_block_wall.amplitude));
                 else if (gy == d_block_wall.ny - 2) reconstruct_top_reservoir(f, RHO);
             }
 #if COLLISION_MODEL == 2
-            // Uniform MRT sequence (collide_dispatch, zero forcing); SRT path below unchanged.
-            float rho, ux, uy;
-            compute_rho_u(f, rho, ux, uy);
-            collide_mrt_no_force(f, rho, ux, uy,
-                fminf(OMEGA_COLLISION_MAX, fmaxf(OMEGA_COLLISION_MIN, d_params.omega)));
+            collide_mrt_unforced(f);  // SRT path below unchanged.
 #else
             float rho, ux, uy, feq[NQ];
             compute_rho_u(f, rho, ux, uy);

src/CelerisLab/lbm/kernels/core/layout.cuh

@@ -53,6 +53,18 @@ __device__ __forceinline__ void index_from_thread(unsigned int& x,
     k = (unsigned long)y * NX + x;
 }
 
+// Global cell of window cell (x, y) in block blockIdx.z of a row-major,
+// full-domain block layout domain_nx cells wide. NX/NY are the local strides.
+__device__ __forceinline__ void block_global_xy(unsigned int x, unsigned int y,
+                                                unsigned int halo, unsigned int domain_nx,
+                                                unsigned int& gx, unsigned int& gy)
+{
+    const unsigned int bx = NX - 2 * halo, by = NY - 2 * halo;
+    const unsigned int nbx = domain_nx / bx;
+    gx = (blockIdx.z % nbx) * bx + x - halo;
+    gy = (blockIdx.z / nbx) * by + y - halo;
+}
+
 // ---------------------------------------------------------------------------
 // Neighbor list (periodic BCs via modular arithmetic)
 // ---------------------------------------------------------------------------

src/CelerisLab/lbm/kernels/operators/collision_mrt.cuh

@@ -114,6 +114,16 @@ __device__ __forceinline__ void collide_mrt_no_force(float* __restrict__ g,
     collide_mrt(g, rho, ux, uy, Fin, omega);
 }
 
+// Unforced MRT with the clamped device omega, as in collide_dispatch with zero
+// forcing. Shared by the blocked, channel-root and dense-patch collisions.
+__device__ __forceinline__ void collide_mrt_unforced(float* __restrict__ g)
+{
+    float rho, ux, uy;
+    compute_rho_u(g, rho, ux, uy);
+    collide_mrt_no_force(g, rho, ux, uy,
+        fminf(OMEGA_COLLISION_MAX, fmaxf(OMEGA_COLLISION_MIN, d_params.omega)));
+}
+
 #elif LATTICE_MODEL == LATTICE_D3Q19
 
 __device__ __forceinline__ void collide_mrt(float* __restrict__ g,

src/CelerisLab/lbm/kernels/refinement.cu

@@ -37,10 +37,7 @@ __device__ unsigned int incoming_counts[NQ * TOTAL_CELLS];
 
 __device__ __forceinline__ void patch_collide(float* f, unsigned long k) {
 #if COLLISION_MODEL == 2
-    float rho, ux, uy;
-    compute_rho_u(f, rho, ux, uy);
-    collide_mrt_no_force(f, rho, ux, uy,
-        fminf(OMEGA_COLLISION_MAX, fmaxf(OMEGA_COLLISION_MIN, d_params.omega)));
+    collide_mrt_unforced(f);
 #else
     float rho, ux, uy, feq[NQ];
     compute_rho_u(f, rho, ux, uy);

src/CelerisLab/lbm/kernels/step/block_channel.cu

@@ -15,10 +15,8 @@ extern "C" __global__ void BlockChannelStep(
     unsigned int x, y; unsigned long k;
     index_from_thread(x, y, k);
     if (x < halo || y < halo || x >= NX - halo || y >= NY - halo) return;
-    const unsigned int bx = NX - 2 * halo, by = NY - 2 * halo;
-    const unsigned int nbx = d_block_channel.nx / bx;
-    const unsigned int gx = (blockIdx.z % nbx) * bx + x - halo;
-    const unsigned int gy = (blockIdx.z / nbx) * by + y - halo;
+    unsigned int gx, gy;
+    block_global_xy(x, y, halo, d_block_channel.nx, gx, gy);
     const unsigned long base = (unsigned long)blockIdx.z * NQ * TOTAL_CELLS;
     const unsigned long cell = (unsigned long)blockIdx.z * TOTAL_CELLS + k;
     float f[NQ];
@@ -55,11 +53,7 @@ extern "C" __global__ void BlockChannelStep(
         }
         if (!wall && !outlet) {
 #if COLLISION_MODEL == 2
-            // Match uniform MRT arithmetic (collide_dispatch, zero forcing).
-            float rho, ux, uy;
-            compute_rho_u(f, rho, ux, uy);
-            collide_mrt_no_force(f, rho, ux, uy,
-                fminf(OMEGA_COLLISION_MAX, fmaxf(OMEGA_COLLISION_MIN, d_params.omega)));
+            collide_mrt_unforced(f);
 #else
             // Match uniform SRT arithmetic, including its shifted equilibrium path.
             float rho, ux, uy, feq[NQ], forcing[NQ] = {};

src/CelerisLab/simulation.py

@@ -336,13 +336,19 @@ class Simulation:
     def read_surface_exchange(self, id: int):
         """Latest step's wall/aperture (Fx,Fy,Tz) exchange, not total nozzle force.
 
+        Supports SurfaceActuation and Jet-driven bodies, including zero-amplitude
+        apertures. Passive bodies without an aperture are rejected.
         Unlike read_body this is not accumulated/time-averaged. It resets after
         geometry sync or checkpoint load; advance before interpreting it.
         """
-        if self.bodies.get(id).surface_actuation is None:
+        obj = self.bodies.get(id)
+        curved = self.field.curved
+        has_aperture = (curved.aperture is not None
+                        and np.any(curved.aperture & (curved.body_id == id)))
+        if obj.surface_actuation is None and not has_aperture:
             raise ValueError("Body has no surface actuation")
         self.stream.synchronize()
-        return self.field.curved.surface_exchange(id)
+        return curved.surface_exchange(id)
 
     @context_bound
     def read_body(self, id: int, *,
@@ -451,18 +457,21 @@ class Simulation:
     @context_bound
     def initialize(self):
         """Initialize flow field and sync objects to GPU."""
-        # Recompile if objects were added after construction.
         self._assert_allocation_contract()
+        # Validate the complete geometry before flags, populations or modules
+        # change. Compact-list construction publishes no outputs on failure.
+        next_flags = self.bodies.build_flags(self.field.build_channel_flags())
+        if self.bodies.jets and self.bodies.count == 0:
+            raise ValueError("Jets need bodies with cut links")
+        self.bodies.build_compact_lists_for(self.bodies.objects, next_flags)
+
+        # Recompile if objects were added after construction.
         if self._read_generated_n_objects() != self.bodies.count:
             self.recompile()
 
-        self.field.flag = self.field.build_channel_flags()
-        if self.bodies.count > 0:
-            self.field.flag = self.bodies.build_flags(self.field.flag)
+        self.field.flag = next_flags
         self.field.upload_flags()
 
-        if self.bodies.jets and self.bodies.count == 0:
-            raise ValueError("Jets need bodies with cut links")
         self.stepper.initialize()
         if self.bodies.count > 0:
             self.bodies.sync_to_gpu(self.field, rebuild_flags=False)

tests/unit/test_dfg_re20.py

@@ -0,0 +1,79 @@
+"""CPU-only contract tests for run_dfg_re20. Not CUDA or DFG acceptance evidence."""
+
+import sys
+from pathlib import Path
+import unittest
+
+sys.path.insert(0, str(Path(__file__).resolve().parents[1] / "validation"))
+import run_dfg_re20 as v  # noqa: E402
+import run_refined_dfg as rr  # noqa: E402
+
+h, _ = rr.helpers(rr.DEFAULT_SOURCE)
+
+
+def rows(values, tstar_end=v.TSTAR_MAX):
+    n = int(round(tstar_end / v.SAMPLE_TSTAR))
+    return [dict(tstar=(i + 1) * v.SAMPLE_TSTAR, **values(i)) for i in range(n)]
+
+
+class Re20Contract(unittest.TestCase):
+    def test_lattice_parameters_and_bounds(self):
+        root, uniform = v.lattice_parameters(40), v.lattice_parameters(80)
+        self.assertAlmostEqual(root["tau"], 0.56, places=12)
+        self.assertAlmostEqual(uniform["tau"], 0.62, places=12)
+        self.assertEqual((root["steps"], root["interval"]), (240000, 2000))
+        self.assertEqual((uniform["steps"], uniform["interval"]), (480000, 4000))
+        self.assertAlmostEqual(v.plan()["refined_fine_tau"], 0.62, places=12)
+
+    def test_config_only_changes_viscosity(self):
+        base = v._re100_config(h, 40, "SRT", "none")
+        cfg, body, p = v.config(h, 40, "SRT")
+        self.assertAlmostEqual(cfg["physics"]["viscosity"], 0.01 * 40 / 20, places=15)
+        self.assertEqual((p["re"], p["viscosity"]), (20.0, cfg["physics"]["viscosity"]))
+        base[0]["physics"]["viscosity"] = cfg["physics"]["viscosity"]
+        self.assertEqual(base[0], cfg)
+        self.assertEqual(base[1], body)
+        with self.assertRaisesRegex(ValueError, "no Jets"):
+            v.config(h, 40, "MRT", "zero")
+
+    def test_units(self):
+        s = v.sample([2.0, -0.5], 4, 40, 3.0)
+        den = rr.SPEED**2 * 40 / 2
+        self.assertAlmostEqual(s["cd"], 2.0 / 4 / den)
+        self.assertAlmostEqual(s["cl"], -0.5 / 4 / den)
+        self.assertAlmostEqual(s["p_diff"], 3.0 * 0.04)
+        self.assertEqual(s["dp_scaled"], 3.0)
+
+    def test_steady_and_verdict(self):
+        inside = dict(cd=5.58, cl=0.0106, p_diff=0.1174)
+        out = v.summarize(rows(lambda i: inside))
+        self.assertEqual((out["status"], out["steady"], out["window_samples"]),
+                         ("WITHIN_INTERVALS", True, 21))
+        self.assertTrue(out["cd_positive"])
+        self.assertAlmostEqual(out["edge_distance"]["cl"], 0.0002)
+        self.assertTrue(all(out["verdict"].values()))
+        low = v.summarize(rows(lambda i: dict(inside, cl=0.0100)))
+        self.assertEqual(low["status"], "OUTSIDE_INTERVALS")
+        self.assertFalse(low["verdict"]["cl"])
+
+    def test_slow_drift_gives_no_verdict(self):
+        # Range 2e-5 passes (limit 6e-5); slope * window 2e-5 exceeds 1.2e-5.
+        out = v.summarize(rows(lambda i: dict(cd=5.58, cl=0.0106 + 1e-6 * i, p_diff=0.1174)))
+        self.assertEqual((out["status"], out["verdict"]), ("NOT_STEADY", None))
+        self.assertLessEqual(out["ranges"]["cl"], out["range_limits"]["cl"])
+        self.assertGreater(out["drifts"]["cl"], out["slope_limits"]["cl"])
+
+    def test_noise_range(self):
+        quiet = v.summarize(rows(lambda i: dict(cd=5.58, cl=0.0106 + 2e-5 * (i % 2), p_diff=0.1174)))
+        self.assertTrue(quiet["steady"])  # within the range limit, no trend
+        noisy = v.summarize(rows(lambda i: dict(cd=5.58, cl=0.0106 + 1e-4 * (i % 2), p_diff=0.1174)))
+        self.assertEqual(noisy["status"], "NOT_STEADY")
+        self.assertGreater(noisy["ranges"]["cl"], noisy["range_limits"]["cl"])
+
+    def test_incomplete_run_gives_no_verdict(self):
+        out = v.summarize(rows(lambda i: dict(cd=5.58, cl=0.0106, p_diff=0.1174), tstar_end=30))
+        self.assertEqual((out["status"], out["verdict"]), ("INCOMPLETE", None))
+
+
+if __name__ == "__main__":
+    unittest.main()

tests/unit/test_jet_circle_cv.py

@@ -16,6 +16,7 @@ from run_jet_circle_cv import (
     case,
     state,
     cv,
+    cv_from_macros,
     aperture_probe,
     measured_aperture_flux,
     verify,
@@ -28,6 +29,39 @@ def eq(rho, u, v):
 
 
 class Host(unittest.TestCase):
+    def test_public_macros_pressure_advection_and_cropped_frames(self):
+        for h, origin, shape, rect in (
+            (.5, (0., 0.), (48, 64), (5., 4., 25., 20.)),
+            (.5, (.25, .5), (48, 64), (5.25, 4., 25.25, 20.)),
+            (.25, (.375, .75), (96, 128), (5.125, 4., 25.125, 20.)),
+        ):
+            y, x = np.indices(shape)
+            x = origin[0] + h * (x + .5)
+            k, u, v = 1e-5, .02, -.01
+            rho = 1 + 3 * k * x  # p=(rho-1)/3=k*x
+            ux, uy, fluid = np.full(shape, u), np.full(shape, v), np.ones(shape, bool)
+            result = cv_from_macros(rho, ux, uy, fluid, origin, rect, .004, h)
+            expected = 320 * np.array([3*k*u, k + 3*k*u*u, 3*k*u*v])
+            np.testing.assert_allclose(result[1], expected, rtol=1e-11, atol=1e-13)
+            np.testing.assert_allclose(result, cv(eq(rho, u, v), fluid, origin, rect, .004, h), atol=1e-12)
+            x0, y0, x1, y1 = np.rint((np.array(rect)-np.tile(origin, 2))/h).astype(int)
+            selection = np.s_[y0-2:y1+2, x0-2:x1+2]
+            cropped_origin = np.asarray(origin) + h*np.array([x0-2, y0-2])
+            cropped = cv_from_macros(rho[selection], ux[selection], uy[selection],
+                                    fluid[selection], cropped_origin, rect, .004, h)
+            np.testing.assert_array_equal(cropped, result)
+
+    def test_public_macros_full_normal_viscous_stress(self):
+        y, x = np.indices((48, 64))
+        x = (x + .5) * .5
+        rho, ux, uy, fluid = np.ones_like(x), 1e-4*x*x, np.zeros_like(x), np.ones(x.shape, bool)
+        args = (rho, ux, uy, fluid, (0., 0.), (5., 4., 25., 20.))
+        _, viscous = cv_from_macros(*args, .004)
+        _, inviscid = cv_from_macros(*args, 0.)
+        np.testing.assert_allclose(viscous-inviscid, [0, -4*.004*1e-4*320, 0], atol=1e-13)
+        with self.assertRaisesRegex(ValueError, "matching 2D"):
+            cv_from_macros(rho, ux, uy[:-1], fluid, (0, 0), (5, 4, 25, 20), .004)
+
     def test_descriptor_and_uniform_closed_flux(self):
         from CelerisLab.lbm.descriptors import D2Q9_EX, D2Q9_EY
 

tests/unit/test_jets.py

@@ -188,6 +188,55 @@ def jet_case(device, jets):
     return field, bodies
 
 
+def test_public_surface_exchange_for_jet_preserves_aperture_at_zero_and_reverse(device):
+    from CelerisLab.simulation import Simulation
+    jet = Jet(Sector(CENTER, 0., .6, 3.), Radial(CENTER, inward=False), "quartic", 2e-3)
+    field, bodies = jet_case(device, [jet])
+    sim = SimpleNamespace(bodies=bodies, field=field, _initialized=True,
+                          stream=SimpleNamespace(synchronize=device.synchronize))
+    cl = field.curved
+    assert bodies.get(0).surface_actuation is None
+    aperture, velocity = cl.aperture, cl.surface_velocity.copy()
+    assert aperture.any() and (~aperture).any()
+    # Synthetic per-link exchanges test readback/splitting, not kernel physics.
+    values = np.arange(cl.count * 3, dtype=np.float32).reshape(-1, 3)
+    device.htod(cl.link_exchange_gpu, values)
+    for amplitude in (2e-3, 0., -1e-3):
+        Simulation.set_jet_amplitude(sim, 0, amplitude)
+        result = Simulation.read_surface_exchange(sim, 0)
+        assert cl.aperture is aperture
+        np.testing.assert_array_equal(aperture, cl.jet_id >= 0)
+        np.testing.assert_allclose(cl.surface_velocity, velocity * (amplitude / 2e-3))
+        for name, mask in (("wall", ~aperture), ("aperture", aperture)):
+            np.testing.assert_array_equal(result[name], values[mask].sum(axis=0, dtype=np.float64))
+
+
+def test_public_surface_exchange_keeps_legacy_and_passive_guards(device):
+    from CelerisLab.simulation import Simulation
+    field = make_field(device)
+    bodies = manager(field, [circle(SurfaceActuation(0., .6, .002), radius=2.)])
+    bodies.sync_to_gpu(field)
+    sim = SimpleNamespace(bodies=bodies, field=field,
+                          stream=SimpleNamespace(synchronize=device.synchronize))
+    for value in Simulation.read_surface_exchange(sim, 0).values():
+        np.testing.assert_array_equal(value, 0.)
+    field.curved.free_gpu_columns()
+    with pytest.raises(RuntimeError, match="diagnostic is allocated"):
+        Simulation.read_surface_exchange(sim, 0)
+
+    # An exchange buffer elsewhere in the scene must not admit a passive body.
+    for jets in ([], [Jet(Sector(CENTER, 0., .6, 3.), Radial(CENTER))]):
+        field, bodies = jet_case(device, jets)
+        passive = bodies.add(circle(center=(2., 3.), radius=.6))
+        bodies.sync_to_gpu(field)
+        sim.bodies, sim.field = bodies, field
+        with pytest.raises(ValueError, match="Body has no surface actuation"):
+            Simulation.read_surface_exchange(sim, passive)
+        if not jets:
+            with pytest.raises(ValueError, match="Body has no surface actuation"):
+                Simulation.read_surface_exchange(sim, 0)
+
+
 def test_manager_passes_true_hits_and_reuploads_only_velocity(device):
     # CPU memory double only: checks host/device bookkeeping, not GPU numerics.
     jet = Jet(Sector(CENTER, 0., .6, 3.), Radial(CENTER, inward=False), "quartic", 2e-3)

tests/unit/test_refined_dfg.py

@@ -146,23 +146,26 @@ def test_full_requires_completed_pilot():
         r.verify_pilot(None, r.verify_source(r.DEFAULT_SOURCE, "MRT", "window"))
 
 
-def pilot_fixture(path, observation_mode="window"):
+def pilot_fixture(path, observation_mode="window", jet_scenario="none", case_selection="both", uniform_diameter=80, placement="wide"):
     """Synthetic contract fixture only; never a physical result or run receipt."""
-    manifest = (r.verify_source(r.DEFAULT_SOURCE, "MRT", "window")
+    manifest = (r.verify_source(r.DEFAULT_SOURCE, "MRT", "window", jet_scenario)
                 if observation_mode == "window" else
                 json.loads((r.HERE / "data/refined_dfg/source_manifest_mrt.json").read_text()))
+    selection = dict(case_selection=case_selection, uniform_diameter=uniform_diameter, placement=placement)
     (path / "plan.json").write_text(
         json.dumps(
             dict(
                 source_manifest=manifest,
+                **selection,
                 collision="MRT",
+                jet_scenario=jet_scenario,
                 observation_mode=observation_mode,
-                bounds_root_edge=list(r.BOUNDS),
+                bounds_root_edge=list(r.PLACEMENTS[placement]),
                 runner_sha256=r.runner_hash(),
             )
         )
     )
-    for case, diameter in (("uniform", 80), ("refined", 40)):
+    for case, diameter in r.selected_cases(case_selection, uniform_diameter):
         dest = path / case
         dest.mkdir()
         interval = round(0.02 * diameter / r.SPEED)
@@ -189,7 +192,9 @@ def pilot_fixture(path, observation_mode="window"):
             json.dumps(
                 dict(
                     case=case,
+                    **selection,
                     collision="MRT",
+                    jet_scenario=jet_scenario,
                     observation_mode=observation_mode,
                     mode="pilot",
                     status="pilot_complete",
@@ -206,7 +211,9 @@ def pilot_fixture(path, observation_mode="window"):
             json.dumps(
                 dict(
                     case=case,
+                    **selection,
                     collision="MRT",
+                    jet_scenario=jet_scenario,
                     observation_mode=observation_mode,
                     mode="pilot",
                     step=interval,
@@ -451,6 +458,169 @@ def test_window_contract_rejection():
     assert not backend.events
 
 
+def test_public_jet_configuration_and_geometry():
+    for diameter, center, radius in ((40, (80.5, 81), 20), (80, (160, 160.5), 40)):
+        cfg, _, _ = r.config(h, diameter, "MRT", "fixed")
+        assert not cfg["method"]["ddf_shifting"] and not cfg["method"]["les"]["enabled"]
+        jets = r.public_jets(center, radius, "fixed")
+        assert [j.amplitude for j in jets] == [.001, -.001]
+        assert all(j.field.inward is False and j.profile == "parabolic" for j in jets)
+        assert all(j.region.r_max == radius * 1.005 for j in jets)
+        assert all(j.amplitude == 0 for j in r.public_jets(center, radius, "zero"))
+    cfg, _, _, host = r.host_geometry(r.DEFAULT_SOURCE, h, "MRT", "fixed")
+    assert not cfg.ddf_shifting and len(host.boundary_cells) > 0
+    assert r.public_jets((0, 0), 1, "none") == ()
+    with unittest.TestCase().assertRaises(ValueError):
+        r.config(h, 40, "SRT", "fixed")
+
+
+def test_public_jet_reversal_boundary_and_windows():
+    from types import SimpleNamespace
+
+    calls = []
+    handle = SimpleNamespace(set_jet_amplitude=lambda i, a: calls.append((i, a)))
+    for diameter in (40, 80):
+        boundary = round(250 * diameter / r.SPEED)
+        assert r.jet_interval(handle, "fixed", boundary - 3, 80, diameter) == (3, None)
+        switch = round(300 * diameter / r.SPEED)
+        assert r.jet_interval(handle, "reverse", switch - 3, 80, diameter) == (3, None)
+        assert not calls
+        n, event = r.jet_interval(handle, "reverse", switch, 80, diameter)
+        assert n == 80 and event["step"] == switch and event["tstar"] == 300
+        assert calls == [(0, -.001), (1, .001)]
+        calls.clear()
+        assert r.jet_interval(handle, "reverse", switch + 80, 80, diameter) == (80, None)
+        assert r.jet_interval(handle, "fixed", switch, 80, diameter) == (80, None)
+        assert not calls
+    rows = [dict(tstar=t, tstar_force=t - .5, cd=2.0, cl=-.1) for t in range(251, 306)]
+    windows = r.jet_diagnostics(rows, "reverse")
+    assert len(windows) == 6 and all(w["complete"] for w in windows)
+    assert all(w["cd"]["mean"] == 2 and np.isclose(w["cl"]["mean"], -.1) for w in windows)
+    assert windows[-1]["covered_tstar"] == 5
+    with unittest.TestCase().assertRaisesRegex(ValueError, "crosses"):
+        r.jet_diagnostics([dict(tstar=250.5, tstar_force=250, cd=1, cl=0)], "fixed")
+    assert r.plan(h, "MRT", "window", "reverse")["modes"]["full_tstar"] == 305
+
+
+def test_public_jet_source_and_pilot_separation():
+    from tempfile import TemporaryDirectory
+
+    with TemporaryDirectory() as tmp:
+        path = Path(tmp)
+        manifest = pilot_fixture(path, jet_scenario="fixed")
+        assert manifest["source_capture"].startswith("current checkout")
+        assert len(manifest["checkout_revision"]) == 40
+        assert r.verify_pilot(path, manifest, "MRT", "window", "fixed") == 3606.0
+        for scenario in ("none", "zero", "reverse"):
+            with unittest.TestCase().assertRaisesRegex(ValueError, "Jet scenario"):
+                r.verify_pilot(path, manifest, "MRT", "window", scenario)
+        for relative in ("uniform/summary.json", "refined/ready.json"):
+            receipt = path / relative
+            record = json.loads(receipt.read_text())
+            receipt.write_text(json.dumps(dict(record, jet_scenario="zero")))
+            with unittest.TestCase().assertRaises(ValueError):
+                r.verify_pilot(path, manifest, "MRT", "window", "fixed")
+            receipt.write_text(json.dumps(record))
+    with unittest.TestCase().assertRaises(ValueError):
+        r.verify_source(r.DEFAULT_SOURCE, "MRT", "last_base_step", "fixed")
+
+
+def test_cv_snapshot_common_units_and_window_endpoints():
+    records = []
+    for refined, shape, origin, diameter, impulse in (
+        (True, (240, 568), (38., 22.), 40, [4., -8.]),
+        (False, (330, 1761), (.25, .5), 80, [16., -32.]),
+        (False, (658, 3521), (.375, .75), 160, [64., -128.]),
+    ):
+        rho, ux, uy, fluid = np.ones(shape), np.full(shape, .01), np.zeros(shape), np.ones(shape, bool)
+        begin, n = round(290*diameter/r.SPEED), round(.02*diameter/r.SPEED)
+        record = r.cv_snapshot(rho, ux, uy, fluid, origin, refined, begin, n, diameter, impulse)
+        records.append(record)
+        np.testing.assert_allclose(record["outward_flux"], 0, atol=1e-12)
+        assert r.cv_selected(begin, diameter, "full") and not r.cv_selected(begin-n, diameter, "full")
+        end = round(300*diameter/r.SPEED)
+        assert r.cv_selected(end, diameter, "full") and not r.cv_selected(end+n, diameter, "full")
+        assert r.cv_selected(n, diameter, "pilot")
+        assert sum(r.cv_selected(step, diameter, "full") for step in range(begin-n, end+n+1, n)) == 501
+    for key in ("time_root", "interval_start_root", "interval_dt_root", "interval_impulse_root", "inventory"):
+        for record in records[1:]:
+            np.testing.assert_allclose(records[0][key], record[key], rtol=0, atol=1e-10)
+    assert records[0]["interval_dt_root"] == 80 and np.isclose(records[0]["tstar"], 290.02)
+    np.testing.assert_array_equal(records[0]["interval_impulse_root"], [4, -8])
+
+
+def test_cv_pilot_mode_and_helper_provenance():
+    from tempfile import TemporaryDirectory
+
+    manifest = r.verify_source(r.DEFAULT_SOURCE, "MRT", "window", "fixed", True)
+    assert "tests/validation/run_jet_circle_cv.py" in manifest["sha256"]
+    with TemporaryDirectory() as tmp:
+        path = Path(tmp)
+        old = pilot_fixture(path, jet_scenario="fixed")
+        with unittest.TestCase().assertRaisesRegex(ValueError, "CV observation mode"):
+            r.verify_pilot(path, old, "MRT", "window", "fixed", True)
+        for relative in ("plan.json", "uniform/summary.json", "refined/summary.json",
+                         "uniform/ready.json", "refined/ready.json"):
+            file = path / relative
+            record = json.loads(file.read_text())
+            record.update(observe_cv=True, cv_samples=250)
+            if relative == "plan.json":
+                record["source_manifest"] = manifest
+            file.write_text(json.dumps(record))
+        assert r.verify_pilot(path, manifest, "MRT", "window", "fixed", True) == 3606
+
+
+def test_compact_geometry_and_cv_stencils():
+    from CelerisLab.lbm.refinement import ACTIVE
+    from CelerisLab.lbm.descriptors import SOLID
+
+    _, pair, _, host = r.host_geometry(r.DEFAULT_SOURCE, h, "MRT", "fixed", "compact")
+    assert pair.fine_shape == (168, 168) and tuple(pair.fine_origin) == (46, 46)
+    fluid = (pair.fine_kind == ACTIVE) & ((host.flags.reshape(pair.fine_shape) & SOLID) == 0)
+    rho, ux, uy = np.ones(pair.fine_shape), np.full(pair.fine_shape, .01), np.zeros(pair.fine_shape)
+    record = r.cv_snapshot(rho, ux, uy, fluid, pair.fine_origin, True, 1160000, 80, 40, [1, 2], "compact")
+    np.testing.assert_allclose(record["outward_flux"], 0, atol=1e-12)
+    stencil = np.zeros(pair.fine_shape, bool)
+    for rect in r.cv_contours(True, 40, "compact"):
+        x0, y0, x1, y1 = np.rint((rect - np.tile(pair.fine_origin, 2))/.5).astype(int)
+        stencil[y0-2:y1+2, x0-2:x0+2] = stencil[y0-2:y1+2, x1-2:x1+2] = True
+        stencil[y0-2:y0+2, x0-2:x1+2] = stencil[y1-2:y1+2, x0-2:x1+2] = True
+    assert fluid[stencil].all() and not stencil.ravel()[host.transfer_fine_cells].any()
+
+
+def test_d160_config_and_single_case_receipts():
+    from tempfile import TemporaryDirectory
+    from unittest.mock import patch
+
+    cfg, _, p = r.config(h, 160, "MRT", "fixed")
+    assert (p["nx"], p["ny"], p["center"], p["radius"]) == (3521, 658, [320, 320.5], 80)
+    assert p["viscosity"] == .016 and p["mean_speed"] == .01 and not cfg["method"]["ddf_shifting"]
+    assert r.uniform_origin(160) == (.375, .75)
+    np.testing.assert_array_equal(r.cv_contours(False, 160), r.CV_CONTOURS + [.125, 0, .125, 0])
+    for scenario, expected_exit in (("fixed", 0), ("zero", 2)):
+        with TemporaryDirectory() as tmp:
+            path = Path(tmp)
+            manifest = pilot_fixture(path, jet_scenario=scenario, case_selection="uniform", uniform_diameter=160)
+            assert r.verify_pilot(path, manifest, "MRT", "window", scenario, False, "uniform", 160) == 1803
+            for selection, diameter, placement in (("both", 160, "wide"), ("uniform", 80, "wide"), ("uniform", 160, "compact")):
+                with unittest.TestCase().assertRaises(ValueError):
+                    r.verify_pilot(path, manifest, "MRT", "window", scenario, False, selection, diameter, placement)
+            # Synthetic dispatch/result check: no CUDA imports or execution.
+            output = path / "full"
+            argv = ["runner", "--collision", "MRT", "--exchange-window", "--jet-scenario", scenario,
+                    "--case", "uniform", "--uniform-diameter", "160", "--mode", "full",
+                    "--pilot-results", str(path), "--output", str(output), "--max-wall-seconds", "10", "--gpu-gates-approved"]
+            result = dict(case="uniform", healthy=True, periodic=scenario == "zero", jet_diagnostic_windows=[],
+                          status="driven_diagnostics_complete" if scenario == "fixed" else "periodic",
+                          reference_comparison=dict(reference_agreement=False))
+            with patch.object(sys, "argv", argv), patch.dict(r.os.environ, CUDA_VISIBLE_DEVICES="mock-no-gpu"), \
+                    patch.object(r, "run_case", return_value=result) as run:
+                assert r.main() == expected_exit and run.call_count == 1
+            comparison = json.loads((output / "comparison.json").read_text())
+            assert comparison["matched_case_pass"] is False and "refined_vs_uniform" not in comparison
+            assert comparison["status"].startswith("single_case_")
+
+
 if __name__ == "__main__":
     suite = unittest.TestSuite(
         unittest.FunctionTestCase(fn)

tests/unit/test_refinement_mrt.py

@@ -37,8 +37,13 @@ class RefinementMRTHost(unittest.TestCase):
             self.assertIn("STORE_PRECISION != 0", source)
             self.assertIn('#if COLLISION_MODEL == 2\n#include "operators/collision_mrt.cuh"\n#endif', source)
         self.assertIn("USE_DDF_SHIFTING ||", refinement)  # dense/mixed shifted stays rejected
+        # One shared unforced MRT body; each blocked/patch path calls it exactly once.
+        mrt = (KERNELS / "operators/collision_mrt.cuh").read_text()
+        self.assertEqual(mrt.count("void collide_mrt_unforced("), 1)
         for source in (blocks, channel, refinement):
-            self.assertEqual(source.count("collide_mrt_no_force("), 1)
+            self.assertEqual(source.count("collide_mrt_unforced(f);"), 1)
+            self.assertNotIn("collide_mrt_no_force(", source)
+            self.assertNotIn("compute_rho_u(f, rho, ux, uy);\n            collide_mrt", source)
 
 
 if __name__ == "__main__": unittest.main()

tests/unit/test_state_regressions.py

@@ -238,6 +238,81 @@ def test_overlapping_force_regions_rejected(device):
         bodies.build_compact_lists(bodies.build_flags(field.flag))
 
 
+@pytest.mark.parametrize("second_x,error", [(14., "unique cut-link writers"),
+                                           (17., "active fluid receivers")])
+def test_passive_overlap_rejected_before_publishing_lists(second_x, error):
+    cfg = LBMConfig(nx=32, ny=24)
+    cfg.validate()
+    bodies = ObjectManager(cfg.nx, cfg.ny, cfg.nz, cfg.nq, cfg)
+    for x in (14., second_x):
+        bodies.add(obj(x=x, y=12., r=4.3))
+    bodies.add(obj(x=4., y=4., r=2., is_sensor=True))
+    counts = np.full(bodies.count, 91, np.int32)
+    hits = []
+    flags = bodies.build_flags(np.full(cfg.nx * cfg.ny, FLUID, np.uint16))
+    for domain_flags in (flags, None):
+        with pytest.raises(ValueError, match=error):
+            bodies.build_compact_lists_for(bodies.objects, domain_flags,
+                                          sensor_cell_counts_out=counts, hits_out=hits)
+        np.testing.assert_array_equal(counts, 91)
+        assert hits == []
+
+
+@pytest.mark.parametrize("centers", [((10., 12.), (22., 12.)),
+                                    ((10.5, 12.), (19.5, 12.))])
+def test_separated_passive_bodies_keep_valid_writers(centers):
+    # The second case has a subcell physical gap with a resolved fluid column.
+    cfg = LBMConfig(nx=32, ny=24)
+    cfg.validate()
+    bodies = ObjectManager(cfg.nx, cfg.ny, cfg.nz, cfg.nq, cfg)
+    for x, y in centers:
+        bodies.add(obj(x=x, y=y, r=4.3))
+    flags = bodies.build_flags(np.full(cfg.nx * cfg.ny, FLUID, np.uint16))
+    indices, directions, _, ids, *_ = bodies.build_compact_lists(flags)
+    assert set(ids) == {0, 1}
+    assert np.all(flags[indices] & FLUID) and not np.any(flags[indices] & SOLID)
+    assert len(np.unique(indices.astype(np.uint64) * cfg.nq + directions)) == len(indices)
+
+
+@pytest.mark.parametrize("entry", ["sync", "initialize", "runtime_edit"])
+@pytest.mark.parametrize("second_x", [5., 6.])
+def test_passive_overlap_failure_keeps_live_state(device, entry, second_x):
+    from CelerisLab.simulation import Simulation
+    field = make_field(device)
+    bodies = manager(field, [obj(), obj(x=9., y=3., r=1., is_sensor=True)])
+    bodies.sync_to_gpu(field)
+    overlapping = obj(x=second_x)
+    if entry == "runtime_edit":
+        bodies.stage_add(overlapping)
+    else:
+        bodies.add(overlapping)
+    objects = bodies.objects
+    flags, curved, counts = field.flag.copy(), field.curved.fluid_idx.copy(), bodies.sensor_cell_counts.copy()
+    action = bodies.action.copy()
+    buffers = [(block, bytes(block.data), block.freed) for block in device.blocks]
+    writes = device.writes
+    sim = SimpleNamespace(bodies=bodies, field=field, lbm_cfg=field.cfg,
+                          _initialized=entry == "runtime_edit",
+                          _assert_allocation_contract=lambda: None,
+                          stream=SimpleNamespace(synchronize=device.synchronize))
+    with pytest.raises(ValueError, match="active fluid receivers|unique cut-link writers"):
+        if entry == "sync":
+            bodies.sync_to_gpu(field)
+        elif entry == "initialize":
+            Simulation.initialize(sim)
+        else:
+            Simulation.sync_bodies(sim)
+    assert bodies.objects == objects
+    assert bodies.has_pending_edit() == (entry == "runtime_edit")
+    assert sim._initialized == (entry == "runtime_edit")
+    assert device.writes == writes and len(device.blocks) == len(buffers)
+    assert all(bytes(block.data) == data and block.freed == freed for block, data, freed in buffers)
+    np.testing.assert_array_equal(field.flag, flags)
+    np.testing.assert_array_equal(field.curved.fluid_idx, curved)
+    np.testing.assert_array_equal(bodies.sensor_cell_counts, counts)
+    np.testing.assert_array_equal(bodies.action, action)
+
+
 def test_action_upload_and_scratch_are_pinned(device):
     field = make_field(device, streaming="esopull")
     bodies = manager(field, [obj(is_force_region=True)])

tests/validation/multigrid/test_refinement_three_level.py

@@ -80,11 +80,12 @@ class ThreeLevelCPU(unittest.TestCase):
         f, g = run._levels[1:]
         b = g.boundary
         events, feeds = [], []
-        advance, gather = run._advance_child, run._gather_halo
-        def record_feed(buffer, **kw):
-            self.assertIs(buffer, (f.current, f.spare)[len(feeds)])
-            feeds.append(buffer)
-            advance(buffer, **kw)
+        advance, gather = run._advance, run._gather_halo
+        def record_feed(index, buffer, **kw):  # index 2: L1 hop feeds L2
+            if index == 2:
+                self.assertIs(buffer, (f.current, f.spare)[len(feeds)])
+                feeds.append(buffer)
+            advance(index, buffer, **kw)
         def record_halo(level, buffer, **kw):
             if level is g:
                 events.append(("halo", buffer))
@@ -95,7 +96,7 @@ class ThreeLevelCPU(unittest.TestCase):
             self.assertIs(kind, g.kind)
             events.append(("step", src))
         g.kernel.side_effect = record_step
-        with patch.object(run, "_advance_child", side_effect=record_feed), \
+        with patch.object(run, "_advance", side_effect=record_feed), \
                 patch.object(run, "_gather_halo", side_effect=record_halo):
             run.step()
         self.assertEqual(feeds, [f.current, f.spare])
@@ -105,8 +106,8 @@ class ThreeLevelCPU(unittest.TestCase):
         self.assertGreater(len(np.unique(b.tables["block"])), 1)
         # Negative control: reusing L1's old source at the midpoint must fail.
         feeds.clear()
-        with patch.object(run, "_advance_child", side_effect=lambda buffer, **kw:
-                          record_feed(f.current, **kw)):
+        with patch.object(run, "_advance", side_effect=lambda index, buffer, **kw:
+                          record_feed(index, f.current if index == 2 else buffer, **kw)):
             with self.assertRaises(AssertionError):
                 run.step()
         run.close()
@@ -172,11 +173,12 @@ class ThreeLevelGPU(unittest.TestCase):
             p1, p2 = run.patch, run.child_patch
             run.initialize(state(16, 16, 1), state(*p1.fine_shape, 2), state(*p2.fine_shape, 3))
             f = run._levels[1]
-            feeds, original = [], run._advance_child
-            def record(buffer, **kw):
-                feeds.append(int(buffer))
-                original(buffer, **kw)
-            with patch.object(run, "_advance_child", side_effect=record):
+            feeds, original = [], run._advance
+            def record(index, buffer, **kw):  # index 2: L1 hop feeds L2
+                if index == 2:
+                    feeds.append(int(buffer))
+                original(index, buffer, **kw)
+            with patch.object(run, "_advance", side_effect=record):
                 cur, spare = int(f.current), int(f.spare)
                 run.step(1)
             self.assertEqual(feeds, [cur, spare])  # current G, then the new G of hop 1

tests/validation/run_dfg_re20.py

@@ -0,0 +1,222 @@
+"""Steady DFG 2D-1 (Re 20): refined and uniform runs against the official reference intervals.
+
+Not a full benchmark certification. Declared deviations from the official setup:
+pressure-NEQ outlet (``neq_extrap``) instead of do-nothing, local Zou-He inlet.
+Geometry, inflow profile, initial state, refined layout and observation reuse the
+pinned Re100 runner (``run_refined_dfg``) and ``re100_helpers`` unchanged; only the
+lattice viscosity is set for Re 20 (nu = U_lattice * D / 20 at the root level).
+
+Units. The helpers use scaled DFG units with mean inflow speed 1, so
+Cd = 2 Fx / (rho U^2 D) and Cl = 2 Fy / (rho U^2 D) are scale-free, and
+``pressure_probes`` returns dp / (rho U^2). The official p_diff = p(0.15, 0.2) -
+p(0.25, 0.2) uses U = 0.2 m/s, rho = 1, so p_diff = dp * 0.04. Both are reported;
+only p_diff is compared with the official interval. Forces use the existing sign
+convention: F is the force of the fluid on the cylinder, i.e. the refined raw
+exchange impulse (window ledger, ``total.impulse``) or the uniform ``read_force``,
+with x along the inflow and y up from the bottom wall. Cd must be positive, and the
+official Cl is positive (centre 0.20 below the centreline 0.205), so a flipped sign
+shows up as Cl outside its interval.
+
+Sampling. One sample every SAMPLE_TSTAR (t* = U t / D; 0.25 s), taken at the end of
+a completed root step with all levels synchronized; the step index is recorded. Cd
+and Cl are means over the sample interval (window exchange ledger refined, per-batch
+forces uniform), which filters acoustic and step-parity oscillation; p_diff is the
+end-of-interval value at the exact surface points.
+
+Steady rule (our engineering choice, frozen before any run; not official). Over the
+trailing WINDOW_TSTAR (t* 50..60 inclusive, 21 samples), for each of Cd, Cl and
+p_diff: range (max - min) <= 10 % and |least-squares slope * window| <= 2 % of the
+width of its official interval. Absolute limits, so the small Cl is never a divisor;
+the slope term bounds slow monotone drift that the range alone would pass. If the
+rule fails at TSTAR_MAX the run reports "not steady" and gives no interval verdict;
+limits are never relaxed after a run. The verdict uses the window mean, and the
+distance of each mean to its nearest interval edge is reported (negative outside).
+"""
+
+import argparse
+import json
+import math
+import os
+from pathlib import Path
+import sys
+import time
+from tempfile import TemporaryDirectory
+
+import numpy as np
+
+HERE = Path(__file__).resolve().parent
+sys.path.insert(0, str(HERE))
+import run_refined_dfg as rr  # noqa: E402
+
+RE = 20.0
+U_PHYS = 0.2                   # m/s mean inflow; rho = 1
+TSTAR_MAX = 60.0               # 30 s physical
+SAMPLE_TSTAR = 0.5             # 0.25 s
+WINDOW_TSTAR = 10.0            # trailing 5 s, 21 samples
+# Schaefer & Turek (1996), 2D-1 lower/upper bounds.
+BANDS = dict(cd=(5.57, 5.59), cl=(0.0104, 0.0110), p_diff=(0.1172, 0.1176))
+STEADY_RANGE = {k: (hi - lo) / 10 for k, (lo, hi) in BANDS.items()}
+STEADY_SLOPE = {k: (hi - lo) / 50 for k, (lo, hi) in BANDS.items()}
+DEVIATIONS = ("pressure-NEQ outlet (neq_extrap), not do-nothing", "local Zou-He inlet")
+
+_re100_config = rr.config
+
+
+def config(h, diameter, collision="SRT", jet_scenario="none"):
+    """The pinned Re100 configuration with the lattice viscosity set for Re 20."""
+    if jet_scenario != "none":
+        raise ValueError("DFG 2D-1 runs have no Jets")
+    cfg, body, p = _re100_config(h, diameter, collision, jet_scenario)
+    nu = p["mean_speed"] * p["diameter"] / RE
+    cfg["physics"]["viscosity"] = nu
+    return cfg, body, dict(p, viscosity=nu, re=RE)
+
+
+def lattice_parameters(diameter, speed=rr.SPEED):
+    nu = speed * diameter / RE
+    return dict(viscosity=nu, tau=0.5 + 3 * nu, steps=math.ceil(TSTAR_MAX * diameter / speed),
+                interval=round(SAMPLE_TSTAR * diameter / speed))
+
+
+def sample(impulse, n, diameter, dp):
+    den = rr.SPEED**2 * diameter / 2
+    return dict(cd=float(impulse[0] / n / den), cl=float(impulse[1] / n / den),
+                dp_scaled=float(dp), p_diff=float(dp) * U_PHYS**2)
+
+
+def summarize(rows):
+    """Steady rule over the trailing window, then the interval verdict (or none)."""
+    if not rows or rows[-1]["tstar"] < TSTAR_MAX - 1e-9:
+        return dict(status="INCOMPLETE", steady=False, verdict=None)
+    window = [r for r in rows if r["tstar"] >= TSTAR_MAX - WINDOW_TSTAR - 1e-9]
+    t = np.array([r["tstar"] for r in window])
+    ranges = {k: max(r[k] for r in window) - min(r[k] for r in window) for k in BANDS}
+    drifts = {k: abs(np.polyfit(t, [r[k] for r in window], 1)[0]) * WINDOW_TSTAR for k in BANDS}
+    steady = all(ranges[k] <= STEADY_RANGE[k] and drifts[k] <= STEADY_SLOPE[k] for k in BANDS)
+    final = {k: float(np.mean([r[k] for r in window])) for k in BANDS}
+    edge = {k: min(final[k] - BANDS[k][0], BANDS[k][1] - final[k]) for k in BANDS}
+    result = dict(window_samples=len(window), ranges=ranges, drifts=drifts,
+                  range_limits=STEADY_RANGE, slope_limits=STEADY_SLOPE, steady=steady,
+                  window_mean=final, edge_distance=edge, bands=BANDS,
+                  deviations=DEVIATIONS, cd_positive=final["cd"] > 0)
+    if not steady:
+        return dict(result, status="NOT_STEADY", verdict=None)
+    inside = {k: BANDS[k][0] <= final[k] <= BANDS[k][1] for k in BANDS}
+    return dict(result, status="WITHIN_INTERVALS" if all(inside.values()) else "OUTSIDE_INTERVALS",
+                verdict=inside)
+
+
+def healthy(row):
+    return row["max_mach"] <= 0.2 and row["rho_min"] >= 0.5 and row["rho_max"] <= 1.5
+
+
+def run_case(a, h, case):
+    from contextlib import ExitStack
+    from CelerisLab.cuda.context import CudaContext
+    from CelerisLab.lbm.descriptors import FLUID
+    from CelerisLab.lbm.refinement_stepper import FixedPatchStepper
+    from CelerisLab.simulation import Simulation
+
+    refined = case == "refined"
+    cfgdict, bodydict, p = config(h, 40 if refined else 80, a.collision)
+    lp = lattice_parameters(p["diameter"])
+    rows = []
+    with ExitStack() as stack:
+        if refined:
+            cfg, pair, body, host = rr.host_geometry(a.source, h, a.collision)
+            context = stack.enter_context(CudaContext(0))
+            backend = stack.enter_context(FixedPatchStepper(
+                cfg, rr.PLACEMENTS["wide"], context=context, coarse_boundary="channel",
+                base_block=rr.BASE_BLOCK, fine_block=rr.FINE_BLOCK, fine_objects=(body,),
+                observe_raw_exchange=True, observe_window_exchange=True))
+            from CelerisLab.lbm.channel import channel_masks
+            from CelerisLab.lbm.refinement import ACTIVE
+            from CelerisLab.lbm.descriptors import SOLID
+            masks = [channel_masks(pair.coarse_shape)[0] & ~pair.covered,
+                     (pair.fine_kind == ACTIVE)
+                     & ((host.flags.reshape(pair.fine_shape) & SOLID) == 0)]
+            backend.initialize(rr.initial_state(pair.coarse_shape, (0.0, 0.0), 1.0, root=True),
+                               rr.initial_state(pair.fine_shape, pair.fine_origin, 0.5))
+            probe_p = dict(p, center=[(80.5 - pair.fine_origin[0]) / 0.5 - 0.5,
+                                      (81.0 - pair.fine_origin[1]) / 0.5 - 0.5], radius=40.0)
+        else:
+            tmp = Path(stack.enter_context(TemporaryDirectory()))
+            (tmp / "lbm.json").write_text(json.dumps(cfgdict))
+            (tmp / "body.json").write_text(json.dumps(bodydict))
+            sim = stack.enter_context(Simulation(str(tmp / "lbm.json"), str(tmp / "body.json"),
+                                                 device_id=0))
+            sim.initialize()
+            probe_p = p
+            fluid = (sim.field.flag.reshape(p["ny"], p["nx"]) & FLUID) != 0
+        begin = 0
+        while begin < lp["steps"]:
+            rr.check_deadline(a.deadline)
+            n = min(lp["interval"], lp["steps"] - begin)
+            if refined:
+                impulse = rr.advance_refined_interval(backend, n, a.deadline, "window")
+                fields = [rr.macros(g) for g in backend.download()]
+                rho, ux, uy = fields[1]
+                fluid = masks[1]
+                vals = [tuple(v[m] for v in f) for m, f in zip(masks, fields)]
+            else:
+                impulse, done = np.zeros(2), 0
+                while done < n:
+                    batch = min(100, n - done)
+                    sim.run(batch)
+                    impulse += sim.read_force(0).astype(np.float64) * batch
+                    done += batch
+                m = sim.get_macroscopic()
+                rho, ux, uy = [np.asarray(m[k], np.float64).reshape(p["ny"], p["nx"])
+                               for k in ("rho", "ux", "uy")]
+                vals = [(rho[fluid], ux[fluid], uy[fluid])]
+            begin += n
+            row = dict(step=begin, tstar=begin * rr.SPEED / p["diameter"],
+                       **sample(impulse, n, p["diameter"],
+                                h.pressure_probes(rho, fluid, probe_p)["dp"]),
+                       rho_min=float(min(v[0].min() for v in vals)),
+                       rho_max=float(max(v[0].max() for v in vals)),
+                       max_mach=float(max(np.sqrt(3 * (v[1]**2 + v[2]**2)).max() for v in vals)))
+            rr.ensure_finite(row)
+            rows.append(row)
+            if not healthy(row):
+                break
+    summary = summarize(rows) if healthy(rows[-1]) else dict(status="UNHEALTHY", steady=False,
+                                                             verdict=None)
+    return dict(case=case, collision=a.collision, lattice=lp, rows=rows, **summary)
+
+
+def plan(collision="SRT"):
+    return dict(re=RE, collision=collision, tstar_max=TSTAR_MAX, sample_tstar=SAMPLE_TSTAR,
+                window_tstar=WINDOW_TSTAR, bands=BANDS, range_limits=STEADY_RANGE, slope_limits=STEADY_SLOPE,
+                deviations=DEVIATIONS, pressure_scale=U_PHYS**2,
+                refined_root=lattice_parameters(40), refined_fine_tau=0.5 + 3 * 2 * rr.SPEED * 40 / RE,
+                uniform=lattice_parameters(80),
+                label="compared against the official reference bands (non-canonical neq_extrap outlet, zou_he_local inlet); not a full benchmark certification")
+
+
+def main():
+    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
+    parser.add_argument("--case", choices=["refined", "uniform", "both"], default="refined")
+    parser.add_argument("--collision", choices=["SRT", "MRT"], default="SRT")
+    parser.add_argument("--source", type=Path, default=rr.DEFAULT_SOURCE)
+    parser.add_argument("--output", type=Path, required=True)
+    parser.add_argument("--plan", action="store_true", help="Write the frozen plan; no CUDA")
+    parser.add_argument("--max-wall-seconds", type=float)
+    a = parser.parse_args()
+    a.source = a.source.resolve()
+    a.output.mkdir(parents=True, exist_ok=False)
+    (a.output / "plan.json").write_text(json.dumps(plan(a.collision), indent=2, allow_nan=False))
+    if a.plan:
+        return
+    if not a.max_wall_seconds or a.max_wall_seconds <= 0 or not os.environ.get("CUDA_VISIBLE_DEVICES"):
+        raise SystemExit("GPU run needs --max-wall-seconds > 0 and explicit CUDA_VISIBLE_DEVICES")
+    h, _ = rr.helpers(a.source)
+    rr.config = config  # host_geometry builds its root configuration through this name
+    a.deadline = time.monotonic() + a.max_wall_seconds
+    cases = ["refined", "uniform"] if a.case == "both" else [a.case]
+    results = [run_case(a, h, case) for case in cases]
+    (a.output / "result.json").write_text(json.dumps(results, indent=2, allow_nan=False))
+
+
+if __name__ == "__main__":
+    main()

tests/validation/run_jet_circle_cv.py

@@ -74,7 +74,25 @@ def cv(g, fluid, origin, rectangle, nu, h=0.5):
     Cauchy stress from centred velocity gradients, NOT postcollision non-equilibrium.
     Rectangle faces lie on cell edges; fluid mask excludes the staircase cylinder.
     """
-    rho, mom, vel = moments(g)
+    return _cv_quantities(*moments(g), fluid, origin, rectangle, nu, h)
+
+
+def cv_from_macros(rho, ux, uy, fluid, origin, rectangle, nu, h=0.5):
+    """Same CV calculation from public macros, in one common length/time frame.
+
+    ``origin`` is the lower cell edge, ``h`` the cell width, and ``nu`` uses
+    that frame. Returns [mass, Px, Py] inventory and outward total flux.
+    Crop fields/mask together and translate origin before calling if desired.
+    No boundary-exchange observation enters this independent estimator.
+    """
+    rho = np.asarray(rho, np.float64)
+    if rho.ndim != 2 or any(np.shape(v) != rho.shape for v in (ux, uy, fluid)):
+        raise ValueError("CV macros and fluid mask must have matching 2D shapes")
+    vel = np.asarray([ux, uy], np.float64)
+    return _cv_quantities(rho, rho[None] * vel, vel, fluid, origin, rectangle, nu, h)
+
+
+def _cv_quantities(rho, mom, vel, fluid, origin, rectangle, nu, h):
     x0, y0, x1, y1 = np.rint((np.array(rectangle) - np.tile(origin, 2)) / h).astype(int)
     np.testing.assert_allclose(
         np.array([x0, y0, x1, y1]) * h + np.tile(origin, 2), rectangle, atol=1e-12

tests/validation/run_refined_dfg.py

@@ -17,8 +17,109 @@ HERE = Path(__file__).resolve().parent
 DEFAULT_SOURCE = HERE.parents[1]
 BOUNDS = (40, 24, 320, 140)
 BASE_BLOCK = (2, 881)  # Exact 166 x 881 domain; no geometric padding.
-FINE_BLOCK = (8, 8)  # 240 x 568 including four fine halo cells.
+FINE_BLOCK = (8, 8)  # Wide 240 x 568 or compact 168 x 168, including fine halos.
 SPEED = 0.01
+JET_PEAK = 0.001
+JET_WINDOWS = [(t, t + 10) for t in range(250, 300, 10)]
+CV_CONTOURS = np.array([(48., 44., 160., 120.), (44., 36., 180., 128.)])
+PLACEMENTS = {"wide": BOUNDS, "compact": (48, 48, 128, 128)}
+COMPACT_CV_CONTOURS = np.array([(52., 52., 112., 112.), (50., 50., 120., 120.)])
+
+
+def selected_cases(selection="both", uniform_diameter=80):
+    return [(case, diameter) for case, diameter in (("uniform", uniform_diameter), ("refined", 40))
+            if selection in ("both", case)]
+
+
+def uniform_origin(diameter):
+    h = 40 / diameter
+    return (.5 - .5*h, 1 - h)
+
+
+def cv_contours(refined, diameter, placement="wide"):
+    contours = CV_CONTOURS if placement == "wide" else COMPACT_CV_CONTOURS
+    return contours if refined else contours + [20/diameter, 0., 20/diameter, 0.]
+
+
+def cv_selected(step, diameter, mode):
+    return mode == "pilot" or round(290 * diameter / SPEED) <= step <= round(300 * diameter / SPEED)
+
+
+def cv_snapshot(rho, ux, uy, fluid, origin, refined, begin, n, diameter, impulse, placement="wide"):
+    """Cropped public macros only; all inventories, fluxes and impulses use root units."""
+    from run_jet_circle_cv import cv_from_macros
+
+    rectangles = cv_contours(refined, diameter, placement)
+    h_cell = .5 if refined else 40 / diameter
+    origin = np.asarray(origin, dtype=float)
+    x0, y0, x1, y1 = np.rint((rectangles[-1] - np.tile(origin, 2)) / h_cell).astype(int)
+    selection = np.s_[y0-2:y1+2, x0-2:x1+2]
+    cropped_origin = origin + h_cell * np.array([x0-2, y0-2])
+    fields = [v[selection] for v in (rho, ux, uy, fluid)]
+    values = [cv_from_macros(*fields, cropped_origin, rect, .004, h=h_cell)
+              for rect in rectangles]
+    h_native = 1.0 if refined else 40 / diameter
+    return dict(step=begin+n, tstar=(begin+n)*SPEED/diameter,
+                time_root=(begin+n)*h_native, interval_start_root=begin*h_native,
+                interval_dt_root=n*h_native,
+                interval_impulse_root=(np.asarray(impulse)*h_native**2).tolist(),
+                inventory=[inventory.tolist() for inventory, _ in values],
+                outward_flux=[flux.tolist() for _, flux in values])
+
+
+def public_jets(center, radius, scenario):
+    """Same physical apertures; caller supplies its public geometry frame."""
+    if scenario == "none":
+        return ()
+    from CelerisLab.body.jets import Jet, Sector, Radial
+
+    peak = 0.0 if scenario == "zero" else JET_PEAK
+    return tuple(
+        Jet(Sector(center, angle, math.pi / 12, radius * 1.005),
+            Radial(center, inward=False), "parabolic", amplitude)
+        for angle, amplitude in ((math.pi / 2, peak), (3 * math.pi / 2, -peak))
+    )
+
+
+def jet_interval(handle, scenario, begin, n, diameter):
+    """Apply a reversal only at a completed interval boundary, before advancing."""
+    if scenario != "none":
+        boundaries = [round(t * diameter / SPEED) for t in (250, 260, 270, 280, 290, 300, 305)]
+        n = min([n] + [step - begin for step in boundaries if step > begin])
+    if scenario != "reverse":
+        return n, None
+    switch = round(300 * diameter / SPEED)
+    if begin < switch:
+        return min(n, switch - begin), None
+    if begin == switch:
+        handle.set_jet_amplitude(0, -JET_PEAK)
+        handle.set_jet_amplitude(1, JET_PEAK)
+        return n, dict(step=begin, tstar=300.0, amplitudes=[-JET_PEAK, JET_PEAK])
+    return n, None
+
+
+def jet_diagnostics(rows, scenario):
+    """Raw interval-weighted diagnostics only; no driven-flow qualification gate."""
+    windows = JET_WINDOWS + ([(300, 305)] if scenario == "reverse" else [])
+    result = []
+    for start, end in windows:
+        selected = [r for r in rows if start <= r["tstar_force"] < end]
+        if not selected:
+            continue
+        if any(2 * r["tstar_force"] - r["tstar"] < start - 1e-9
+               or r["tstar"] > end + 1e-9 for r in selected):
+            raise ValueError("Jet diagnostic interval crosses a window boundary")
+        weights = np.array([2 * (r["tstar"] - r["tstar_force"]) for r in selected])
+        record = dict(start_tstar=start, end_tstar=end, samples=len(selected),
+                      covered_tstar=float(weights.sum()),
+                      complete=bool(np.isclose(weights.sum(), end - start, rtol=0, atol=1e-9)))
+        for key in ("cd", "cl"):
+            values = np.array([r[key] for r in selected])
+            record[key] = dict(mean=float(np.average(values, weights=weights)),
+                               min=float(values.min()), max=float(values.max()),
+                               rms=float(np.sqrt(np.average(values**2, weights=weights))))
+        result.append(record)
+    return result
 
 
 def helpers(source):
@@ -39,26 +140,34 @@ def helpers(source):
     return h, periodic
 
 
-def config(h, diameter, collision="SRT"):
+def config(h, diameter, collision="SRT", jet_scenario="none"):
     cfg, body, p = h.make_config(diameter, SPEED, collision, "neq_extrap", "zou_he_local")
     cfg["method"]["outlet"]["srt_neq_damp"] = 0.5
+    if jet_scenario != "none":
+        if collision != "MRT":
+            raise ValueError("Public Jet scenarios require MRT")
+        cfg["method"]["ddf_shifting"] = False
     return cfg, body, p
 
 
-def plan(h, collision="SRT", observation_mode="last_base_step"):
-    _, _, c = config(h, 40, collision)
-    _, _, f = config(h, 80, collision)
-    x0, y0, x1, y1 = BOUNDS
+def plan(h, collision="SRT", observation_mode="last_base_step", jet_scenario="none", uniform_diameter=80, placement="wide"):
+    _, _, c = config(h, 40, collision, jet_scenario)
+    _, _, f = config(h, uniform_diameter, collision, jet_scenario)
+    bounds = PLACEMENTS[placement]
+    x0, y0, x1, y1 = bounds
     fine_active = 4 * (x1 - x0) * (y1 - y0)
     coarse_uncovered = c["nx"] * c["ny"] - fine_active // 4
     return dict(
         status="prepared_not_run",
         collision=collision,
+        jet_scenario=jet_scenario,
+        ddf_shifting=jet_scenario == "none",
         observation_mode=observation_mode,
         root_gpu_gates_required=True,
         root=c,
         uniform=f,
-        bounds_root_edge=list(BOUNDS),
+        bounds_root_edge=list(bounds),
+        fine_origin_root_edge=[x0 - 2, y0 - 2],
         physical_patch_m=[
             (x0 - 0.5) * c["dx"],
             (y0 - 1) * c["dx"],
@@ -78,19 +187,31 @@ def plan(h, collision="SRT", observation_mode="last_base_step"):
         physical_viscosity_m2_s=0.001,
         finest_dx_m=f["dx"],
         finest_dt_s=f["dt"],
+        refined_finest_dx_m=c["dx"]/2,
+        refined_finest_dt_s=c["dt"]/2,
         approximate_leaf_cell_ratio=(coarse_uncovered + fine_active)
         / (f["nx"] * f["ny"]),
         approximate_collision_work_ratio=(coarse_uncovered + 2 * fine_active)
-        / (2 * f["nx"] * f["ny"]),
+        / ((uniform_diameter/40) * f["nx"] * f["ny"]),
         cost_caveat="Geometry-only estimates include ghosts/solids; exclude block halos, transfers, observation and launch overhead. Not measured speedup.",
-        sampling_offset="For origin (38,22), fine physical x=(j+75.5)*dx80 versus uniform i*dx80: half-fine-cell x offset. Fine physical y=(k+42.5)*dx80 equals uniform (l-.5)*dx80 at l=k+43: y samples align. Body, wall and source planes coincide.",
+        sampling_offset="Uniform nodes map to root edges X=.5+i*(40/D), Y=1+(j-.5)*(40/D). Refined centers are fine_origin_root_edge+(index+.5)*.5. Body, wall and source planes coincide; compare observables, not pointwise arrays.",
         outlet=(
             "SRT pressure NEQ, all nine fneq damped by .5, no backflow clamp; noncanonical DFG outlet"
             if collision == "SRT" else
             "MRT pressure NEQ, unknowns q2/6/8 extrapolated; no backflow clamp; noncanonical DFG outlet"
         ),
-        modes={"pilot_tstar": 5.0, "full_tstar": 300.0},
+        modes={"pilot_tstar": 5.0, "full_tstar": 305.0 if jet_scenario == "reverse" else 300.0},
         observation_dense_tstar=0.02,
+        **(dict(jets=dict(
+            uniform_origin_node=f["center"], refined_origin_root_edge=[80.5, 81.0],
+            angles_rad=[math.pi / 2, 3 * math.pi / 2], half_width_rad=math.pi / 12,
+            radial_extent_over_radius=[0.0, 1.005],
+            field="Radial(outward)", profile="parabolic", condition="velocity",
+            initial_amplitudes=[0.0, 0.0] if jet_scenario == "zero" else [JET_PEAK, -JET_PEAK],
+            reversal_tstar=300.0 if jet_scenario == "reverse" else None,
+            diagnostic_windows_tstar=JET_WINDOWS + ([(300, 305)] if jet_scenario == "reverse" else []),
+            transfer="constant", driven_qualification="not assessed",
+        )) if jet_scenario != "none" else {}),
     )
 
 
@@ -126,7 +247,7 @@ def initial_state(shape, origin, spacing, height=164.0, speed=SPEED, root=False)
     return w * (1 + 3 * cu + 4.5 * cu * cu - 1.5 * velocity * velocity)
 
 
-def host_geometry(source, h, collision="SRT"):
+def host_geometry(source, h, collision="SRT", jet_scenario="none", placement="wide"):
     """Production donor/transfer and complete cut-link checks, without CUDA."""
     from CelerisLab.config import load_lbm_config
     from CelerisLab.lbm.refinement import FixedPatch2D, prepare_fine_boundary
@@ -139,12 +260,12 @@ def host_geometry(source, h, collision="SRT"):
     from CelerisLab.body.geometry.circle import CircleGeometry
     from CelerisLab.body.objects import SimObject
 
-    cfgdict, _, _ = config(h, 40, collision)
+    cfgdict, _, _ = config(h, 40, collision, jet_scenario)
     with TemporaryDirectory() as tmp:
         p = Path(tmp) / "cfg.json"
         p.write_text(json.dumps(cfgdict))
         cfg = load_lbm_config(str(p))
-    pair = FixedPatch2D.from_config(cfg, BOUNDS)
+    pair = FixedPatch2D.from_config(cfg, PLACEMENTS[placement])
     layout = BlockLayout2D.build(cfg.ny, cfg.nx, *BASE_BLOCK)
     validate_channel_config(cfg, [BASE_BLOCK, FINE_BLOCK])
     targets = blocked_base_tables(pair, layout, np.argsort(pair.coalesce_coarse))[1]
@@ -153,18 +274,41 @@ def host_geometry(source, h, collision="SRT"):
     body = SimObject(
         0, geometry=CircleGeometry(80.5, 81.0, 20.0), center=(80.5, 81.0), radius=20.0
     )
-    host = prepare_fine_boundary(cfg, pair, (body,), _shifted_blocked=True)
+    host = prepare_fine_boundary(
+        cfg, pair, (body,), jets=public_jets((80.5, 81.0), 20.0, jet_scenario),
+        _shifted_blocked=jet_scenario == "none",
+    )
     return cfg, pair, body, host
 
 
-def verify_source(source, collision="SRT", observation_mode="last_base_step"):
+def verify_source(source, collision="SRT", observation_mode="last_base_step", jet_scenario="none", observe_cv=False):
     if collision not in ("SRT", "MRT"):
         raise ValueError("Matched collision must be SRT or MRT")
     if observation_mode not in ("last_base_step", "window"):
         raise ValueError("Unknown refined observation mode")
+    if observe_cv and jet_scenario == "none":
+        raise ValueError("--observe-cv requires an explicit public Jet scenario")
     name = ("source_manifest_window.json" if observation_mode == "window" else
             "source_manifest.json" if collision == "SRT" else "source_manifest_mrt.json")
     expected = json.loads((HERE / "data/refined_dfg" / name).read_text())
+    if jet_scenario != "none":
+        if collision != "MRT" or observation_mode != "window":
+            raise ValueError("Public Jet scenarios require MRT and --exchange-window")
+        import subprocess
+        sys.path.insert(0, str(HERE))
+        from source_provenance import checkout_provenance
+
+        paths = set(expected["sha256"])
+        if observe_cv:
+            paths.add("tests/validation/run_jet_circle_cv.py")
+        paths.update(subprocess.check_output(
+            ["git", "-C", str(source), "ls-files", "src"], text=True).splitlines())
+        return dict(
+            source_capture="current checkout, not historical DFG qualification",
+            **checkout_provenance(source), observation_mode=observation_mode,
+            sha256={name: hashlib.sha256((source / name).read_bytes()).hexdigest()
+                    for name in sorted(paths)},
+        )
     for name, digest in expected["sha256"].items():
         if hashlib.sha256((source / name).read_bytes()).hexdigest() != digest:
             raise RuntimeError("Source mismatch: " + name)
@@ -219,29 +363,33 @@ def run_case(a, h, periodic, case):
     from contextlib import ExitStack
 
     refined = case == "refined"
-    cfgdict, bodydict, p = config(h, 40 if refined else 80, a.collision)
-    cap = 5.0 if a.mode == "pilot" else 300.0
+    cfgdict, bodydict, p = config(h, 40 if refined else a.uniform_diameter, a.collision, a.jet_scenario)
+    cap = 5.0 if a.mode == "pilot" else (305.0 if a.jet_scenario == "reverse" else 300.0)
     max_steps = math.ceil(cap * p["diameter"] / SPEED)
     rows = []
     healthy = True
     step_seconds = 0.0
+    cv_seconds, cv_samples = 0.0, 0
+    amplitude_changes = []
     started = time.monotonic()
     check_deadline(a.deadline)
     dest = a.output / case
     dest.mkdir()
     with ExitStack() as stack:
+        cv_out = stack.enter_context((dest / "cv_history.jsonl").open("w")) if a.observe_cv else None
         if refined:
-            cfg, pair, body, host = host_geometry(a.source, h, a.collision)
+            cfg, pair, body, host = host_geometry(a.source, h, a.collision, a.jet_scenario, a.placement)
             context = stack.enter_context(CudaContext(0))
             backend = stack.enter_context(
                 FixedPatchStepper(
                     cfg,
-                    BOUNDS,
+                    PLACEMENTS[a.placement],
                     context=context,
                     coarse_boundary="channel",
                     base_block=BASE_BLOCK,
                     fine_block=FINE_BLOCK,
                     fine_objects=(body,),
+                    jets=public_jets((80.5, 81.0), 20.0, a.jet_scenario),
                     observe_raw_exchange=True,
                     **({"observe_window_exchange": True} if a.observation_mode == "window" else {}),
                 )
@@ -274,6 +422,9 @@ def run_case(a, h, periodic, case):
             sim = stack.enter_context(
                 Simulation(str(tmp / "lbm.json"), str(tmp / "body.json"), device_id=0)
             )
+            for index, jet in enumerate(public_jets(p["center"], p["radius"], a.jet_scenario)):
+                if sim.add_jet(jet) != index:
+                    raise RuntimeError("Unexpected public Jet registration index")
             sim.initialize()
             probe_p = p
             fluid = (sim.field.flag.reshape(p["ny"], p["nx"]) & FLUID) != 0
@@ -290,6 +441,10 @@ def run_case(a, h, periodic, case):
                     else 0.5
                 )
                 n = min(max(1, round(width * p["diameter"] / SPEED)), max_steps - begin)
+                n, change = jet_interval(backend if refined else sim, a.jet_scenario,
+                                         begin, n, p["diameter"])
+                if change is not None:
+                    amplitude_changes.append(change)
                 impulse = np.zeros(2)
                 tick = time.monotonic()
                 if refined:
@@ -359,6 +514,19 @@ def run_case(a, h, periodic, case):
                     / SPEED,
                     **h.pressure_probes(rho, fluid, probe_p),
                 )
+                if a.jet_scenario != "none":
+                    row.update(step_start=begin, tstar_start=begin * SPEED / p["diameter"],
+                               interval_steps=n, impulse_x=float(impulse[0]),
+                               impulse_y=float(impulse[1]))
+                if a.observe_cv and cv_selected(begin+n, p["diameter"], a.mode):
+                    tick = time.monotonic()
+                    record = cv_snapshot(rho, ux, uy, fluid,
+                                         pair.fine_origin if refined else uniform_origin(p["diameter"]),
+                                         refined, begin, n, p["diameter"], impulse, a.placement)
+                    cv_out.write(json.dumps(record, allow_nan=False) + "\n")
+                    cv_out.flush()
+                    cv_samples += 1
+                    cv_seconds += time.monotonic() - tick
                 check_deadline(a.deadline)
                 ensure_finite(row)
                 rows.append(row)
@@ -402,14 +570,24 @@ def run_case(a, h, periodic, case):
         steps=begin,
         startup_seconds=startup,
         step_seconds=step_seconds,
+        observation_and_overhead_seconds=time.monotonic() - started - startup - step_seconds,
         wall_seconds=time.monotonic() - started,
         force="raw stationary-body link momentum reaction, per-unit-depth; average over entire observation interval; normalized in each base lattice",
         mass_units="rho_reference * m^2 per unit depth",
         flux_units="rho_reference * m^2/s per unit depth",
         pressure="postcollision end-sample; physical pressure difference / (rho_reference * 1 m/s squared)",
         suite_validated=False,
-        **periodic.assess(rows),
+        **(periodic.assess(rows) if a.jet_scenario in ("none", "zero") else
+           dict(periodic=False, checks={}, cycles=[])),
     )
+    if a.jet_scenario != "none":
+        result.update(jet_diagnostic_windows=jet_diagnostics(rows, a.jet_scenario),
+                      amplitude_changes=amplitude_changes,
+                      pressure_classification=("DFG reference verdict retained, including pressure"
+                          if a.jet_scenario == "zero" else "diagnostic only; no official DFG reference gate"))
+    if a.observe_cv:
+        result.update(cv_observation_seconds=cv_seconds, cv_samples=cv_samples,
+                      cv_qualification="not assessed; scalar observations only")
     if not healthy:
         result["periodic"] = False
     reference = json.loads(
@@ -425,7 +603,8 @@ def run_case(a, h, periodic, case):
         else (
             "pilot_complete"
             if a.mode == "pilot"
-            else ("periodic" if result["periodic"] else "incomplete_periodicity")
+            else ("driven_diagnostics_complete" if a.jet_scenario in ("fixed", "reverse") else
+                  "periodic" if result["periodic"] else "incomplete_periodicity")
         )
     )
     (dest / "summary.json").write_text(json.dumps(result, indent=2, allow_nan=False))
@@ -464,27 +643,39 @@ def check_deadline(deadline):
         )
 
 
-def verify_pilot(path, manifest, collision="SRT", observation_mode="last_base_step"):
+def verify_pilot(path, manifest, collision="SRT", observation_mode="last_base_step", jet_scenario="none", observe_cv=False,
+                 case_selection="both", uniform_diameter=80, placement="wide"):
     if path is None:
         raise ValueError(
             "Full comparison requires --pilot-results from a completed matched pilot"
         )
     previous = read_finite_json(path / "plan.json")
+    options = dict(case_selection=(case_selection, "both"), uniform_diameter=(uniform_diameter, 80), placement=(placement, "wide"))
+    if any(previous.get(k, default) != expected for k, (expected, default) in options.items()):
+        raise ValueError("Pilot case, resolution or placement differs")
+    if previous.get("observe_cv", False) != observe_cv:
+        raise ValueError("Pilot CV observation mode differs")
+    if previous.get("jet_scenario", "none") != jet_scenario:
+        raise ValueError("Pilot Jet scenario differs")
     if previous.get("observation_mode") != observation_mode:
         raise ValueError("Pilot observation mode differs")
     if previous.get("collision") != collision:
         raise ValueError("Pilot collision differs")
     if previous["source_manifest"] != manifest or previous["bounds_root_edge"] != list(
-        BOUNDS
+        PLACEMENTS[placement]
     ):
         raise ValueError("Pilot source or frozen geometry differs")
     if previous.get("runner_sha256") != runner_hash():
         raise ValueError("Pilot runner differs")
     calibrated_seconds = 0.0
-    for case, diameter in (("uniform", 80), ("refined", 40)):
+    for case, diameter in selected_cases(case_selection, uniform_diameter):
         summary = read_finite_json(path / case / "summary.json")
         if (
-            summary.get("observation_mode") != observation_mode
+            any(summary.get(k, default) != expected for k, (expected, default) in options.items())
+            or summary.get("observe_cv", False) != observe_cv
+            or (observe_cv and summary.get("cv_samples") != 250)
+            or summary.get("jet_scenario", "none") != jet_scenario
+            or summary.get("observation_mode") != observation_mode
             or summary.get("collision") != collision
             or summary.get("case") != case
             or summary.get("mode") != "pilot"
@@ -537,7 +728,10 @@ def verify_pilot(path, manifest, collision="SRT", observation_mode="last_base_st
                 raise ValueError("Unhealthy pilot observations")
         ready = read_finite_json(path / case / "ready.json")
         if (
-            ready.get("observation_mode") != observation_mode
+            any(ready.get(k, default) != expected for k, (expected, default) in options.items())
+            or ready.get("observe_cv", False) != observe_cv
+            or ready.get("jet_scenario", "none") != jet_scenario
+            or ready.get("observation_mode") != observation_mode
             or ready.get("collision") != collision
             or ready.get("case") != case
             or ready.get("mode") != "pilot"
@@ -555,9 +749,9 @@ def verify_pilot(path, manifest, collision="SRT", observation_mode="last_base_st
             or not 0 < stepping <= wall
         ):
             raise ValueError("Invalid pilot calibration timings")
-        # Full physical duration is 60 times pilot; dense pilot sampling makes
+        # Full duration is 60 (or 61 with reversal) times pilot; dense sampling makes
         # this conservative for the sparser early full observations. Not a guarantee.
-        calibrated_seconds += startup + 60 * (wall - startup)
+        calibrated_seconds += startup + (61 if jet_scenario == "reverse" else 60) * (wall - startup)
     return 3 * calibrated_seconds
 
 
@@ -566,6 +760,13 @@ def main():
     parser.add_argument("--exchange-window", action="store_true",
                         help="Opt in to refined window-ledger observations on the pinned candidate")
     parser.add_argument("--collision", choices=["SRT", "MRT"], default="SRT")
+    parser.add_argument("--case", choices=["both", "uniform", "refined"], default="both")
+    parser.add_argument("--uniform-diameter", type=int, choices=[80, 160], default=80)
+    parser.add_argument("--placement", choices=list(PLACEMENTS), default="wide")
+    parser.add_argument("--jet-scenario", choices=["none", "zero", "fixed", "reverse"],
+                        default="none", help="Opt in to public unshifted MRT Jets; reverse switches at t*=300 and ends at 305")
+    parser.add_argument("--observe-cv", action="store_true",
+                        help="Record independent cropped-macro CV samples during pilot or full t*=290..300")
     parser.add_argument("--source", type=Path, default=DEFAULT_SOURCE)
     parser.add_argument("--output", type=Path, required=True)
     parser.add_argument("--mode", choices=["plan", "pilot", "full"], default="plan")
@@ -577,15 +778,26 @@ def main():
         help="Required explicit campaign wall-time ceiling for GPU execution",
     )
     a = parser.parse_args()
+    if a.uniform_diameter == 160 and a.case != "uniform":
+        raise ValueError("D160 requires --case uniform; no matched-resolution claim")
+    if a.placement == "compact" and a.case != "refined":
+        raise ValueError("Compact placement requires --case refined")
+    if (a.uniform_diameter != 80 or a.placement != "wide") and a.jet_scenario == "none":
+        raise ValueError("Resolution/placement variants require an explicit public Jet scenario")
     a.source = a.source.resolve()
     a.observation_mode = "window" if a.exchange_window else "last_base_step"
-    manifest = verify_source(a.source, a.collision, a.observation_mode)
+    manifest = verify_source(a.source, a.collision, a.observation_mode, a.jet_scenario, a.observe_cv)
     h, periodic = helpers(a.source)
     from source_provenance import checkout_provenance
 
     a.provenance = checkout_provenance(a.source)
+    a.provenance.update(jet_scenario=a.jet_scenario, ddf_shifting=a.jet_scenario == "none")
+    a.provenance.update(case_selection=a.case, uniform_diameter=a.uniform_diameter, placement=a.placement)
+    if a.observe_cv:
+        a.provenance["observe_cv"] = True
     calibration = (
-        verify_pilot(a.pilot_results, manifest, a.collision, a.observation_mode)
+        verify_pilot(a.pilot_results, manifest, a.collision, a.observation_mode, a.jet_scenario, a.observe_cv,
+                     a.case, a.uniform_diameter, a.placement)
         if a.mode == "full" else None
     )
     if a.mode != "plan" and (
@@ -602,17 +814,31 @@ def main():
     if a.output.exists() and any(a.output.iterdir()):
         raise ValueError("Output must be empty/new")
     a.output.mkdir(parents=True, exist_ok=True)
-    specification = plan(h, a.collision, a.observation_mode)
+    specification = plan(h, a.collision, a.observation_mode, a.jet_scenario, a.uniform_diameter, a.placement)
     specification.update(
         source_manifest=manifest,
         **a.provenance,
-        gates=periodic.GATES,
-        reference_gates=periodic.REFERENCE_GATES,
+        gates=periodic.GATES if a.jet_scenario in ("none", "zero") else None,
+        reference_gates=periodic.REFERENCE_GATES if a.jet_scenario in ("none", "zero") else None,
         runner_sha256=runner_hash(),
         wall_time_budget_seconds=budget,
         full_pilot_calibration_seconds=calibration,
     )
-    host_geometry(a.source, h, a.collision)
+    if a.observe_cv:
+        specification["cv_observation"] = dict(
+            full_tstar=[290, 300], pilot_tstar=[.02, 5], spacing_tstar=.02,
+            refined_contours_root=cv_contours(True, 40, a.placement).tolist(),
+            uniform_contours_root=cv_contours(False, a.uniform_diameter, a.placement).tolist(),
+            uniform_grid_origin_root=uniform_origin(a.uniform_diameter),
+            refined_grid_origin_root=specification["fine_origin_root_edge"],
+            cell_width_root={"uniform": 40/a.uniform_diameter, "refined": .5},
+            viscosity_root=.004, components=["mass", "Px", "Py"],
+            units="root lattice per unit depth; outward flux per root time",
+            interval="Impulse belongs to the interval ending at each snapshot; first retained endpoint (pilot .02, full 290) supplies initial inventory only: exclude its preceding impulse",
+            qualification="not assessed; trapezoidal integration and time-coarsening are offline",
+        )
+    if a.case != "uniform":
+        host_geometry(a.source, h, a.collision, a.jet_scenario, a.placement)
     (a.output / "plan.json").write_text(json.dumps(specification, indent=2))
     if a.mode == "plan":
         return 0
@@ -621,8 +847,9 @@ def main():
             "GPU execution blocked: root GPU gates approval and explicit device selection required"
         )
     results = []
+    cases = selected_cases(a.case, a.uniform_diameter)
     a.deadline = time.monotonic() + budget
-    for case in ("uniform", "refined"):
+    for case, _ in cases:
         try:
             result = run_case(a, h, periodic, case)
         except TimeoutError as exc:
@@ -650,7 +877,12 @@ def main():
         status="pilot_only" if a.mode == "pilot" else "incomplete",
         matched_case_pass=False,
     )
-    if len(results) == 2 and all(r["healthy"] and r["periodic"] for r in results):
+    if a.jet_scenario in ("fixed", "reverse"):
+        comparison.update(status=("pilot_only" if a.mode == "pilot" else "driven_diagnostics_complete")
+                          if len(results) == len(cases) and all(r["healthy"] for r in results) else "invalid_state",
+                          qualification="not assessed; execution completion is not physical acceptance",
+                          jet_diagnostic_windows={r["case"]: r["jet_diagnostic_windows"] for r in results})
+    if a.case == "both" and len(results) == 2 and all(r["healthy"] and r["periodic"] for r in results):
         comparison.update(
             status="periodic_comparison",
             refined_vs_uniform=periodic.compare(
@@ -660,14 +892,20 @@ def main():
         comparison["matched_case_pass"] = comparison["refined_vs_uniform"][
             "reference_agreement"
         ]
+    if a.case != "both":
+        comparison.update(status="single_case_" + results[0]["status"],
+                          own_reference_comparison=results[0].get("reference_comparison"))
     (a.output / "comparison.json").write_text(
         json.dumps(comparison, indent=2, allow_nan=False)
     )
     return (
         0
-        if len(results) == 2
+        if len(results) == len(cases)
         and all(r["healthy"] for r in results)
-        and (a.mode == "pilot" or comparison["matched_case_pass"])
+        and (a.mode == "pilot" or comparison["matched_case_pass"]
+             or a.jet_scenario in ("fixed", "reverse")
+             or (a.case != "both" and results[0]["periodic"]
+                 and results[0].get("reference_comparison", {}).get("reference_agreement", False)))
         else 2
     )