feat(runtime): freeze initial placement inbound admission

src/AcDream.Runtime/Entities/InboundPhysicsStateController.cs

@@ -20,13 +20,35 @@ public sealed class InboundPhysicsStateController
     public bool TryGetSnapshot(uint guid, out WorldSession.EntitySpawn spawn) =>
         _snapshots.TryGetValue(guid, out spawn);
 
+    internal bool TryGetAcceptedTimestamps(
+        uint guid,
+        out AcceptedPhysicsTimestamps timestamps)
+    {
+        if (_gates.TryGetValue(guid, out PhysicsTimestampGate? gate))
+        {
+            timestamps = Current(gate);
+            return true;
+        }
+        timestamps = default;
+        return false;
+    }
+
     public CreateObjectTimestampDisposition PreviewCreateDisposition(
         WorldSession.EntitySpawn incoming) =>
         _gates.TryGetValue(incoming.Guid, out PhysicsTimestampGate? gate)
             ? gate.PreviewCreateObject(incoming.InstanceSequence)
             : CreateObjectTimestampDisposition.InitialGeneration;
 
-    public InboundCreateResult AcceptCreate(WorldSession.EntitySpawn incoming)
+    public InboundCreateResult AcceptCreate(WorldSession.EntitySpawn incoming) =>
+        AcceptCreateCore(incoming, deferSameGenerationWeenieDescription: false);
+
+    internal InboundCreateResult AcceptCreateDeferredSameGeneration(
+        WorldSession.EntitySpawn incoming) =>
+        AcceptCreateCore(incoming, deferSameGenerationWeenieDescription: true);
+
+    private InboundCreateResult AcceptCreateCore(
+        WorldSession.EntitySpawn incoming,
+        bool deferSameGenerationWeenieDescription)
     {
         if (!_gates.TryGetValue(incoming.Guid, out PhysicsTimestampGate? gate))
         {
@@ -56,8 +78,11 @@ public sealed class InboundPhysicsStateController
             return new InboundCreateResult(disposition, incoming, null, Current(gate));
         }
 
-        WorldSession.EntitySpawn merged = MergeUntimestampedCreate(retained, incoming);
-        _snapshots[incoming.Guid] = merged;
+        WorldSession.EntitySpawn merged = deferSameGenerationWeenieDescription
+            ? retained
+            : MergeUntimestampedCreate(retained, incoming);
+        if (!deferSameGenerationWeenieDescription)
+            _snapshots[incoming.Guid] = merged;
         return new InboundCreateResult(
             disposition,
             merged,
@@ -422,6 +447,181 @@ public sealed class InboundPhysicsStateController
         return true;
     }
 
+    /// <summary>
+    /// Consumes only the retail Position timestamp gates for a deferred
+    /// initial-Create continuation. The raw PositionPack is not transformed
+    /// and no pose, parent, placement, or velocity field is installed. The
+    /// returned authority is sufficient for one later execution without
+    /// running the gate a second time.
+    /// </summary>
+    internal bool TryAcceptDeferredPosition(
+        WorldSession.EntityPositionUpdate update,
+        bool isLocalPlayer,
+        out PositionTimestampDisposition disposition,
+        out AcceptedPhysicsTimestamps timestamps,
+        out bool hasTimestampMutation)
+    {
+        if (!TryGet(
+                update.Guid,
+                out PhysicsTimestampGate? gate,
+                out WorldSession.EntitySpawn old))
+        {
+            disposition = PositionTimestampDisposition.Rejected;
+            timestamps = default;
+            hasTimestampMutation = false;
+            return false;
+        }
+
+        ushort previousPosition = gate.PositionTimestamp;
+        ushort previousTeleport = gate.TeleportTimestamp;
+        ushort previousForcePosition = gate.ForcePositionTimestamp;
+        bool advancesTeleport = PhysicsTimestampGate.IsNewer(
+            previousTeleport,
+            update.TeleportSequence);
+        disposition = gate.TryAcceptPositionEvent(
+            update.InstanceSequence,
+            update.PositionSequence,
+            update.TeleportSequence,
+            update.ForcePositionSequence,
+            isLocalPlayer);
+        timestamps = Current(
+            gate,
+            teleportAdvanced: disposition is PositionTimestampDisposition.Apply
+                && advancesTeleport,
+            previousTeleport: previousTeleport);
+        hasTimestampMutation = previousPosition != gate.PositionTimestamp
+            || previousTeleport != gate.TeleportTimestamp
+            || previousForcePosition != gate.ForcePositionTimestamp;
+        return true;
+    }
+
+    internal bool TryAcceptDeferredObjDesc(
+        ObjDescEvent.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps)
+    {
+        if (!TryGet(update.Guid, out PhysicsTimestampGate? gate, out _)
+            || !gate.TryAcceptObjDescEvent(
+                update.InstanceSequence,
+                update.ObjDescSequence))
+        {
+            timestamps = default;
+            return false;
+        }
+        timestamps = Current(gate);
+        return true;
+    }
+
+    internal bool TryAcceptDeferredPickup(
+        PickupEvent.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps)
+    {
+        if (!TryGet(update.Guid, out PhysicsTimestampGate? gate, out _)
+            || !gate.TryAcceptPositionChannelEvent(
+                update.InstanceSequence,
+                update.PositionSequence))
+        {
+            timestamps = default;
+            return false;
+        }
+        timestamps = Current(gate);
+        return true;
+    }
+
+    internal bool TryAcceptDeferredCreateParent(
+        CreateParentUpdate update,
+        out AcceptedPhysicsTimestamps timestamps)
+    {
+        if (!TryGet(update.ChildGuid, out PhysicsTimestampGate? gate, out _)
+            || !gate.TryAcceptPositionChannelEvent(
+                update.ChildInstanceSequence,
+                update.ChildPositionSequence))
+        {
+            timestamps = default;
+            return false;
+        }
+        timestamps = Current(gate);
+        return true;
+    }
+
+    internal bool TryAcceptDeferredParent(
+        ParentEvent.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps)
+    {
+        if (!_gates.TryGetValue(
+                update.ParentGuid,
+                out PhysicsTimestampGate? parentGate)
+            || !parentGate.IsCurrentInstance(update.ParentInstanceSequence)
+            || !TryGet(
+                update.ChildGuid,
+                out PhysicsTimestampGate? childGate,
+                out _)
+            || !childGate.TryAcceptPositionChannelEvent(
+                childGate.InstanceTimestamp,
+                update.ChildPositionSequence))
+        {
+            timestamps = default;
+            return false;
+        }
+        timestamps = Current(childGate);
+        return true;
+    }
+
+    internal bool TryAcceptDeferredMotion(
+        WorldSession.EntityMotionUpdate update,
+        out AcceptedPhysicsTimestamps timestamps,
+        out bool hasTimestampMutation)
+    {
+        if (!TryGet(update.Guid, out PhysicsTimestampGate? gate, out _))
+        {
+            timestamps = default;
+            hasTimestampMutation = false;
+            return false;
+        }
+
+        ushort previousMovement = gate.MovementTimestamp;
+        ushort previousServerControl = gate.ServerControlledMoveTimestamp;
+        bool accepted = gate.TryAcceptMovementEvent(
+            update.InstanceSequence,
+            update.MovementSequence,
+            update.ServerControlSequence);
+        timestamps = Current(gate);
+        hasTimestampMutation = previousMovement != gate.MovementTimestamp
+            || previousServerControl != gate.ServerControlledMoveTimestamp;
+        return accepted;
+    }
+
+    internal bool TryAcceptDeferredState(
+        SetState.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps)
+    {
+        if (!TryGet(update.Guid, out PhysicsTimestampGate? gate, out _)
+            || !gate.TryAcceptStateEvent(
+                update.InstanceSequence,
+                update.StateSequence))
+        {
+            timestamps = default;
+            return false;
+        }
+        timestamps = Current(gate);
+        return true;
+    }
+
+    internal bool TryAcceptDeferredVector(
+        VectorUpdate.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps)
+    {
+        if (!TryGet(update.Guid, out PhysicsTimestampGate? gate, out _)
+            || !gate.TryAcceptVectorEvent(
+                update.InstanceSequence,
+                update.VectorSequence))
+        {
+            timestamps = default;
+            return false;
+        }
+        timestamps = Current(gate);
+        return true;
+    }
+
     /// <summary>
     /// F751 is a notification gate only. Retail compares it to TELEPORT_TS but
     /// advances that timestamp later, with the accepted Position packet.
@@ -465,12 +665,15 @@ public sealed class InboundPhysicsStateController
 
     private static AcceptedPhysicsTimestamps Current(
         PhysicsTimestampGate gate,
-        bool teleportAdvanced = false) => new(
+        bool teleportAdvanced = false,
+        ushort previousTeleport = 0) => new(
         gate.InstanceTimestamp,
         gate.ServerControlledMoveTimestamp,
         gate.TeleportTimestamp,
         gate.ForcePositionTimestamp,
-        teleportAdvanced);
+        teleportAdvanced,
+        TeleportHookRequired: false,
+        previousTeleport);
 
     private static WorldSession.EntitySpawn MirrorGateTimestamps(
         WorldSession.EntitySpawn spawn,
@@ -671,7 +874,8 @@ public readonly record struct AcceptedPhysicsTimestamps(
     ushort Teleport,
     ushort ForcePosition,
     bool TeleportAdvanced = false,
-    bool TeleportHookRequired = false);
+    bool TeleportHookRequired = false,
+    ushort PreviousTeleport = 0);
 
 public readonly record struct CreateParentUpdate(
     uint ChildGuid,

src/AcDream.Runtime/Entities/ParentAttachmentState.cs

@@ -1,3 +1,4 @@
+using AcDream.Core.Net;
 using AcDream.Core.Net.Messages;
 using AcDream.Core.Physics;
 
@@ -17,12 +18,119 @@ public sealed class ParentAttachmentState
     private readonly Dictionary<uint, ParentAttachmentRelation> _recoveryByChild = new();
     private readonly Dictionary<uint, ParentAttachmentRelation> _lastAcceptedByChild = new();
     private readonly Dictionary<ParentIncarnation, List<uint>> _committedChildrenByParent = new();
+    private readonly Dictionary<uint, Queue<DeferredParentCreate>>
+        _deferredCreatesByParent = [];
+    private ulong _nextDeferredCreateAdmissionId;
 
     public int UnresolvedRelationCount =>
         _unresolvedByChild.Values.Sum(queue => queue.Count);
     public int StagedRelationCount => _stagedByChild.Count;
     public int RecoveryRelationCount => _recoveryByChild.Count;
     public int CommittedRelationCount => _lastAcceptedByChild.Count;
+    internal int DeferredCreateCount =>
+        _deferredCreatesByParent.Values.Sum(queue => queue.Count);
+
+    /// <summary>
+    /// Retains the complete unaccepted CreateObject packet when its nonzero
+    /// parent is not addressable. Retail queues the raw blob before object
+    /// lookup and before any child timestamp is consumed; storing a decoded
+    /// relation after AcceptCreate would partially admit the child.
+    /// </summary>
+    internal void EnqueueDeferredCreate(
+        WorldSession.EntitySpawn spawn,
+        bool isLocalPlayer)
+    {
+        uint parentGuid = spawn.ParentGuid
+            ?? spawn.Physics?.Parent?.Guid
+            ?? 0u;
+        if (spawn.Guid == 0u || parentGuid == 0u)
+        {
+            throw new ArgumentException(
+                "A deferred parent CreateObject requires nonzero child and parent GUIDs.",
+                nameof(spawn));
+        }
+        if (_nextDeferredCreateAdmissionId == ulong.MaxValue)
+        {
+            throw new InvalidOperationException(
+                "The deferred parent CreateObject admission sequence is exhausted.");
+        }
+        if (!_deferredCreatesByParent.TryGetValue(
+                parentGuid,
+                out Queue<DeferredParentCreate>? queue))
+        {
+            queue = new Queue<DeferredParentCreate>();
+            _deferredCreatesByParent.Add(parentGuid, queue);
+        }
+        ulong admissionId = _nextDeferredCreateAdmissionId + 1UL;
+        queue.Enqueue(new DeferredParentCreate(
+            admissionId,
+            RuntimeInitialCreateAdmissionFreezer.Freeze(spawn),
+            isLocalPlayer));
+        _nextDeferredCreateAdmissionId = admissionId;
+    }
+
+    internal bool TryPeekDeferredCreate(
+        uint parentGuid,
+        out DeferredParentCreate deferred)
+    {
+        if (!_deferredCreatesByParent.TryGetValue(
+                parentGuid,
+                out Queue<DeferredParentCreate>? queue)
+            || !queue.TryPeek(out deferred))
+        {
+            deferred = default;
+            return false;
+        }
+        return true;
+    }
+
+    internal bool ConsumeDeferredCreate(
+        uint parentGuid,
+        in DeferredParentCreate expected)
+    {
+        if (!_deferredCreatesByParent.TryGetValue(
+                parentGuid,
+                out Queue<DeferredParentCreate>? queue)
+            || !queue.TryPeek(out DeferredParentCreate current)
+            || current != expected)
+        {
+            return false;
+        }
+        _ = queue.Dequeue();
+        if (queue.Count == 0)
+            _deferredCreatesByParent.Remove(parentGuid);
+        return true;
+    }
+
+    internal bool ContainsDeferredCreate(
+        uint childGuid,
+        ushort instanceSequence)
+    {
+        foreach (Queue<DeferredParentCreate> queue
+            in _deferredCreatesByParent.Values)
+        {
+            if (queue.Any(candidate =>
+                    candidate.Spawn.Guid == childGuid
+                    && candidate.Spawn.InstanceSequence == instanceSequence))
+            {
+                return true;
+            }
+        }
+        return false;
+    }
+
+    /// <summary>
+    /// Cancels only the raw, still-unaccepted child generation addressed by a
+    /// terminal packet. Instance zero is a normal retail timestamp and is not
+    /// treated as an empty sentinel.
+    /// </summary>
+    internal void CancelDeferredChildGeneration(
+        uint childGuid,
+        ushort terminalInstanceSequence) => FilterDeferredCreates(
+            candidate => candidate.Spawn.Guid != childGuid
+                || PhysicsTimestampGate.IsNewer(
+                    terminalInstanceSequence,
+                    candidate.Spawn.InstanceSequence));
 
     public void AcceptCreateObjectRelation(ParentAttachmentRelation relation)
     {
@@ -270,6 +378,7 @@ public sealed class ParentAttachmentState
 
     public void RemoveObject(uint guid)
     {
+        RemoveDeferredChildCreates(guid);
         _stagedByChild.Remove(guid);
         _recoveryByChild.Remove(guid);
         RemoveCommittedChild(guid);
@@ -298,6 +407,12 @@ public sealed class ParentAttachmentState
     /// </summary>
     public void EndGeneration(uint guid, ushort replacementGeneration)
     {
+        FilterDeferredCreates(candidate =>
+            candidate.Spawn.Guid != guid
+            || candidate.Spawn.InstanceSequence == replacementGeneration
+            || PhysicsTimestampGate.IsNewer(
+                replacementGeneration,
+                candidate.Spawn.InstanceSequence));
         FilterChildCandidates(
             guid,
             relation => relation.WaitOwner is ParentAttachmentWaitOwner.Parent);
@@ -322,6 +437,7 @@ public sealed class ParentAttachmentState
     /// </summary>
     public void DeleteGeneration(uint guid, ushort deletedGeneration)
     {
+        CancelDeferredChildGeneration(guid, deletedGeneration);
         FilterChildCandidates(
             guid,
             relation => relation.WaitOwner is ParentAttachmentWaitOwner.Parent);
@@ -351,6 +467,7 @@ public sealed class ParentAttachmentState
 
     public void RemoveChild(uint childGuid)
     {
+        RemoveDeferredChildCreates(childGuid);
         _stagedByChild.Remove(childGuid);
         _recoveryByChild.Remove(childGuid);
         RemoveCommittedChild(childGuid);
@@ -359,6 +476,7 @@ public sealed class ParentAttachmentState
 
     public void Clear()
     {
+        _deferredCreatesByParent.Clear();
         _unresolvedByChild.Clear();
         _stagedByChild.Clear();
         _recoveryByChild.Clear();
@@ -368,6 +486,26 @@ public sealed class ParentAttachmentState
         _committedChildrenByParent.Clear();
     }
 
+    private void RemoveDeferredChildCreates(uint childGuid)
+        => FilterDeferredCreates(
+            candidate => candidate.Spawn.Guid != childGuid);
+
+    private void FilterDeferredCreates(
+        Func<DeferredParentCreate, bool> retain)
+    {
+        uint[] parents = _deferredCreatesByParent.Keys.ToArray();
+        for (int index = 0; index < parents.Length; index++)
+        {
+            uint parentGuid = parents[index];
+            Queue<DeferredParentCreate> retained = new(
+                _deferredCreatesByParent[parentGuid].Where(retain));
+            if (retained.Count == 0)
+                _deferredCreatesByParent.Remove(parentGuid);
+            else
+                _deferredCreatesByParent[parentGuid] = retained;
+        }
+    }
+
     private void RemoveCommittedChild(uint childGuid)
     {
         if (!_lastAcceptedByChild.Remove(
@@ -462,6 +600,15 @@ public sealed class ParentAttachmentState
         ushort InstanceSequence);
 }
 
+internal readonly record struct DeferredParentCreate(
+    ulong AdmissionId,
+    WorldSession.EntitySpawn Spawn,
+    bool IsLocalPlayer)
+{
+    internal bool IsValid => AdmissionId != 0UL
+        && Spawn.Guid != 0u;
+}
+
 public readonly record struct ParentAttachmentRelation(
     uint ParentGuid,
     uint ChildGuid,

src/AcDream.Runtime/Entities/RuntimeEntityDirectory.cs

@@ -1,4 +1,5 @@
 using AcDream.Core.Net;
+using AcDream.Core.Net.Messages;
 using AcDream.Core.Physics;
 using AcDream.Runtime.Physics;
 
@@ -47,6 +48,10 @@ public sealed class RuntimeEntityDirectory
     public InboundCreateResult AcceptCreate(WorldSession.EntitySpawn incoming) =>
         _inbound.AcceptCreate(incoming);
 
+    internal InboundCreateResult AcceptCreateDeferredSameGeneration(
+        WorldSession.EntitySpawn incoming) =>
+        _inbound.AcceptCreateDeferredSameGeneration(incoming);
+
     public CreateObjectTimestampDisposition PreviewCreateDisposition(
         WorldSession.EntitySpawn incoming) =>
         _inbound.PreviewCreateDisposition(incoming);
@@ -59,6 +64,11 @@ public sealed class RuntimeEntityDirectory
     public bool TryGetSnapshot(uint guid, out WorldSession.EntitySpawn spawn) =>
         _inbound.TryGetSnapshot(guid, out spawn);
 
+    internal bool TryGetAcceptedTimestamps(
+        uint guid,
+        out AcceptedPhysicsTimestamps timestamps) =>
+        _inbound.TryGetAcceptedTimestamps(guid, out timestamps);
+
     public bool TryGetActive(uint guid, out RuntimeEntityRecord record) =>
         _activeByGuid.TryGetValue(guid, out record!);
 
@@ -482,6 +492,58 @@ public sealed class RuntimeEntityDirectory
             out accepted,
             out timestamps);
 
+    internal bool TryAcceptDeferredPosition(
+        WorldSession.EntityPositionUpdate update,
+        bool isLocalPlayer,
+        out PositionTimestampDisposition disposition,
+        out AcceptedPhysicsTimestamps timestamps,
+        out bool hasTimestampMutation) =>
+        _inbound.TryAcceptDeferredPosition(
+            update,
+            isLocalPlayer,
+            out disposition,
+            out timestamps,
+            out hasTimestampMutation);
+
+    internal bool TryAcceptDeferredObjDesc(
+        ObjDescEvent.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps) =>
+        _inbound.TryAcceptDeferredObjDesc(update, out timestamps);
+
+    internal bool TryAcceptDeferredPickup(
+        PickupEvent.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps) =>
+        _inbound.TryAcceptDeferredPickup(update, out timestamps);
+
+    internal bool TryAcceptDeferredCreateParent(
+        CreateParentUpdate update,
+        out AcceptedPhysicsTimestamps timestamps) =>
+        _inbound.TryAcceptDeferredCreateParent(update, out timestamps);
+
+    internal bool TryAcceptDeferredParent(
+        ParentEvent.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps) =>
+        _inbound.TryAcceptDeferredParent(update, out timestamps);
+
+    internal bool TryAcceptDeferredMotion(
+        WorldSession.EntityMotionUpdate update,
+        out AcceptedPhysicsTimestamps timestamps,
+        out bool hasTimestampMutation) =>
+        _inbound.TryAcceptDeferredMotion(
+            update,
+            out timestamps,
+            out hasTimestampMutation);
+
+    internal bool TryAcceptDeferredState(
+        SetState.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps) =>
+        _inbound.TryAcceptDeferredState(update, out timestamps);
+
+    internal bool TryAcceptDeferredVector(
+        VectorUpdate.Parsed update,
+        out AcceptedPhysicsTimestamps timestamps) =>
+        _inbound.TryAcceptDeferredVector(update, out timestamps);
+
     public bool IsFreshTeleportStart(uint guid, ushort teleportSequence) =>
         _inbound.IsFreshTeleportStart(guid, teleportSequence);
 

src/AcDream.Runtime/Entities/RuntimeEntityObjectLifetime.cs

@@ -1,3 +1,4 @@
+using System.Collections.Immutable;
 using AcDream.Core.Items;
 using AcDream.Core.Net;
 using AcDream.Core.Net.Messages;
@@ -11,7 +12,8 @@ public readonly record struct RuntimeEntityRegistrationResult(
     RuntimeEntityRecord? Canonical,
     bool LogicalRegistrationCreated,
     bool ReplacedExistingGeneration,
-    Exception? PriorGenerationCleanupFailure = null);
+    Exception? PriorGenerationCleanupFailure = null,
+    bool DeferredForParent = false);
 
 public readonly record struct RuntimeEntityObjectOwnershipSnapshot(
     int ActiveEntityCount,
@@ -19,6 +21,7 @@ public readonly record struct RuntimeEntityObjectOwnershipSnapshot(
     int ClaimedLocalIdCount,
     int AcceptedSnapshotCount,
     int UnresolvedParentRelationCount,
+    int DeferredParentCreateCount,
     int StagedParentRelationCount,
     int RecoveryParentRelationCount,
     int CommittedParentRelationCount,
@@ -44,6 +47,7 @@ public readonly record struct RuntimeEntityObjectOwnershipSnapshot(
         && ClaimedLocalIdCount == 0
         && AcceptedSnapshotCount == 0
         && UnresolvedParentRelationCount == 0
+        && DeferredParentCreateCount == 0
         && StagedParentRelationCount == 0
         && RecoveryParentRelationCount == 0
         && CommittedParentRelationCount == 0
@@ -205,6 +209,7 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
             Entities.ClaimedLocalIdCount,
             Entities.Snapshots.Count,
             parents.UnresolvedRelationCount,
+            parents.DeferredCreateCount,
             parents.StagedRelationCount,
             parents.RecoveryRelationCount,
             parents.CommittedRelationCount,
@@ -272,6 +277,35 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
             throw new InvalidOperationException(
                 "A Runtime entity cannot register while its session lifetime is clearing.");
         }
+        if (beginInitialResidence
+            && !HasConsistentCreateIdentityAndParent(incoming))
+        {
+            throw new InvalidOperationException(
+                $"CreateObject 0x{incoming.Guid:X8} has inconsistent instance or parent projections.");
+        }
+        if (beginInitialResidence)
+            incoming = RuntimeInitialCreateAdmissionFreezer.Freeze(incoming);
+        uint parentGuid = incoming.ParentGuid
+            ?? incoming.Physics?.Parent?.Guid
+            ?? 0u;
+        if (beginInitialResidence
+            && parentGuid != 0u
+            && !Entities.TryGetActive(parentGuid, out _))
+        {
+            // SmartBox::HandleCreateObject resolves a nonzero parent before
+            // object lookup or timestamp admission. Retain the complete raw
+            // CreateObject so no child gate/canonical/projection state can
+            // escape before the parent becomes addressable.
+            Entities.ParentAttachments.EnqueueDeferredCreate(
+                incoming,
+                isLocalPlayer);
+            return new RuntimeEntityRegistrationResult(
+                SupersededCreateResult(),
+                Canonical: null,
+                LogicalRegistrationCreated: false,
+                ReplacedExistingGeneration: false,
+                DeferredForParent: true);
+        }
         CreateObjectTimestampDisposition preview =
             Entities.PreviewCreateDisposition(incoming);
         bool requiresFreshResidenceAdmission = preview is
@@ -285,7 +319,44 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
                 $"CreateObject 0x{incoming.Guid:X8} cannot acquire a structurally valid initial residence lease.");
         }
 
-        InboundCreateResult result = Entities.AcceptCreate(incoming);
+        RuntimeEntityRecord? pendingResidenceRecord = null;
+        RuntimeInitialCreateResidenceLease pendingResidence = default;
+        bool admitIntoPendingResidence = beginInitialResidence
+            && preview is CreateObjectTimestampDisposition.ExistingGeneration
+            && Entities.TryGetActive(
+                incoming.Guid,
+                out pendingResidenceRecord)
+            && InitialCreateResidences.TryGetTransaction(
+                pendingResidenceRecord,
+                out pendingResidence);
+        if (admitIntoPendingResidence
+            && !InitialCreateResidences.CanEnqueue(
+                pendingResidenceRecord!,
+                pendingResidence))
+        {
+            throw new InvalidOperationException(
+                $"CreateObject 0x{incoming.Guid:X8} cannot append to its pending initial residence FIFO.");
+        }
+        if (admitIntoPendingResidence
+            && !IsStructurallyValidDeferredCreate(incoming))
+        {
+            _ = Entities.TryGetAcceptedTimestamps(
+                incoming.Guid,
+                out AcceptedPhysicsTimestamps timestamps);
+            return new RuntimeEntityRegistrationResult(
+                new InboundCreateResult(
+                    CreateObjectTimestampDisposition.ExistingGeneration,
+                    pendingResidenceRecord!.Snapshot,
+                    SameGenerationEvents: null,
+                    timestamps),
+                pendingResidenceRecord,
+                LogicalRegistrationCreated: false,
+                ReplacedExistingGeneration: false);
+        }
+
+        InboundCreateResult result = admitIntoPendingResidence
+            ? Entities.AcceptCreateDeferredSameGeneration(incoming)
+            : Entities.AcceptCreate(incoming);
         if (result.Disposition
             is CreateObjectTimestampDisposition.StaleGeneration)
         {
@@ -307,6 +378,33 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
                     incoming.Guid,
                     out RuntimeEntityRecord retained))
             {
+                if (admitIntoPendingResidence)
+                {
+                    if (!ReferenceEquals(retained, pendingResidenceRecord)
+                        || !AdmitSameGenerationCreate(
+                            retained,
+                            pendingResidence,
+                            incoming,
+                            result,
+                            isLocalPlayer))
+                    {
+                        throw FailInitialResidenceRegistration(
+                            retained,
+                            publishDeleted: true);
+                    }
+
+                    InboundCreateResult dormant = result with
+                    {
+                        Snapshot = retained.Snapshot,
+                        SameGenerationEvents = null,
+                    };
+                    return new RuntimeEntityRegistrationResult(
+                        dormant,
+                        retained,
+                        LogicalRegistrationCreated: false,
+                        ReplacedExistingGeneration: false);
+                }
+
                 // Existing-generation CreateObject contributes untimestamped
                 // description fields here. Position/Parent/Pickup/State/etc.
                 // remain separate freshness-gated events and must not churn a
@@ -592,6 +690,33 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out WorldSession.EntitySpawn accepted)
     {
         EnsureNotDisposed();
+        if (TryGetPendingInitialResidence(
+                update.Guid,
+                out RuntimeEntityRecord pending,
+                out RuntimeInitialCreateResidenceLease lease))
+        {
+            if (!InitialCreateResidences.CanEnqueue(pending, lease))
+            {
+                accepted = pending.Snapshot;
+                return false;
+            }
+            bool acceptedByGate = Entities.TryAcceptDeferredObjDesc(
+                update,
+                out _);
+            accepted = pending.Snapshot;
+            if (!acceptedByGate)
+                return false;
+            EnqueueDormant(
+                pending,
+                lease,
+                RuntimeInitialCreateContinuationKind.ObjDesc,
+                RuntimeAcceptedPositionSource.Unknown,
+                new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.ObjDesc,
+                    update.Guid,
+                    ObjDesc: update));
+            return true;
+        }
         bool applied = Entities.TryApplyObjDesc(update, out accepted);
         if (!applied
             || !Entities.TryGetActive(
@@ -617,6 +742,33 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out WorldSession.EntitySpawn accepted)
     {
         EnsureNotDisposed();
+        if (TryGetPendingInitialResidence(
+                update.Guid,
+                out RuntimeEntityRecord pending,
+                out RuntimeInitialCreateResidenceLease lease))
+        {
+            if (!InitialCreateResidences.CanEnqueue(pending, lease))
+            {
+                accepted = pending.Snapshot;
+                return false;
+            }
+            bool acceptedByGate = Entities.TryAcceptDeferredPickup(
+                update,
+                out _);
+            accepted = pending.Snapshot;
+            if (!acceptedByGate)
+                return false;
+            EnqueueDormant(
+                pending,
+                lease,
+                RuntimeInitialCreateContinuationKind.Pickup,
+                RuntimeAcceptedPositionSource.Unknown,
+                new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.Pickup,
+                    update.Guid,
+                    Pickup: update));
+            return true;
+        }
         bool applied = Entities.TryApplyPickup(update, out accepted);
         if (!applied
             || !Entities.TryGetActive(
@@ -655,6 +807,14 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out WorldSession.EntitySpawn accepted)
     {
         EnsureNotDisposed();
+        if (TryGetPendingInitialResidence(
+                update.ChildGuid,
+                out _,
+                out _))
+        {
+            throw new InvalidOperationException(
+                "A CreateObject parent relation must be admitted inside its atomic same-generation Create envelope.");
+        }
         bool applied = Entities.TryApplyCreateParent(update, out accepted);
         return CommitPositionChannelUpdate(
             applied,
@@ -669,6 +829,44 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out WorldSession.EntitySpawn accepted)
     {
         EnsureNotDisposed();
+        if (TryGetPendingInitialResidence(
+                update.ChildGuid,
+                out RuntimeEntityRecord pending,
+                out RuntimeInitialCreateResidenceLease lease))
+        {
+            if (!InitialCreateResidences.CanEnqueue(pending, lease))
+            {
+                accepted = pending.Snapshot;
+                return false;
+            }
+            if (!Entities.TryGetActive(
+                    update.ParentGuid,
+                    out RuntimeEntityRecord parent)
+                || parent.Incarnation != update.ParentInstanceSequence)
+            {
+                Entities.ParentAttachments.Enqueue(update);
+                accepted = pending.Snapshot;
+                return false;
+            }
+
+            bool acceptedByGate = Entities.TryAcceptDeferredParent(
+                update,
+                out AcceptedPhysicsTimestamps timestamps);
+            accepted = pending.Snapshot;
+            if (!acceptedByGate)
+                return false;
+            EnqueueDormant(
+                pending,
+                lease,
+                RuntimeInitialCreateContinuationKind.Parent,
+                RuntimeAcceptedPositionSource.Unknown,
+                new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.Parent,
+                    update.ChildGuid,
+                    Parent: update,
+                    AcceptedTimestamps: timestamps));
+            return true;
+        }
         bool applied = Entities.TryApplyParent(update, out accepted);
         return CommitPositionChannelUpdate(
             applied,
@@ -750,6 +948,39 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out AcceptedPhysicsTimestamps timestamps)
     {
         EnsureNotDisposed();
+        if (TryGetPendingInitialResidence(
+                update.Guid,
+                out RuntimeEntityRecord pending,
+                out RuntimeInitialCreateResidenceLease lease))
+        {
+            if (!InitialCreateResidences.CanEnqueue(pending, lease))
+            {
+                accepted = pending.Snapshot;
+                timestamps = default;
+                return false;
+            }
+            bool payloadApplied = Entities.TryAcceptDeferredMotion(
+                update,
+                out timestamps,
+                out bool timestampMutation);
+            accepted = pending.Snapshot;
+            if (!payloadApplied && !timestampMutation)
+                return false;
+            EnqueueDormant(
+                pending,
+                lease,
+                RuntimeInitialCreateContinuationKind.Movement,
+                RuntimeAcceptedPositionSource.Unknown,
+                new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.Movement,
+                    update.Guid,
+                    Movement: update,
+                    AcceptedTimestamps: timestamps,
+                    AppliesMovementPayload: payloadApplied,
+                    RetainMovementPayload: retainPayload,
+                    HasTimestampMutation: timestampMutation));
+            return payloadApplied;
+        }
         bool applied = Entities.TryApplyMotion(
             update,
             retainPayload,
@@ -790,6 +1021,35 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out WorldSession.EntitySpawn accepted)
     {
         EnsureNotDisposed();
+        if (TryGetPendingInitialResidence(
+                update.Guid,
+                out RuntimeEntityRecord pending,
+                out RuntimeInitialCreateResidenceLease lease))
+        {
+            if (!IsFinite(update.Velocity)
+                || !IsFinite(update.Omega)
+                || !InitialCreateResidences.CanEnqueue(pending, lease))
+            {
+                accepted = pending.Snapshot;
+                return false;
+            }
+            bool acceptedByGate = Entities.TryAcceptDeferredVector(
+                update,
+                out _);
+            accepted = pending.Snapshot;
+            if (!acceptedByGate)
+                return false;
+            EnqueueDormant(
+                pending,
+                lease,
+                RuntimeInitialCreateContinuationKind.Vector,
+                RuntimeAcceptedPositionSource.Unknown,
+                new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.Vector,
+                    update.Guid,
+                    Vector: update));
+            return true;
+        }
         bool applied = Entities.TryApplyVector(update, out accepted);
         if (!applied
             || !Entities.TryGetActive(
@@ -817,6 +1077,35 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out RetailPhysicsStateTransition transition)
     {
         EnsureNotDisposed();
+        if (TryGetPendingInitialResidence(
+                update.Guid,
+                out RuntimeEntityRecord pending,
+                out RuntimeInitialCreateResidenceLease lease))
+        {
+            if (!InitialCreateResidences.CanEnqueue(pending, lease))
+            {
+                accepted = pending.Snapshot;
+                transition = default;
+                return false;
+            }
+            bool acceptedByGate = Entities.TryAcceptDeferredState(
+                update,
+                out _);
+            accepted = pending.Snapshot;
+            transition = default;
+            if (!acceptedByGate)
+                return false;
+            EnqueueDormant(
+                pending,
+                lease,
+                RuntimeInitialCreateContinuationKind.State,
+                RuntimeAcceptedPositionSource.Unknown,
+                new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.State,
+                    update.Guid,
+                    State: update));
+            return true;
+        }
         bool applied = Entities.TryApplyState(update, out accepted);
         transition = default;
         if (!applied
@@ -883,24 +1172,58 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out AcceptedPhysicsTimestamps timestamps)
     {
         EnsureNotDisposed();
-        RuntimeInitialCreateResidenceLease priorInitialResidence = default;
-        bool hadPendingInitialResidence =
-            Entities.TryGetActive(
+        if (TryGetPendingInitialResidence(
                 update.Guid,
-                out RuntimeEntityRecord pendingCanonical)
-            && InitialCreateResidences.TryGetTransaction(
-                pendingCanonical,
-                out priorInitialResidence);
-        if (hadPendingInitialResidence
-            && !InitialCreateResidences.CanEnqueueAcceptedPosition(
-                pendingCanonical,
-                priorInitialResidence,
-                update))
+                out RuntimeEntityRecord pendingCanonical,
+                out RuntimeInitialCreateResidenceLease pendingLease))
         {
-            disposition = PositionTimestampDisposition.Rejected;
-            accepted = default;
-            timestamps = default;
-            return false;
+            if (!RuntimeAuthoritativePositionRouteClassifier
+                    .IsValidCreateWirePosition(update.Position)
+                || update.Velocity is { } velocity
+                    && !IsFinite(velocity)
+                || !InitialCreateResidences.CanEnqueue(
+                    pendingCanonical,
+                    pendingLease))
+            {
+                disposition = PositionTimestampDisposition.Rejected;
+                accepted = default;
+                timestamps = default;
+                return false;
+            }
+
+            bool deferredKnown = Entities.TryAcceptDeferredPosition(
+                update,
+                isLocalPlayer,
+                out disposition,
+                out timestamps,
+                out bool timestampMutation);
+            accepted = pendingCanonical.Snapshot;
+            if (!deferredKnown)
+                return false;
+
+            if (disposition is PositionTimestampDisposition.Rejected
+                && !timestampMutation)
+            {
+                return true;
+            }
+
+            EnqueueDormant(
+                pendingCanonical,
+                pendingLease,
+                RuntimeInitialCreateContinuationKind.Position,
+                RuntimeAcceptedPositionSource.PositionEvent,
+                new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.Position,
+                    update.Guid,
+                    Position: update,
+                    PositionSource:
+                        RuntimeAcceptedPositionSource.PositionEvent,
+                    PositionDisposition: disposition,
+                    PreviousTeleportSequence:
+                        timestamps.PreviousTeleport,
+                    AcceptedTimestamps: timestamps,
+                    HasTimestampMutation: timestampMutation));
+            return true;
         }
         bool hadCanonical = Entities.TryGetActive(
             update.Guid,
@@ -938,43 +1261,6 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
                     || projectionRequiresTeleportHook,
             };
         }
-
-
-        // Initial CreateObject residence is one immutable transaction. A
-        // Position packet accepted before its 0x11 placement completes is
-        // retained in the transaction's ordered continuation batch; it must
-        // not replace the initial mover operation, mutate the Runtime record
-        // used to prepare that operation, or escape through a host callback.
-        if (hadPendingInitialResidence)
-        {
-            if (!acceptedPosition)
-                return true;
-            if (!ReferenceEquals(canonical, pendingCanonical))
-                throw FailInitialResidenceRegistration(
-                    canonical,
-                    publishDeleted: true);
-
-            RuntimeInitialCreateResidenceLease retained =
-                InitialCreateResidences.EnqueueAcceptedPosition(
-                    canonical,
-                    priorInitialResidence,
-                    update,
-                    accepted,
-                    disposition,
-                    timestamps,
-                    isLocalPlayer,
-                    forcePositionRotation,
-                    currentLocalVelocity,
-                    projectionRequiresTeleportHook);
-            if (!retained.IsValid)
-            {
-                throw FailInitialResidenceRegistration(
-                    canonical,
-                    publishDeleted: true);
-            }
-            return true;
-        }
-
         RuntimePlacementCancellationReceipt cancellation = default;
         if (acceptedPosition)
         {
@@ -1118,6 +1404,15 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         out RuntimeEntityDeleteAcceptance acceptance)
     {
         EnsureNotDisposed();
+        if (!isLocalPlayer)
+        {
+            // A child whose complete raw CreateObject is waiting on a missing
+            // parent has no timestamp gate yet. Cancel its exact/older raw
+            // generation before the normal known-object delete gate returns.
+            Entities.ParentAttachments.CancelDeferredChildGeneration(
+                delete.Guid,
+                delete.InstanceSequence);
+        }
         if (!Entities.TryDelete(delete, isLocalPlayer))
         {
             acceptance = null!;
@@ -1414,6 +1709,288 @@ public sealed class RuntimeEntityObjectLifetime : IDisposable
         Entities.IsCurrent(canonical)
         && matchesCommittedMutation();
 
+    private bool TryGetPendingInitialResidence(
+        uint guid,
+        out RuntimeEntityRecord canonical,
+        out RuntimeInitialCreateResidenceLease lease)
+    {
+        if (Entities.TryGetActive(guid, out canonical)
+            && InitialCreateResidences.TryGetTransaction(
+                canonical,
+                out lease))
+        {
+            return true;
+        }
+
+        canonical = null!;
+        lease = default;
+        return false;
+    }
+
+    private void EnqueueDormant(
+        RuntimeEntityRecord canonical,
+        in RuntimeInitialCreateResidenceLease prior,
+        RuntimeInitialCreateContinuationKind kind,
+        RuntimeAcceptedPositionSource positionSource,
+        in RuntimeInitialCreateTailAction action)
+    {
+        RuntimeInitialCreateResidenceLease retained = InitialCreateResidences
+            .EnqueueAccepted(
+                canonical,
+                prior,
+                kind,
+                positionSource,
+                ImmutableArray.Create(action));
+        if (!retained.IsValid)
+        {
+            throw new InvalidOperationException(
+                $"Accepted {kind} for 0x{canonical.ServerGuid:X8}/{canonical.Incarnation} could not be retained by its initial-placement FIFO.");
+        }
+    }
+
+    private static bool IsFinite(System.Numerics.Vector3 value) =>
+        float.IsFinite(value.X)
+        && float.IsFinite(value.Y)
+        && float.IsFinite(value.Z);
+
+    private static bool HasConsistentCreateIdentityAndParent(
+        in WorldSession.EntitySpawn incoming)
+    {
+        if (incoming.Guid == 0u)
+            return false;
+
+        bool hasTopParentGuid = incoming.ParentGuid is not null;
+        bool hasTopParentLocation = incoming.ParentLocation is not null;
+        if (hasTopParentGuid != hasTopParentLocation)
+            return false;
+
+        if (incoming.Physics is not { } physics)
+        {
+            // These flattened values are parser projections of PhysicsDesc.
+            // Without that source block, accepting any of them would create
+            // contradictory admission authority before the raw create is
+            // either queued for a parent or assigned a residence lease.
+            return incoming.Position is null
+                && incoming.SetupTableId is null
+                && incoming.MotionState is null
+                && incoming.MotionTableId is null
+                && incoming.PhysicsState is null
+                && incoming.ObjScale is null
+                && incoming.Friction is null
+                && incoming.Elasticity is null
+                && incoming.InstanceSequence == 0
+                && incoming.MovementSequence == 0
+                && incoming.ServerControlSequence == 0
+                && incoming.PositionSequence == 0
+                && !hasTopParentGuid
+                && incoming.PlacementId is null;
+        }
+        if (physics.Timestamps.Instance != incoming.InstanceSequence
+            || physics.Timestamps.Position != incoming.PositionSequence
+            || physics.Timestamps.Movement != incoming.MovementSequence
+            || physics.Timestamps.ServerControlledMove
+                != incoming.ServerControlSequence
+            || physics.Position != incoming.Position)
+            return false;
+
+        PhysicsAttachment? flattenedParent = incoming.ParentGuid is { } parentGuid
+            && incoming.ParentLocation is { } parentLocation
+                ? new PhysicsAttachment(parentGuid, parentLocation)
+                : null;
+        if (flattenedParent != physics.Parent
+            || incoming.PlacementId != physics.AnimationFrame)
+        {
+            return false;
+        }
+        return true;
+    }
+
+    private static bool IsStructurallyValidDeferredCreate(
+        in WorldSession.EntitySpawn incoming)
+    {
+        if (incoming.Guid == 0u)
+            return false;
+        if (incoming.Physics is not { } physics)
+            return true;
+        if (physics.Parent is null
+            && physics.Position is { LandblockId: not 0u } position
+            && !RuntimeAuthoritativePositionRouteClassifier
+                .IsValidCreateWirePosition(position))
+        {
+            return false;
+        }
+        if (physics.Velocity is { } velocity && !IsFinite(velocity)
+            || physics.Acceleration is { } acceleration
+                && !IsFinite(acceleration)
+            || physics.AngularVelocity is { } angularVelocity
+                && !IsFinite(angularVelocity)
+            || physics.Scale is { } scale && !float.IsFinite(scale)
+            || physics.Friction is { } friction && !float.IsFinite(friction)
+            || physics.Elasticity is { } elasticity
+                && !float.IsFinite(elasticity)
+            || physics.Translucency is { } translucency
+                && !float.IsFinite(translucency))
+        {
+            return false;
+        }
+        return true;
+    }
+
+    private bool AdmitSameGenerationCreate(
+        RuntimeEntityRecord canonical,
+        in RuntimeInitialCreateResidenceLease prior,
+        in WorldSession.EntitySpawn incoming,
+        in InboundCreateResult admitted,
+        bool isLocalPlayer)
+    {
+        if (!ReferenceEquals(
+                canonical,
+                Entities.TryGetActive(
+                    incoming.Guid,
+                    out RuntimeEntityRecord current)
+                        ? current
+                        : null)
+            || canonical.Incarnation != incoming.InstanceSequence
+            || admitted.Disposition
+                is not CreateObjectTimestampDisposition.ExistingGeneration
+            || !InitialCreateResidences.CanEnqueue(canonical, prior))
+        {
+            return false;
+        }
+
+        var actions = ImmutableArray.CreateBuilder<
+            RuntimeInitialCreateTailAction>();
+        RuntimeAcceptedPositionSource positionSource =
+            RuntimeAcceptedPositionSource.Unknown;
+
+        if (admitted.SameGenerationEvents is { } events)
+        {
+            actions.Add(new RuntimeInitialCreateTailAction(
+                RuntimeInitialCreateTailActionKind
+                    .PreTailDescriptionAdaptation,
+                incoming.Guid,
+                Description: events.Description));
+
+            if (Entities.TryAcceptDeferredObjDesc(
+                    events.Appearance,
+                    out _))
+            {
+                actions.Add(new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.ObjDesc,
+                    incoming.Guid,
+                    ObjDesc: events.Appearance));
+            }
+
+            if (events.Parent is { } parent)
+            {
+                if (Entities.TryAcceptDeferredCreateParent(
+                        parent,
+                        out _))
+                {
+                    actions.Add(new RuntimeInitialCreateTailAction(
+                        RuntimeInitialCreateTailActionKind.CreateParent,
+                        incoming.Guid,
+                        CreateParent: parent));
+                }
+            }
+            else if (events.Position is { } position)
+            {
+                if (!RuntimeAuthoritativePositionRouteClassifier
+                        .IsValidCreateWirePosition(position.Position)
+                    || position.Velocity is { } velocity
+                        && !IsFinite(velocity))
+                {
+                    return false;
+                }
+
+                if (!Entities.TryAcceptDeferredPosition(
+                        position,
+                        isLocalPlayer,
+                        out PositionTimestampDisposition disposition,
+                        out AcceptedPhysicsTimestamps timestamps,
+                        out bool timestampMutation))
+                {
+                    return false;
+                }
+                if (disposition is not PositionTimestampDisposition.Rejected
+                    || timestampMutation)
+                {
+                    positionSource = RuntimeAcceptedPositionSource
+                        .SameIncarnationCreate;
+                    actions.Add(new RuntimeInitialCreateTailAction(
+                        RuntimeInitialCreateTailActionKind.Position,
+                        incoming.Guid,
+                        Position: position,
+                        PositionSource: positionSource,
+                        PositionDisposition: disposition,
+                        PreviousTeleportSequence:
+                            timestamps.PreviousTeleport,
+                        AcceptedTimestamps: timestamps,
+                        HasTimestampMutation: timestampMutation));
+                }
+            }
+            else if (events.Pickup is { } pickup
+                && Entities.TryAcceptDeferredPickup(pickup, out _))
+            {
+                actions.Add(new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.Pickup,
+                    incoming.Guid,
+                    Pickup: pickup));
+            }
+
+            if (events.Movement is { } movement)
+            {
+                bool payloadApplied = Entities.TryAcceptDeferredMotion(
+                    movement,
+                    out AcceptedPhysicsTimestamps timestamps,
+                    out bool timestampMutation);
+                if (payloadApplied || timestampMutation)
+                {
+                    actions.Add(new RuntimeInitialCreateTailAction(
+                        RuntimeInitialCreateTailActionKind.Movement,
+                        incoming.Guid,
+                        Movement: movement,
+                        AcceptedTimestamps: timestamps,
+                        AppliesMovementPayload: payloadApplied,
+                        RetainMovementPayload: true,
+                        HasTimestampMutation: timestampMutation));
+                }
+            }
+
+            if (Entities.TryAcceptDeferredState(events.State, out _))
+            {
+                actions.Add(new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.State,
+                    incoming.Guid,
+                    State: events.State));
+            }
+            if (Entities.TryAcceptDeferredVector(events.Vector, out _))
+            {
+                actions.Add(new RuntimeInitialCreateTailAction(
+                    RuntimeInitialCreateTailActionKind.Vector,
+                    incoming.Guid,
+                    Vector: events.Vector));
+            }
+        }
+
+        actions.Add(new RuntimeInitialCreateTailAction(
+            RuntimeInitialCreateTailActionKind.WeenieDescription,
+            incoming.Guid,
+            WeenieDescription: incoming));
+        actions.Add(new RuntimeInitialCreateTailAction(
+            RuntimeInitialCreateTailActionKind.ResidentCellCleanup,
+            incoming.Guid));
+
+        RuntimeInitialCreateResidenceLease retained = InitialCreateResidences
+            .EnqueueAccepted(
+                canonical,
+                prior,
+                RuntimeInitialCreateContinuationKind.SameIncarnationCreate,
+                positionSource,
+                actions.ToImmutable());
+        return retained.IsValid;
+    }
+
     private void EnsureNotDisposed() =>
         ObjectDisposedException.ThrowIf(_disposed, this);
 

src/AcDream.Runtime/Entities/RuntimeInitialCreateAdmissionFreezer.cs

@@ -0,0 +1,92 @@
+using System.Collections.Immutable;
+using AcDream.Core.Net;
+using AcDream.Core.Net.Messages;
+
+namespace AcDream.Runtime.Entities;
+
+/// <summary>
+/// Takes ownership of decoded wire collections retained beyond the inbound
+/// callback. The protocol records expose read-only views, but those views may
+/// still wrap parser-owned arrays. Initial-placement admission must therefore
+/// copy every collection before an asynchronous residence lease can retain it.
+/// </summary>
+internal static class RuntimeInitialCreateAdmissionFreezer
+{
+    internal static WorldSession.EntitySpawn Freeze(
+        in WorldSession.EntitySpawn spawn) => spawn with
+    {
+        AnimPartChanges = spawn.AnimPartChanges.ToImmutableArray(),
+        TextureChanges = spawn.TextureChanges.ToImmutableArray(),
+        SubPalettes = spawn.SubPalettes.ToImmutableArray(),
+        MotionState = Freeze(spawn.MotionState),
+        Physics = Freeze(spawn.Physics),
+    };
+
+    internal static ObjDescEvent.Parsed Freeze(
+        in ObjDescEvent.Parsed update) => update with
+    {
+        ModelData = Freeze(update.ModelData),
+    };
+
+    internal static WorldSession.EntityMotionUpdate Freeze(
+        in WorldSession.EntityMotionUpdate update) => update with
+    {
+        MotionState = Freeze(update.MotionState),
+    };
+
+    internal static RuntimeInitialCreateTailAction Freeze(
+        in RuntimeInitialCreateTailAction action) => action with
+    {
+        Description = Freeze(action.Description),
+        ObjDesc = action.ObjDesc is { } objDesc
+            ? Freeze(objDesc)
+            : null,
+        Movement = action.Movement is { } movement
+            ? Freeze(movement)
+            : null,
+        WeenieDescription = action.WeenieDescription is { } spawn
+            ? Freeze(spawn)
+            : null,
+    };
+
+    private static CreateObject.ModelData Freeze(
+        in CreateObject.ModelData model) => model with
+    {
+        SubPalettes = model.SubPalettes.ToImmutableArray(),
+        TextureChanges = model.TextureChanges.ToImmutableArray(),
+        AnimPartChanges = model.AnimPartChanges.ToImmutableArray(),
+    };
+
+    private static CreateObject.ServerMotionState Freeze(
+        in CreateObject.ServerMotionState motion) => motion with
+    {
+        Commands = motion.Commands?.ToImmutableArray(),
+    };
+
+    private static CreateObject.ServerMotionState? Freeze(
+        CreateObject.ServerMotionState? motion) => motion is { } value
+            ? Freeze(value)
+            : null;
+
+    private static PhysicsSpawnData? Freeze(PhysicsSpawnData? physics)
+    {
+        if (physics is not { } value)
+            return null;
+
+        PhysicsMovementData? movement = value.Movement is { } source
+            ? source with
+            {
+                RawData = source.RawData.ToArray(),
+                MotionState = Freeze(source.MotionState),
+            }
+            : null;
+        ReadOnlyMemory<PhysicsAttachment>? children = value.Children is { } list
+            ? list.ToArray()
+            : null;
+        return value with
+        {
+            Movement = movement,
+            Children = children,
+        };
+    }
+}

src/AcDream.Runtime/Entities/RuntimeInitialCreateResidenceState.cs

@@ -30,11 +30,14 @@ internal readonly record struct RuntimeInitialCreateResidenceLease(
     RuntimeInitialCreateResidenceToken Token,
     RuntimeAuthoritativePositionRoute Route,
     RuntimeEntityPlacementToken Placement,
+    WorldSession.EntitySpawn InitialCreate,
     ImmutableArray<RuntimeInitialCreateResidenceContinuation> Continuations)
 {
     internal bool IsValid => Token.IsValid
         && Route.Accepted
         && Route.Authority.Entity == Token.Entity
+        && InitialCreate.Guid != 0u
+        && InitialCreate.InstanceSequence == Token.Entity.Incarnation
         && !Continuations.IsDefault
         && HasValidContinuationChain()
         && (!Route.PerformsSetPosition
@@ -43,7 +46,7 @@ internal readonly record struct RuntimeInitialCreateResidenceLease(
 
     private bool HasValidContinuationChain()
     {
-        ushort previousTeleport = Route.Authority.AcceptedTeleportSequence;
+        uint ownerGuid = InitialCreate.Guid;
         for (int index = 0; index < Continuations.Length; index++)
         {
             RuntimeInitialCreateResidenceContinuation continuation =
@@ -51,52 +54,291 @@ internal readonly record struct RuntimeInitialCreateResidenceLease(
             if (!continuation.IsValid
                 || continuation.Sequence != (ulong)index + 1UL
                 || continuation.InstanceSequence != Token.Entity.Incarnation
-                || continuation.PositionAuthorityVersion
-                    != Token.PositionAuthorityVersion
-                || continuation.PreviousTeleportSequence
-                    != previousTeleport)
+                || continuation.Actions.Any(
+                    action => action.OwnerGuid != ownerGuid))
             {
                 return false;
             }
-            previousTeleport = continuation.AcceptedTeleportSequence;
         }
         return true;
     }
 }
 
+internal enum RuntimeInitialCreateContinuationKind : byte
+{
+    SameIncarnationCreate,
+    ObjDesc,
+    Parent,
+    Pickup,
+    Position,
+    Movement,
+    State,
+    Vector,
+}
+
+internal enum RuntimeInitialCreateTailActionKind : byte
+{
+    /// <summary>
+    /// Isolated AP-119 compatibility behavior. Retail's equal-generation
+    /// Create tail starts at ObjDesc and does not call set_description again.
+    /// </summary>
+    PreTailDescriptionAdaptation,
+    ObjDesc,
+    CreateParent,
+    Parent,
+    Pickup,
+    Position,
+    Movement,
+    State,
+    Vector,
+    WeenieDescription,
+    ResidentCellCleanup,
+}
+
+internal readonly record struct RuntimeInitialCreateTailAction(
+    RuntimeInitialCreateTailActionKind Kind,
+    uint OwnerGuid,
+    PhysicsSpawnData? Description = null,
+    ObjDescEvent.Parsed? ObjDesc = null,
+    CreateParentUpdate? CreateParent = null,
+    ParentEvent.Parsed? Parent = null,
+    PickupEvent.Parsed? Pickup = null,
+    WorldSession.EntityPositionUpdate? Position = null,
+    WorldSession.EntityMotionUpdate? Movement = null,
+    SetState.Parsed? State = null,
+    VectorUpdate.Parsed? Vector = null,
+    WorldSession.EntitySpawn? WeenieDescription = null,
+    RuntimeAcceptedPositionSource PositionSource =
+        RuntimeAcceptedPositionSource.Unknown,
+    PositionTimestampDisposition PositionDisposition =
+        PositionTimestampDisposition.Rejected,
+    ushort PreviousTeleportSequence = 0,
+    AcceptedPhysicsTimestamps AcceptedTimestamps = default,
+    bool AppliesMovementPayload = false,
+    bool RetainMovementPayload = true,
+    bool HasTimestampMutation = false)
+{
+    internal bool IsStructurallyValid => HasExclusivePayload()
+        && Kind switch
+    {
+        RuntimeInitialCreateTailActionKind.PreTailDescriptionAdaptation =>
+            Description is not null,
+        RuntimeInitialCreateTailActionKind.ObjDesc => ObjDesc is { } objDesc
+            && objDesc.Guid == OwnerGuid,
+        RuntimeInitialCreateTailActionKind.CreateParent =>
+            CreateParent is { } createParent
+            && createParent.ChildGuid == OwnerGuid,
+        RuntimeInitialCreateTailActionKind.Parent => Parent is { } parent
+            && parent.ChildGuid == OwnerGuid,
+        RuntimeInitialCreateTailActionKind.Pickup => Pickup is { } pickup
+            && pickup.Guid == OwnerGuid,
+        RuntimeInitialCreateTailActionKind.Position => Position is { } position
+            && position.Guid == OwnerGuid
+            && PositionSource is RuntimeAcceptedPositionSource.PositionEvent
+                or RuntimeAcceptedPositionSource.SameIncarnationCreate
+            && (PositionDisposition is PositionTimestampDisposition.Apply
+                    or PositionTimestampDisposition.ForcePosition
+                || PositionDisposition is PositionTimestampDisposition.Rejected
+                    && HasTimestampMutation),
+        RuntimeInitialCreateTailActionKind.Movement => Movement is { } movement
+            && movement.Guid == OwnerGuid
+            && (AppliesMovementPayload || HasTimestampMutation),
+        RuntimeInitialCreateTailActionKind.State => State is { } state
+            && state.Guid == OwnerGuid,
+        RuntimeInitialCreateTailActionKind.Vector => Vector is { } vector
+            && vector.Guid == OwnerGuid,
+        RuntimeInitialCreateTailActionKind.WeenieDescription =>
+            WeenieDescription is { } weenie
+            && weenie.Guid == OwnerGuid,
+        RuntimeInitialCreateTailActionKind.ResidentCellCleanup => true,
+        _ => false,
+    };
+
+    internal bool MatchesInstance(ushort instanceSequence) => Kind switch
+    {
+        RuntimeInitialCreateTailActionKind.PreTailDescriptionAdaptation =>
+            Description is { } description
+            && description.Timestamps.Instance == instanceSequence,
+        RuntimeInitialCreateTailActionKind.ObjDesc =>
+            ObjDesc is { } objDesc
+            && objDesc.InstanceSequence == instanceSequence,
+        RuntimeInitialCreateTailActionKind.CreateParent =>
+            CreateParent is { } createParent
+            && createParent.ChildInstanceSequence == instanceSequence,
+        // ParentEvent carries only the parent's INSTANCE_TS. Acceptance
+        // already exact-gated the child's current incarnation; preserve that
+        // proof in AcceptedTimestamps for the later no-regate executor.
+        RuntimeInitialCreateTailActionKind.Parent =>
+            AcceptedTimestamps.Instance == instanceSequence,
+        RuntimeInitialCreateTailActionKind.Pickup =>
+            Pickup is { } pickup
+            && pickup.InstanceSequence == instanceSequence,
+        RuntimeInitialCreateTailActionKind.Position =>
+            Position is { } position
+            && position.InstanceSequence == instanceSequence,
+        RuntimeInitialCreateTailActionKind.Movement =>
+            Movement is { } movement
+            && movement.InstanceSequence == instanceSequence,
+        RuntimeInitialCreateTailActionKind.State =>
+            State is { } state
+            && state.InstanceSequence == instanceSequence,
+        RuntimeInitialCreateTailActionKind.Vector =>
+            Vector is { } vector
+            && vector.InstanceSequence == instanceSequence,
+        RuntimeInitialCreateTailActionKind.WeenieDescription =>
+            WeenieDescription is { } weenie
+            && weenie.InstanceSequence == instanceSequence,
+        RuntimeInitialCreateTailActionKind.ResidentCellCleanup => true,
+        _ => false,
+    };
+
+    private bool HasExclusivePayload()
+    {
+        int payloadCount = (Description is null ? 0 : 1)
+            + (ObjDesc is null ? 0 : 1)
+            + (CreateParent is null ? 0 : 1)
+            + (Parent is null ? 0 : 1)
+            + (Pickup is null ? 0 : 1)
+            + (Position is null ? 0 : 1)
+            + (Movement is null ? 0 : 1)
+            + (State is null ? 0 : 1)
+            + (Vector is null ? 0 : 1)
+            + (WeenieDescription is null ? 0 : 1);
+        return Kind is RuntimeInitialCreateTailActionKind.ResidentCellCleanup
+            ? payloadCount == 0
+            : payloadCount == 1;
+    }
+}
+
 /// <summary>
-/// One accepted Position packet which arrived before the immutable initial
-/// CreateObject admission completed. These records remain dormant until a
-/// host adopts the completed batch; accepting them never replaces or mutates
-/// the initial 0x11 SetPosition operation.
+/// One immutable inbound envelope which arrived while retail's synchronous
+/// CreateObject critical section was virtualized by an asynchronous initial
+/// SetPosition. Envelopes are never coalesced. A same-incarnation Create is
+/// one atomic envelope whose ordered tail is expanded only by the executor.
+/// Position retains the raw PositionPack and is classified only at the FIFO
+/// head, after every earlier envelope has committed.
 /// </summary>
 internal readonly record struct RuntimeInitialCreateResidenceContinuation(
     ulong Sequence,
-    RuntimePositionEntityKind EntityKind,
+    RuntimeInitialCreateContinuationKind Kind,
     ushort InstanceSequence,
-    ushort PositionSequence,
-    ushort PreviousTeleportSequence,
-    ushort TeleportSequence,
-    ushort ForcePositionSequence,
-    ushort AcceptedTeleportSequence,
-    ushort AcceptedForcePositionSequence,
-    PositionTimestampDisposition TimestampDisposition,
-    CreateObject.ServerPosition AcceptedWirePosition,
-    Vector3? PositionPackVelocity,
-    Vector3? AcceptedVelocity,
-    Quaternion? ForcePositionRotation,
-    Vector3? CurrentLocalVelocity,
-    bool ProjectionRequiresTeleportHook,
-    uint PlacementFrame,
-    ulong PositionAuthorityVersion)
+    RuntimeAcceptedPositionSource PositionSource,
+    ImmutableArray<RuntimeInitialCreateTailAction> Actions)
 {
     internal bool IsValid => Sequence != 0UL
-        && EntityKind is RuntimePositionEntityKind.LocalPlayer
-            or RuntimePositionEntityKind.Remote
-            or RuntimePositionEntityKind.Projectile
-        && PositionAuthorityVersion != 0UL
-        && TimestampDisposition is PositionTimestampDisposition.Apply
-            or PositionTimestampDisposition.ForcePosition;
+        && !Actions.IsDefaultOrEmpty
+        && Actions.All(static action => action.IsStructurallyValid)
+        && HasMatchingInstances()
+        && HasValidShape();
+
+    private bool HasMatchingInstances()
+    {
+        for (int index = 0; index < Actions.Length; index++)
+        {
+            if (!Actions[index].MatchesInstance(InstanceSequence))
+                return false;
+        }
+        return true;
+    }
+
+    private bool HasValidShape()
+    {
+        if (Kind is not RuntimeInitialCreateContinuationKind.SameIncarnationCreate)
+        {
+            if (Actions.Length != 1)
+                return false;
+            RuntimeInitialCreateTailAction action = Actions[0];
+            RuntimeInitialCreateTailActionKind expected = Kind switch
+            {
+                RuntimeInitialCreateContinuationKind.ObjDesc =>
+                    RuntimeInitialCreateTailActionKind.ObjDesc,
+                RuntimeInitialCreateContinuationKind.Parent =>
+                    RuntimeInitialCreateTailActionKind.Parent,
+                RuntimeInitialCreateContinuationKind.Pickup =>
+                    RuntimeInitialCreateTailActionKind.Pickup,
+                RuntimeInitialCreateContinuationKind.Position =>
+                    RuntimeInitialCreateTailActionKind.Position,
+                RuntimeInitialCreateContinuationKind.Movement =>
+                    RuntimeInitialCreateTailActionKind.Movement,
+                RuntimeInitialCreateContinuationKind.State =>
+                    RuntimeInitialCreateTailActionKind.State,
+                RuntimeInitialCreateContinuationKind.Vector =>
+                    RuntimeInitialCreateTailActionKind.Vector,
+                _ => throw new InvalidOperationException(
+                    $"Unsupported initial-Create continuation kind {Kind}."),
+            };
+            return action.Kind == expected
+                && (Kind is RuntimeInitialCreateContinuationKind.Position
+                    ? PositionSource is RuntimeAcceptedPositionSource.PositionEvent
+                        && action.PositionSource == PositionSource
+                    : PositionSource is RuntimeAcceptedPositionSource.Unknown);
+        }
+
+        if (Actions.Length < 2
+            || Actions[^2].Kind
+                is not RuntimeInitialCreateTailActionKind.WeenieDescription
+            || Actions[^1].Kind
+                is not RuntimeInitialCreateTailActionKind.ResidentCellCleanup)
+        {
+            return false;
+        }
+
+        bool hasPosition = Actions.Any(
+            static action => action.Kind
+                is RuntimeInitialCreateTailActionKind.Position);
+        if (hasPosition
+                ? PositionSource
+                    is not RuntimeAcceptedPositionSource.SameIncarnationCreate
+                : PositionSource is not RuntimeAcceptedPositionSource.Unknown)
+        {
+            return false;
+        }
+
+        int previousStage = -1;
+        int positionBranchCount = 0;
+        for (int index = 0; index < Actions.Length; index++)
+        {
+            RuntimeInitialCreateTailAction action = Actions[index];
+            int stage = SameCreateStage(action.Kind);
+            if (stage <= previousStage)
+                return false;
+            if (action.Kind is RuntimeInitialCreateTailActionKind.Position
+                && action.PositionSource != PositionSource)
+            {
+                return false;
+            }
+            if (action.Kind is RuntimeInitialCreateTailActionKind.CreateParent
+                or RuntimeInitialCreateTailActionKind.Pickup
+                or RuntimeInitialCreateTailActionKind.Position)
+            {
+                positionBranchCount++;
+            }
+            previousStage = stage;
+        }
+        bool hasPhysicsDescription = Actions.Any(
+            static action => action.Kind
+                is RuntimeInitialCreateTailActionKind
+                    .PreTailDescriptionAdaptation);
+        return hasPhysicsDescription
+            ? positionBranchCount <= 1
+            : positionBranchCount == 0;
+    }
+
+    private static int SameCreateStage(RuntimeInitialCreateTailActionKind kind) =>
+        kind switch
+        {
+            RuntimeInitialCreateTailActionKind.PreTailDescriptionAdaptation => 0,
+            RuntimeInitialCreateTailActionKind.ObjDesc => 1,
+            RuntimeInitialCreateTailActionKind.CreateParent
+                or RuntimeInitialCreateTailActionKind.Pickup
+                or RuntimeInitialCreateTailActionKind.Position => 2,
+            RuntimeInitialCreateTailActionKind.Movement => 3,
+            RuntimeInitialCreateTailActionKind.State => 4,
+            RuntimeInitialCreateTailActionKind.Vector => 5,
+            RuntimeInitialCreateTailActionKind.WeenieDescription => 6,
+            RuntimeInitialCreateTailActionKind.ResidentCellCleanup => 7,
+            _ => int.MinValue,
+        };
 }
 
 internal readonly record struct RuntimeInitialCreateResidenceAdoptionToken(
@@ -259,125 +501,37 @@ internal sealed class RuntimeInitialCreateResidenceState
         return Own(record, route);
     }
 
-    internal RuntimeInitialCreateResidenceLease EnqueueAcceptedPosition(
+    internal RuntimeInitialCreateResidenceLease EnqueueAccepted(
         RuntimeEntityRecord record,
         in RuntimeInitialCreateResidenceLease prior,
-        WorldSession.EntityPositionUpdate update,
-        in WorldSession.EntitySpawn accepted,
-        PositionTimestampDisposition disposition,
-        in AcceptedPhysicsTimestamps timestamps,
-        bool isLocalPlayer,
-        Quaternion? forcePositionRotation,
-        Vector3? currentLocalVelocity,
-        bool projectionRequiresTeleportHook)
+        RuntimeInitialCreateContinuationKind kind,
+        RuntimeAcceptedPositionSource positionSource,
+        ImmutableArray<RuntimeInitialCreateTailAction> actions)
     {
-        ArgumentNullException.ThrowIfNull(record);
-        if (!_entities.IsCurrent(record)
-            || record.Key is not { } key
-            || update.Guid != record.ServerGuid
-            || accepted.Guid != record.ServerGuid
-            || disposition is PositionTimestampDisposition.Rejected)
+        var owned = ImmutableArray.CreateBuilder<
+            RuntimeInitialCreateTailAction>(actions.Length);
+        foreach (RuntimeInitialCreateTailAction action in actions)
         {
-            return default;
+            owned.Add(RuntimeInitialCreateAdmissionFreezer.Freeze(action));
         }
-
-        RuntimeInitialCreateResidenceLease current;
-        Entry? active = null;
-        CompletedEntry? completed = null;
-        if (_entries.TryGetValue(key, out active)
-            && ReferenceEquals(active.Record, record)
-            && active.Lease.Token == prior.Token
-            && IsCurrent(active))
-        {
-            current = active.Lease;
-        }
-        else if (_completed.TryGetValue(key, out completed)
-            && ReferenceEquals(completed.Record, record)
-            && completed.Lease.Token == prior.Token
-            && IsCompletedCurrent(completed))
-        {
-            current = completed.Lease;
-        }
-        else
-        {
-            return default;
-        }
-        if (current.Continuations.Length == int.MaxValue
-            || completed is not null
-                && completed.Receipt.Adoption.Revision == ulong.MaxValue)
-            return default;
-
-        RuntimePositionEntityKind entityKind = isLocalPlayer
-            ? RuntimePositionEntityKind.LocalPlayer
-            : (record.FinalPhysicsState & PhysicsStateFlags.Missile) != 0
-                ? RuntimePositionEntityKind.Projectile
-                : RuntimePositionEntityKind.Remote;
-        CreateObject.ServerPosition acceptedPosition =
-            accepted.Position ?? update.Position;
-        ushort previousTeleport = current.Continuations.IsEmpty
-            ? current.Route.Authority.AcceptedTeleportSequence
-            : current.Continuations[^1].AcceptedTeleportSequence;
-        ulong sequence = (ulong)current.Continuations.Length + 1UL;
-        var continuation = new RuntimeInitialCreateResidenceContinuation(
-            sequence,
-            entityKind,
-            update.InstanceSequence,
-            update.PositionSequence,
-            previousTeleport,
-            update.TeleportSequence,
-            update.ForcePositionSequence,
-            timestamps.Teleport,
-            timestamps.ForcePosition,
-            disposition,
-            acceptedPosition,
-            update.Velocity,
-            accepted.Physics?.Velocity,
-            forcePositionRotation,
-            currentLocalVelocity,
-            projectionRequiresTeleportHook,
-            accepted.PlacementId ?? 0u,
-            record.PositionAuthorityVersion);
-        if (!continuation.IsValid)
-            return default;
-
-        RuntimeInitialCreateResidenceLease revised = current with
-        {
-            Continuations = current.Continuations.Add(continuation),
-        };
-        if (active is not null)
-        {
-            active.Lease = revised;
-        }
-        else
-        {
-            completed!.Lease = revised;
-            RuntimeInitialCreateResidenceAdoptionToken revisedAdoption =
-                completed.Receipt.Adoption with
-                {
-                    Revision = completed.Receipt.Adoption.Revision + 1UL,
-                };
-            completed.Receipt = completed.Receipt with
-            {
-                Adoption = revisedAdoption,
-                Continuations = revised.Continuations,
-            };
-        }
-        return revised;
+        return Enqueue(
+            record,
+            prior,
+            new RuntimeInitialCreateResidenceContinuation(
+                NextSequence(prior),
+                kind,
+                record.Incarnation,
+                positionSource,
+                owned.MoveToImmutable()));
     }
 
-    internal bool CanEnqueueAcceptedPosition(
+    internal bool CanEnqueue(
         RuntimeEntityRecord record,
-        in RuntimeInitialCreateResidenceLease prior,
-        in WorldSession.EntityPositionUpdate update)
+        in RuntimeInitialCreateResidenceLease prior)
     {
         ArgumentNullException.ThrowIfNull(record);
-        if (record.Key is not { } key
-            || update.Guid != record.ServerGuid
-            || !RuntimeAuthoritativePositionRouteClassifier
-                .IsValidCreateWirePosition(update.Position))
-        {
+        if (record.Key is not { } key)
             return false;
-        }
         if (_entries.TryGetValue(key, out Entry? entry))
         {
             return ReferenceEquals(entry.Record, record)
@@ -393,6 +547,61 @@ internal sealed class RuntimeInitialCreateResidenceState
             && completed.Receipt.Adoption.Revision < ulong.MaxValue;
     }
 
+    private RuntimeInitialCreateResidenceLease Enqueue(
+        RuntimeEntityRecord record,
+        in RuntimeInitialCreateResidenceLease prior,
+        in RuntimeInitialCreateResidenceContinuation continuation)
+    {
+        ArgumentNullException.ThrowIfNull(record);
+        if (!continuation.IsValid
+            || continuation.InstanceSequence != record.Incarnation
+            || !CanEnqueue(record, prior))
+        {
+            return default;
+        }
+
+        RuntimeEntityKey key = record.Key!.Value;
+        Entry? active = null;
+        CompletedEntry? completed = null;
+        RuntimeInitialCreateResidenceLease current;
+        if (_entries.TryGetValue(key, out active))
+            current = active.Lease;
+        else if (_completed.TryGetValue(key, out completed))
+            current = completed.Lease;
+        else
+            return default;
+
+        if (continuation.Sequence != NextSequence(current))
+            return default;
+        RuntimeInitialCreateResidenceLease revised = current with
+        {
+            Continuations = current.Continuations.Add(continuation),
+        };
+        if (active is not null)
+        {
+            active.Lease = revised;
+        }
+        else
+        {
+            completed!.Lease = revised;
+            RuntimeInitialCreateResidenceAdoptionToken adoption =
+                completed.Receipt.Adoption with
+                {
+                    Revision = completed.Receipt.Adoption.Revision + 1UL,
+                };
+            completed.Receipt = completed.Receipt with
+            {
+                Adoption = adoption,
+                Continuations = revised.Continuations,
+            };
+        }
+        return revised;
+    }
+
+    private static ulong NextSequence(
+        in RuntimeInitialCreateResidenceLease lease) =>
+        (ulong)lease.Continuations.Length + 1UL;
+
     internal bool TryGetTransaction(
         RuntimeEntityRecord record,
         out RuntimeInitialCreateResidenceLease lease)
@@ -457,6 +666,7 @@ internal sealed class RuntimeInitialCreateResidenceState
             token,
             route,
             placement,
+            RuntimeInitialCreateAdmissionFreezer.Freeze(record.Snapshot),
             ImmutableArray<RuntimeInitialCreateResidenceContinuation>.Empty);
         _entries.Add(key, new Entry
         {
@@ -600,6 +810,12 @@ internal sealed class RuntimeInitialCreateResidenceState
             Retire(current);
             return false;
         }
+        // Admission-only checkpoint: a completed initial placement remains
+        // owned until the next slice's continuation executor has drained the
+        // exact FIFO revision. Letting a host acknowledge here would silently
+        // discard accepted packets.
+        if (!current.Lease.Continuations.IsEmpty)
+            return false;
         if (current.Lease.Route.PerformsSetPosition
             && !_setPosition.ConsumeAcknowledgedPlacement(
                 current.Lease.Placement,

src/AcDream.Runtime/Physics/RuntimeAuthoritativePositionRouteClassifier.cs

@@ -54,6 +54,19 @@ internal enum RuntimeTeleportHookPhase : byte
     AfterEnterWorld,
 }
 
+/// <summary>
+/// Exact placement of retail's <c>ConstrainTo</c> relative to the selected
+/// position operation. Local ordinary corrections constrain before their
+/// optional interpolation; teleports and remote hard moves constrain only
+/// after the position operation succeeds.
+/// </summary>
+internal enum RuntimePositionConstrainPhase : byte
+{
+    None,
+    BeforePositionOperation,
+    AfterPositionOperation,
+}
+
 /// <summary>
 /// Exact accepted-wire authority for one presentation-independent position
 /// route. <see cref="RuntimeEntityKey"/> identifies the incarnation while
@@ -147,7 +160,7 @@ internal readonly record struct RuntimeAuthoritativePositionRoute(
     bool LeaveWorld,
     RuntimeTeleportHookPhase TeleportHookPhase,
     bool StopInterpolating,
-    bool ConstrainAfterRouting,
+    RuntimePositionConstrainPhase ConstrainPhase,
     bool PreserveHeading,
     bool ZeroVelocity,
     bool SendPositionImmediately,
@@ -163,6 +176,12 @@ internal readonly record struct RuntimeAuthoritativePositionRoute(
 
     internal bool RunsTeleportHook =>
         TeleportHookPhase is not RuntimeTeleportHookPhase.None;
+
+    internal bool ConstrainBeforeRouting =>
+        ConstrainPhase is RuntimePositionConstrainPhase.BeforePositionOperation;
+
+    internal bool ConstrainAfterRouting =>
+        ConstrainPhase is RuntimePositionConstrainPhase.AfterPositionOperation;
 }
 
 /// <summary>
@@ -214,7 +233,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
                 LeaveWorld: false,
                 TeleportHookPhase: RuntimeTeleportHookPhase.None,
                 StopInterpolating: false,
-                ConstrainAfterRouting: false,
+                ConstrainPhase: RuntimePositionConstrainPhase.None,
                 PreserveHeading: false,
                 ZeroVelocity: false,
                 SendPositionImmediately: false,
@@ -246,7 +265,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
                 ? RuntimeTeleportHookPhase.AfterEnterWorld
                 : RuntimeTeleportHookPhase.None,
             StopInterpolating: false,
-            ConstrainAfterRouting: false,
+            ConstrainPhase: RuntimePositionConstrainPhase.None,
             PreserveHeading: false,
             ZeroVelocity: false,
             SendPositionImmediately: false,
@@ -286,7 +305,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
                 LeaveWorld: false,
                 TeleportHookPhase: RuntimeTeleportHookPhase.None,
                 StopInterpolating: false,
-                ConstrainAfterRouting: false,
+                ConstrainPhase: RuntimePositionConstrainPhase.None,
                 PreserveHeading: true,
                 ZeroVelocity: false,
                 SendPositionImmediately: true,
@@ -309,7 +328,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
                     LeaveWorld: false,
                     TeleportHookPhase: RuntimeTeleportHookPhase.AfterPositionOperation,
                     StopInterpolating: false,
-                    ConstrainAfterRouting: true,
+                    ConstrainPhase: RuntimePositionConstrainPhase.AfterPositionOperation,
                     PreserveHeading: false,
                     ZeroVelocity: true,
                     SendPositionImmediately: false,
@@ -331,7 +350,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
                 LeaveWorld: false,
                 TeleportHookPhase: RuntimeTeleportHookPhase.None,
                 StopInterpolating: false,
-                ConstrainAfterRouting: true,
+                ConstrainPhase: RuntimePositionConstrainPhase.BeforePositionOperation,
                 PreserveHeading: false,
                 ZeroVelocity: false,
                 SendPositionImmediately: false,
@@ -357,7 +376,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
                 LeaveWorld: false,
                 TeleportHookPhase: RuntimeTeleportHookPhase.BeforePositionOperation,
                 StopInterpolating: false,
-                ConstrainAfterRouting: true,
+                ConstrainPhase: RuntimePositionConstrainPhase.AfterPositionOperation,
                 PreserveHeading: false,
                 ZeroVelocity: false,
                 SendPositionImmediately: false,
@@ -383,7 +402,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
                 LeaveWorld: false,
                 TeleportHookPhase: RuntimeTeleportHookPhase.None,
                 StopInterpolating: false,
-                ConstrainAfterRouting: false,
+                ConstrainPhase: RuntimePositionConstrainPhase.None,
                 PreserveHeading: false,
                 ZeroVelocity: false,
                 SendPositionImmediately: false,
@@ -413,7 +432,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
             LeaveWorld: false,
             TeleportHookPhase: RuntimeTeleportHookPhase.None,
             StopInterpolating: !nearby,
-            ConstrainAfterRouting: true,
+            ConstrainPhase: RuntimePositionConstrainPhase.AfterPositionOperation,
             PreserveHeading: false,
             ZeroVelocity: false,
             SendPositionImmediately: false,
@@ -445,7 +464,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
             LeaveWorld: true,
             TeleportHookPhase: RuntimeTeleportHookPhase.None,
             StopInterpolating: false,
-            ConstrainAfterRouting: false,
+            ConstrainPhase: RuntimePositionConstrainPhase.None,
             PreserveHeading: false,
             ZeroVelocity: false,
             SendPositionImmediately: false,
@@ -532,7 +551,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
             LeaveWorld: false,
             TeleportHookPhase: RuntimeTeleportHookPhase.None,
             StopInterpolating: false,
-            ConstrainAfterRouting: false,
+            ConstrainPhase: RuntimePositionConstrainPhase.None,
             PreserveHeading: false,
             ZeroVelocity: false,
             SendPositionImmediately: false,
@@ -552,7 +571,7 @@ internal static class RuntimeAuthoritativePositionRouteClassifier
             LeaveWorld: false,
             TeleportHookPhase: RuntimeTeleportHookPhase.None,
             StopInterpolating: false,
-            ConstrainAfterRouting: false,
+            ConstrainPhase: RuntimePositionConstrainPhase.None,
             PreserveHeading: false,
             ZeroVelocity: false,
             SendPositionImmediately: false,

tests/AcDream.Runtime.Tests/Physics/RuntimeAuthoritativePositionRouteClassifierTests.cs

@@ -140,6 +140,7 @@ public sealed class RuntimeAuthoritativePositionRouteClassifierTests
             playerDistance: distance);
 
         Assert.Equal(expected, route.Disposition);
+        Assert.False(route.ConstrainBeforeRouting);
         Assert.True(route.ConstrainAfterRouting);
     }
 
@@ -326,7 +327,8 @@ public sealed class RuntimeAuthoritativePositionRouteClassifierTests
                 : null);
 
         Assert.Equal(expected, route.Disposition);
-        Assert.True(route.ConstrainAfterRouting);
+        Assert.True(route.ConstrainBeforeRouting);
+        Assert.False(route.ConstrainAfterRouting);
     }
 
     [Theory]