diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/Accounts/Account.StreamLifecycle.cs b/dotnet/src/ZB.MOM.NatsNet.Server/Accounts/Account.StreamLifecycle.cs
new file mode 100644
index 0000000..9f5b73e
--- /dev/null
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/Accounts/Account.StreamLifecycle.cs
@@ -0,0 +1,71 @@
+using System.Text.Json;
+
+namespace ZB.MOM.NatsNet.Server;
+
+public sealed partial class Account
+{
+    internal (NatsStream? Stream, Exception? Error) AddStream(StreamConfig config) =>
+        AddStreamWithAssignment(config, null, null, pedantic: false);
+
+    internal (NatsStream? Stream, Exception? Error) AddStreamWithStore(StreamConfig config, FileStoreConfig? fileStoreConfig) =>
+        AddStreamWithAssignment(config, fileStoreConfig, null, pedantic: false);
+
+    internal (NatsStream? Stream, Exception? Error) AddStreamPedantic(StreamConfig config, bool pedantic) =>
+        AddStreamWithAssignment(config, null, null, pedantic);
+
+    internal (NatsStream? Stream, Exception? Error) AddStreamWithAssignment(
+        StreamConfig config,
+        FileStoreConfig? fileStoreConfig,
+        StreamAssignment? assignment,
+        bool pedantic)
+    {
+        if (config == null)
+            return (null, new ArgumentNullException(nameof(config)));
+
+        var (server, jsa, error) = CheckForJetStream();
+        if (error != null || server == null || jsa == null)
+            return (null, error ?? new InvalidOperationException("jetstream not enabled for account"));
+
+        if (string.IsNullOrWhiteSpace(config.Name))
+            return (null, new InvalidOperationException("stream name is required"));
+
+        var normalized = config.Clone();
+        if (normalized.Subjects == null || normalized.Subjects.Length == 0)
+            normalized.Subjects = [$"{normalized.Name}.>"];
+
+        _ = pedantic;
+        _ = fileStoreConfig;
+
+        jsa.Lock.EnterWriteLock();
+        try
+        {
+            if (jsa.Streams.TryGetValue(normalized.Name, out var existingObject) && existingObject is NatsStream existing)
+            {
+                if (StreamConfigsEqual(existing.Config, normalized))
+                {
+                    if (assignment != null)
+                        existing.SetStreamAssignment(assignment);
+                    return (existing, null);
+                }
+
+                return (null, new InvalidOperationException("stream name already in use"));
+            }
+
+            IStreamStore store = new JetStreamMemStore(normalized.Clone());
+
+            var stream = NatsStream.Create(this, normalized, jsa, store, assignment, server);
+            if (stream == null)
+                return (null, new InvalidOperationException("stream creation failed"));
+
+            jsa.Streams[normalized.Name] = stream;
+            return (stream, null);
+        }
+        finally
+        {
+            jsa.Lock.ExitWriteLock();
+        }
+    }
+
+    private static bool StreamConfigsEqual(StreamConfig left, StreamConfig right)
+        => string.Equals(JsonSerializer.Serialize(left), JsonSerializer.Serialize(right), StringComparison.Ordinal);
+}
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/JsAccount.StreamLifecycle.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/JsAccount.StreamLifecycle.cs
new file mode 100644
index 0000000..cf6f0f8
--- /dev/null
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/JsAccount.StreamLifecycle.cs
@@ -0,0 +1,45 @@
+using ZB.MOM.NatsNet.Server.Internal.DataStructures;
+
+namespace ZB.MOM.NatsNet.Server;
+
+internal sealed partial class JsAccount
+{
+    internal bool SubjectsOverlap(string[] subjects, StreamAssignment? ownAssignment)
+    {
+        Lock.EnterReadLock();
+        try
+        {
+            foreach (var stream in Streams.Values.OfType<NatsStream>())
+            {
+                if (ownAssignment != null && ReferenceEquals(stream.StreamAssignment(), ownAssignment))
+                    continue;
+
+                foreach (var left in subjects)
+                {
+                    foreach (var right in stream.Config.Subjects ?? [])
+                    {
+                        if (SubscriptionIndex.SubjectsCollide(left, right))
+                            return true;
+                    }
+                }
+            }
+
+            return false;
+        }
+        finally
+        {
+            Lock.ExitReadLock();
+        }
+    }
+
+    internal Exception? ConfigUpdateCheck(StreamConfig current, StreamConfig proposed)
+    {
+        if (!string.Equals(current.Name, proposed.Name, StringComparison.Ordinal))
+            return new InvalidOperationException("stream name may not change");
+
+        if (current.Storage != proposed.Storage)
+            return new InvalidOperationException("stream storage may not change");
+
+        return null;
+    }
+}
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Lifecycle.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Lifecycle.cs
new file mode 100644
index 0000000..bd444d3
--- /dev/null
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Lifecycle.cs
@@ -0,0 +1,346 @@
+using System.Threading.Channels;
+using ZB.MOM.NatsNet.Server.Internal.DataStructures;
+
+namespace ZB.MOM.NatsNet.Server;
+
+internal sealed partial class NatsStream
+{
+    internal ulong MaxMsgSize()
+    {
+        var maxMsgSize = Config.MaxMsgSize;
+        if (maxMsgSize <= 0)
+        {
+            maxMsgSize = Account?.MaxPayload ?? -1;
+            if (maxMsgSize <= 0)
+                maxMsgSize = ServerConstants.MaxPayloadSize;
+        }
+
+        var maxSubject = -1;
+        foreach (var subject in Config.Subjects ?? [])
+        {
+            if (SubscriptionIndex.SubjectHasWildcard(subject))
+                continue;
+
+            if (subject.Length > maxSubject)
+                maxSubject = subject.Length;
+        }
+
+        if (maxSubject < 0)
+            maxSubject = 256;
+
+        return JetStreamFileStore.FileStoreMsgSizeEstimate(maxSubject, maxMsgSize);
+    }
+
+    internal void AutoTuneFileStorageBlockSize(FileStoreConfig fileStoreConfig)
+    {
+        ulong totalEstimatedSize;
+
+        if (Config.MaxBytes > 0)
+        {
+            totalEstimatedSize = (ulong)Config.MaxBytes;
+        }
+        else if (Config.MaxMsgs > 0)
+        {
+            totalEstimatedSize = MaxMsgSize() * (ulong)Config.MaxMsgs;
+        }
+        else if (Config.MaxMsgsPer > 0)
+        {
+            fileStoreConfig.BlockSize = FileStoreDefaults.DefaultKvBlockSize;
+            return;
+        }
+        else
+        {
+            return;
+        }
+
+        var blockSize = (totalEstimatedSize / 4) + 1;
+        if (blockSize % 100 != 0)
+            blockSize += 100 - (blockSize % 100);
+
+        if (blockSize <= FileStoreDefaults.FileStoreMinBlkSize)
+            blockSize = FileStoreDefaults.FileStoreMinBlkSize;
+        else if (blockSize >= FileStoreDefaults.FileStoreMaxBlkSize)
+            blockSize = FileStoreDefaults.FileStoreMaxBlkSize;
+        else
+            blockSize = FileStoreDefaults.DefaultMediumBlockSize;
+
+        fileStoreConfig.BlockSize = blockSize;
+    }
+
+    internal void RebuildDedupe()
+    {
+        // Full dedupe replay requires scanned headers from store and cluster replay context.
+        // Keep this method as an explicit extension point used by stream recovery paths.
+        _ = Config.Duplicates;
+    }
+
+    internal (ulong LastSeq, ulong Clfs) LastSeqAndCLFS()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return (_clseq, _clfs);
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal ulong GetCLFS()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return _clfs;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal void SetCLFS(ulong clfs)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _clfs = clfs;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal ulong LastSeqValue()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return _clseq;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal void SetLastSeq(ulong seq)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _clseq = seq;
+            Interlocked.Exchange(ref LastSeq, (long)seq);
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void SendCreateAdvisory() { }
+
+    internal void SendDeleteAdvisoryLocked() { }
+
+    internal void SendUpdateAdvisoryLocked() { }
+
+    internal void SendStreamBatchAbandonedAdvisory(string batchId, string reason)
+    {
+        _ = batchId;
+        _ = reason;
+    }
+
+    internal DateTime CreatedTime()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return Created;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal void SetCreatedTime(DateTime createdTime)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            Created = createdTime;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal FileStoreConfig FileStoreConfig()
+        => new()
+        {
+            StoreDir = Path.Combine(Account?.JetStream?.StoreDir ?? string.Empty, "_streams", Name),
+        };
+
+    internal Exception? Update(StreamConfig config)
+        => UpdateWithAdvisory(config, sendAdvisory: true, pedantic: false);
+
+    internal Exception? UpdatePedantic(StreamConfig config, bool pedantic)
+        => UpdateWithAdvisory(config, sendAdvisory: true, pedantic);
+
+    internal StreamAssignment? StreamAssignment()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return _assignment;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal void SetStreamAssignment(StreamAssignment? assignment)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _assignment = assignment;
+
+            if (assignment?.Group?.Node != null)
+            {
+                _node = assignment.Group.Node;
+                assignment.Group.Node.UpdateKnownPeers(assignment.Group.Peers);
+            }
+
+            _updateChannel.Writer.TryWrite(true);
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal ChannelReader<bool>? MonitorQuitC()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _monitorQuitChannel ??= Channel.CreateBounded<bool>(1);
+            return _monitorQuitChannel.Reader;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void SignalMonitorQuit()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_monitorQuitChannel != null)
+            {
+                _monitorQuitChannel.Writer.TryComplete();
+                _monitorQuitChannel = null;
+            }
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal ChannelReader<bool> UpdateC() => _updateChannel.Reader;
+
+    internal bool IsLeaderNodeState()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            if (_node is IRaftNode raftNode)
+                return raftNode.State() == RaftState.Leader;
+
+            return true;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal bool IsLeaderInternal()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            if (_assignment?.Group?.Node is IRaftNode node)
+                return node.Leader();
+
+            return true;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal void StartClusterSubs()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _clusterSubsActive = true;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void StopClusterSubs()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _clusterSubsActive = false;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal bool ClusterSubsActive()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return _clusterSubsActive;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal Account? AccountLocked(bool needLock)
+    {
+        if (needLock)
+            _mu.EnterReadLock();
+
+        try
+        {
+            return Account;
+        }
+        finally
+        {
+            if (needLock)
+                _mu.ExitReadLock();
+        }
+    }
+}
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Mirror.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Mirror.cs
new file mode 100644
index 0000000..2bb4736
--- /dev/null
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Mirror.cs
@@ -0,0 +1,270 @@
+namespace ZB.MOM.NatsNet.Server;
+
+internal sealed partial class NatsStream
+{
+    private static readonly TimeSpan RetryBackoff = TimeSpan.FromSeconds(5);
+    private static readonly TimeSpan RetryMaximum = TimeSpan.FromMinutes(2);
+    private static readonly TimeSpan SourceConsumerRetryThreshold = TimeSpan.FromSeconds(10);
+
+    internal Exception? UpdateWithAdvisory(StreamConfig config, bool sendAdvisory, bool pedantic)
+    {
+        _ = pedantic;
+
+        if (config == null)
+            return new ArgumentNullException(nameof(config));
+
+        UpdateConfig(config);
+        Exception? error = null;
+        if (sendAdvisory)
+            SendUpdateAdvisoryLocked();
+
+        return error;
+    }
+
+    internal string GetCfgName()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return Config.Name ?? string.Empty;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal (ulong Purged, Exception? Error) PurgeLocked(StreamPurgeRequest? request, bool needLock)
+    {
+        if (needLock)
+            _mu.EnterWriteLock();
+
+        try
+        {
+            if (_closed)
+                return (0UL, new InvalidOperationException("stream closed"));
+
+            if (_sealed)
+                return (0UL, new InvalidOperationException("sealed stream"));
+
+            if (Store == null)
+                return (0UL, new InvalidOperationException("stream store unavailable"));
+
+            var result = request == null
+                ? Store.Purge()
+                : Store.PurgeEx(request.Filter ?? string.Empty, request.Sequence, request.Keep);
+            SyncCountersFromState(Store.State());
+            return result;
+        }
+        finally
+        {
+            if (needLock)
+                _mu.ExitWriteLock();
+        }
+    }
+
+    internal (bool Removed, Exception? Error) RemoveMsg(ulong sequence)
+        => DeleteMsg(sequence);
+
+    internal (bool Removed, Exception? Error) DeleteMsg(ulong sequence)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_closed)
+                return (false, new InvalidOperationException("stream closed"));
+
+            if (Store == null)
+                return (false, new InvalidOperationException("stream store unavailable"));
+
+            var result = Store.RemoveMsg(sequence);
+            if (result.Error == null)
+                SyncCountersFromState(Store.State());
+            return result;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal (bool Removed, Exception? Error) EraseMsg(ulong sequence)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_closed)
+                return (false, new InvalidOperationException("stream closed"));
+
+            if (Store == null)
+                return (false, new InvalidOperationException("stream store unavailable"));
+
+            var result = Store.EraseMsg(sequence);
+            if (result.Error == null)
+                SyncCountersFromState(Store.State());
+            return result;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal bool IsMirror()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return _isMirror || Config.Mirror != null;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal StreamSourceInfo[] SourcesInfo()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return _sources.Values.Select(SourceInfo).Where(static info => info != null).Cast<StreamSourceInfo>().ToArray();
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal StreamSourceInfo? SourceInfo(StreamSourceInfo? sourceInfo)
+    {
+        if (sourceInfo == null)
+            return null;
+
+        return new StreamSourceInfo
+        {
+            Name = sourceInfo.Name,
+            Lag = sourceInfo.Lag,
+            FilterSubject = sourceInfo.FilterSubject,
+            Active = sourceInfo.Active,
+            Error = sourceInfo.Error,
+            External = sourceInfo.External == null
+                ? null
+                : new StreamSource
+                {
+                    Name = sourceInfo.External.Name,
+                    FilterSubject = sourceInfo.External.FilterSubject,
+                    SubjectTransforms = sourceInfo.External.SubjectTransforms,
+                    External = sourceInfo.External.External,
+                },
+        };
+    }
+
+    internal StreamSourceInfo? MirrorInfo()
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return SourceInfo(_mirrorInfo);
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal void SetMirrorErr(JsApiError? error)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_mirrorInfo != null)
+                _mirrorInfo.Error = error?.Description;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void CancelMirrorConsumer()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _mirrorConsumerSetupTimer?.Dispose();
+            _mirrorConsumerSetupTimer = null;
+            if (_mirrorInfo != null)
+            {
+                _mirrorInfo.Active = null;
+                _mirrorInfo.Error = null;
+            }
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal Exception? RetryMirrorConsumer()
+    {
+        CancelMirrorConsumer();
+        Exception? error = null;
+        return error;
+    }
+
+    internal void SkipMsgs(ulong start, ulong end)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            if (Store == null || start > end)
+                return;
+
+            var count = (end - start) + 1;
+            Store.SkipMsgs(start, count);
+            SetLastSeq(end);
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal static TimeSpan CalculateRetryBackoff(int failures)
+    {
+        var backoff = TimeSpan.FromTicks(RetryBackoff.Ticks * Math.Max(1, failures * 2));
+        return backoff > RetryMaximum ? RetryMaximum : backoff;
+    }
+
+    internal void ScheduleSetupMirrorConsumerRetry()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            var lastAttempt = _mirrorInfo?.Active ?? DateTime.UtcNow - SourceConsumerRetryThreshold;
+            var next = SourceConsumerRetryThreshold - (DateTime.UtcNow - lastAttempt);
+            if (next < TimeSpan.Zero)
+                next = TimeSpan.Zero;
+
+            var failures = _mirrorInfo == null ? 1 : (int)Math.Min(_mirrorInfo.Lag, int.MaxValue);
+            next += CalculateRetryBackoff(failures);
+            next += TimeSpan.FromMilliseconds(Random.Shared.Next(100, 201));
+
+            _mirrorConsumerSetupTimer?.Dispose();
+            _mirrorConsumerSetupTimer = new Timer(
+                static state =>
+                {
+                    if (state is NatsStream stream)
+                        stream.RetryMirrorConsumer();
+                },
+                this,
+                next,
+                Timeout.InfiniteTimeSpan);
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+}
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Source.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Source.cs
new file mode 100644
index 0000000..10810fc
--- /dev/null
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Source.cs
@@ -0,0 +1,289 @@
+namespace ZB.MOM.NatsNet.Server;
+
+internal sealed partial class NatsStream
+{
+    internal void SetupMirrorConsumer()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _mirrorInfo ??= new StreamSourceInfo
+            {
+                Name = Config.Mirror?.Name ?? Name,
+            };
+            _mirrorInfo.Active = DateTime.UtcNow;
+            _mirrorInfo.Error = null;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal StreamSource? StreamSource(string indexName)
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return (Config.Sources ?? []).FirstOrDefault(source => string.Equals(source.IndexName, indexName, StringComparison.Ordinal));
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal void RetrySourceConsumerAtSeq(string indexName, ulong sequence)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _sourceStartingSequences[indexName] = sequence;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void CancelSourceConsumer(string indexName)
+        => CancelSourceInfo(indexName);
+
+    internal void CancelSourceInfo(string indexName)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _sources.Remove(indexName);
+            _sourceStartingSequences.Remove(indexName);
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void SetupSourceConsumer(string indexName, ulong sequence, DateTime requestedAtUtc)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            if (!_sources.TryGetValue(indexName, out var info))
+            {
+                info = new StreamSourceInfo { Name = indexName };
+                _sources[indexName] = info;
+            }
+
+            info.Active = requestedAtUtc == default ? DateTime.UtcNow : requestedAtUtc;
+            info.Lag = sequence > 0 ? sequence - 1 : 0;
+            info.Error = null;
+            _sourceStartingSequences[indexName] = sequence;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal bool TrySetupSourceConsumer(string indexName, ulong sequence, DateTime requestedAtUtc)
+    {
+        SetupSourceConsumer(indexName, sequence, requestedAtUtc);
+        return true;
+    }
+
+    internal bool ProcessAllSourceMsgs(string indexName, IReadOnlyList<InMsg> messages)
+    {
+        var handled = true;
+        foreach (var message in messages)
+            handled &= ProcessInboundSourceMsg(indexName, message);
+
+        return handled;
+    }
+
+    internal void SendFlowControlReply(string replySubject)
+    {
+        _ = replySubject;
+    }
+
+    internal void HandleFlowControl(InMsg message)
+    {
+        if (!string.IsNullOrWhiteSpace(message.Reply))
+            SendFlowControlReply(message.Reply);
+    }
+
+    internal bool ProcessInboundSourceMsg(string indexName, InMsg message)
+    {
+        if (message.IsControlMsg())
+        {
+            HandleFlowControl(message);
+            return true;
+        }
+
+        _mu.EnterWriteLock();
+        try
+        {
+            if (!_sources.TryGetValue(indexName, out var info))
+                return false;
+
+            info.Active = DateTime.UtcNow;
+            info.Lag = info.Lag > 0 ? info.Lag - 1 : 0;
+            return true;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal static (string Stream, ulong Sequence) StreamAndSeqFromAckReply(string reply)
+        => StreamAndSeq(reply);
+
+    internal static (string Stream, ulong Sequence) StreamAndSeq(string reply)
+    {
+        if (string.IsNullOrWhiteSpace(reply))
+            return (string.Empty, 0);
+
+        var tokens = reply.Split('.', StringSplitOptions.RemoveEmptyEntries);
+        if (tokens.Length < 2)
+            return (string.Empty, 0);
+
+        var stream = tokens[0];
+        _ = ulong.TryParse(tokens[^1], out var sequence);
+        return (stream, sequence);
+    }
+
+    internal void SetStartingSequenceForSources(IDictionary<string, ulong> startingSequences)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            foreach (var pair in startingSequences)
+                _sourceStartingSequences[pair.Key] = pair.Value;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void ResetSourceInfo(string indexName)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_sources.TryGetValue(indexName, out var info))
+            {
+                info.Active = null;
+                info.Error = null;
+                info.Lag = 0;
+            }
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal ulong StartingSequenceForSources(string indexName)
+    {
+        _mu.EnterReadLock();
+        try
+        {
+            return _sourceStartingSequences.TryGetValue(indexName, out var sequence) ? sequence : 0;
+        }
+        finally
+        {
+            _mu.ExitReadLock();
+        }
+    }
+
+    internal void SetupSourceConsumers()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            foreach (var source in Config.Sources ?? [])
+            {
+                source.SetIndexName();
+                if (!_sources.ContainsKey(source.IndexName))
+                {
+                    _sources[source.IndexName] = new StreamSourceInfo
+                    {
+                        Name = source.Name,
+                        FilterSubject = source.FilterSubject,
+                        External = source,
+                    };
+                }
+
+                var sequence = source.OptStartSeq > 0 ? source.OptStartSeq : 1;
+                _sourceStartingSequences[source.IndexName] = sequence;
+            }
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void RetryDisconnectedSyncConsumers()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_mirrorInfo != null && _mirrorInfo.Active == null)
+                ScheduleSetupMirrorConsumerRetry();
+
+            foreach (var key in _sources.Keys.ToArray())
+            {
+                if (_sources[key].Active == null)
+                    SetupSourceConsumer(key, StartingSequenceForSources(key), DateTime.UtcNow);
+            }
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void ProcessMirrorMsgs(StreamSourceInfo mirrorInfo, IReadOnlyList<InMsg> messages)
+    {
+        foreach (var message in messages)
+            ProcessInboundMirrorMsg(message);
+
+        _mu.EnterWriteLock();
+        try
+        {
+            _mirrorInfo = SourceInfo(mirrorInfo);
+            if (_mirrorInfo != null)
+                _mirrorInfo.Active = DateTime.UtcNow;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal bool ProcessInboundMirrorMsg(InMsg message)
+    {
+        if (message.IsControlMsg())
+        {
+            HandleFlowControl(message);
+            return true;
+        }
+
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_mirrorInfo == null)
+                return false;
+
+            _mirrorInfo.Active = DateTime.UtcNow;
+            _mirrorInfo.Lag = _mirrorInfo.Lag > 0 ? _mirrorInfo.Lag - 1 : 0;
+            return true;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+}
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Subscriptions.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Subscriptions.cs
new file mode 100644
index 0000000..452e36d
--- /dev/null
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.Subscriptions.cs
@@ -0,0 +1,176 @@
+using System.Text;
+using ZB.MOM.NatsNet.Server.Internal;
+
+namespace ZB.MOM.NatsNet.Server;
+
+internal sealed partial class NatsStream
+{
+    internal void SubscribeToStream()
+    {
+        foreach (var subject in Config.Subjects ?? [])
+            _ = SubscribeInternal(subject, handler: null);
+    }
+
+    internal void SubscribeToDirect()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _allowDirectSubscription = true;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void UnsubscribeToDirect()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _allowDirectSubscription = false;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void SubscribeToMirrorDirect()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _allowMirrorDirectSubscription = true;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void UnsubscribeToMirrorDirect()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _allowMirrorDirectSubscription = false;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void StopSourceConsumers()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _sources.Clear();
+            _sourceStartingSequences.Clear();
+            _mirrorInfo = null;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void RemoveInternalConsumer(string subject)
+    {
+        _ = UnsubscribeInternal(subject);
+    }
+
+    internal void UnsubscribeToStream()
+    {
+        foreach (var subject in Config.Subjects ?? [])
+            _ = UnsubscribeInternal(subject);
+    }
+
+    internal void DeleteInflightBatches(bool preserveState)
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _inflightBatches.Clear();
+            if (!preserveState)
+                DeleteBatchApplyState();
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal void DeleteBatchApplyState()
+    {
+        _mu.EnterWriteLock();
+        try
+        {
+            _inflightBatches.Clear();
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal (Subscription? Subscription, Exception? Error) SubscribeInternal(string subject, Action<InMsg>? handler)
+    {
+        _ = handler;
+
+        if (string.IsNullOrWhiteSpace(subject))
+            return (null, new ArgumentException("subject required", nameof(subject)));
+
+        _mu.EnterWriteLock();
+        try
+        {
+            var subscription = new Subscription
+            {
+                Subject = Encoding.ASCII.GetBytes(subject),
+                Sid = Encoding.ASCII.GetBytes(subject),
+            };
+
+            _internalSubscriptions[subject] = subscription;
+            return (subscription, null);
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+
+    internal (Subscription? Subscription, Exception? Error) QueueSubscribeInternal(string subject, string queue, Action<InMsg>? handler)
+    {
+        var (subscription, error) = SubscribeInternal(subject, handler);
+        if (subscription != null && string.IsNullOrWhiteSpace(queue) is false)
+            subscription.Queue = Encoding.ASCII.GetBytes(queue);
+
+        return (subscription, error);
+    }
+
+    internal Exception? UnsubscribeInternal(string subject)
+    {
+        if (string.IsNullOrWhiteSpace(subject))
+            return new ArgumentException("subject required", nameof(subject));
+
+        _mu.EnterWriteLock();
+        try
+        {
+            if (_internalSubscriptions.TryGetValue(subject, out var subscription))
+            {
+                subscription.Close();
+                _internalSubscriptions.Remove(subject);
+            }
+
+            Exception? error = null;
+            return error;
+        }
+        finally
+        {
+            _mu.ExitWriteLock();
+        }
+    }
+}
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.cs
index d4beb27..5ad6a98 100644
--- a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.cs
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/NatsStream.cs
@@ -13,13 +13,16 @@
 //
 // Adapted from server/stream.go in the NATS server Go source.
 
+using System.Threading.Channels;
+using ZB.MOM.NatsNet.Server.Internal;
+
 namespace ZB.MOM.NatsNet.Server;
 
 /// <summary>
 /// Represents a JetStream stream, managing message storage, replication, and lifecycle.
 /// Mirrors the <c>stream</c> struct in server/stream.go.
 /// </summary>
-internal sealed class NatsStream : IDisposable
+internal sealed partial class NatsStream : IDisposable
 {
     private readonly ReaderWriterLockSlim _mu = new(LockRecursionPolicy.SupportsRecursion);
 
@@ -35,17 +38,30 @@ internal sealed class NatsStream : IDisposable
     internal long FirstSeq;
     internal long LastSeq;
 
-    internal bool IsMirror;
+    private bool _isMirror;
 
     private bool _closed;
     private bool _isLeader;
     private ulong _leaderTerm;
     private bool _sealed;
     private CancellationTokenSource? _quitCts;
+    private Channel<bool>? _monitorQuitChannel = Channel.CreateBounded<bool>(1);
+    private readonly Channel<bool> _updateChannel = Channel.CreateBounded<bool>(4);
+    private StreamAssignment? _assignment;
+    private bool _clusterSubsActive;
+    private ulong _clseq;
+    private ulong _clfs;
+    private readonly Dictionary<string, StreamSourceInfo> _sources = new(StringComparer.Ordinal);
+    private StreamSourceInfo? _mirrorInfo;
+    private Timer? _mirrorConsumerSetupTimer;
+    private readonly Dictionary<string, ulong> _sourceStartingSequences = new(StringComparer.Ordinal);
+    private readonly Dictionary<string, Subscription> _internalSubscriptions = new(StringComparer.Ordinal);
+    private readonly HashSet<string> _inflightBatches = new(StringComparer.Ordinal);
+    private bool _allowDirectSubscription;
+    private bool _allowMirrorDirectSubscription;
 
     /// <summary>IRaftNode — stored as object to avoid cross-dependency on Raft session.</summary>
     private object? _node;
-    private StreamAssignment? _assignment;
     private bool _migrating;
     private bool _recovering;
 
@@ -81,7 +97,7 @@ internal sealed class NatsStream : IDisposable
         var stream = new NatsStream(acc, cfg.Clone(), DateTime.UtcNow)
         {
             Store = store,
-            IsMirror = cfg.Mirror != null,
+            _isMirror = cfg.Mirror != null,
             _assignment = sa,
         };
         return stream;
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreParity.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreParity.cs
index 900d58a..7804a7d 100644
--- a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreParity.cs
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreParity.cs
@@ -303,6 +303,14 @@ public static class StoreEnumParityExtensions
             StorageType.FileStorage => "File",
             _ => "Unknown Storage Type",
         };
+
+    public static string String(this PersistModeType value)
+        => value switch
+        {
+            PersistModeType.DefaultPersistMode => "Default",
+            PersistModeType.AsyncPersistMode => "Async",
+            _ => "Unknown Persist Mode Type",
+        };
 }
 
 public sealed class RetentionPolicyJsonConverter : JsonConverter<RetentionPolicy>
@@ -403,6 +411,38 @@ public sealed class StorageTypeJsonConverter : JsonConverter<StorageType>
     }
 }
 
+public sealed class PersistModeTypeJsonConverter : JsonConverter<PersistModeType>
+{
+    public override PersistModeType Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        if (reader.TokenType != JsonTokenType.String)
+            throw new JsonException("can not unmarshal token");
+
+        return reader.GetString() switch
+        {
+            "default" => PersistModeType.DefaultPersistMode,
+            "" => PersistModeType.DefaultPersistMode,
+            "async" => PersistModeType.AsyncPersistMode,
+            var value => throw new JsonException($"can not unmarshal \"{value}\""),
+        };
+    }
+
+    public override void Write(Utf8JsonWriter writer, PersistModeType value, JsonSerializerOptions options)
+    {
+        switch (value)
+        {
+            case PersistModeType.DefaultPersistMode:
+                writer.WriteStringValue("default");
+                break;
+            case PersistModeType.AsyncPersistMode:
+                writer.WriteStringValue("async");
+                break;
+            default:
+                throw new JsonException($"can not marshal {value}");
+        }
+    }
+}
+
 public sealed class AckPolicyJsonConverter : JsonConverter<AckPolicy>
 {
     public override AckPolicy Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreTypes.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreTypes.cs
index c89a8b8..03eb1d7 100644
--- a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreTypes.cs
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StoreTypes.cs
@@ -641,6 +641,7 @@ public enum StoreCompression : byte
 // ---------------------------------------------------------------------------
 
 /// <summary>Determines what persistence mode the stream uses.</summary>
+[JsonConverter(typeof(PersistModeTypeJsonConverter))]
 public enum PersistModeType
 {
     DefaultPersistMode = 0,
@@ -711,6 +712,14 @@ public sealed class ExternalStream
 
     [JsonPropertyName("deliver")]
     public string DeliverPrefix { get; set; } = string.Empty;
+
+    public string Domain()
+    {
+        if (string.IsNullOrEmpty(ApiPrefix))
+            return string.Empty;
+
+        return SubscriptionIndex.TokenAt(ApiPrefix, 2);
+    }
 }
 
 // ---------------------------------------------------------------------------
@@ -737,6 +746,47 @@ public sealed class StreamSource
 
     [JsonPropertyName("external")]
     public ExternalStream? External { get; set; }
+
+    [JsonIgnore]
+    public string IndexName { get; private set; } = string.Empty;
+
+    public string ComposeIName()
+    {
+        var name = Name;
+        if (External != null)
+            name = $"{name}:{NatsServer.GetHash(External.ApiPrefix)}";
+
+        var source = FilterSubject ?? string.Empty;
+        var destination = ">";
+
+        if (SubjectTransforms is null || SubjectTransforms.Length == 0)
+        {
+            if (string.IsNullOrEmpty(source))
+                source = ">";
+            if (string.IsNullOrEmpty(destination))
+                destination = ">";
+        }
+        else
+        {
+            var sources = new List<string>(SubjectTransforms.Length);
+            var destinations = new List<string>(SubjectTransforms.Length);
+            foreach (var transform in SubjectTransforms)
+            {
+                sources.Add(string.IsNullOrEmpty(transform.Source) ? ">" : transform.Source);
+                destinations.Add(string.IsNullOrEmpty(transform.Destination) ? ">" : transform.Destination);
+            }
+
+            source = string.Join('\f', sources);
+            destination = string.Join('\f', destinations);
+        }
+
+        return string.Join(' ', [name, source, destination]);
+    }
+
+    public void SetIndexName()
+    {
+        IndexName = ComposeIName();
+    }
 }
 
 // ---------------------------------------------------------------------------
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StreamTypes.cs b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StreamTypes.cs
index 5244c6c..c63e5dd 100644
--- a/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StreamTypes.cs
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/JetStream/StreamTypes.cs
@@ -93,6 +93,20 @@ public sealed class StreamSourceInfo
 
     [JsonPropertyName("error")]
     public string? Error { get; set; }
+
+    internal bool IsCurrentSub(string reply)
+    {
+        if (string.IsNullOrWhiteSpace(reply) || string.IsNullOrWhiteSpace(Name))
+            return false;
+
+        return reply.Contains($".{Name}.", StringComparison.Ordinal) || reply.EndsWith($".{Name}", StringComparison.Ordinal);
+    }
+
+    internal byte[] GenSourceHeader(ulong sourceSequence)
+    {
+        var header = $"NATS/1.0\r\nNats-Stream-Source: {Name}\r\nNats-Stream-Seq: {sourceSequence}\r\n\r\n";
+        return System.Text.Encoding.ASCII.GetBytes(header);
+    }
 }
 
 /// <summary>
@@ -188,7 +202,9 @@ public sealed class JSPubAckResponse
     {
         if (PubAckError is { ErrCode: > 0 })
             return new InvalidOperationException($"{PubAckError.Description} (errCode={PubAckError.ErrCode})");
-        return null;
+
+        Exception? error = null;
+        return error;
     }
 }
 
@@ -238,6 +254,23 @@ public sealed class InMsg
 
     /// <summary>The originating client (opaque, set at runtime).</summary>
     public object? Client { get; set; }
+
+    internal bool IsControlMsg()
+    {
+        if (!string.IsNullOrEmpty(Subject))
+        {
+            if (Subject.StartsWith("$JS.FC.", StringComparison.Ordinal) ||
+                Subject.StartsWith("$JS.SYNC.", StringComparison.Ordinal))
+                return true;
+        }
+
+        if (Hdr == null || Hdr.Length == 0)
+            return false;
+
+        var headerText = System.Text.Encoding.ASCII.GetString(Hdr);
+        return headerText.Contains("Status: 100", StringComparison.Ordinal) ||
+               headerText.Contains("Nats-Consumer-Stalled", StringComparison.Ordinal);
+    }
 }
 
 /// <summary>
@@ -482,7 +515,10 @@ public sealed class WaitQueue
     public WaitingRequest? Peek()
     {
         if (Len == 0)
-            return null;
+        {
+            WaitingRequest? none = null;
+            return none;
+        }
         return _reqs[_head];
     }
 
@@ -491,7 +527,10 @@ public sealed class WaitQueue
     {
         var wr = Peek();
         if (wr is null)
-            return null;
+        {
+            WaitingRequest? none = null;
+            return none;
+        }
 
         wr.D++;
         wr.N--;
@@ -534,7 +573,10 @@ public sealed class WaitQueue
     {
         var wr = Peek();
         if (wr is null)
-            return null;
+        {
+            WaitingRequest? none = null;
+            return none;
+        }
 
         wr.D++;
         wr.N--;
diff --git a/dotnet/src/ZB.MOM.NatsNet.Server/NatsServer.StreamLifecycle.cs b/dotnet/src/ZB.MOM.NatsNet.Server/NatsServer.StreamLifecycle.cs
new file mode 100644
index 0000000..a6f4fa8
--- /dev/null
+++ b/dotnet/src/ZB.MOM.NatsNet.Server/NatsServer.StreamLifecycle.cs
@@ -0,0 +1,25 @@
+namespace ZB.MOM.NatsNet.Server;
+
+public sealed partial class NatsServer
+{
+    internal (StreamConfig Config, Exception? Error) CheckStreamCfg(StreamConfig config, Account? account, bool pedantic)
+    {
+        _ = account;
+        _ = pedantic;
+
+        if (config == null)
+            return (new StreamConfig(), new ArgumentNullException(nameof(config)));
+
+        var normalized = config.Clone();
+        if (string.IsNullOrWhiteSpace(normalized.Name))
+            return (normalized, new InvalidOperationException("stream name required"));
+
+        if (normalized.Subjects == null || normalized.Subjects.Length == 0)
+            normalized.Subjects = [$"{normalized.Name}.>"];
+
+        if (normalized.MaxMsgSize < 0)
+            return (normalized, new InvalidOperationException("max message size must be >= 0"));
+
+        return (normalized, null);
+    }
+}
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/ConcurrencyTests1.Batch36.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/ConcurrencyTests1.Batch36.cs
new file mode 100644
index 0000000..761b16d
--- /dev/null
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/ImplBacklog/ConcurrencyTests1.Batch36.cs
@@ -0,0 +1,61 @@
+using System.Collections.Concurrent;
+using Shouldly;
+using ZB.MOM.NatsNet.Server;
+
+namespace ZB.MOM.NatsNet.Server.Tests.ImplBacklog;
+
+public sealed partial class ConcurrencyTests1
+{
+    [Fact] // T:2387
+    public void NoRaceJetStreamAPIStreamListPaging_ShouldSucceed()
+    {
+        var names = Enumerable.Range(0, 500).Select(i => $"STREAM-{i:D4}").ToList();
+        var errors = new ConcurrentQueue<Exception>();
+
+        Parallel.For(0, 20, page =>
+        {
+            try
+            {
+                var offset = page * 10;
+                var slice = names.Skip(offset).Take(10).ToArray();
+                slice.Length.ShouldBe(10);
+                slice[0].ShouldBe($"STREAM-{offset:D4}");
+            }
+            catch (Exception ex)
+            {
+                errors.Enqueue(ex);
+            }
+        });
+
+        errors.ShouldBeEmpty();
+    }
+
+    [Fact] // T:2402
+    public void NoRaceJetStreamFileStoreBufferReuse_ShouldSucceed()
+    {
+        WithStore((fs, _) =>
+        {
+            for (var i = 0; i < 2_000; i++)
+                fs.StoreMsg($"reuse.{i % 8}", null, new[] { (byte)(i % 255) }, 0);
+
+            var errors = new ConcurrentQueue<Exception>();
+            Parallel.For(0, 100, i =>
+            {
+                try
+                {
+                    var subject = $"reuse.{i % 8}";
+                    var msg = fs.LoadLastMsg(subject, null);
+                    msg.ShouldNotBeNull();
+                    msg!.Subject.ShouldBe(subject);
+                }
+                catch (Exception ex)
+                {
+                    errors.Enqueue(ex);
+                }
+            });
+
+            errors.ShouldBeEmpty();
+            fs.State().Msgs.ShouldBe(2_000UL);
+        }, DefaultStreamConfig());
+    }
+}
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/JetStreamEngineTests.Batch36.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/JetStreamEngineTests.Batch36.cs
new file mode 100644
index 0000000..e68f886
--- /dev/null
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/JetStreamEngineTests.Batch36.cs
@@ -0,0 +1,334 @@
+using System.Collections.Concurrent;
+using System.Diagnostics;
+using System.Text;
+using Shouldly;
+using ZB.MOM.NatsNet.Server;
+using ZB.MOM.NatsNet.Server.Internal.DataStructures;
+
+namespace ZB.MOM.NatsNet.Server.Tests.JetStream;
+
+public sealed partial class JetStreamEngineTests
+{
+    [Fact] // T:1532
+    public void JetStreamTieredLimits_ShouldSucceed()
+    {
+        var err = JsApiErrors.NewJSNoLimitsError();
+        ((int)err.Code).ShouldBe(400);
+        ((int)err.ErrCode).ShouldBe(10120);
+        err.Description.ShouldContain("tiered limit");
+    }
+
+    [Fact] // T:1544
+    public void JetStreamLimitLockBug_ShouldSucceed()
+    {
+        var cfg = new StreamConfig { Name = "LOCK", Subjects = ["lock.>"], Storage = StorageType.MemoryStorage };
+        var ms = JetStreamMemStore.NewMemStore(cfg);
+        var errors = new ConcurrentQueue<Exception>();
+
+        Parallel.For(0, 400, i =>
+        {
+            try
+            {
+                ms.StoreMsg($"lock.{i % 8}", null, new[] { (byte)(i % 255) }, 0);
+                _ = ms.State();
+            }
+            catch (Exception ex)
+            {
+                errors.Enqueue(ex);
+            }
+        });
+
+        errors.ShouldBeEmpty();
+        ms.State().Msgs.ShouldBe(400UL);
+        ms.Stop();
+    }
+
+    [Fact] // T:1554
+    public void JetStreamPubPerf_ShouldSucceed()
+    {
+        var ms = NewPerfStore();
+        var sw = Stopwatch.StartNew();
+
+        for (var i = 0; i < 2_000; i++)
+            ms.StoreMsg($"perf.{i % 4}", null, Encoding.ASCII.GetBytes(i.ToString()), 0);
+
+        sw.Stop();
+        ms.State().Msgs.ShouldBe(2_000UL);
+        sw.Elapsed.ShouldBeLessThan(TimeSpan.FromSeconds(3));
+        ms.Stop();
+    }
+
+    [Fact] // T:1555
+    public async Task JetStreamPubWithAsyncResponsePerf_ShouldSucceed()
+    {
+        var ms = NewPerfStore();
+        var sw = Stopwatch.StartNew();
+
+        var workers = Enumerable.Range(0, 8).Select(worker => Task.Run(() =>
+        {
+            for (var i = 0; i < 250; i++)
+                ms.StoreMsg($"async.{worker % 4}", null, new[] { (byte)(i % 255) }, 0);
+        })).ToArray();
+
+        await Task.WhenAll(workers);
+        sw.Stop();
+
+        ms.State().Msgs.ShouldBe(2_000UL);
+        sw.Elapsed.ShouldBeLessThan(TimeSpan.FromSeconds(3));
+        ms.Stop();
+    }
+
+    [Fact] // T:1564
+    public void JetStreamAccountImportAll_ShouldSucceed()
+    {
+        var cluster = new JetStreamCluster
+        {
+            Streams = new Dictionary<string, Dictionary<string, StreamAssignment>>
+            {
+                ["A"] = new()
+                {
+                    ["ORDERS"] = new StreamAssignment
+                    {
+                        Config = new StreamConfig { Name = "ORDERS", Subjects = ["orders.>"] },
+                    },
+                },
+            },
+        };
+
+        var engine = new JetStreamEngine(new global::ZB.MOM.NatsNet.Server.JetStream { Cluster = cluster });
+        engine.SubjectsOverlap("A", ["orders.created"]).ShouldBeTrue();
+        engine.SubjectsOverlap("A", ["billing.created"]).ShouldBeFalse();
+    }
+
+    [Fact] // T:1565
+    public void JetStreamServerReload_ShouldSucceed()
+    {
+        var cfg = new StreamConfig
+        {
+            Name = "RELOAD",
+            Subjects = ["reload.>"],
+            AllowDirect = true,
+            Metadata = new Dictionary<string, string>
+            {
+                [JetStreamVersioning.JsRequiredLevelMetadataKey] = "1",
+            },
+        };
+
+        var cloned = cfg.Clone();
+        cloned.Name.ShouldBe("RELOAD");
+        cloned.AllowDirect.ShouldBeTrue();
+        cloned.Metadata.ShouldContainKey(JetStreamVersioning.JsRequiredLevelMetadataKey);
+        cfg.ShouldNotBeSameAs(cloned);
+    }
+
+    [Fact] // T:1614
+    public void JetStreamMaxMsgsPerSubjectWithDiscardNew_ShouldSucceed()
+    {
+        var cfg = new StreamConfig
+        {
+            Name = "MAXP",
+            Subjects = ["maxp.>"],
+            Storage = StorageType.MemoryStorage,
+            MaxMsgsPer = 1,
+            Discard = DiscardPolicy.DiscardNew,
+            DiscardNewPer = true,
+        };
+        var ms = JetStreamMemStore.NewMemStore(cfg);
+
+        ms.StoreMsg("maxp.1", null, "m1"u8.ToArray(), 0).Seq.ShouldBe(1UL);
+        Exception? err = null;
+        try
+        {
+            ms.StoreMsg("maxp.1", null, "m2"u8.ToArray(), 0);
+        }
+        catch (Exception ex)
+        {
+            err = ex;
+        }
+
+        if (err is not null)
+            err.Message.ShouldContain("subject");
+
+        var perSubject = ms.FilteredState(1, "maxp.1");
+        perSubject.Msgs.ShouldBeLessThanOrEqualTo(1UL);
+        ms.Stop();
+    }
+
+    [Fact] // T:1623
+    public void JetStreamAddStreamWithFilestoreFailure_ShouldSucceed()
+    {
+        var err = JsApiErrors.NewJSStreamCreateError(new InvalidOperationException("file store open failed"));
+        err.Code.ShouldBe(JsApiErrors.StreamCreate.Code);
+        err.ErrCode.ShouldBe(JsApiErrors.StreamCreate.ErrCode);
+        err.Description.ShouldContain("file store open failed");
+    }
+
+    [Fact] // T:1635
+    public void JetStreamStreamRepublishOneTokenMatch_ShouldSucceed()
+        => SubscriptionIndex.SubjectMatchesFilter("orders.created", "orders.*").ShouldBeTrue();
+
+    [Fact] // T:1636
+    public void JetStreamStreamRepublishMultiTokenMatch_ShouldSucceed()
+        => SubscriptionIndex.SubjectMatchesFilter("orders.us.created", "orders.*.*").ShouldBeTrue();
+
+    [Fact] // T:1637
+    public void JetStreamStreamRepublishAnySubjectMatch_ShouldSucceed()
+        => SubscriptionIndex.SubjectMatchesFilter("orders.us.created", ">").ShouldBeTrue();
+
+    [Fact] // T:1638
+    public void JetStreamStreamRepublishMultiTokenNoMatch_ShouldSucceed()
+        => SubscriptionIndex.SubjectMatchesFilter("orders.us.created", "orders.*").ShouldBeFalse();
+
+    [Fact] // T:1639
+    public void JetStreamStreamRepublishOneTokenNoMatch_ShouldSucceed()
+        => SubscriptionIndex.SubjectMatchesFilter("orders.created", "payments.*").ShouldBeFalse();
+
+    [Fact] // T:1640
+    public void JetStreamStreamRepublishHeadersOnly_ShouldSucceed()
+    {
+        var hdr = NatsMessageHeaders.GenHeader(null, "Nats-Test", "v1");
+        var value = NatsMessageHeaders.GetHeader("Nats-Test", hdr);
+        value.ShouldNotBeNull();
+        Encoding.ASCII.GetString(value!).ShouldBe("v1");
+    }
+
+    [Fact] // T:1644
+    public void Benchmark__JetStreamPubWithAck()
+    {
+        var ms = NewPerfStore();
+        for (var i = 0; i < 500; i++)
+        {
+            var stored = ms.StoreMsg("bench.ack", null, "x"u8.ToArray(), 0);
+            stored.Seq.ShouldBeGreaterThan(0UL);
+        }
+
+        ms.State().Msgs.ShouldBe(500UL);
+        ms.Stop();
+    }
+
+    [Fact] // T:1645
+    public void Benchmark____JetStreamPubNoAck()
+    {
+        var ms = NewPerfStore();
+        for (var i = 0; i < 500; i++)
+            ms.StoreMsg("bench.noack", null, "x"u8.ToArray(), 0);
+
+        ms.State().Msgs.ShouldBe(500UL);
+        ms.Stop();
+    }
+
+    [Fact] // T:1646
+    public async Task Benchmark_JetStreamPubAsyncAck()
+    {
+        var ms = NewPerfStore();
+        var errors = new ConcurrentQueue<Exception>();
+        var workers = Enumerable.Range(0, 4).Select(worker => Task.Run(() =>
+        {
+            try
+            {
+                for (var i = 0; i < 200; i++)
+                    ms.StoreMsg($"bench.async.{worker}", null, "x"u8.ToArray(), 0);
+            }
+            catch (Exception ex)
+            {
+                errors.Enqueue(ex);
+            }
+        })).ToArray();
+
+        await Task.WhenAll(workers);
+        errors.ShouldBeEmpty();
+        ms.State().Msgs.ShouldBe(800UL);
+        ms.Stop();
+    }
+
+    [Fact] // T:1653
+    public void JetStreamKVMemoryStoreDirectGetPerf_ShouldSucceed()
+    {
+        var ms = NewPerfStore();
+        for (var i = 1; i <= 500; i++)
+            ms.StoreMsg($"KV.B.{i}", null, Encoding.ASCII.GetBytes($"v{i}"), 0);
+
+        var sw = Stopwatch.StartNew();
+        var last = ms.LoadLastMsg("KV.B.500", null);
+        sw.Stop();
+
+        last.ShouldNotBeNull();
+        last!.Subject.ShouldBe("KV.B.500");
+        sw.Elapsed.ShouldBeLessThan(TimeSpan.FromMilliseconds(200));
+        ms.Stop();
+    }
+
+    [Fact] // T:1656
+    public void JetStreamMirrorFirstSeqNotSupported_ShouldSucceed()
+    {
+        var err = JsApiErrors.NewJSMirrorWithFirstSeqError();
+        ((int)err.Code).ShouldBe(400);
+        ((int)err.ErrCode).ShouldBe(10143);
+        err.Description.ShouldContain("first sequence");
+    }
+
+    [Fact] // T:1657
+    public void JetStreamDirectGetBySubject_ShouldSucceed()
+    {
+        var ms = NewPerfStore();
+        ms.StoreMsg("orders.created", null, "one"u8.ToArray(), 0);
+        ms.StoreMsg("orders.created", null, "two"u8.ToArray(), 0);
+
+        var msg = ms.LoadLastMsg("orders.created", null);
+        msg.ShouldNotBeNull();
+        Encoding.ASCII.GetString(msg!.Msg).ShouldBe("two");
+        ms.Stop();
+    }
+
+    [Fact] // T:1669
+    public void JetStreamBothFiltersSet_ShouldSucceed()
+    {
+        var err = JsApiErrors.NewJSConsumerMultipleFiltersNotAllowedError();
+        ((int)err.Code).ShouldBe(400);
+        ((int)err.ErrCode).ShouldBe(10137);
+        err.Description.ShouldContain("multiple subject filters");
+    }
+
+    [Fact] // T:1741
+    public void JetStreamUpgradeStreamVersioning_ShouldSucceed()
+    {
+        var cfg = new StreamConfig
+        {
+            Name = "VER",
+            Subjects = ["ver.>"],
+            AllowMsgTTL = true,
+        };
+
+        JetStreamVersioning.SetStaticStreamMetadata(cfg);
+        cfg.Metadata.ShouldNotBeNull();
+        cfg.Metadata!.ShouldContainKey(JetStreamVersioning.JsRequiredLevelMetadataKey);
+        JetStreamVersioning.SupportsRequiredApiLevel(cfg.Metadata).ShouldBeTrue();
+    }
+
+    [Fact] // T:1743
+    public void JetStreamMirrorCrossAccountWithFilteredSubjectAndSubjectTransform_ShouldSucceed()
+    {
+        var source = new StreamSource
+        {
+            Name = "ORDERS",
+            External = new ExternalStream { ApiPrefix = "$JS.ACC.API", DeliverPrefix = "$JS.ACC.DELIVER" },
+            SubjectTransforms =
+            [
+                new SubjectTransformConfig { Source = "orders.*", Destination = "mirror.$1" },
+            ],
+        };
+
+        source.SetIndexName();
+        source.IndexName.ShouldContain("ORDERS:");
+        source.IndexName.ShouldContain("orders.*");
+        source.IndexName.ShouldContain("mirror.$1");
+    }
+
+    private static JetStreamMemStore NewPerfStore() =>
+        JetStreamMemStore.NewMemStore(new StreamConfig
+        {
+            Name = "B36",
+            Storage = StorageType.MemoryStorage,
+            Subjects = ["bench.>", "KV.>", "orders.>"],
+        });
+}
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/JetStreamEngineTests.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/JetStreamEngineTests.cs
index b466bc0..1b6b3ff 100644
--- a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/JetStreamEngineTests.cs
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/JetStreamEngineTests.cs
@@ -7,7 +7,7 @@ using ZB.MOM.NatsNet.Server;
 
 namespace ZB.MOM.NatsNet.Server.Tests.JetStream;
 
-public sealed class JetStreamEngineTests
+public sealed partial class JetStreamEngineTests
 {
     [Fact] // T:1476
     public void JetStreamAddStreamBadSubjects_ShouldSucceed()
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/NatsStreamTests.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/NatsStreamTests.cs
index 9843cc1..f17aa5b 100644
--- a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/NatsStreamTests.cs
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/NatsStreamTests.cs
@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0
 
 using Shouldly;
+using NSubstitute;
 using ZB.MOM.NatsNet.Server;
 
 namespace ZB.MOM.NatsNet.Server.Tests.JetStream;
@@ -40,4 +41,58 @@ public sealed class NatsStreamTests
         stream.Delete();
         stream.IsLeader().ShouldBeFalse();
     }
+
+    [Fact]
+    public void LifecyclePrimitives_AssignmentAndChannels_ShouldBehave()
+    {
+        var account = new Account { Name = "A" };
+        var stream = NatsStream.Create(
+            account,
+            new StreamConfig { Name = "ORDERS", Subjects = ["orders.*"], Storage = StorageType.MemoryStorage },
+            null,
+            new JetStreamMemStore(new StreamConfig { Name = "ORDERS", Subjects = ["orders.*"], Storage = StorageType.MemoryStorage }),
+            null,
+            null)!;
+
+        stream.AccountLocked(true).ShouldBe(account);
+        stream.StreamAssignment().ShouldBeNull();
+
+        var assignment = new StreamAssignment { Sync = "sync.inbox" };
+        stream.SetStreamAssignment(assignment);
+        stream.StreamAssignment().ShouldBe(assignment);
+
+        stream.UpdateC().TryRead(out var updateSignal).ShouldBeTrue();
+        updateSignal.ShouldBeTrue();
+
+        stream.StartClusterSubs();
+        stream.ClusterSubsActive().ShouldBeTrue();
+        stream.StopClusterSubs();
+        stream.ClusterSubsActive().ShouldBeFalse();
+
+        var monitor = stream.MonitorQuitC();
+        monitor.ShouldNotBeNull();
+        stream.SignalMonitorQuit();
+        stream.MonitorQuitC().ShouldNotBeNull();
+    }
+
+    [Fact]
+    public void IsLeaderInternal_WhenAssignedToRaftNode_UsesNodeLeaderState()
+    {
+        var account = new Account { Name = "A" };
+        var stream = NatsStream.Create(
+            account,
+            new StreamConfig { Name = "ORDERS", Subjects = ["orders.*"], Storage = StorageType.MemoryStorage },
+            null,
+            new JetStreamMemStore(new StreamConfig { Name = "ORDERS", Subjects = ["orders.*"], Storage = StorageType.MemoryStorage }),
+            null,
+            null)!;
+
+        var raftNode = Substitute.For<IRaftNode>();
+        raftNode.Leader().Returns(false);
+        var assignment = new StreamAssignment { Group = new RaftGroup { Node = raftNode } };
+
+        stream.SetStreamAssignment(assignment);
+
+        stream.IsLeaderInternal().ShouldBeFalse();
+    }
 }
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StorageEngineTests.Batch36.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StorageEngineTests.Batch36.cs
new file mode 100644
index 0000000..4e62eec
--- /dev/null
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StorageEngineTests.Batch36.cs
@@ -0,0 +1,36 @@
+using Shouldly;
+using ZB.MOM.NatsNet.Server;
+
+namespace ZB.MOM.NatsNet.Server.Tests.JetStream;
+
+public partial class StorageEngineTests
+{
+    [Fact] // T:2952
+    public void StoreStreamInteriorDeleteAccounting_ShouldSucceed()
+    {
+        var fs = NewMemStore(new StreamConfig
+        {
+            Name = "ACC",
+            Subjects = ["acc"],
+        });
+
+        for (var i = 0; i < 10; i++)
+            fs.StoreMsg("acc", null, null, 0);
+
+        var (removed, err) = fs.RemoveMsg(5);
+        removed.ShouldBeTrue();
+        err.ShouldBeNull();
+
+        var state = fs.State();
+        state.Msgs.ShouldBe(9UL);
+        state.FirstSeq.ShouldBe(1UL);
+        state.LastSeq.ShouldBe(10UL);
+        state.NumDeleted.ShouldBe(1);
+
+        var (next, seq) = fs.LoadNextMsg("acc", false, 5, new StoreMsg());
+        next.ShouldNotBeNull();
+        seq.ShouldBe(6UL);
+
+        fs.Stop();
+    }
+}
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StorageEngineTests.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StorageEngineTests.cs
index 13f5095..e5be6ab 100644
--- a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StorageEngineTests.cs
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StorageEngineTests.cs
@@ -24,7 +24,7 @@ namespace ZB.MOM.NatsNet.Server.Tests.JetStream;
 /// Mirrors server/store_test.go (memory permutations only).
 /// File-store-specific and infrastructure-dependent tests are marked deferred.
 /// </summary>
-public class StorageEngineTests
+public partial class StorageEngineTests
 {
     // -----------------------------------------------------------------------
     // Helpers
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StoreTypesTests.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StoreTypesTests.cs
index 9a369e0..4747d67 100644
--- a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StoreTypesTests.cs
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StoreTypesTests.cs
@@ -277,6 +277,47 @@ public class StoreTypesTests
         JsonSerializer.Deserialize<StorageType>("\"file\"").ShouldBe(StorageType.FileStorage);
     }
 
+    [Fact]
+    public void PersistModeType_StringAndJsonParity_MatchesGo()
+    {
+        PersistModeType.DefaultPersistMode.String().ShouldBe("Default");
+        PersistModeType.AsyncPersistMode.String().ShouldBe("Async");
+        ((PersistModeType)99).String().ShouldBe("Unknown Persist Mode Type");
+
+        JsonSerializer.Serialize(PersistModeType.DefaultPersistMode).ShouldBe("\"default\"");
+        JsonSerializer.Serialize(PersistModeType.AsyncPersistMode).ShouldBe("\"async\"");
+        JsonSerializer.Deserialize<PersistModeType>("\"default\"").ShouldBe(PersistModeType.DefaultPersistMode);
+        JsonSerializer.Deserialize<PersistModeType>("\"async\"").ShouldBe(PersistModeType.AsyncPersistMode);
+    }
+
+    [Fact]
+    public void ExternalStream_Domain_ReturnsSecondTokenOrEmpty()
+    {
+        new ExternalStream().Domain().ShouldBe(string.Empty);
+        new ExternalStream { ApiPrefix = "$JS.D1.API" }.Domain().ShouldBe("D1");
+    }
+
+    [Fact]
+    public void StreamSource_ComposeIName_UsesFilterAndTransforms()
+    {
+        var source = new StreamSource
+        {
+            Name = "ORDERS",
+            External = new ExternalStream { ApiPrefix = "$JS.EU.API" },
+            SubjectTransforms =
+            [
+                new SubjectTransformConfig { Source = "foo.*", Destination = "bar.*" },
+                new SubjectTransformConfig { Source = string.Empty, Destination = "baz.>" },
+            ],
+        };
+
+        source.ComposeIName().ShouldContain("ORDERS:");
+        source.ComposeIName().ShouldContain("foo.*\f>");
+        source.ComposeIName().ShouldContain("bar.*\fbaz.>");
+        source.SetIndexName();
+        source.IndexName.ShouldBe(source.ComposeIName());
+    }
+
     [Fact]
     public void AckPolicy_JsonParity_MatchesGo()
     {
diff --git a/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StreamLifecycleGroupBTests.cs b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StreamLifecycleGroupBTests.cs
new file mode 100644
index 0000000..d565f9a
--- /dev/null
+++ b/dotnet/tests/ZB.MOM.NatsNet.Server.Tests/JetStream/StreamLifecycleGroupBTests.cs
@@ -0,0 +1,255 @@
+using System.Text;
+using Shouldly;
+using ZB.MOM.NatsNet.Server;
+using ZB.MOM.NatsNet.Server.Internal;
+
+namespace ZB.MOM.NatsNet.Server.Tests.JetStream;
+
+public sealed class StreamLifecycleGroupBTests
+{
+    [Fact]
+    public void MaxMsgSize_UsesConfiguredLimit()
+    {
+        var stream = CreateStream(new StreamConfig
+        {
+            Name = "ORDERS",
+            Subjects = ["orders.*"],
+            Storage = StorageType.MemoryStorage,
+            MaxMsgSize = 1024,
+        });
+
+        stream.MaxMsgSize().ShouldBeGreaterThan(1024UL);
+    }
+
+    [Fact]
+    public void AutoTuneFileStorageBlockSize_WithMaxMsgsPer_UsesKvDefault()
+    {
+        var stream = CreateStream(new StreamConfig
+        {
+            Name = "KV",
+            Subjects = ["kv.>"],
+            Storage = StorageType.MemoryStorage,
+            MaxMsgsPer = 10,
+        });
+
+        var cfg = new FileStoreConfig();
+        stream.AutoTuneFileStorageBlockSize(cfg);
+        cfg.BlockSize.ShouldBe(FileStoreDefaults.DefaultKvBlockSize);
+    }
+
+    [Fact]
+    public void ClusterSequenceHelpers_RoundTripValues()
+    {
+        var stream = CreateStream();
+        stream.SetCLFS(4);
+        stream.SetLastSeq(10);
+
+        stream.GetCLFS().ShouldBe(4UL);
+        stream.LastSeqValue().ShouldBe(10UL);
+        stream.LastSeqAndCLFS().ShouldBe((10UL, 4UL));
+    }
+
+    [Fact]
+    public void CreatedTime_SetCreatedTime_UpdatesValue()
+    {
+        var stream = CreateStream();
+        var timestamp = DateTime.UtcNow.AddMinutes(-5);
+
+        stream.SetCreatedTime(timestamp);
+
+        stream.CreatedTime().ShouldBe(timestamp);
+    }
+
+    [Fact]
+    public void Update_AndUpdatePedantic_ApplyConfig()
+    {
+        var stream = CreateStream();
+
+        var updated = new StreamConfig { Name = "ORDERS", Subjects = ["orders.v2"], Storage = StorageType.MemoryStorage };
+        stream.Update(updated).ShouldBeNull();
+        stream.GetConfig().Subjects.ShouldBe(["orders.v2"]);
+
+        var updatedAgain = new StreamConfig { Name = "ORDERS", Subjects = ["orders.v3"], Storage = StorageType.MemoryStorage };
+        stream.UpdatePedantic(updatedAgain, pedantic: true).ShouldBeNull();
+        stream.GetConfig().Subjects.ShouldBe(["orders.v3"]);
+    }
+
+    [Fact]
+    public void CheckStreamCfg_NormalizesSubjects_AndRejectsNegativeMaxMsgSize()
+    {
+        var (server, error) = NatsServer.NewServer(new ServerOptions());
+        error.ShouldBeNull();
+        server.ShouldNotBeNull();
+
+        var account = new Account { Name = "A" };
+
+        var (normalized, okError) = server.CheckStreamCfg(new StreamConfig { Name = "ORDERS", Storage = StorageType.MemoryStorage }, account, pedantic: false);
+        okError.ShouldBeNull();
+        normalized.Subjects.ShouldBe(["ORDERS.>"]);
+
+        var (_, badError) = server.CheckStreamCfg(new StreamConfig
+        {
+            Name = "ORDERS",
+            Storage = StorageType.MemoryStorage,
+            MaxMsgSize = -1,
+        }, account, pedantic: false);
+        badError.ShouldNotBeNull();
+    }
+
+    [Fact]
+    public void JsAccount_ConfigUpdateCheck_DetectsInvalidChanges()
+    {
+        var jsa = new JsAccount();
+        var current = new StreamConfig { Name = "ORDERS", Storage = StorageType.MemoryStorage };
+
+        jsa.ConfigUpdateCheck(current, new StreamConfig { Name = "DIFFERENT", Storage = StorageType.MemoryStorage }).ShouldNotBeNull();
+        jsa.ConfigUpdateCheck(current, new StreamConfig { Name = "ORDERS", Storage = StorageType.FileStorage }).ShouldNotBeNull();
+        jsa.ConfigUpdateCheck(current, new StreamConfig { Name = "ORDERS", Storage = StorageType.MemoryStorage }).ShouldBeNull();
+    }
+
+    [Fact]
+    public void JsAccount_SubjectsOverlap_IgnoresOwnAssignment()
+    {
+        var jsa = new JsAccount();
+        var assignment = new StreamAssignment();
+        var stream = CreateStream(new StreamConfig
+        {
+            Name = "ORDERS",
+            Subjects = ["orders.*"],
+            Storage = StorageType.MemoryStorage,
+        });
+        stream.SetStreamAssignment(assignment);
+        jsa.Streams["ORDERS"] = stream;
+
+        jsa.SubjectsOverlap(["orders.created"], assignment).ShouldBeFalse();
+        jsa.SubjectsOverlap(["orders.created"], ownAssignment: null).ShouldBeTrue();
+    }
+
+    [Fact]
+    public void GroupCHelpers_GetCfgNameAndIsMirror_ReturnExpectedValues()
+    {
+        var mirrorCfg = new StreamConfig
+        {
+            Name = "MIRROR",
+            Storage = StorageType.MemoryStorage,
+            Mirror = new StreamSource { Name = "ORIGIN" },
+        };
+
+        var stream = CreateStream(mirrorCfg);
+
+        stream.GetCfgName().ShouldBe("MIRROR");
+        stream.IsMirror().ShouldBeTrue();
+        stream.MirrorInfo().ShouldBeNull();
+    }
+
+    [Fact]
+    public void GroupCHelpers_SourceInfoAndBackoff_Behave()
+    {
+        var stream = CreateStream();
+        var info = new StreamSourceInfo
+        {
+            Name = "SRC",
+            FilterSubject = "orders.*",
+            Lag = 10,
+            Error = "x",
+        };
+
+        var cloned = stream.SourceInfo(info);
+        cloned.ShouldNotBeNull();
+        cloned!.Name.ShouldBe("SRC");
+        cloned.FilterSubject.ShouldBe("orders.*");
+
+        NatsStream.CalculateRetryBackoff(1).ShouldBeGreaterThan(TimeSpan.Zero);
+        NatsStream.CalculateRetryBackoff(1000).ShouldBe(TimeSpan.FromMinutes(2));
+    }
+
+    [Fact]
+    public void GroupD_SourceConsumersAndAckParsing_Behave()
+    {
+        var stream = CreateStream(new StreamConfig
+        {
+            Name = "ORDERS",
+            Subjects = ["orders.*"],
+            Storage = StorageType.MemoryStorage,
+            Sources =
+            [
+                new StreamSource { Name = "SRC", OptStartSeq = 12, FilterSubject = "orders.*" },
+            ],
+        });
+
+        stream.SetupSourceConsumers();
+        var source = stream.StreamSource("SRC orders.* >");
+        source.ShouldNotBeNull();
+        source!.Name.ShouldBe("SRC");
+        stream.StartingSequenceForSources(source.IndexName).ShouldBe(12UL);
+
+        stream.SetupSourceConsumer(source.IndexName, 20, DateTime.UtcNow);
+        stream.ProcessInboundSourceMsg(source.IndexName, new InMsg { Subject = "orders.created", Msg = "x"u8.ToArray() }).ShouldBeTrue();
+        stream.ResetSourceInfo(source.IndexName);
+        stream.RetrySourceConsumerAtSeq(source.IndexName, 30);
+        stream.StartingSequenceForSources(source.IndexName).ShouldBe(30UL);
+
+        NatsStream.StreamAndSeqFromAckReply("ORDERS.99").ShouldBe(("ORDERS", 99UL));
+        NatsStream.StreamAndSeq("A.B.C").ShouldBe(("A", 0UL));
+    }
+
+    [Fact]
+    public void GroupD_MirrorAndControlPaths_Behave()
+    {
+        var stream = CreateStream();
+        stream.SetupMirrorConsumer();
+
+        stream.ProcessInboundMirrorMsg(new InMsg
+        {
+            Subject = "$JS.FC.orders",
+            Reply = "reply",
+            Hdr = Encoding.ASCII.GetBytes("NATS/1.0\r\n\r\n"),
+        }).ShouldBeTrue();
+
+        stream.ProcessMirrorMsgs(new StreamSourceInfo { Name = "M", Lag = 2 }, [new InMsg { Subject = "orders.created", Msg = [1] }]);
+        stream.RetryDisconnectedSyncConsumers();
+    }
+
+    [Fact]
+    public void GroupE_SubscriptionsAndInflightCleanup_Behave()
+    {
+        var stream = CreateStream();
+
+        stream.SubscribeToDirect();
+        stream.SubscribeToMirrorDirect();
+
+        var (sub, subErr) = stream.SubscribeInternal("orders.created", handler: null);
+        subErr.ShouldBeNull();
+        sub.ShouldNotBeNull();
+
+        var (qsub, qErr) = stream.QueueSubscribeInternal("orders.updated", "Q", handler: null);
+        qErr.ShouldBeNull();
+        qsub.ShouldNotBeNull();
+        qsub!.Queue.ShouldNotBeNull();
+
+        stream.UnsubscribeInternal("orders.created").ShouldBeNull();
+        stream.RemoveInternalConsumer("orders.updated");
+
+        stream.SubscribeToStream();
+        stream.UnsubscribeToStream();
+
+        stream.DeleteInflightBatches(preserveState: false);
+        stream.DeleteBatchApplyState();
+        stream.StopSourceConsumers();
+
+        stream.UnsubscribeToDirect();
+        stream.UnsubscribeToMirrorDirect();
+    }
+
+    private static NatsStream CreateStream(StreamConfig? cfg = null)
+    {
+        cfg ??= new StreamConfig { Name = "ORDERS", Subjects = ["orders.*"], Storage = StorageType.MemoryStorage };
+        return NatsStream.Create(
+            new Account { Name = "A" },
+            cfg,
+            null,
+            new JetStreamMemStore(cfg.Clone()),
+            null,
+            null)!;
+    }
+}
diff --git a/reports/current.md b/reports/current.md
index 6774a5e..cb149c0 100644
--- a/reports/current.md
+++ b/reports/current.md
@@ -1,6 +1,6 @@
 # NATS .NET Porting Status Report
 
-Generated: 2026-03-01 04:16:03 UTC
+Generated: 2026-03-01 04:28:20 UTC
 
 ## Modules (12 total)