diff --git a/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/DataConnection/WriteTagBatchRequest.cs b/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/DataConnection/WriteTagBatchRequest.cs
new file mode 100644
index 00000000..8c55f4d2
--- /dev/null
+++ b/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/DataConnection/WriteTagBatchRequest.cs
@@ -0,0 +1,40 @@
+namespace ZB.MOM.WW.ScadaBridge.Commons.Messages.DataConnection;
+
+/// <summary>
+/// Request to write a SET of device tags through the DCL in ONE batch round-trip,
+/// optionally followed by a trigger-flag write. Composes the adapter's
+/// <see cref="ZB.MOM.WW.ScadaBridge.Commons.Interfaces.Protocol.IDataConnection.WriteBatchAsync"/>
+/// (the batch) with a single <c>WriteAsync</c> (the trigger) so the script-facing
+/// <c>Attributes.WriteBatchAndWaitAsync</c> helper replaces N sequential per-attribute
+/// writes with one gateway call. The wait half is the EXISTING event-driven
+/// <c>WaitForAttribute</c> waiter — it is NOT part of this DCL message; failures are
+/// returned synchronously to the calling Instance Actor.
+/// </summary>
+/// <param name="CorrelationId">Per-write correlation id; echoed on the response.</param>
+/// <param name="ConnectionName">The data connection that owns every tag in the batch (and the trigger).</param>
+/// <param name="Values">Device tag path → value to write in the single batch round-trip.</param>
+/// <param name="TriggerTagPath">Optional device tag path of a flag written AFTER the batch succeeds; null to skip.</param>
+/// <param name="TriggerValue">Value to write to <paramref name="TriggerTagPath"/> (ignored when it is null/empty).</param>
+/// <param name="Timestamp">When the request was issued (UTC).</param>
+public record WriteTagBatchRequest(
+    string CorrelationId,
+    string ConnectionName,
+    IReadOnlyDictionary<string, object?> Values,   // device tagPath -> value
+    string? TriggerTagPath,                          // optional flag written AFTER the batch
+    object? TriggerValue,
+    DateTimeOffset Timestamp);
+
+/// <summary>
+/// Response for a <see cref="WriteTagBatchRequest"/>. <see cref="Success"/> is true only
+/// when the whole batch AND the optional trigger committed; otherwise
+/// <see cref="ErrorMessage"/> describes the first failing leg.
+/// </summary>
+/// <param name="CorrelationId">Echoes the request's correlation id.</param>
+/// <param name="Success">True when the batch (and trigger, if any) all committed.</param>
+/// <param name="ErrorMessage">Non-null on failure — the aggregated batch error, the trigger error, a timeout, or an adapter exception.</param>
+/// <param name="Timestamp">When the response was produced (UTC).</param>
+public record WriteTagBatchResponse(
+    string CorrelationId,
+    bool Success,
+    string? ErrorMessage,
+    DateTimeOffset Timestamp);
diff --git a/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Instance/WriteAttributeBatch.cs b/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Instance/WriteAttributeBatch.cs
new file mode 100644
index 00000000..b836246b
--- /dev/null
+++ b/src/ZB.MOM.WW.ScadaBridge.Commons/Messages/Instance/WriteAttributeBatch.cs
@@ -0,0 +1,43 @@
+namespace ZB.MOM.WW.ScadaBridge.Commons.Messages.Instance;
+
+/// <summary>
+/// Request to write a SET of data-sourced attributes on one instance to the device in a
+/// single DCL batch round-trip, optionally followed by a trigger-flag attribute write.
+/// The Instance Actor resolves each attribute's data binding (connection + device tag
+/// path), decodes List values, enforces single-connection scope, and forwards one
+/// <c>WriteTagBatchRequest</c> to the DCL. This is the write half of the script-facing
+/// <c>Attributes.WriteBatchAndWaitAsync</c> helper; the wait half reuses the existing
+/// event-driven <c>WaitForAttribute</c> waiter.
+///
+/// <para>
+/// <b>Site-local only.</b> Values are carried codec-ENCODED (strings), so this message
+/// would serialize — but the helper composing it issues the wait via the in-process
+/// predicate-capable <c>WaitForAttribute</c> path, so the whole flow stays within one
+/// site node's actor system (script execution → Instance Actor → DCL).
+/// </para>
+/// </summary>
+/// <param name="CorrelationId">Per-write correlation id; echoed on the response.</param>
+/// <param name="InstanceName">The instance whose attributes are written.</param>
+/// <param name="AttributeEncodedValues">Canonical (scope-resolved) attribute name → codec-encoded value.</param>
+/// <param name="TriggerAttribute">Optional canonical attribute name of a flag written AFTER the batch; null to skip.</param>
+/// <param name="TriggerEncodedValue">Codec-encoded value for <paramref name="TriggerAttribute"/>.</param>
+/// <param name="OccurredAtUtc">When the request was issued (UTC).</param>
+public record WriteAttributeBatchRequest(
+    string CorrelationId,
+    string InstanceName,
+    IReadOnlyDictionary<string, string?> AttributeEncodedValues, // canonical attr name -> codec-encoded value
+    string? TriggerAttribute,
+    string? TriggerEncodedValue,
+    DateTimeOffset OccurredAtUtc);
+
+/// <summary>
+/// Reply to a <see cref="WriteAttributeBatchRequest"/>. <see cref="Success"/> is true only
+/// when the DCL batch (and trigger, if any) all committed.
+/// </summary>
+/// <param name="CorrelationId">Echoes the request's correlation id.</param>
+/// <param name="Success">True when the batch (and trigger, if any) all committed at the device.</param>
+/// <param name="ErrorMessage">Non-null on failure — an unresolved/non-data-sourced attribute, a multi-connection batch, a list-decode failure, or the DCL error/timeout.</param>
+public record WriteAttributeBatchResponse(
+    string CorrelationId,
+    bool Success,
+    string? ErrorMessage);
diff --git a/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionActor.cs b/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionActor.cs
index 24b71a04..60ad161a 100644
--- a/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionActor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionActor.cs
@@ -245,6 +245,7 @@ public class DataConnectionActor : UntypedActor, IWithStash, IWithTimers
                 break;
             case SubscribeTagsRequest:
             case WriteTagRequest:
+            case WriteTagBatchRequest:
             case UnsubscribeTagsRequest:
             case SubscribeAlarmsRequest:
             case UnsubscribeAlarmsRequest:
@@ -331,6 +332,9 @@ public class DataConnectionActor : UntypedActor, IWithStash, IWithTimers
             case WriteTagRequest req:
                 HandleWrite(req);
                 break;
+            case WriteTagBatchRequest req:
+                HandleWriteBatch(req);
+                break;
             case TagValueReceived tvr:
                 HandleTagValueReceived(tvr);
                 break;
@@ -457,6 +461,7 @@ public class DataConnectionActor : UntypedActor, IWithStash, IWithTimers
                 break;
             case SubscribeTagsRequest:
             case WriteTagRequest:
+            case WriteTagBatchRequest:
             case SubscribeAlarmsRequest:
                 Stash.Stash();
                 break;
@@ -1059,6 +1064,67 @@ public class DataConnectionActor : UntypedActor, IWithStash, IWithTimers
         }).PipeTo(sender);
     }
 
+    /// <summary>
+    /// Batch write counterpart of <see cref="HandleWrite"/>. Writes every value in
+    /// <see cref="WriteTagBatchRequest.Values"/> to the device in ONE adapter
+    /// <c>WriteBatchAsync</c> round-trip, then (if present) writes the trigger flag with
+    /// a single <c>WriteAsync</c>. Both legs share one <see cref="DataConnectionOptions.WriteTimeout"/>
+    /// budget (DataConnectionLayer-005). Any failed value in the batch, a failed trigger,
+    /// the timeout, or an adapter exception is translated into a failed
+    /// <see cref="WriteTagBatchResponse"/> returned synchronously to the caller — never a
+    /// dropped reply. NOTE: this deliberately composes the batch + trigger primitives and
+    /// uses the EXISTING event-driven WaitForAttribute waiter for the wait half; it does
+    /// NOT call the adapter's poll-based <c>WriteBatchAndWaitAsync</c>.
+    /// </summary>
+    private void HandleWriteBatch(WriteTagBatchRequest request)
+    {
+        _log.Debug("[{0}] Batch-writing {1} tag(s)", _connectionName, request.Values.Count);
+        var sender = Sender;
+        var cts = new CancellationTokenSource(_options.WriteTimeout);
+
+        async Task<WriteTagBatchResponse> RunAsync()
+        {
+            try
+            {
+                var results = await _adapter.WriteBatchAsync(
+                    new Dictionary<string, object?>(request.Values), cts.Token);
+                var failed = results.Values.Where(r => !r.Success).Select(r => r.ErrorMessage).ToList();
+                if (failed.Count > 0)
+                    return new WriteTagBatchResponse(
+                        request.CorrelationId, false,
+                        "Batch write failed: " + string.Join("; ", failed), DateTimeOffset.UtcNow);
+
+                if (!string.IsNullOrEmpty(request.TriggerTagPath))
+                {
+                    var tr = await _adapter.WriteAsync(request.TriggerTagPath, request.TriggerValue, cts.Token);
+                    if (!tr.Success)
+                        return new WriteTagBatchResponse(
+                            request.CorrelationId, false,
+                            "Trigger write failed: " + tr.ErrorMessage, DateTimeOffset.UtcNow);
+                }
+
+                return new WriteTagBatchResponse(request.CorrelationId, true, null, DateTimeOffset.UtcNow);
+            }
+            catch (OperationCanceledException)
+            {
+                return new WriteTagBatchResponse(
+                    request.CorrelationId, false,
+                    $"Write timeout after {_options.WriteTimeout.TotalSeconds:F0}s", DateTimeOffset.UtcNow);
+            }
+            catch (Exception ex)
+            {
+                return new WriteTagBatchResponse(
+                    request.CorrelationId, false, ex.GetBaseException().Message, DateTimeOffset.UtcNow);
+            }
+            finally
+            {
+                cts.Dispose();
+            }
+        }
+
+        RunAsync().PipeTo(sender);
+    }
+
     // ── OPC UA Tag Browser (interactive design-time query) ──
 
     /// <summary>
diff --git a/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionManagerActor.cs b/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionManagerActor.cs
index 5069c1b1..a46b020e 100644
--- a/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionManagerActor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.DataConnectionLayer/Actors/DataConnectionManagerActor.cs
@@ -46,6 +46,7 @@ public class DataConnectionManagerActor : ReceiveActor
         Receive<SubscribeAlarmsRequest>(HandleRouteAlarms);
         Receive<UnsubscribeAlarmsRequest>(HandleRouteAlarms);
         Receive<WriteTagRequest>(HandleRouteWrite);
+        Receive<WriteTagBatchRequest>(HandleRouteWriteBatch);
         Receive<RemoveConnectionCommand>(HandleRemoveConnection);
         Receive<GetAllHealthReports>(HandleGetAllHealthReports);
         Receive<BrowseNodeCommand>(HandleBrowse);
@@ -141,6 +142,26 @@ public class DataConnectionManagerActor : ReceiveActor
         }
     }
 
+    /// <summary>
+    /// Routes a <see cref="WriteTagBatchRequest"/> to the child
+    /// <see cref="DataConnectionActor"/> that owns the named connection — the batch
+    /// counterpart of <see cref="HandleRouteWrite"/>. The manager owns only the
+    /// unknown-connection failure (the same split as every other routed message);
+    /// the child resolves connected/not-connected and the per-write outcomes.
+    /// </summary>
+    private void HandleRouteWriteBatch(WriteTagBatchRequest request)
+    {
+        if (_connectionActors.TryGetValue(request.ConnectionName, out var actor))
+            actor.Forward(request);
+        else
+        {
+            _log.Warning("No connection actor for {0}", request.ConnectionName);
+            Sender.Tell(new WriteTagBatchResponse(
+                request.CorrelationId, false,
+                $"Unknown connection: {request.ConnectionName}", DateTimeOffset.UtcNow));
+        }
+    }
+
     /// <summary>
     /// Routes a <see cref="BrowseNodeCommand"/> from the central UI's OPC UA
     /// Tag Browser to the child <see cref="DataConnectionActor"/> that owns the
diff --git a/src/ZB.MOM.WW.ScadaBridge.ScriptAnalysis/ScriptCompileSurface.cs b/src/ZB.MOM.WW.ScadaBridge.ScriptAnalysis/ScriptCompileSurface.cs
index 03390ae1..3e3911fc 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ScriptAnalysis/ScriptCompileSurface.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ScriptAnalysis/ScriptCompileSurface.cs
@@ -193,6 +193,9 @@ public sealed class ScriptCompileSurface
         /// <summary>Mirrors <c>AttributeAccessor.WaitForAsync</c>.</summary>
         public Task<WaitResult> WaitForAsync(string key, object? targetValue, TimeSpan timeout, bool requireGoodQuality = false) => throw new NotSupportedException(CompileOnly);
         public Task<WaitResult> WaitForAsync(string key, Func<object?, bool> predicate, TimeSpan timeout, bool requireGoodQuality = false) => throw new NotSupportedException(CompileOnly);
+
+        /// <summary>Mirrors <c>AttributeAccessor.WriteBatchAndWaitAsync</c>.</summary>
+        public Task<bool> WriteBatchAndWaitAsync(IReadOnlyDictionary<string, object?> values, string flagKey, object? flagValue, string responseKey, object? responseValue, TimeSpan timeout) => throw new NotSupportedException(CompileOnly);
     }
 
     /// <summary>Compile-only mirror of <c>ChildrenAccessor</c>.</summary>
diff --git a/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/InstanceActor.cs b/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/InstanceActor.cs
index c640db9b..d6cea648 100644
--- a/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/InstanceActor.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Actors/InstanceActor.cs
@@ -188,6 +188,12 @@ public class InstanceActor : ReceiveActor
         Receive<WaitForAttributeRequest>(HandleWaitForAttribute);
         Receive<WaitForAttributeTimeout>(HandleWaitForAttributeTimeout);
 
+        // Batch write + (event-driven) wait: resolves a set of data-sourced
+        // attributes to one DCL connection and forwards a single WriteTagBatchRequest.
+        // Backs the script-facing Attributes.WriteBatchAndWaitAsync helper; the wait
+        // half is the WaitForAttribute waiter above.
+        Receive<WriteAttributeBatchRequest>(HandleWriteAttributeBatch);
+
         // Handle tag value updates from DCL — convert to AttributeValueChanged
         Receive<TagValueUpdate>(HandleTagValueUpdate);
         Receive<SubscribeTagsResponse>(_ => { }); // Ack from DCL subscribe — no action needed
@@ -499,6 +505,118 @@ public class InstanceActor : ReceiveActor
             }).PipeTo(caller);
     }
 
+    /// <summary>
+    /// Batch write: resolves a SET of data-sourced attributes (and an optional trigger
+    /// attribute) to their device bindings, enforces a single data connection across the
+    /// whole batch, decodes List values (same rule as <see cref="HandleSetDataAttribute"/>),
+    /// and forwards ONE <see cref="WriteTagBatchRequest"/> to the DCL — replacing N
+    /// sequential per-attribute writes with a single gateway round-trip. The write outcome
+    /// is returned synchronously to the caller; the EVENT-DRIVEN wait for the response
+    /// attribute is performed separately by the caller via the existing WaitForAttribute
+    /// waiter (this handler does not wait). Resolution mirrors the data-sourced
+    /// SetAttribute path: an attribute is data-sourced only when it resolves AND has both a
+    /// <see cref="ResolvedAttribute.DataSourceReference"/> and a
+    /// <see cref="ResolvedAttribute.BoundDataConnectionName"/>.
+    /// </summary>
+    private void HandleWriteAttributeBatch(WriteAttributeBatchRequest request)
+    {
+        var caller = Sender;
+        var cid = request.CorrelationId;
+
+        if (_dclManager == null)
+        {
+            caller.Tell(new WriteAttributeBatchResponse(
+                cid, false, "Data Connection Layer not available for write."));
+            return;
+        }
+
+        var values = new Dictionary<string, object?>();
+        string? connName = null;
+
+        foreach (var kv in request.AttributeEncodedValues)
+        {
+            if (!_resolvedAttributeByName.TryGetValue(kv.Key, out var resolved)
+                || string.IsNullOrEmpty(resolved.DataSourceReference)
+                || string.IsNullOrEmpty(resolved.BoundDataConnectionName))
+            {
+                caller.Tell(new WriteAttributeBatchResponse(
+                    cid, false, $"Attribute '{kv.Key}' is not a data-sourced attribute."));
+                return;
+            }
+
+            if (connName == null)
+                connName = resolved.BoundDataConnectionName;
+            else if (!string.Equals(connName, resolved.BoundDataConnectionName, StringComparison.Ordinal))
+            {
+                caller.Tell(new WriteAttributeBatchResponse(
+                    cid, false, "Batch write spans multiple data connections; not supported."));
+                return;
+            }
+
+            object? wv = kv.Value;
+            // MV: a data-sourced List attribute's encoded value is the canonical JSON
+            // array string — decode it to a typed List<T> so the DCL/Variant write
+            // produces a real array (same poison-rejection rule as HandleSetDataAttribute).
+            if (IsListAttribute(resolved) && !string.IsNullOrWhiteSpace(kv.Value))
+            {
+                var decoded = DecodeAttributeValue(resolved, kv.Value);
+                if (decoded == null)
+                {
+                    caller.Tell(new WriteAttributeBatchResponse(
+                        cid, false, $"Invalid list value for attribute '{kv.Key}'"));
+                    return;
+                }
+                wv = decoded;
+            }
+
+            values[resolved.DataSourceReference!] = wv;
+        }
+
+        string? triggerPath = null;
+        object? triggerVal = null;
+        if (!string.IsNullOrEmpty(request.TriggerAttribute))
+        {
+            if (!_resolvedAttributeByName.TryGetValue(request.TriggerAttribute, out var tr)
+                || string.IsNullOrEmpty(tr.DataSourceReference)
+                || string.IsNullOrEmpty(tr.BoundDataConnectionName))
+            {
+                caller.Tell(new WriteAttributeBatchResponse(
+                    cid, false, $"Trigger attribute '{request.TriggerAttribute}' is not data-sourced."));
+                return;
+            }
+
+            if (connName != null && !string.Equals(connName, tr.BoundDataConnectionName, StringComparison.Ordinal))
+            {
+                caller.Tell(new WriteAttributeBatchResponse(
+                    cid, false, "Trigger attribute is on a different data connection."));
+                return;
+            }
+
+            connName ??= tr.BoundDataConnectionName;
+            triggerPath = tr.DataSourceReference;
+            triggerVal = request.TriggerEncodedValue;
+        }
+
+        if (connName == null)
+        {
+            caller.Tell(new WriteAttributeBatchResponse(cid, false, "No attributes to write."));
+            return;
+        }
+
+        var dclReq = new WriteTagBatchRequest(
+            cid, connName!, values, triggerPath, triggerVal, DateTimeOffset.UtcNow);
+
+        // Ask the DCL and pipe the batch outcome back to the original caller. The DCL
+        // bounds its own write with WriteTimeout; this Ask is bounded a bit longer so a
+        // device timeout is surfaced as a DCL failure rather than an Ask timeout.
+        _dclManager.Ask<WriteTagBatchResponse>(dclReq, TimeSpan.FromSeconds(30))
+            .ContinueWith(t => t.IsCompletedSuccessfully
+                ? new WriteAttributeBatchResponse(cid, t.Result.Success, t.Result.ErrorMessage)
+                : new WriteAttributeBatchResponse(
+                    cid, false, t.Exception?.GetBaseException().Message ?? "DCL batch write timed out"))
+            .PipeTo(caller);
+    }
+
     /// <summary>
     /// WP-15: Routes script call requests to the appropriate Script Actor.
     /// Uses Ask pattern (WP-22).
diff --git a/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/ScopeAccessors.cs b/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/ScopeAccessors.cs
index 35d29d7c..2e1fa43f 100644
--- a/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/ScopeAccessors.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/ScopeAccessors.cs
@@ -74,6 +74,40 @@ public class AttributeAccessor
     public Task SetAsync(string key, object? value)
         => _ctx.SetAttribute(Resolve(key), AttributeValueCodec.Encode(value) ?? string.Empty);
 
+    /// <summary>
+    /// Writes a SET of data-sourced attributes to the device in ONE gateway batch
+    /// round-trip, then writes <paramref name="flagKey"/>=<paramref name="flagValue"/>,
+    /// then waits EVENT-DRIVEN (reusing the existing <c>WaitForAttribute</c> waiter — not a
+    /// poll) for <paramref name="responseKey"/> to reach <paramref name="responseValue"/>,
+    /// bounded by <paramref name="timeout"/>. Replaces N sequential per-attribute writes
+    /// with one batched call before the wait. All keys are scope-resolved (<see cref="Resolve"/>)
+    /// and all values codec-encoded just like the other accessors. Returns <c>true</c> if
+    /// the response was observed within the timeout, <c>false</c> on timeout (no throw on
+    /// timeout); throws <see cref="System.InvalidOperationException"/> if the batch/trigger
+    /// write itself fails.
+    /// </summary>
+    /// <param name="values">Attribute key → value to batch-write (keys scope-resolved, values codec-encoded).</param>
+    /// <param name="flagKey">Trigger attribute key written AFTER the batch.</param>
+    /// <param name="flagValue">Value to write to the trigger.</param>
+    /// <param name="responseKey">Attribute key to wait on.</param>
+    /// <param name="responseValue">Target value to wait for (<c>null</c> ⇒ any change).</param>
+    /// <param name="timeout">How long to wait before returning false.</param>
+    /// <returns><c>true</c> on response match within the timeout; <c>false</c> on timeout.</returns>
+    public Task<bool> WriteBatchAndWaitAsync(
+        IReadOnlyDictionary<string, object?> values, string flagKey, object? flagValue,
+        string responseKey, object? responseValue, TimeSpan timeout)
+    {
+        var encoded = new Dictionary<string, string?>(values.Count);
+        foreach (var kv in values)
+            encoded[Resolve(kv.Key)] = AttributeValueCodec.Encode(kv.Value);
+
+        return _ctx.WriteBatchAndWait(
+            encoded,
+            Resolve(flagKey), AttributeValueCodec.Encode(flagValue),
+            Resolve(responseKey), AttributeValueCodec.Encode(responseValue),
+            timeout);
+    }
+
     /// <summary>
     /// WaitForAttribute (spec §3-§5): waits event-driven until the attribute equals
     /// <paramref name="targetValue"/> (value-equality, codec-normalized), bounded by
diff --git a/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/ScriptRuntimeContext.cs b/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/ScriptRuntimeContext.cs
index 7ace9074..054bc31f 100644
--- a/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/ScriptRuntimeContext.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.SiteRuntime/Scripts/ScriptRuntimeContext.cs
@@ -525,6 +525,44 @@ public class ScriptRuntimeContext
         }
     }
 
+    /// <summary>
+    /// Writes a SET of data-sourced attributes to the device in ONE DCL batch round-trip,
+    /// then writes a trigger flag, then waits EVENT-DRIVEN (reusing the existing
+    /// <see cref="WaitAttribute"/> waiter — not a poll) for <paramref name="responseAttr"/>
+    /// to reach <paramref name="responseEncoded"/>, bounded by <paramref name="timeout"/>.
+    /// Replaces N sequential per-attribute writes with a single gateway call before the
+    /// wait. Throws <see cref="InvalidOperationException"/> if the write/trigger leg fails
+    /// (resolution error, multi-connection batch, device error); returns the wait result
+    /// otherwise (true = matched, false = timeout, never throws on timeout).
+    /// </summary>
+    /// <param name="encodedValues">Scope-resolved attribute name → codec-encoded value to batch-write.</param>
+    /// <param name="triggerAttr">Scope-resolved trigger attribute name written AFTER the batch.</param>
+    /// <param name="triggerEncoded">Codec-encoded value for the trigger.</param>
+    /// <param name="responseAttr">Scope-resolved attribute to wait on.</param>
+    /// <param name="responseEncoded">Codec-encoded target value (null ⇒ any change).</param>
+    /// <param name="timeout">How long to wait for the response before returning false.</param>
+    /// <returns><c>true</c> on response match within the timeout; <c>false</c> on timeout.</returns>
+    public async Task<bool> WriteBatchAndWait(
+        IReadOnlyDictionary<string, string?> encodedValues, string triggerAttr, string? triggerEncoded,
+        string responseAttr, string? responseEncoded, TimeSpan timeout)
+    {
+        var cid = Guid.NewGuid().ToString();
+        var batchReq = new WriteAttributeBatchRequest(
+            cid, _instanceName, encodedValues, triggerAttr, triggerEncoded, DateTimeOffset.UtcNow);
+
+        // 35s: the InstanceActor's DCL Ask is internally bounded at 30s, so allow a small
+        // margin so the DCL's own typed failure/timeout reply is the one we observe rather
+        // than an AskTimeoutException here. Honors the script execution-timeout token.
+        var batchResp = await _instanceActor.Ask<WriteAttributeBatchResponse>(
+            batchReq, TimeSpan.FromSeconds(35), _scriptTimeoutToken);
+
+        if (!batchResp.Success)
+            throw new InvalidOperationException(
+                $"WriteBatchAndWait write failed: {batchResp.ErrorMessage}");
+
+        return await WaitAttribute(responseAttr, responseEncoded, null, timeout);
+    }
+
     /// <summary>
     /// Calls a sibling script on the same instance by name (Ask pattern).
     /// WP-20: Enforces recursion limit.