diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/AlarmsHistorian.razor b/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/AlarmsHistorian.razor
new file mode 100644
index 0000000..b8dcbfe
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/AlarmsHistorian.razor
@@ -0,0 +1,79 @@
+@page "/alarms/historian"
+@using ZB.MOM.WW.OtOpcUa.Admin.Services
+@using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian
+@inject HistorianDiagnosticsService Diag
+
+<h1>Alarm historian</h1>
+<p class="text-muted">Local store-and-forward queue that ships alarm events to Aveva Historian via Galaxy.Host.</p>
+
+<div class="card mb-3">
+    <div class="card-body">
+        <div class="row">
+            <div class="col-md-3">
+                <small class="text-muted">Drain state</small>
+                <h4><span class="badge @BadgeFor(_status.DrainState)">@_status.DrainState</span></h4>
+            </div>
+            <div class="col-md-3">
+                <small class="text-muted">Queue depth</small>
+                <h4>@_status.QueueDepth.ToString("N0")</h4>
+            </div>
+            <div class="col-md-3">
+                <small class="text-muted">Dead-letter depth</small>
+                <h4 class="@(_status.DeadLetterDepth > 0 ? "text-warning" : "")">@_status.DeadLetterDepth.ToString("N0")</h4>
+            </div>
+            <div class="col-md-3">
+                <small class="text-muted">Last success</small>
+                <h4>@(_status.LastSuccessUtc?.ToString("u") ?? "—")</h4>
+            </div>
+        </div>
+
+        @if (!string.IsNullOrEmpty(_status.LastError))
+        {
+            <div class="alert alert-warning mt-3 mb-0">
+                <strong>Last error:</strong> @_status.LastError
+            </div>
+        }
+    </div>
+</div>
+
+<div class="d-flex gap-2">
+    <button class="btn btn-outline-secondary" @onclick="RefreshAsync">Refresh</button>
+    <button class="btn btn-warning" disabled="@(_status.DeadLetterDepth == 0)" @onclick="RetryDeadLetteredAsync">
+        Retry dead-lettered (@_status.DeadLetterDepth)
+    </button>
+</div>
+
+@if (_retryResult is not null)
+{
+    <div class="alert alert-success mt-3">Requeued @_retryResult row(s) for retry.</div>
+}
+
+@code {
+    private HistorianSinkStatus _status = new(0, 0, null, null, null, HistorianDrainState.Disabled);
+    private int? _retryResult;
+
+    protected override void OnInitialized() => _status = Diag.GetStatus();
+
+    private Task RefreshAsync()
+    {
+        _status = Diag.GetStatus();
+        _retryResult = null;
+        return Task.CompletedTask;
+    }
+
+    private Task RetryDeadLetteredAsync()
+    {
+        _retryResult = Diag.TryRetryDeadLettered();
+        _status = Diag.GetStatus();
+        return Task.CompletedTask;
+    }
+
+    private static string BadgeFor(HistorianDrainState s) => s switch
+    {
+        HistorianDrainState.Idle => "bg-success",
+        HistorianDrainState.Draining => "bg-info",
+        HistorianDrainState.BackingOff => "bg-warning text-dark",
+        HistorianDrainState.Disabled => "bg-secondary",
+        _ => "bg-secondary",
+    };
+}
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/DraftEditor.razor b/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/DraftEditor.razor
index dfef4b9..e92f284 100644
--- a/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/DraftEditor.razor
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/DraftEditor.razor
@@ -23,6 +23,7 @@
     <li class="nav-item"><button class="nav-link @Active("namespaces")" @onclick='() => _tab = "namespaces"'>Namespaces</button></li>
     <li class="nav-item"><button class="nav-link @Active("drivers")" @onclick='() => _tab = "drivers"'>Drivers</button></li>
     <li class="nav-item"><button class="nav-link @Active("acls")" @onclick='() => _tab = "acls"'>ACLs</button></li>
+    <li class="nav-item"><button class="nav-link @Active("scripts")" @onclick='() => _tab = "scripts"'>Scripts</button></li>
 </ul>
 
 <div class="row">
@@ -32,6 +33,7 @@
         else if (_tab == "namespaces") { <NamespacesTab GenerationId="@GenerationId" ClusterId="@ClusterId"/> }
         else if (_tab == "drivers") { <DriversTab GenerationId="@GenerationId" ClusterId="@ClusterId"/> }
         else if (_tab == "acls") { <AclsTab GenerationId="@GenerationId" ClusterId="@ClusterId"/> }
+        else if (_tab == "scripts") { <ScriptsTab GenerationId="@GenerationId" ClusterId="@ClusterId"/> }
     </div>
     <div class="col-md-4">
         <div class="card sticky-top">
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptEditor.razor b/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptEditor.razor
new file mode 100644
index 0000000..2f4339c
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptEditor.razor
@@ -0,0 +1,41 @@
+@using Microsoft.AspNetCore.Components.Web
+@inject IJSRuntime JS
+
+@*
+    Monaco-backed C# code editor (Phase 7 Stream F). Progressive enhancement:
+    textarea renders immediately, Monaco mounts via JS interop after first render.
+    Monaco script tags are loaded once from the parent layout (wwwroot/js/monaco-loader.js
+    pulls the CDN bundle).
+
+    Stream F keeps the interop surface small — bind `Source` two-way, and the parent
+    tab re-renders on change for the dependency preview. The test-harness button
+    lives in the parent so one editor can drive multiple script types.
+*@
+
+<div class="script-editor">
+    <textarea class="form-control font-monospace" rows="14" spellcheck="false"
+              @bind="Source" @bind:event="oninput" id="@_editorId">@Source</textarea>
+</div>
+
+@code {
+    [Parameter] public string Source { get; set; } = string.Empty;
+    [Parameter] public EventCallback<string> SourceChanged { get; set; }
+
+    private readonly string _editorId = $"script-editor-{Guid.NewGuid():N}";
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (firstRender)
+        {
+            try
+            {
+                await JS.InvokeVoidAsync("otOpcUaScriptEditor.attach", _editorId);
+            }
+            catch (JSException)
+            {
+                // Monaco bundle not yet loaded on this page — textarea fallback is
+                // still functional.
+            }
+        }
+    }
+}
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptsTab.razor b/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptsTab.razor
new file mode 100644
index 0000000..b0d5eb7
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Components/Pages/Clusters/ScriptsTab.razor
@@ -0,0 +1,224 @@
+@using ZB.MOM.WW.OtOpcUa.Admin.Services
+@using ZB.MOM.WW.OtOpcUa.Configuration.Entities
+@using ZB.MOM.WW.OtOpcUa.Core.Abstractions
+@using ZB.MOM.WW.OtOpcUa.Core.Scripting
+@inject ScriptService ScriptSvc
+@inject ScriptTestHarnessService Harness
+
+<div class="d-flex justify-content-between align-items-center mb-3">
+    <div>
+        <h4 class="mb-0">Scripts</h4>
+        <small class="text-muted">C# (Roslyn). Used by virtual tags + scripted alarms.</small>
+    </div>
+    <button class="btn btn-primary" @onclick="StartNew">+ New script</button>
+</div>
+
+<script src="/js/monaco-loader.js"></script>
+
+@if (_loading) { <p class="text-muted">Loading…</p> }
+else if (_scripts.Count == 0 && _editing is null)
+{
+    <div class="alert alert-info">No scripts yet in this draft.</div>
+}
+else
+{
+    <div class="row">
+        <div class="col-md-4">
+            <div class="list-group">
+                @foreach (var s in _scripts)
+                {
+                    <button class="list-group-item list-group-item-action @(_editing?.ScriptId == s.ScriptId ? "active" : "")"
+                            @onclick="() => Open(s)">
+                        <strong>@s.Name</strong>
+                        <div class="small text-muted font-monospace">@s.ScriptId</div>
+                    </button>
+                }
+            </div>
+        </div>
+        <div class="col-md-8">
+            @if (_editing is not null)
+            {
+                <div class="card">
+                    <div class="card-header d-flex justify-content-between align-items-center">
+                        <strong>@(_isNew ? "New script" : _editing.Name)</strong>
+                        <div>
+                            @if (!_isNew)
+                            {
+                                <button class="btn btn-sm btn-outline-danger me-2" @onclick="DeleteAsync">Delete</button>
+                            }
+                            <button class="btn btn-sm btn-primary" disabled="@_busy" @onclick="SaveAsync">Save</button>
+                        </div>
+                    </div>
+                    <div class="card-body">
+                        <div class="mb-2">
+                            <label class="form-label">Name</label>
+                            <input class="form-control" @bind="_editing.Name"/>
+                        </div>
+                        <label class="form-label">Source</label>
+                        <ScriptEditor @bind-Source="_editing.SourceCode"/>
+
+                        <div class="mt-3">
+                            <button class="btn btn-sm btn-outline-secondary" @onclick="PreviewDependencies">Analyze dependencies</button>
+                            <button class="btn btn-sm btn-outline-info ms-2" @onclick="RunHarnessAsync" disabled="@_harnessBusy">Run test harness</button>
+                        </div>
+
+                        @if (_dependencies is not null)
+                        {
+                            <div class="mt-3">
+                                <strong>Inferred reads</strong>
+                                @if (_dependencies.Reads.Count == 0) { <span class="text-muted ms-2">none</span> }
+                                else
+                                {
+                                    <ul class="mb-1">
+                                        @foreach (var r in _dependencies.Reads) { <li><code>@r</code></li> }
+                                    </ul>
+                                }
+                                <strong>Inferred writes</strong>
+                                @if (_dependencies.Writes.Count == 0) { <span class="text-muted ms-2">none</span> }
+                                else
+                                {
+                                    <ul class="mb-1">
+                                        @foreach (var w in _dependencies.Writes) { <li><code>@w</code></li> }
+                                    </ul>
+                                }
+                                @if (_dependencies.Rejections.Count > 0)
+                                {
+                                    <div class="alert alert-danger mt-2">
+                                        <strong>Non-literal paths rejected:</strong>
+                                        <ul class="mb-0">
+                                            @foreach (var r in _dependencies.Rejections) { <li>@r.Message</li> }
+                                        </ul>
+                                    </div>
+                                }
+                            </div>
+                        }
+
+                        @if (_testResult is not null)
+                        {
+                            <div class="mt-3 border-top pt-3">
+                                <strong>Harness result:</strong> <span class="badge bg-secondary">@_testResult.Outcome</span>
+                                @if (_testResult.Outcome == ScriptTestOutcome.Success)
+                                {
+                                    <div>Output: <code>@(_testResult.Output?.ToString() ?? "null")</code></div>
+                                    @if (_testResult.Writes.Count > 0)
+                                    {
+                                        <div class="mt-1"><strong>Writes:</strong>
+                                            <ul class="mb-0">
+                                                @foreach (var kv in _testResult.Writes) { <li><code>@kv.Key</code> = <code>@(kv.Value?.ToString() ?? "null")</code></li> }
+                                            </ul>
+                                        </div>
+                                    }
+                                }
+                                @if (_testResult.Errors.Count > 0)
+                                {
+                                    <div class="alert alert-warning mt-2 mb-0">
+                                        @foreach (var e in _testResult.Errors) { <div>@e</div> }
+                                    </div>
+                                }
+                                @if (_testResult.LogEvents.Count > 0)
+                                {
+                                    <div class="mt-2"><strong>Script log output:</strong>
+                                        <ul class="small mb-0">
+                                            @foreach (var e in _testResult.LogEvents) { <li>[@e.Level] @e.RenderMessage()</li> }
+                                        </ul>
+                                    </div>
+                                }
+                            </div>
+                        }
+                    </div>
+                </div>
+            }
+        </div>
+    </div>
+}
+
+@code {
+    [Parameter] public long GenerationId { get; set; }
+    [Parameter] public string ClusterId { get; set; } = string.Empty;
+
+    private bool _loading = true;
+    private bool _busy;
+    private bool _harnessBusy;
+    private bool _isNew;
+    private List<Script> _scripts = [];
+    private Script? _editing;
+    private DependencyExtractionResult? _dependencies;
+    private ScriptTestResult? _testResult;
+
+    protected override async Task OnParametersSetAsync()
+    {
+        _loading = true;
+        _scripts = await ScriptSvc.ListAsync(GenerationId, CancellationToken.None);
+        _loading = false;
+    }
+
+    private void Open(Script s)
+    {
+        _editing = new Script
+        {
+            ScriptRowId = s.ScriptRowId, GenerationId = s.GenerationId,
+            ScriptId = s.ScriptId, Name = s.Name, SourceCode = s.SourceCode,
+            SourceHash = s.SourceHash, Language = s.Language,
+        };
+        _isNew = false;
+        _dependencies = null;
+        _testResult = null;
+    }
+
+    private void StartNew()
+    {
+        _editing = new Script
+        {
+            GenerationId = GenerationId, ScriptId = "",
+            Name = "new-script", SourceCode = "return 0;", SourceHash = "",
+        };
+        _isNew = true;
+        _dependencies = null;
+        _testResult = null;
+    }
+
+    private async Task SaveAsync()
+    {
+        if (_editing is null) return;
+        _busy = true;
+        try
+        {
+            if (_isNew)
+                await ScriptSvc.AddAsync(GenerationId, _editing.Name, _editing.SourceCode, CancellationToken.None);
+            else
+                await ScriptSvc.UpdateAsync(GenerationId, _editing.ScriptId, _editing.Name, _editing.SourceCode, CancellationToken.None);
+            _scripts = await ScriptSvc.ListAsync(GenerationId, CancellationToken.None);
+            _isNew = false;
+        }
+        finally { _busy = false; }
+    }
+
+    private async Task DeleteAsync()
+    {
+        if (_editing is null || _isNew) return;
+        await ScriptSvc.DeleteAsync(GenerationId, _editing.ScriptId, CancellationToken.None);
+        _editing = null;
+        _scripts = await ScriptSvc.ListAsync(GenerationId, CancellationToken.None);
+    }
+
+    private void PreviewDependencies()
+    {
+        if (_editing is null) return;
+        _dependencies = DependencyExtractor.Extract(_editing.SourceCode);
+    }
+
+    private async Task RunHarnessAsync()
+    {
+        if (_editing is null) return;
+        _harnessBusy = true;
+        try
+        {
+            _dependencies ??= DependencyExtractor.Extract(_editing.SourceCode);
+            var inputs = new Dictionary<string, DataValueSnapshot>();
+            foreach (var read in _dependencies.Reads)
+                inputs[read] = new DataValueSnapshot(0.0, 0u, DateTime.UtcNow, DateTime.UtcNow);
+            _testResult = await Harness.RunVirtualTagAsync(_editing.SourceCode, inputs, CancellationToken.None);
+        }
+        finally { _harnessBusy = false; }
+    }
+}
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Program.cs b/src/ZB.MOM.WW.OtOpcUa.Admin/Program.cs
index 135f6b9..97fb633 100644
--- a/src/ZB.MOM.WW.OtOpcUa.Admin/Program.cs
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Program.cs
@@ -57,6 +57,18 @@ builder.Services.AddScoped<EquipmentImportBatchService>();
 builder.Services.AddScoped<ZB.MOM.WW.OtOpcUa.Configuration.Services.ILdapGroupRoleMappingService,
     ZB.MOM.WW.OtOpcUa.Configuration.Services.LdapGroupRoleMappingService>();
 
+// Phase 7 Stream F — scripting + virtual tag + scripted alarm draft services, test
+// harness, and historian diagnostics. The historian sink is the Null variant here —
+// the real SqliteStoreAndForwardSink lives in the server process. Admin reads status
+// from whichever sink is provided at composition time.
+builder.Services.AddScoped<ScriptService>();
+builder.Services.AddScoped<VirtualTagService>();
+builder.Services.AddScoped<ScriptedAlarmService>();
+builder.Services.AddScoped<ScriptTestHarnessService>();
+builder.Services.AddScoped<HistorianDiagnosticsService>();
+builder.Services.AddSingleton<ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.IAlarmHistorianSink>(
+    ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.NullAlarmHistorianSink.Instance);
+
 // Cert-trust management — reads the OPC UA server's PKI store root so rejected client certs
 // can be promoted to trusted via the Admin UI. Singleton: no per-request state, just
 // filesystem operations.
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Services/HistorianDiagnosticsService.cs b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/HistorianDiagnosticsService.cs
new file mode 100644
index 0000000..73f2b4d
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/HistorianDiagnosticsService.cs
@@ -0,0 +1,32 @@
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>
+///     Surfaces the local-node historian queue health on the Admin UI's
+///     <c>/alarms/historian</c> diagnostics page (Phase 7 plan decisions #16/#21).
+///     Exposes queue depth / drain state / last-error, and lets the operator retry
+///     dead-lettered rows without restarting the node.
+/// </summary>
+/// <remarks>
+///     The sink injected here is the server-process <see cref="IAlarmHistorianSink"/>.
+///     When <see cref="NullAlarmHistorianSink"/> is bound (historian disabled for this
+///     deployment), <see cref="TryRetryDeadLettered"/> silently returns 0 and
+///     <see cref="GetStatus"/> reports <see cref="HistorianDrainState.Disabled"/>.
+/// </remarks>
+public sealed class HistorianDiagnosticsService(IAlarmHistorianSink sink)
+{
+    public HistorianSinkStatus GetStatus() => sink.GetStatus();
+
+    /// <summary>
+    ///     Operator action from the UI's "Retry dead-lettered" button. Returns the number
+    ///     of rows revived so the UI can flash a confirmation. When the live sink doesn't
+    ///     implement retry (test doubles, Null sink), returns 0.
+    /// </summary>
+    public int TryRetryDeadLettered()
+    {
+        if (sink is SqliteStoreAndForwardSink concrete)
+            return concrete.RetryDeadLettered();
+        return 0;
+    }
+}
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptService.cs b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptService.cs
new file mode 100644
index 0000000..a869afa
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptService.cs
@@ -0,0 +1,66 @@
+using System.Security.Cryptography;
+using System.Text;
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>
+///     Draft-generation CRUD for <see cref="Script"/> rows — the C# source code referenced
+///     by Phase 7 virtual tags and scripted alarms. <see cref="Script.SourceHash"/> is
+///     recomputed on every save so Core.Scripting's compile cache sees a fresh key when
+///     source changes and reuses the compile when it doesn't.
+/// </summary>
+public sealed class ScriptService(OtOpcUaConfigDbContext db)
+{
+    public Task<List<Script>> ListAsync(long generationId, CancellationToken ct) =>
+        db.Scripts.AsNoTracking()
+            .Where(s => s.GenerationId == generationId)
+            .OrderBy(s => s.Name)
+            .ToListAsync(ct);
+
+    public Task<Script?> GetAsync(long generationId, string scriptId, CancellationToken ct) =>
+        db.Scripts.AsNoTracking()
+            .FirstOrDefaultAsync(s => s.GenerationId == generationId && s.ScriptId == scriptId, ct);
+
+    public async Task<Script> AddAsync(long generationId, string name, string sourceCode, CancellationToken ct)
+    {
+        var s = new Script
+        {
+            GenerationId = generationId,
+            ScriptId = $"scr-{Guid.NewGuid():N}"[..20],
+            Name = name,
+            SourceCode = sourceCode,
+            SourceHash = ComputeHash(sourceCode),
+        };
+        db.Scripts.Add(s);
+        await db.SaveChangesAsync(ct);
+        return s;
+    }
+
+    public async Task<Script> UpdateAsync(long generationId, string scriptId, string name, string sourceCode, CancellationToken ct)
+    {
+        var s = await db.Scripts.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.ScriptId == scriptId, ct)
+            ?? throw new InvalidOperationException($"Script '{scriptId}' not found in generation {generationId}");
+        s.Name = name;
+        s.SourceCode = sourceCode;
+        s.SourceHash = ComputeHash(sourceCode);
+        await db.SaveChangesAsync(ct);
+        return s;
+    }
+
+    public async Task DeleteAsync(long generationId, string scriptId, CancellationToken ct)
+    {
+        var s = await db.Scripts.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.ScriptId == scriptId, ct);
+        if (s is null) return;
+        db.Scripts.Remove(s);
+        await db.SaveChangesAsync(ct);
+    }
+
+    internal static string ComputeHash(string source)
+    {
+        var bytes = SHA256.HashData(Encoding.UTF8.GetBytes(source ?? string.Empty));
+        return Convert.ToHexString(bytes);
+    }
+}
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptTestHarnessService.cs b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptTestHarnessService.cs
new file mode 100644
index 0000000..571d6de
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptTestHarnessService.cs
@@ -0,0 +1,121 @@
+using Serilog;  // resolves Serilog.ILogger explicitly in signatures
+using Serilog.Core;
+using Serilog.Events;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.Scripting;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>
+///     Dry-run harness for the Phase 7 scripting UI. Takes a script + a synthetic input
+///     map + evaluates once, returns the output (or rejection / exception) plus any
+///     logger emissions the script produced. Per Phase 7 plan decision #22: only inputs
+///     the <see cref="DependencyExtractor"/> identified can be supplied, so a dependency
+///     the harness can't prove statically surfaces as a harness error, not a runtime
+///     surprise later.
+/// </summary>
+public sealed class ScriptTestHarnessService
+{
+    /// <summary>
+    ///     Evaluate <paramref name="source"/> as a virtual-tag script (return value is the
+    ///     tag's new value). <paramref name="inputs"/> supplies synthetic
+    ///     <see cref="DataValueSnapshot"/>s for every path the extractor found.
+    /// </summary>
+    public async Task<ScriptTestResult> RunVirtualTagAsync(
+        string source, IDictionary<string, DataValueSnapshot> inputs, CancellationToken ct)
+    {
+        var deps = DependencyExtractor.Extract(source);
+        if (!deps.IsValid)
+            return ScriptTestResult.DependencyRejections(deps.Rejections);
+
+        var missing = deps.Reads.Where(r => !inputs.ContainsKey(r)).ToArray();
+        if (missing.Length > 0)
+            return ScriptTestResult.MissingInputs(missing);
+
+        var extra = inputs.Keys.Where(k => !deps.Reads.Contains(k)).ToArray();
+        if (extra.Length > 0)
+            return ScriptTestResult.UnknownInputs(extra);
+
+        ScriptEvaluator<HarnessVirtualTagContext, object?> evaluator;
+        try
+        {
+            evaluator = ScriptEvaluator<HarnessVirtualTagContext, object?>.Compile(source);
+        }
+        catch (Exception compileEx)
+        {
+            return ScriptTestResult.Threw(compileEx.Message, []);
+        }
+        var capturing = new CapturingSink();
+        var logger = new LoggerConfiguration().MinimumLevel.Verbose().WriteTo.Sink(capturing).CreateLogger();
+        var ctx = new HarnessVirtualTagContext(inputs, logger);
+
+        try
+        {
+            var result = await evaluator.RunAsync(ctx, ct);
+            return ScriptTestResult.Ok(result, ctx.Writes, capturing.Events);
+        }
+        catch (Exception ex)
+        {
+            return ScriptTestResult.Threw(ex.Message, capturing.Events);
+        }
+    }
+
+    // Public so Roslyn's script compilation can reference the context type through the
+    // ScriptGlobals<T> surface. The harness instantiates this directly; operators never see it.
+    public sealed class HarnessVirtualTagContext(
+        IDictionary<string, DataValueSnapshot> inputs, Serilog.ILogger logger) : ScriptContext
+    {
+        public Dictionary<string, object?> Writes { get; } = [];
+        public override DataValueSnapshot GetTag(string path) =>
+            inputs.TryGetValue(path, out var v)
+                ? v
+                : new DataValueSnapshot(null, Ua.StatusCodes.BadNotFound, null, DateTime.UtcNow);
+        public override void SetVirtualTag(string path, object? value) => Writes[path] = value;
+        public override DateTime Now => DateTime.UtcNow;
+        public override Serilog.ILogger Logger => logger;
+    }
+
+    private sealed class CapturingSink : ILogEventSink
+    {
+        public List<LogEvent> Events { get; } = [];
+        public void Emit(LogEvent e) => Events.Add(e);
+    }
+}
+
+/// <summary>Harness outcome: outputs, write-set, logger events, or a rejection/throw reason.</summary>
+public sealed record ScriptTestResult(
+    ScriptTestOutcome Outcome,
+    object? Output,
+    IReadOnlyDictionary<string, object?> Writes,
+    IReadOnlyList<LogEvent> LogEvents,
+    IReadOnlyList<string> Errors)
+{
+    public static ScriptTestResult Ok(object? output, IReadOnlyDictionary<string, object?> writes, IReadOnlyList<LogEvent> logs) =>
+        new(ScriptTestOutcome.Success, output, writes, logs, []);
+    public static ScriptTestResult Threw(string reason, IReadOnlyList<LogEvent> logs) =>
+        new(ScriptTestOutcome.Threw, null, new Dictionary<string, object?>(), logs, [reason]);
+    public static ScriptTestResult DependencyRejections(IReadOnlyList<DependencyRejection> rejs) =>
+        new(ScriptTestOutcome.DependencyRejected, null, new Dictionary<string, object?>(), [],
+            rejs.Select(r => r.Message).ToArray());
+    public static ScriptTestResult MissingInputs(string[] paths) =>
+        new(ScriptTestOutcome.MissingInputs, null, new Dictionary<string, object?>(), [],
+            paths.Select(p => $"Missing synthetic input: {p}").ToArray());
+    public static ScriptTestResult UnknownInputs(string[] paths) =>
+        new(ScriptTestOutcome.UnknownInputs, null, new Dictionary<string, object?>(), [],
+            paths.Select(p => $"Input '{p}' is not referenced by the script — remove it").ToArray());
+}
+
+public enum ScriptTestOutcome
+{
+    Success,
+    Threw,
+    DependencyRejected,
+    MissingInputs,
+    UnknownInputs,
+}
+
+file static class Ua
+{
+    // Mirrors OPC UA StatusCodes.BadNotFound without pulling the OPC stack into Admin.
+    public static class StatusCodes { public const uint BadNotFound = 0x803E0000; }
+}
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptedAlarmService.cs b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptedAlarmService.cs
new file mode 100644
index 0000000..18a42c5
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/ScriptedAlarmService.cs
@@ -0,0 +1,55 @@
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>Draft-generation CRUD for <see cref="ScriptedAlarm"/> rows.</summary>
+public sealed class ScriptedAlarmService(OtOpcUaConfigDbContext db)
+{
+    public Task<List<ScriptedAlarm>> ListAsync(long generationId, CancellationToken ct) =>
+        db.ScriptedAlarms.AsNoTracking()
+            .Where(a => a.GenerationId == generationId)
+            .OrderBy(a => a.EquipmentId).ThenBy(a => a.Name)
+            .ToListAsync(ct);
+
+    public async Task<ScriptedAlarm> AddAsync(
+        long generationId, string equipmentId, string name, string alarmType,
+        int severity, string messageTemplate, string predicateScriptId,
+        bool historizeToAveva, bool retain, CancellationToken ct)
+    {
+        var a = new ScriptedAlarm
+        {
+            GenerationId = generationId,
+            ScriptedAlarmId = $"sal-{Guid.NewGuid():N}"[..20],
+            EquipmentId = equipmentId,
+            Name = name,
+            AlarmType = alarmType,
+            Severity = severity,
+            MessageTemplate = messageTemplate,
+            PredicateScriptId = predicateScriptId,
+            HistorizeToAveva = historizeToAveva,
+            Retain = retain,
+        };
+        db.ScriptedAlarms.Add(a);
+        await db.SaveChangesAsync(ct);
+        return a;
+    }
+
+    public async Task DeleteAsync(long generationId, string scriptedAlarmId, CancellationToken ct)
+    {
+        var a = await db.ScriptedAlarms.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.ScriptedAlarmId == scriptedAlarmId, ct);
+        if (a is null) return;
+        db.ScriptedAlarms.Remove(a);
+        await db.SaveChangesAsync(ct);
+    }
+
+    /// <summary>
+    ///     Returns the persistent state row (ack/confirm/shelve) for this alarm identity —
+    ///     alarm state is NOT generation-scoped per Phase 7 plan decision #14, so the
+    ///     lookup is by <see cref="ScriptedAlarm.ScriptedAlarmId"/> only.
+    /// </summary>
+    public Task<ScriptedAlarmState?> GetStateAsync(string scriptedAlarmId, CancellationToken ct) =>
+        db.ScriptedAlarmStates.AsNoTracking()
+            .FirstOrDefaultAsync(s => s.ScriptedAlarmId == scriptedAlarmId, ct);
+}
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/Services/VirtualTagService.cs b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/VirtualTagService.cs
new file mode 100644
index 0000000..aa50e83
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/Services/VirtualTagService.cs
@@ -0,0 +1,53 @@
+using Microsoft.EntityFrameworkCore;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Configuration.Entities;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Services;
+
+/// <summary>Draft-generation CRUD for <see cref="VirtualTag"/> rows.</summary>
+public sealed class VirtualTagService(OtOpcUaConfigDbContext db)
+{
+    public Task<List<VirtualTag>> ListAsync(long generationId, CancellationToken ct) =>
+        db.VirtualTags.AsNoTracking()
+            .Where(v => v.GenerationId == generationId)
+            .OrderBy(v => v.EquipmentId).ThenBy(v => v.Name)
+            .ToListAsync(ct);
+
+    public async Task<VirtualTag> AddAsync(
+        long generationId, string equipmentId, string name, string dataType, string scriptId,
+        bool changeTriggered, int? timerIntervalMs, bool historize, CancellationToken ct)
+    {
+        var v = new VirtualTag
+        {
+            GenerationId = generationId,
+            VirtualTagId = $"vt-{Guid.NewGuid():N}"[..20],
+            EquipmentId = equipmentId,
+            Name = name,
+            DataType = dataType,
+            ScriptId = scriptId,
+            ChangeTriggered = changeTriggered,
+            TimerIntervalMs = timerIntervalMs,
+            Historize = historize,
+        };
+        db.VirtualTags.Add(v);
+        await db.SaveChangesAsync(ct);
+        return v;
+    }
+
+    public async Task DeleteAsync(long generationId, string virtualTagId, CancellationToken ct)
+    {
+        var v = await db.VirtualTags.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.VirtualTagId == virtualTagId, ct);
+        if (v is null) return;
+        db.VirtualTags.Remove(v);
+        await db.SaveChangesAsync(ct);
+    }
+
+    public async Task<VirtualTag> UpdateEnabledAsync(long generationId, string virtualTagId, bool enabled, CancellationToken ct)
+    {
+        var v = await db.VirtualTags.FirstOrDefaultAsync(x => x.GenerationId == generationId && x.VirtualTagId == virtualTagId, ct)
+            ?? throw new InvalidOperationException($"VirtualTag '{virtualTagId}' not found in generation {generationId}");
+        v.Enabled = enabled;
+        await db.SaveChangesAsync(ct);
+        return v;
+    }
+}
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/ZB.MOM.WW.OtOpcUa.Admin.csproj b/src/ZB.MOM.WW.OtOpcUa.Admin/ZB.MOM.WW.OtOpcUa.Admin.csproj
index 3a322a8..99ccb1e 100644
--- a/src/ZB.MOM.WW.OtOpcUa.Admin/ZB.MOM.WW.OtOpcUa.Admin.csproj
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/ZB.MOM.WW.OtOpcUa.Admin.csproj
@@ -23,6 +23,8 @@
     <ItemGroup>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Configuration\ZB.MOM.WW.OtOpcUa.Configuration.csproj"/>
         <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core\ZB.MOM.WW.OtOpcUa.Core.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.Scripting\ZB.MOM.WW.OtOpcUa.Core.Scripting.csproj"/>
+        <ProjectReference Include="..\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian\ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian.csproj"/>
     </ItemGroup>
 
     <ItemGroup>
diff --git a/src/ZB.MOM.WW.OtOpcUa.Admin/wwwroot/js/monaco-loader.js b/src/ZB.MOM.WW.OtOpcUa.Admin/wwwroot/js/monaco-loader.js
new file mode 100644
index 0000000..c88822a
--- /dev/null
+++ b/src/ZB.MOM.WW.OtOpcUa.Admin/wwwroot/js/monaco-loader.js
@@ -0,0 +1,59 @@
+// Phase 7 Stream F — Monaco editor loader for ScriptEditor.razor.
+// Progressive enhancement: the textarea is authoritative until Monaco attaches;
+// after attach, Monaco syncs back into the textarea on every change so Blazor's
+// @bind still sees the latest value.
+
+(function () {
+    if (window.otOpcUaScriptEditor) return;
+
+    const MONACO_CDN = 'https://cdn.jsdelivr.net/npm/monaco-editor@0.52.2/min/vs';
+    let loaderPromise = null;
+
+    function ensureLoader() {
+        if (loaderPromise) return loaderPromise;
+        loaderPromise = new Promise((resolve, reject) => {
+            const script = document.createElement('script');
+            script.src = `${MONACO_CDN}/loader.js`;
+            script.onload = () => {
+                window.require.config({ paths: { vs: MONACO_CDN } });
+                window.require(['vs/editor/editor.main'], () => resolve(window.monaco));
+            };
+            script.onerror = () => reject(new Error('Monaco CDN unreachable'));
+            document.head.appendChild(script);
+        });
+        return loaderPromise;
+    }
+
+    window.otOpcUaScriptEditor = {
+        attach: async function (textareaId) {
+            const ta = document.getElementById(textareaId);
+            if (!ta) return;
+            const monaco = await ensureLoader();
+
+            // Mount Monaco over the textarea. The textarea stays in the DOM as the
+            // source of truth for Blazor's @bind — Monaco mirrors into it on every
+            // keystroke so server-side state stays in sync.
+            const host = document.createElement('div');
+            host.style.height = '340px';
+            host.style.border = '1px solid #ced4da';
+            host.style.borderRadius = '0.25rem';
+            ta.style.display = 'none';
+            ta.parentNode.insertBefore(host, ta);
+
+            const editor = monaco.editor.create(host, {
+                value: ta.value,
+                language: 'csharp',
+                theme: 'vs',
+                automaticLayout: true,
+                fontSize: 13,
+                minimap: { enabled: false },
+                scrollBeyondLastLine: false,
+            });
+
+            editor.onDidChangeModelContent(() => {
+                ta.value = editor.getValue();
+                ta.dispatchEvent(new Event('input', { bubbles: true }));
+            });
+        },
+    };
+})();
diff --git a/tests/ZB.MOM.WW.OtOpcUa.Admin.Tests/Phase7ServicesTests.cs b/tests/ZB.MOM.WW.OtOpcUa.Admin.Tests/Phase7ServicesTests.cs
new file mode 100644
index 0000000..ac32e1e
--- /dev/null
+++ b/tests/ZB.MOM.WW.OtOpcUa.Admin.Tests/Phase7ServicesTests.cs
@@ -0,0 +1,196 @@
+using Microsoft.EntityFrameworkCore;
+using Shouldly;
+using Xunit;
+using ZB.MOM.WW.OtOpcUa.Admin.Services;
+using ZB.MOM.WW.OtOpcUa.Configuration;
+using ZB.MOM.WW.OtOpcUa.Core.Abstractions;
+using ZB.MOM.WW.OtOpcUa.Core.AlarmHistorian;
+
+namespace ZB.MOM.WW.OtOpcUa.Admin.Tests;
+
+/// <summary>
+///     Admin-side services shipped in Phase 7 Stream F — draft CRUD for scripts + virtual
+///     tags + scripted alarms, the pre-publish test harness, and the historian
+///     diagnostics façade.
+/// </summary>
+[Trait("Category", "Unit")]
+public sealed class Phase7ServicesTests
+{
+    private static OtOpcUaConfigDbContext NewDb([System.Runtime.CompilerServices.CallerMemberName] string test = "")
+    {
+        var options = new DbContextOptionsBuilder<OtOpcUaConfigDbContext>()
+            .UseInMemoryDatabase($"phase7-{test}-{Guid.NewGuid():N}")
+            .Options;
+        return new OtOpcUaConfigDbContext(options);
+    }
+
+    [Fact]
+    public async Task ScriptService_AddAsync_generates_logical_id_and_hash()
+    {
+        using var db = NewDb();
+        var svc = new ScriptService(db);
+
+        var s = await svc.AddAsync(5, "line-rate", "return ctx.GetTag(\"a\").Value;", default);
+
+        s.ScriptId.ShouldStartWith("scr-");
+        s.GenerationId.ShouldBe(5);
+        s.SourceHash.Length.ShouldBe(64);
+        (await svc.ListAsync(5, default)).Count.ShouldBe(1);
+    }
+
+    [Fact]
+    public async Task ScriptService_UpdateAsync_recomputes_hash_on_source_change()
+    {
+        using var db = NewDb();
+        var svc = new ScriptService(db);
+        var s = await svc.AddAsync(5, "s", "return 1;", default);
+        var hashBefore = s.SourceHash;
+
+        var updated = await svc.UpdateAsync(5, s.ScriptId, "s", "return 2;", default);
+        updated.SourceHash.ShouldNotBe(hashBefore);
+    }
+
+    [Fact]
+    public async Task ScriptService_UpdateAsync_same_source_same_hash()
+    {
+        using var db = NewDb();
+        var svc = new ScriptService(db);
+        var s = await svc.AddAsync(5, "s", "return 1;", default);
+        var updated = await svc.UpdateAsync(5, s.ScriptId, "renamed", "return 1;", default);
+
+        updated.SourceHash.ShouldBe(s.SourceHash, "source unchanged → hash unchanged → compile cache hit preserved");
+    }
+
+    [Fact]
+    public async Task ScriptService_DeleteAsync_is_idempotent()
+    {
+        using var db = NewDb();
+        var svc = new ScriptService(db);
+
+        await Should.NotThrowAsync(() => svc.DeleteAsync(5, "nonexistent", default));
+    }
+
+    [Fact]
+    public async Task VirtualTagService_round_trips_trigger_flags()
+    {
+        using var db = NewDb();
+        var svc = new VirtualTagService(db);
+
+        var v = await svc.AddAsync(7, "eq-1", "LineRate", "Float32", "scr-1",
+            changeTriggered: true, timerIntervalMs: 1000, historize: true, default);
+
+        v.ChangeTriggered.ShouldBeTrue();
+        v.TimerIntervalMs.ShouldBe(1000);
+        v.Historize.ShouldBeTrue();
+        v.Enabled.ShouldBeTrue();
+        (await svc.ListAsync(7, default)).Single().VirtualTagId.ShouldBe(v.VirtualTagId);
+    }
+
+    [Fact]
+    public async Task VirtualTagService_update_enabled_toggles_flag()
+    {
+        using var db = NewDb();
+        var svc = new VirtualTagService(db);
+        var v = await svc.AddAsync(7, "eq-1", "N", "Int32", "scr-1", true, null, false, default);
+
+        var disabled = await svc.UpdateEnabledAsync(7, v.VirtualTagId, false, default);
+        disabled.Enabled.ShouldBeFalse();
+    }
+
+    [Fact]
+    public async Task ScriptedAlarmService_defaults_HistorizeToAveva_true_per_plan_decision_15()
+    {
+        using var db = NewDb();
+        var svc = new ScriptedAlarmService(db);
+
+        var a = await svc.AddAsync(9, "eq-1", "HighTemp", "LimitAlarm", severity: 800,
+            messageTemplate: "{Temp} too high", predicateScriptId: "scr-9",
+            historizeToAveva: true, retain: true, default);
+
+        a.HistorizeToAveva.ShouldBeTrue();
+        a.Severity.ShouldBe(800);
+        a.ScriptedAlarmId.ShouldStartWith("sal-");
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_runs_successful_script_and_captures_writes()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = """
+            ctx.SetVirtualTag("Out", 42);
+            return ctx.GetTag("In").Value;
+            """;
+        var inputs = new Dictionary<string, DataValueSnapshot>
+        {
+            ["In"] = new(123, 0u, DateTime.UtcNow, DateTime.UtcNow),
+        };
+
+        var result = await harness.RunVirtualTagAsync(source, inputs, default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.Success);
+        result.Output.ShouldBe(123);
+        result.Writes["Out"].ShouldBe(42);
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_rejects_missing_synthetic_input()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = """return ctx.GetTag("A").Value;""";
+
+        var result = await harness.RunVirtualTagAsync(source, new Dictionary<string, DataValueSnapshot>(), default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.MissingInputs);
+        result.Errors[0].ShouldContain("A");
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_rejects_extra_synthetic_input_not_referenced_by_script()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = """return 1;""";  // no GetTag calls
+        var inputs = new Dictionary<string, DataValueSnapshot>
+        {
+            ["Unexpected"] = new(0, 0u, DateTime.UtcNow, DateTime.UtcNow),
+        };
+
+        var result = await harness.RunVirtualTagAsync(source, inputs, default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.UnknownInputs);
+        result.Errors[0].ShouldContain("Unexpected");
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_rejects_non_literal_path()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = """
+            var p = "A";
+            return ctx.GetTag(p).Value;
+            """;
+
+        var result = await harness.RunVirtualTagAsync(source, new Dictionary<string, DataValueSnapshot>(), default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.DependencyRejected);
+        result.Errors.ShouldNotBeEmpty();
+    }
+
+    [Fact]
+    public async Task ScriptTestHarness_surfaces_compile_error_as_Threw()
+    {
+        var harness = new ScriptTestHarnessService();
+        var source = "this is not valid C#;";
+
+        var result = await harness.RunVirtualTagAsync(source, new Dictionary<string, DataValueSnapshot>(), default);
+
+        result.Outcome.ShouldBe(ScriptTestOutcome.Threw);
+    }
+
+    [Fact]
+    public void HistorianDiagnosticsService_reports_Disabled_for_null_sink()
+    {
+        var diag = new HistorianDiagnosticsService(NullAlarmHistorianSink.Instance);
+        diag.GetStatus().DrainState.ShouldBe(HistorianDrainState.Disabled);
+        diag.TryRetryDeadLettered().ShouldBe(0);
+    }
+}