diff --git a/docs/player_gm_ux_redesign_plan.md b/docs/player_gm_ux_redesign_plan.md
index 7d883f7..03a8933 100644
--- a/docs/player_gm_ux_redesign_plan.md
+++ b/docs/player_gm_ux_redesign_plan.md
@@ -567,6 +567,10 @@ Acceptance criteria:
 
 ### Phase 5: Advanced curation and diagnostics split
 
+Status:
+
+- implemented in the web app on March 15, 2026
+
 Scope:
 
 - move debug/import details into a separate advanced surface
diff --git a/src/RolemasterDb.App/Components/Shared/CriticalCellEditorDialog.razor b/src/RolemasterDb.App/Components/Shared/CriticalCellEditorDialog.razor
index 85de648..461717a 100644
--- a/src/RolemasterDb.App/Components/Shared/CriticalCellEditorDialog.razor
+++ b/src/RolemasterDb.App/Components/Shared/CriticalCellEditorDialog.razor
@@ -1,6 +1,7 @@
 @using System
 @using System.Collections.Generic
 @using System.Linq
+@using System.Text.Json
 @using RolemasterDb.App.Domain
 @using RolemasterDb.App.Features
 
@@ -94,12 +95,7 @@
                         </div>
                         @if (Model.ValidationMessages.Count > 0)
                         {
-                            <div class="critical-editor-validation-list">
-                                @foreach (var message in Model.ValidationMessages)
-                                {
-                                    <p class="critical-editor-validation-item">@message</p>
-                                }
-                            </div>
+                            <p class="muted critical-editor-advanced-hint">@GetParserNoteSummary(Model.ValidationMessages.Count)</p>
                         }
                         <div class="field-shell">
                             <label>Result Text Override</label>
@@ -228,6 +224,94 @@
                             }
                         }
                     </section>
+
+                    <section class="critical-editor-section critical-editor-diagnostics-section">
+                        <details class="critical-editor-advanced">
+                            <summary class="critical-editor-advanced-summary">
+                                <span>Advanced Diagnostics</span>
+                                <span class="critical-editor-advanced-meta">@GetAdvancedSummary(Model)</span>
+                            </summary>
+
+                            <div class="critical-editor-advanced-body">
+                                <div class="critical-editor-card nested">
+                                    <div class="critical-editor-card-header">
+                                        <div>
+                                            <strong>Parser Metadata</strong>
+                                            <p class="muted critical-editor-inline-copy">Last loaded or re-parsed parser result.</p>
+                                        </div>
+                                    </div>
+
+                                    <dl class="critical-editor-diagnostic-grid">
+                                        <div>
+                                            <dt>Parse Status</dt>
+                                            <dd>@Model.ParseStatus</dd>
+                                        </div>
+                                        <div>
+                                            <dt>Raw Affix Text</dt>
+                                            <dd>@(string.IsNullOrWhiteSpace(Model.RawAffixText) ? "—" : Model.RawAffixText)</dd>
+                                        </div>
+                                    </dl>
+
+                                    @if (Model.ValidationMessages.Count > 0)
+                                    {
+                                        <div class="critical-editor-validation-list">
+                                            @foreach (var message in Model.ValidationMessages)
+                                            {
+                                                <p class="critical-editor-validation-item">@message</p>
+                                            }
+                                        </div>
+                                    }
+
+                                    <div class="field-shell">
+                                        <label>Parsed Effects JSON</label>
+                                        <pre class="critical-editor-diagnostic-block">@FormatJson(Model.ParsedJson)</pre>
+                                    </div>
+                                </div>
+
+                                @{
+                                    var effectMetadata = GetEffectMetadataRows(Model);
+                                }
+
+                                @if (effectMetadata.Count > 0)
+                                {
+                                    <div class="critical-editor-card nested">
+                                        <div class="critical-editor-card-header">
+                                            <div>
+                                                <strong>Effect Source Metadata</strong>
+                                                <p class="muted critical-editor-inline-copy">Stored source markers and labels for the current effect list.</p>
+                                            </div>
+                                        </div>
+
+                                        <div class="critical-editor-diagnostic-list">
+                                            @foreach (var entry in effectMetadata)
+                                            {
+                                                <div class="critical-editor-diagnostic-item">
+                                                    <div>
+                                                        <strong>@entry.Scope</strong>
+                                                        <p class="muted critical-editor-inline-copy">@entry.EffectLabel</p>
+                                                    </div>
+                                                    <div class="critical-editor-diagnostic-values">
+                                                        <span><strong>Type:</strong> @entry.SourceType</span>
+                                                        <span><strong>Text:</strong> @(string.IsNullOrWhiteSpace(entry.SourceText) ? "—" : entry.SourceText)</span>
+                                                    </div>
+                                                </div>
+                                            }
+                                        </div>
+                                    </div>
+                                }
+
+                                <div class="critical-editor-card nested">
+                                    <div class="critical-editor-card-header">
+                                        <div>
+                                            <strong>Current Save Payload</strong>
+                                            <p class="muted critical-editor-inline-copy">Request built from the visible editor state, including generated branch internals.</p>
+                                        </div>
+                                    </div>
+                                    <pre class="critical-editor-diagnostic-block">@BuildCurrentSavePayloadJson(Model)</pre>
+                                </div>
+                            </div>
+                        </details>
+                    </section>
                 </div>
 
                 <footer class="critical-editor-footer">
@@ -272,6 +356,11 @@
     [Parameter, EditorRequired]
     public EventCallback OnSave { get; set; }
 
+    private static readonly JsonSerializerOptions DiagnosticJsonOptions = new()
+    {
+        WriteIndented = true
+    };
+
     private async Task HandleBackdropClicked()
     {
         await OnClose.InvokeAsync();
@@ -393,6 +482,69 @@
         effect.SourceType = AffixDisplayMap.TryGet(effect.EffectCode, out _) ? "symbol" : "manual";
     }
 
+    private static string GetAdvancedSummary(CriticalCellEditorModel model)
+    {
+        var noteCount = model.ValidationMessages.Count;
+        return noteCount == 0 ? "Parser metadata and save payload" : $"{noteCount} parser note{(noteCount == 1 ? string.Empty : "s")}";
+    }
+
+    private static string GetParserNoteSummary(int noteCount) =>
+        noteCount == 1
+            ? "1 parser note is available under Advanced Diagnostics."
+            : $"{noteCount} parser notes are available under Advanced Diagnostics.";
+
+    private static string FormatJson(string json)
+    {
+        if (string.IsNullOrWhiteSpace(json))
+        {
+            return "{}";
+        }
+
+        try
+        {
+            using var document = JsonDocument.Parse(json);
+            return JsonSerializer.Serialize(document.RootElement, DiagnosticJsonOptions);
+        }
+        catch (JsonException)
+        {
+            return json.Trim();
+        }
+    }
+
+    private static string BuildCurrentSavePayloadJson(CriticalCellEditorModel model) =>
+        JsonSerializer.Serialize(model.ToRequest(), DiagnosticJsonOptions);
+
+    private static List<(string Scope, string EffectLabel, string SourceType, string? SourceText)> GetEffectMetadataRows(CriticalCellEditorModel model)
+    {
+        var rows = new List<(string Scope, string EffectLabel, string SourceType, string? SourceText)>();
+
+        foreach (var effect in model.Effects)
+        {
+            if (ShouldIncludeEffectMetadata(effect))
+            {
+                rows.Add(("Base Result", GetEffectLabel(effect), effect.SourceType, effect.SourceText));
+            }
+        }
+
+        foreach (var branch in model.Branches.OrderBy(item => item.SortOrder))
+        {
+            var scope = string.IsNullOrWhiteSpace(branch.ConditionText) ? "Condition" : branch.ConditionText.Trim();
+            foreach (var effect in branch.Effects)
+            {
+                if (ShouldIncludeEffectMetadata(effect))
+                {
+                    rows.Add((scope, GetEffectLabel(effect), effect.SourceType, effect.SourceText));
+                }
+            }
+        }
+
+        return rows;
+    }
+
+    private static bool ShouldIncludeEffectMetadata(CriticalEffectEditorModel effect) =>
+        !string.IsNullOrWhiteSpace(effect.SourceText) ||
+        !string.IsNullOrWhiteSpace(effect.SourceType);
+
     private static IReadOnlyList<CriticalEffectLookupResponse> BuildPreviewEffects(IEnumerable<CriticalEffectEditorModel> effects) =>
         effects.Select(CreatePreviewEffect).ToList();
 
diff --git a/src/RolemasterDb.App/wwwroot/app.css b/src/RolemasterDb.App/wwwroot/app.css
index 1973c18..4ae9c64 100644
--- a/src/RolemasterDb.App/wwwroot/app.css
+++ b/src/RolemasterDb.App/wwwroot/app.css
@@ -843,6 +843,101 @@ textarea {
     color: #6b4c29;
 }
 
+.critical-editor-advanced-hint {
+    margin: 0;
+}
+
+.critical-editor-advanced {
+    border-radius: 18px;
+    border: 1px solid rgba(127, 96, 55, 0.14);
+    background: rgba(247, 239, 225, 0.42);
+    overflow: hidden;
+}
+
+.critical-editor-advanced-summary {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    gap: 0.75rem;
+    padding: 0.9rem 1rem;
+    cursor: pointer;
+    list-style: none;
+    font-family: var(--font-heading);
+    color: #5b4327;
+}
+
+.critical-editor-advanced-summary::-webkit-details-marker {
+    display: none;
+}
+
+.critical-editor-advanced-meta {
+    font-family: var(--font-body);
+    font-size: 0.92rem;
+    color: #7b6243;
+}
+
+.critical-editor-advanced-body {
+    display: grid;
+    gap: 0.85rem;
+    padding: 0 1rem 1rem;
+}
+
+.critical-editor-diagnostic-grid {
+    display: grid;
+    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
+    gap: 0.75rem;
+    margin: 0;
+}
+
+.critical-editor-diagnostic-grid dt {
+    font-size: 0.8rem;
+    text-transform: uppercase;
+    letter-spacing: 0.06em;
+    color: #8a7355;
+}
+
+.critical-editor-diagnostic-grid dd {
+    margin: 0.2rem 0 0;
+    color: #4f3c25;
+}
+
+.critical-editor-diagnostic-block {
+    margin: 0;
+    padding: 0.85rem 0.95rem;
+    border-radius: 14px;
+    background: rgba(92, 68, 41, 0.08);
+    border: 1px solid rgba(92, 68, 41, 0.12);
+    color: #3f311f;
+    white-space: pre-wrap;
+    word-break: break-word;
+    font-size: 0.9rem;
+    overflow-x: auto;
+}
+
+.critical-editor-diagnostic-list {
+    display: grid;
+    gap: 0.65rem;
+}
+
+.critical-editor-diagnostic-item {
+    display: flex;
+    align-items: start;
+    justify-content: space-between;
+    gap: 0.85rem;
+    padding: 0.75rem 0.85rem;
+    border-radius: 14px;
+    background: rgba(255, 255, 255, 0.65);
+    border: 1px solid rgba(127, 96, 55, 0.1);
+}
+
+.critical-editor-diagnostic-values {
+    display: grid;
+    gap: 0.25rem;
+    justify-items: end;
+    color: #5d4429;
+    text-align: right;
+}
+
 .critical-editor-effect-grid {
     grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
 }
@@ -887,8 +982,15 @@ textarea {
 
     .critical-editor-chip-card,
     .critical-editor-card-header,
-    .critical-editor-section-header {
+    .critical-editor-section-header,
+    .critical-editor-advanced-summary,
+    .critical-editor-diagnostic-item {
         flex-direction: column;
         align-items: stretch;
     }
+
+    .critical-editor-diagnostic-values {
+        justify-items: start;
+        text-align: left;
+    }
 }