diff --git a/src/ZB.MOM.WW.ScadaBridge.ManagementService/FlowDebug/FlowDebugRunner.cs b/src/ZB.MOM.WW.ScadaBridge.ManagementService/FlowDebug/FlowDebugRunner.cs
index b1198356..449f246b 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ManagementService/FlowDebug/FlowDebugRunner.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ManagementService/FlowDebug/FlowDebugRunner.cs
@@ -1,4 +1,3 @@
-using System.Collections.Concurrent;
 using System.Diagnostics;
 using System.Text.Json;
 using Microsoft.Extensions.DependencyInjection;
@@ -83,6 +82,14 @@ public sealed class FlowDebugRunner
     /// Live run of an inbound API method (design §7.1): active-node gate, schema validation,
     /// synthesized inbound row (actor = operator), traced execution through the real
     /// <see cref="InboundScriptExecutor"/> with a trace-sink <see cref="RouteHelper"/>.
+    ///
+    /// <para>
+    /// Arch-review F1: the sink is a <see cref="FlowTraceCollector"/> — the same collector the
+    /// site launcher fills — so the returned copy is REDACTED and capped by count and bytes,
+    /// and a Live result shows exactly the filtered rows a later Replay reads back. The
+    /// redactor is <c>AddAuditLog</c>'s <see cref="IAuditRedactor"/> singleton; a host that
+    /// registered none (a test composition root) collects raw but is still capped.
+    /// </para>
     /// </summary>
     public async Task<FlowDebugRunResult> RunMethodAsync(
         IServiceProvider sp, FlowDebugRunMethodCommand cmd, AuthenticatedUser user, CancellationToken ct)
@@ -106,7 +113,7 @@ public sealed class FlowDebugRunner
         }
 
         var root = Guid.NewGuid();
-        var events = new ConcurrentQueue<AuditEvent>();
+        var collector = new FlowTraceCollector(redactor: sp.GetService<IAuditRedactor>());
         var startedAt = DateTimeOffset.UtcNow;
         var sw = Stopwatch.StartNew();
         var timeout = TimeSpan.FromSeconds(Math.Max(1, method.TimeoutSeconds));
@@ -116,7 +123,7 @@ public sealed class FlowDebugRunner
         // only known once the script runs. So the operator's scope is pushed into the
         // RouteHelper and enforced at route time, before any site traffic.
         var scope = await ResolvePermittedSiteIdentifiersAsync(sp, user, ct).ConfigureAwait(false);
-        var route = sp.GetRequiredService<RouteHelper>().WithTraceSink(events.Enqueue).WithSiteScope(scope);
+        var route = sp.GetRequiredService<RouteHelper>().WithTraceSink(collector.Add).WithSiteScope(scope);
         var executor = sp.GetRequiredService<InboundScriptExecutor>();
 
         InboundScriptResult result;
@@ -137,6 +144,9 @@ public sealed class FlowDebugRunner
         }
 
         var finishedAt = DateTimeOffset.UtcNow;
+        // Close the sink here, not at the point the list is built: an un-awaited call finishing
+        // after the run returned must not mutate the snapshot the reply is assembled from.
+        var events = collector.Complete();
         var requestJson = cmd.Parameters is { } p ? p.GetRawText() : null;
         var inboundRow = ScadaBridgeAuditEventFactory.Create(
             AuditChannel.ApiInbound, AuditKind.InboundRequest,
@@ -168,7 +178,7 @@ public sealed class FlowDebugRunner
 
         return new FlowDebugRunResult(
             root, result.Success, result.ErrorMessage, result.Success ? null : result.ErrorCode,
-            ordered, Truncated: false, startedAt, finishedAt);
+            ordered, Truncated: collector.Truncated, startedAt, finishedAt);
     }
 
     /// <summary>
diff --git a/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/FlowDebugRunnerTests.cs b/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/FlowDebugRunnerTests.cs
index 359d9368..b8f700c2 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/FlowDebugRunnerTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.ManagementService.Tests/FlowDebugRunnerTests.cs
@@ -331,4 +331,62 @@ public class FlowDebugRunnerTests
         Assert.NotNull(actual);
         Assert.Equal(new[] { "Administrator", "Deployer", "Viewer" }, actual!.OrderBy(r => r, StringComparer.Ordinal));
     }
+
+    // --- Arch-review F1: the Live result is the REDACTED, capped trace copy ---
+    //
+    // The runner collects sink events through the same FlowTraceCollector the site launcher
+    // uses, so central and site filter identically and a Live run shows exactly the rows a
+    // later Replay reads back out of the audit store.
+
+    /// <summary>Wires a method whose handler pushes <paramref name="events"/> straight at the trace sink.</summary>
+    private void WireSinkPushingMethod(int methodId, IEnumerable<AuditEvent> events)
+    {
+        var method = new ApiMethod("M", "x") { Id = methodId, TimeoutSeconds = 5 };
+        _apiRepo.GetApiMethodByIdAsync(methodId, Arg.Any<CancellationToken>()).Returns(method);
+        _executor.RegisterHandler("M", ctx =>
+        {
+            foreach (var e in events) ctx.Route.TraceSink!(e);
+            return Task.FromResult<object?>(null);
+        });
+    }
+
+    private static AuditEvent TraceRow(string? detailsJson) =>
+        ScadaBridgeAuditEventFactory.Create(
+            AuditChannel.ScriptTrace, AuditKind.ScriptRun, AuditStatus.Delivered,
+            executionId: Guid.NewGuid(), target: "work") with
+        { DetailsJson = detailsJson };
+
+    [Fact]
+    public async Task RunMethod_SinkEvents_AreRedacted_WhenARedactorIsRegistered()
+    {
+        WireSinkPushingMethod(31, [TraceRow("{\"secret\":\"abc\"}")]);
+        _services.AddSingleton<IAuditRedactor>(new UpperRedactor());
+
+        var result = await Runner().RunMethodAsync(_services.BuildServiceProvider(),
+            new FlowDebugRunMethodCommand(31, null), Deployer, CancellationToken.None);
+
+        Assert.True(result.Completed, result.Error);
+        Assert.Equal(2, result.Events.Count); // inbound row + the one sink event
+        Assert.Equal("{\"SECRET\":\"ABC\"}", result.Events[1].DetailsJson);
+        Assert.False(result.Truncated);
+    }
+
+    [Fact]
+    public async Task RunMethod_OverCap_ReportsTruncated()
+    {
+        WireSinkPushingMethod(32, Enumerable.Range(0, 501).Select(_ => TraceRow("{}")).ToList());
+
+        var result = await Runner().RunMethodAsync(_services.BuildServiceProvider(),
+            new FlowDebugRunMethodCommand(32, null), Deployer, CancellationToken.None);
+
+        Assert.True(result.Truncated);
+        Assert.Equal(501, result.Events.Count); // inbound row + the 500 kept
+    }
+
+    /// <summary>Upper-cases <c>DetailsJson</c> so a test can see the filtered copy land.</summary>
+    private sealed class UpperRedactor : IAuditRedactor
+    {
+        public AuditEvent Apply(AuditEvent rawEvent)
+            => rawEvent with { DetailsJson = rawEvent.DetailsJson?.ToUpperInvariant() };
+    }
 }