diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect/MTConnectDriverProbe.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect/MTConnectDriverProbe.cs
index 7768ec7b..85658b9a 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect/MTConnectDriverProbe.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect/MTConnectDriverProbe.cs
@@ -23,6 +23,14 @@ namespace ZB.MOM.WW.OtOpcUa.Driver.MTConnect;
 ///         (<c>MTConnectDriverFactoryExtensions</c>), which is authored separately (Task 15).
 ///     </para>
 ///     <para>
+///         <b>Accepted gap: reachable ≠ deployable.</b> Because only <c>agentUri</c> is read, a
+///         config can show green on Test Connect and still fail to deploy — e.g. a non-positive
+///         <c>requestTimeoutMs</c> or a malformed tag entry the factory's full parse would reject.
+///         This is the direct consequence of the independent-parsing decision above, judged
+///         acceptable because Test Connect's job is "is the endpoint there", not "will this exact
+///         config deploy".
+///     </para>
+///     <para>
 ///         <b>Deliberately DOES reuse <see cref="MTConnectAgentClient"/> and
 ///         <see cref="MTConnectProbeParser"/> for the actual round trip.</b> Hand-rolling the HTTP
 ///         call would have to re-derive the exact behaviour the client already provides: per-call
@@ -63,6 +71,18 @@ public sealed class MTConnectDriverProbe : IDriverProbe
     /// <summary>Replaces a non-positive caller <c>timeout</c> — see the type remarks.</summary>
     private static readonly TimeSpan FallbackTimeout = TimeSpan.FromSeconds(5);
 
+    /// <summary>
+    ///     Caps an excessive caller <c>timeout</c>. <c>CancellationTokenSource.CancelAfter(TimeSpan)</c>'s
+    ///     legal range tops out near ~49.7 days (<see cref="uint.MaxValue"/> ms minus one); an
+    ///     uncapped pathological value (e.g. a caller passing <c>TimeSpan.FromDays(1000)</c>) throws
+    ///     <see cref="ArgumentOutOfRangeException"/> straight out of
+    ///     <c>CancelAfter</c>, which would violate the "Never throws" contract just as surely as a
+    ///     non-positive timeout meaning "wait forever" would (arch-review 01/S-6 — this is the same
+    ///     defect class, the high end rather than the low end). 10 minutes is generous for a
+    ///     reachability probe and leaves an enormous margin under the legal ceiling.
+    /// </summary>
+    private static readonly TimeSpan MaxTimeout = TimeSpan.FromMinutes(10);
+
     private static readonly JsonSerializerOptions JsonOptions = new()
     {
         PropertyNameCaseInsensitive = true,
@@ -131,8 +151,15 @@ public sealed class MTConnectDriverProbe : IDriverProbe
 
         var safeUri = RedactedDisplay(parsed);
 
-        // arch-review 01/S-6: a non-positive timeout must never mean "wait forever".
+        // arch-review 01/S-6: a non-positive timeout must never mean "wait forever" (low end), and a
+        // pathologically large one must never overrun CancelAfter's legal range (high end) — see
+        // MaxTimeout.
         var effectiveTimeout = timeout > TimeSpan.Zero ? timeout : FallbackTimeout;
+        if (effectiveTimeout > MaxTimeout)
+        {
+            effectiveTimeout = MaxTimeout;
+        }
+
         var requestTimeoutMs = Math.Max(1, (int)Math.Ceiling(effectiveTimeout.TotalMilliseconds));
 
         var sw = Stopwatch.StartNew();
@@ -187,7 +214,12 @@ public sealed class MTConnectDriverProbe : IDriverProbe
         }
         catch (Exception ex)
         {
-            return new(false, ex.Message, null);
+            // Last-resort catch for an exception type none of the above enumerate. Deliberately does
+            // NOT forward ex.Message: unlike the typed catches above (each individually audited for
+            // whether its message can carry the raw AgentUri/userinfo), an unenumerated type has no
+            // such audit, so ex.Message is an open door for a credential leak. safeUri + the
+            // exception's TYPE name is enough for an operator to act on without that risk.
+            return new(false, $"Probe against {safeUri} failed unexpectedly ({ex.GetType().Name}).", null);
         }
     }
 
diff --git a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests/MTConnectDriverProbeTests.cs b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests/MTConnectDriverProbeTests.cs
index 8e25ba29..03ce5781 100644
--- a/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests/MTConnectDriverProbeTests.cs
+++ b/tests/Drivers/ZB.MOM.WW.OtOpcUa.Driver.MTConnect.Tests/MTConnectDriverProbeTests.cs
@@ -232,4 +232,88 @@ public sealed class MTConnectDriverProbeTests
 
     /// <summary>Local stand-in so the stub handler's "never returns" branch has a throw statement to satisfy flow analysis.</summary>
     private sealed class UnreachableException : Exception;
+
+    // ── review follow-up: pathological (out-of-CancelAfter-range) timeout ────
+
+    /// <summary>
+    ///     Reproduces the reviewer's finding: <c>CancelAfter</c>'s legal range tops out near ~49.7
+    ///     days, and the caller-supplied <c>timeout</c> reached it uncapped (only floored on the low
+    ///     end). A caller with no clamp of its own — unlike today's only caller,
+    ///     <c>AdminOperationsActor</c>, which clamps to [1,60]s — must still get a
+    ///     <see cref="Core.Abstractions.DriverProbeResult"/>, never an escaping
+    ///     <see cref="ArgumentOutOfRangeException"/>: that is the whole point of the "Never throws"
+    ///     contract.
+    /// </summary>
+    [Fact]
+    public async Task Pathologically_large_timeout_does_not_throw()
+    {
+        var probe = new MTConnectDriverProbe();
+
+        var r = await probe.ProbeAsync(
+            "{\"agentUri\":\"http://127.0.0.1:1/\"}", TimeSpan.FromDays(1000), CancellationToken.None);
+
+        r.Ok.ShouldBeFalse();
+        r.Message.ShouldNotBeNull();
+    }
+
+    // ── review follow-up: unenumerated exception type must not leak ex.Message ──
+
+    /// <summary>Message text crafted to look like it embedded a credentialed URI, exactly what an unaudited <c>ex.Message</c> could leak.</summary>
+    private sealed class LeakyException()
+        : Exception("dial failed for http://leaky-user:leaky-pass@internal-host/probe (boom)");
+
+    /// <summary>
+    ///     Reproduces the reviewer's finding: the final <c>catch (Exception ex)</c> forwarded
+    ///     <c>ex.Message</c> verbatim for any type not enumerated above it, breaking the redaction
+    ///     discipline every other catch was audited for. No currently-reachable exception type
+    ///     exploits this, but nothing stopped a future one from doing so either — this test closes
+    ///     that open door by asserting the final catch never echoes exception text.
+    /// </summary>
+    [Fact]
+    public async Task Unenumerated_exception_type_does_not_leak_ex_Message_via_final_catch()
+    {
+        var probe = ProbeWithHandler((_, _) => Task.FromException<HttpResponseMessage>(new LeakyException()));
+
+        var r = await probe.ProbeAsync(
+            "{\"agentUri\":\"http://stub-agent/\"}", QuickTimeout, CancellationToken.None);
+
+        r.Ok.ShouldBeFalse();
+        r.Message.ShouldNotBeNull();
+        r.Message.ShouldNotContain("leaky-pass");
+        r.Message.ShouldNotContain("leaky-user:leaky-pass");
+    }
+
+    // ── minor: genuine non-2xx status (not just connection-refused) ──────────
+
+    [Fact]
+    public async Task NonSuccess_status_code_returns_not_ok()
+    {
+        var probe = ProbeWithHandler((_, _) => Task.FromResult(new HttpResponseMessage(HttpStatusCode.NotFound)
+        {
+            Content = new StringContent(string.Empty),
+        }));
+
+        var r = await probe.ProbeAsync(
+            "{\"agentUri\":\"http://stub-agent/\"}", QuickTimeout, CancellationToken.None);
+
+        r.Ok.ShouldBeFalse();
+        r.Message.ShouldNotBeNull();
+        r.Latency.ShouldBeNull();
+    }
+
+    // ── minor: credentialed agentUri + a SUCCESSFUL response must still redact ──
+
+    [Fact]
+    public async Task Credentialed_agentUri_is_redacted_even_on_a_successful_probe()
+    {
+        var probe = ProbeWithHandler((_, _) => Task.FromResult(XmlResponse(ValidProbeXml)));
+
+        var r = await probe.ProbeAsync(
+            "{\"agentUri\":\"http://stub-user:stub-pass@stub-agent/\"}", QuickTimeout, CancellationToken.None);
+
+        r.Ok.ShouldBeTrue();
+        r.Message.ShouldNotBeNull();
+        r.Message.ShouldNotContain("stub-pass");
+        r.Message.ShouldNotContain("stub-user:stub-pass");
+    }
 }