1 files changed, 52 insertions, 0 deletions
diff --git a/tests/Agent.Core.Tests/ObservabilityTests.cs b/tests/Agent.Core.Tests/ObservabilityTests.cs
index cd86bc2..c259eb0 100644
--- a/tests/Agent.Core.Tests/ObservabilityTests.cs
+++ b/tests/Agent.Core.Tests/ObservabilityTests.cs
@@ -1,6 +1,8 @@
 using Agent.App.Logging;
 using Agent.Core.Localization;
 using Agent.Mcp;
+using System.Diagnostics;
+using System.Text;
 
 namespace Agent.Core.Tests;
 
@@ -43,4 +45,54 @@ public sealed class ObservabilityTests
         Assert.DoesNotContain("Cookie", httpText, StringComparison.OrdinalIgnoreCase);
         Assert.DoesNotContain("prompt", httpText, StringComparison.OrdinalIgnoreCase);
     }
+
+    [Fact]
+    public void Http_request_callbacks_do_not_wait_for_a_blocked_console_writer()
+    {
+        using var directory = new TestDirectory();
+        using var console = new BlockingTextWriter();
+        LocaleCatalog locale = LocaleCatalog.Load(Path.GetFullPath("config/locales"), "en");
+        using var application = new RollingFileLog(directory.Path, 1024 * 1024, 2, consoleWriter: console);
+        using var observer = new McpHostLogObserver(application, locale, directory.Path, true, 1024 * 1024, 2);
+
+        observer.HttpRequestStarted(new McpHttpRequestStartInfo("connection", "trace-1", "127.0.0.1", 50123, "POST", "/mcp"));
+        Assert.True(console.WaitUntilBlocked(TimeSpan.FromSeconds(5)), "Background writer did not reach the blocking console.");
+
+        var stopwatch = Stopwatch.StartNew();
+        observer.HttpRequest(new McpHttpRequestInfo(DateTimeOffset.UtcNow, "connection", "trace-2", "127.0.0.1", 50124,
+            "127.0.0.1", 8080, "POST", "/mcp", 200, 12.5, "application/json", 100, "test-client",
+            "2026-07-28", "tools/list", null));
+        stopwatch.Stop();
+
+        Assert.True(stopwatch.Elapsed < TimeSpan.FromMilliseconds(250), $"HTTP callback blocked for {stopwatch.Elapsed}.");
+        console.Release();
+    }
+
+    private sealed class BlockingTextWriter : TextWriter
+    {
+        private readonly ManualResetEventSlim _entered = new(false);
+        private readonly ManualResetEventSlim _release = new(false);
+
+        public override Encoding Encoding => Encoding.UTF8;
+
+        public override void WriteLine(string? value)
+        {
+            _entered.Set();
+            _release.Wait(TimeSpan.FromSeconds(30));
+        }
+
+        public bool WaitUntilBlocked(TimeSpan timeout) => _entered.Wait(timeout);
+        public void Release() => _release.Set();
+
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing)
+            {
+                _release.Set();
+                _entered.Dispose();
+                _release.Dispose();
+            }
+            base.Dispose(disposing);
+        }
+    }
 }