1 files changed, 76 insertions, 0 deletions
diff --git a/src/Agent.App/Logging/McpHostLogObserver.cs b/src/Agent.App/Logging/McpHostLogObserver.cs
new file mode 100644
index 0000000..b1410e8
--- /dev/null
+++ b/src/Agent.App/Logging/McpHostLogObserver.cs
@@ -0,0 +1,76 @@
+using System.Globalization;
+using System.Text.Json;
+using Agent.Core.Localization;
+using Agent.Mcp;
+using System.Collections.Concurrent;
+
+namespace Agent.App.Logging;
+
+public sealed class McpHostLogObserver : IMcpHostObserver, IDisposable
+{
+    private readonly RollingFileLog _application;
+    private readonly RollingFileWriter? _http;
+    private readonly LocaleCatalog _locale;
+    private readonly string _logDirectory;
+    private readonly ConcurrentDictionary<string, byte> _observedConnections = new(StringComparer.Ordinal);
+
+    public McpHostLogObserver(RollingFileLog application, LocaleCatalog locale, string logDirectory,
+        bool httpRequests, long maxBytes, int retainedFiles)
+    {
+        _application = application;
+        _locale = locale;
+        _logDirectory = logDirectory;
+        if (httpRequests) _http = new RollingFileWriter(Path.Combine(logDirectory, "http.jsonl"), maxBytes, retainedFiles);
+    }
+
+    public void Ready(McpReadyInfo info)
+    {
+        string message = info.Transport == "http"
+            ? _locale.Format("app.ready.http", new Dictionary<string, object?>
+            {
+                ["endpoint"] = info.Endpoint, ["protocol"] = info.ProtocolVersion, ["stateless"] = info.Stateless.ToString().ToLowerInvariant(),
+                ["fallback"] = info.LegacyFallback.ToString().ToLowerInvariant(), ["pid"] = info.ProcessId, ["logs"] = _logDirectory
+            })
+            : _locale.Format("app.ready.stdio", new Dictionary<string, object?>
+            {
+                ["protocol"] = info.ProtocolVersion, ["pid"] = info.ProcessId, ["logs"] = _logDirectory
+            });
+        _application.Operational(message);
+    }
+
+    public void HttpRequestStarted(McpHttpRequestStartInfo info)
+    {
+        if (_observedConnections.TryAdd(info.ConnectionId, 0))
+            _application.Information($"HTTP connection observed connection={info.ConnectionId} remote={info.RemoteIp}:{info.RemotePort}");
+        _application.Information($"HTTP request started connection={info.ConnectionId} trace={info.TraceId} remote={info.RemoteIp}:{info.RemotePort} method={info.Method} path={info.Path}");
+    }
+
+    public void HttpRequest(McpHttpRequestInfo info)
+    {
+        _application.Information(string.Create(CultureInfo.InvariantCulture,
+            $"HTTP request completed connection={info.ConnectionId} remote={info.RemoteIp}:{info.RemotePort} method={info.Method} path={info.Path} status={info.Status} duration_ms={info.DurationMs:F3}"));
+        _http?.WriteLine(JsonSerializer.Serialize(new
+        {
+            timestamp = info.Timestamp,
+            connection_id = info.ConnectionId,
+            trace_id = info.TraceId,
+            remote_ip = info.RemoteIp,
+            remote_port = info.RemotePort,
+            local_ip = info.LocalIp,
+            local_port = info.LocalPort,
+            method = info.Method,
+            path = info.Path,
+            status = info.Status,
+            duration_ms = info.DurationMs,
+            content_type = info.ContentType,
+            content_length = info.ContentLength,
+            user_agent = info.UserAgent,
+            mcp_protocol_version = NullIfEmpty(info.ProtocolVersion),
+            mcp_method = NullIfEmpty(info.McpMethod),
+            mcp_name = NullIfEmpty(info.McpName)
+        }));
+    }
+
+    private static string? NullIfEmpty(string? value) => string.IsNullOrWhiteSpace(value) ? null : value;
+    public void Dispose() => _http?.Dispose();
+}