Improve IMAP reconnection and error handling in polling

Refactored PollInboxAsync to better handle IMAP connection drops and protocol errors by reconnecting and resuming processing as needed. Switched from using a using statement to explicit disposal in a finally block. Now logs and recovers from transient IMAP issues, and ensures proper cancellation handling by rethrowing OperationCanceledException. This increases service robustness and reliability.

.gitignore

@@ -482,3 +482,6 @@ $RECYCLE.BIN/
 
 # Vim temporary swap files
 *.swp
+
+# User configuration with secrets
+src/SpamGuard/appsettings.json

src/SpamGuard/Configuration/SpamGuardOptions.cs

@@ -4,13 +4,14 @@ public sealed class SpamGuardOptions
 {
     public const string SectionName = "SpamGuard";
 
-    public ImapOptions Imap { get; set; } = new();
+    public List<ImapOptions> Accounts { get; set; } = new();
     public ClaudeOptions Claude { get; set; } = new();
     public MonitoringOptions Monitoring { get; set; } = new();
 }
 
 public sealed class ImapOptions
 {
+    public string Name { get; set; } = "";
     public string Host { get; set; } = "";
     public int Port { get; set; } = 993;
     public bool UseSsl { get; set; } = true;
@@ -21,6 +22,7 @@ public sealed class ImapOptions
 public sealed class ClaudeOptions
 {
     public string ApiKey { get; set; } = "";
+    public string BaseUrl { get; set; } = "https://api.anthropic.com/";
     public string Model { get; set; } = "claude-sonnet-4-6";
     public int MaxBodyLength { get; set; } = 2000;
 }

src/SpamGuard/Configuration/SpamGuardOptionsValidator.cs

@@ -0,0 +1,33 @@
+namespace SpamGuard.Configuration;
+
+using Microsoft.Extensions.Options;
+
+public sealed class SpamGuardOptionsValidator : IValidateOptions<SpamGuardOptions>
+{
+    public ValidateOptionsResult Validate(string? name, SpamGuardOptions options)
+    {
+        var errors = new List<string>();
+
+        if (options.Accounts.Count == 0)
+            errors.Add("SpamGuard:Accounts must contain at least one account.");
+
+        for (int i = 0; i < options.Accounts.Count; i++)
+        {
+            var a = options.Accounts[i];
+            var prefix = $"SpamGuard:Accounts[{i}]";
+            if (string.IsNullOrWhiteSpace(a.Host))
+                errors.Add($"{prefix}:Host is required.");
+            if (string.IsNullOrWhiteSpace(a.Username))
+                errors.Add($"{prefix}:Username is required.");
+            if (string.IsNullOrWhiteSpace(a.Password))
+                errors.Add($"{prefix}:Password is required.");
+        }
+
+        if (string.IsNullOrWhiteSpace(options.Claude.ApiKey))
+            errors.Add("SpamGuard:Claude:ApiKey is required.");
+
+        return errors.Count > 0
+            ? ValidateOptionsResult.Fail(errors)
+            : ValidateOptionsResult.Success;
+    }
+}

src/SpamGuard/Models/ActivityEntry.cs

@@ -10,11 +10,22 @@ public enum Verdict
     Error
 }
 
-public sealed record ActivityEntry(
+public enum UserOverride
-    DateTime Timestamp,
+{
-    string Sender,
+    MarkedSpam,
-    string Subject,
+    MarkedLegitimate
-    Verdict Verdict,
+}
-    double? Confidence,
+
-    string? Reason
+public sealed class ActivityEntry
-);
+{
+    public DateTime Timestamp { get; init; }
+    public string Sender { get; init; } = "";
+    public string Subject { get; init; } = "";
+    public Verdict Verdict { get; set; }
+    public double? Confidence { get; init; }
+    public string? Reason { get; init; }
+    public uint Uid { get; init; }
+    public string AccountName { get; init; } = "";
+    public string? BodySnippet { get; init; }
+    public UserOverride? Override { get; set; }
+}

src/SpamGuard/Program.cs

@@ -1,2 +1,150 @@
-// See https://aka.ms/new-console-template for more information
+using Microsoft.Extensions.Configuration;
-Console.WriteLine("Hello, World!");
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Options;
+using Serilog;
+using SpamGuard.Configuration;
+using SpamGuard.Services;
+using SpamGuard.State;
+using SpamGuard.Tray;
+
+#pragma warning disable CA1416 // Validate platform compatibility
+
+namespace SpamGuard;
+
+static class Program
+{
+    [STAThread]
+    static void Main()
+    {
+        Application.EnableVisualStyles();
+        Application.SetCompatibleTextRenderingDefault(false);
+        Application.SetHighDpiMode(HighDpiMode.SystemAware);
+
+        var dataDir = Path.Combine(
+            Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData),
+            "SpamGuard");
+        Directory.CreateDirectory(dataDir);
+
+        Log.Logger = new LoggerConfiguration()
+            .WriteTo.File(
+                Path.Combine(dataDir, "logs", "spamguard-.log"),
+                rollingInterval: RollingInterval.Day,
+                retainedFileCountLimit: 7)
+            .CreateLogger();
+
+        IHost? host = null;
+        try
+        {
+            host = Host.CreateDefaultBuilder()
+                .UseSerilog()
+                .ConfigureAppConfiguration((context, config) =>
+                {
+                    config.AddJsonFile(
+                        Path.Combine(AppContext.BaseDirectory, "appsettings.json"),
+                        optional: false);
+                    config.AddEnvironmentVariables("SPAMGUARD_");
+                })
+                .ConfigureServices((context, services) =>
+                {
+                    services.Configure<SpamGuardOptions>(
+                        context.Configuration.GetSection(SpamGuardOptions.SectionName));
+
+                    // Validate required configuration on startup
+                    services.AddSingleton<IValidateOptions<SpamGuardOptions>, SpamGuardOptionsValidator>();
+                    services.AddOptionsWithValidateOnStart<SpamGuardOptions>();
+
+                    var opts = context.Configuration
+                        .GetSection(SpamGuardOptions.SectionName)
+                        .Get<SpamGuardOptions>()!;
+
+                    // Shared state / services
+                    services.AddSingleton(new TrustedSenderStore(dataDir));
+                    services.AddSingleton(new BlockedDomainStore(dataDir));
+                    services.AddSingleton(new OverrideStore(dataDir));
+                    services.AddSingleton(new ActivityLog(opts.Monitoring.MaxActivityLogEntries, dataDir));
+                    services.AddSingleton<ImapClientFactory>();
+
+                    // EmailClassifier with managed HttpClient
+                    services.AddHttpClient<EmailClassifier>(client =>
+                    {
+                        client.Timeout = TimeSpan.FromSeconds(30);
+                        client.BaseAddress = new Uri(opts.Claude.BaseUrl);
+                    });
+
+                    // Per-account monitor + trusted sender service
+                    var monitors = new List<InboxMonitorService>();
+                    foreach (var account in opts.Accounts)
+                    {
+                        var accountName = account.Name.Length > 0 ? account.Name : account.Username;
+                        var uidStore = new ProcessedUidStore(dataDir, accountName);
+
+                        services.AddHostedService(sp => new TrustedSenderService(
+                            sp.GetRequiredService<ImapClientFactory>(),
+                            sp.GetRequiredService<TrustedSenderStore>(),
+                            account,
+                            opts.Monitoring,
+                            sp.GetRequiredService<Microsoft.Extensions.Logging.ILogger<TrustedSenderService>>()));
+
+                        var capturedAccount = account;
+                        services.AddSingleton(sp =>
+                        {
+                            var monitor = new InboxMonitorService(
+                                sp.GetRequiredService<ImapClientFactory>(),
+                                sp.GetRequiredService<TrustedSenderStore>(),
+                                sp.GetRequiredService<BlockedDomainStore>(),
+                                uidStore,
+                                sp.GetRequiredService<EmailClassifier>(),
+                                sp.GetRequiredService<ActivityLog>(),
+                                capturedAccount,
+                                opts.Monitoring,
+                                sp.GetRequiredService<Microsoft.Extensions.Logging.ILogger<InboxMonitorService>>());
+                            monitors.Add(monitor);
+                            return monitor;
+                        });
+                    }
+
+                    // Force singleton creation so monitors list is populated before host starts
+                    services.AddHostedService(sp =>
+                    {
+                        // Resolve all InboxMonitorService singletons
+                        sp.GetServices<InboxMonitorService>();
+                        return new MonitorHostedServiceRunner(monitors);
+                    });
+                })
+                .Build();
+
+            // Trigger DI resolution of InboxMonitorService singletons
+            host.Services.GetServices<InboxMonitorService>();
+
+            host.Start();
+
+            Application.Run(new TrayApplicationContext(host));
+        }
+        catch (Exception ex)
+        {
+            Log.Fatal(ex, "Application failed to start");
+        }
+        finally
+        {
+            host?.StopAsync().GetAwaiter().GetResult();
+            host?.Dispose();
+            Log.CloseAndFlush();
+        }
+    }
+}
+
+/// <summary>Bridges per-account InboxMonitorService instances into the hosted service pipeline.</summary>
+sealed class MonitorHostedServiceRunner : IHostedService
+{
+    private readonly List<InboxMonitorService> _monitors;
+
+    public MonitorHostedServiceRunner(List<InboxMonitorService> monitors)
+        => _monitors = monitors;
+
+    public Task StartAsync(CancellationToken ct)
+        => Task.WhenAll(_monitors.Select(m => m.StartAsync(ct)));
+
+    public Task StopAsync(CancellationToken ct)
+        => Task.WhenAll(_monitors.Select(m => m.StopAsync(ct)));
+}

src/SpamGuard/Services/ActivityLog.cs

@@ -1,5 +1,6 @@
 namespace SpamGuard.Services;
 
+using System.Text.Json;
 using SpamGuard.Models;
 
 public sealed class ActivityLog
@@ -7,13 +8,21 @@ public sealed class ActivityLog
     private readonly List<ActivityEntry> _entries = new();
     private readonly object _lock = new();
     private readonly int _maxEntries;
+    private readonly string? _filePath;
+
+    public event Action? EntryChanged;
 
     public int TodayChecked => GetTodayCount(_ => true);
     public int TodaySpam => GetTodayCount(e => e.Verdict == Verdict.Spam);
 
-    public ActivityLog(int maxEntries = 500)
+    public ActivityLog(int maxEntries = 500, string? dataDirectory = null)
     {
         _maxEntries = maxEntries;
+        if (dataDirectory != null)
+        {
+            _filePath = Path.Combine(dataDirectory, "activity-log.json");
+            LoadFromDisk();
+        }
     }
 
     public void Add(ActivityEntry entry)
@@ -24,6 +33,8 @@ public sealed class ActivityLog
             if (_entries.Count > _maxEntries)
                 _entries.RemoveAt(0);
         }
+        SaveToDisk();
+        EntryChanged?.Invoke();
     }
 
     public List<ActivityEntry> GetRecent(int count = 100)
@@ -37,6 +48,29 @@ public sealed class ActivityLog
         }
     }
 
+    public ActivityEntry? GetByIndex(int displayIndex, int displayCount)
+    {
+        lock (_lock)
+        {
+            var ordered = _entries
+                .OrderByDescending(e => e.Timestamp)
+                .Take(displayCount)
+                .ToList();
+            return displayIndex >= 0 && displayIndex < ordered.Count ? ordered[displayIndex] : null;
+        }
+    }
+
+    public void UpdateEntry(ActivityEntry entry, Verdict newVerdict, UserOverride userOverride)
+    {
+        lock (_lock)
+        {
+            entry.Verdict = newVerdict;
+            entry.Override = userOverride;
+        }
+        SaveToDisk();
+        EntryChanged?.Invoke();
+    }
+
     private int GetTodayCount(Func<ActivityEntry, bool> predicate)
     {
         var today = DateTime.UtcNow.Date;
@@ -45,4 +79,39 @@ public sealed class ActivityLog
             return _entries.Count(e => e.Timestamp.Date == today && predicate(e));
         }
     }
+
+    private void SaveToDisk()
+    {
+        if (_filePath == null) return;
+        lock (_lock)
+        {
+            var json = JsonSerializer.Serialize(_entries, new JsonSerializerOptions { WriteIndented = true });
+            var tempPath = _filePath + ".tmp";
+            File.WriteAllText(tempPath, json);
+            File.Move(tempPath, _filePath, overwrite: true);
+        }
+    }
+
+    private void LoadFromDisk()
+    {
+        if (_filePath == null || !File.Exists(_filePath)) return;
+        try
+        {
+            var json = File.ReadAllText(_filePath);
+            var entries = JsonSerializer.Deserialize<List<ActivityEntry>>(json);
+            if (entries != null)
+            {
+                lock (_lock)
+                {
+                    _entries.AddRange(entries);
+                    while (_entries.Count > _maxEntries)
+                        _entries.RemoveAt(0);
+                }
+            }
+        }
+        catch
+        {
+            // Corrupted file -- start fresh
+        }
+    }
 }

src/SpamGuard/Services/EmailClassifier.cs

@@ -0,0 +1,167 @@
+// src/SpamGuard/Services/EmailClassifier.cs
+namespace SpamGuard.Services;
+
+using System.Text;
+using System.Text.Json;
+using System.Text.RegularExpressions;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+using SpamGuard.Configuration;
+using SpamGuard.Models;
+using SpamGuard.State;
+
+public sealed partial class EmailClassifier
+{
+    private readonly SpamGuardOptions _options;
+    private readonly ILogger<EmailClassifier> _logger;
+    private readonly HttpClient _httpClient;
+    private readonly OverrideStore _overrideStore;
+
+    private const string BaseSystemPrompt = """
+        You are an email spam classifier. Analyze the following email and determine if it is spam or legitimate.
+
+        Spam includes:
+        - Unsolicited marketing or promotional emails the recipient never signed up for
+        - AI-generated emails designed to look like legitimate correspondence
+        - Newsletter signups the recipient did not request
+
+        Legitimate includes:
+        - Emails from known contacts or businesses the recipient has a relationship with
+        - Transactional emails (receipts, shipping notifications, password resets)
+        - Emails the recipient would expect to receive
+
+        YOU MUST respond with ONLY a JSON object. No explanation, no preamble, no markdown fencing.
+        Output exactly this structure and nothing else:
+        {"classification": "spam" | "legitimate", "confidence": 0.0-1.0, "reason": "brief explanation"}
+        """;
+
+    public EmailClassifier(
+        IOptions<SpamGuardOptions> options,
+        ILogger<EmailClassifier> logger,
+        HttpClient httpClient,
+        OverrideStore overrideStore)
+    {
+        _options = options.Value;
+        _logger = logger;
+        _httpClient = httpClient;
+        _overrideStore = overrideStore;
+    }
+
+    public string BuildPrompt(EmailSummary email)
+    {
+        var body = email.BodySnippet.Length > _options.Claude.MaxBodyLength
+            ? email.BodySnippet[.._options.Claude.MaxBodyLength]
+            : email.BodySnippet;
+
+        return $"""
+            Email details:
+            From: {email.From}
+            Subject: {email.Subject}
+            Body: {body}
+            """;
+    }
+
+    public async Task<ClassificationResult?> ClassifyAsync(EmailSummary email, CancellationToken ct = default)
+    {
+        var userMessage = BuildPrompt(email);
+
+        _logger.LogDebug("Classifying email UID={Uid} from {From}", email.Uid, email.From);
+
+        var systemPrompt = BaseSystemPrompt + _overrideStore.BuildFewShotText(10);
+
+        var requestBody = new
+        {
+            model = _options.Claude.Model,
+            max_tokens = 256,
+            system = systemPrompt,
+            messages = new[]
+            {
+                new { role = "user", content = userMessage }
+            }
+        };
+
+        var json = JsonSerializer.Serialize(requestBody);
+        var request = new HttpRequestMessage(HttpMethod.Post, "v1/messages")
+        {
+            Content = new StringContent(json, Encoding.UTF8, "application/json")
+        };
+
+        var isAnthropic = _options.Claude.BaseUrl.Contains("anthropic.com", StringComparison.OrdinalIgnoreCase);
+        if (isAnthropic)
+        {
+            request.Headers.Add("x-api-key", _options.Claude.ApiKey);
+            request.Headers.Add("anthropic-version", "2023-06-01");
+        }
+        else
+        {
+            request.Headers.Authorization =
+                new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", _options.Claude.ApiKey);
+        }
+
+        var response = await _httpClient.SendAsync(request, ct);
+
+        if (!response.IsSuccessStatusCode)
+        {
+            var errorBody = await response.Content.ReadAsStringAsync(ct);
+            _logger.LogError("Claude API returned {StatusCode}: {Error}", (int)response.StatusCode, errorBody);
+            return null;
+        }
+
+        var responseJson = await response.Content.ReadAsStringAsync(ct);
+        using var doc = JsonDocument.Parse(responseJson);
+        var text = doc.RootElement
+            .GetProperty("content")[0]
+            .GetProperty("text")
+            .GetString() ?? "";
+
+        var result = ParseResponse(text);
+
+        if (result != null)
+            _logger.LogInformation(
+                "UID={Uid} classified as {Classification} (confidence={Confidence}): {Reason}",
+                email.Uid, result.Classification, result.Confidence, result.Reason);
+        else
+            _logger.LogWarning("UID={Uid} classification failed to parse: {Text}", email.Uid, text);
+
+        return result;
+    }
+
+    public static ClassificationResult? ParseResponse(string text)
+    {
+        // Strip markdown code fencing if present
+        var cleaned = StripMarkdownFencing().Replace(text, "$1").Trim();
+
+        // Try direct parse first (happy path)
+        var result = TryParseJson(cleaned);
+        if (result != null) return result;
+
+        // Fall back: extract first {...} block from prose-wrapped responses
+        var start = cleaned.IndexOf('{');
+        var end = cleaned.LastIndexOf('}');
+        if (start >= 0 && end > start)
+            return TryParseJson(cleaned[start..(end + 1)]);
+
+        return null;
+    }
+
+    private static ClassificationResult? TryParseJson(string json)
+    {
+        try
+        {
+            using var doc = JsonDocument.Parse(json);
+            var root = doc.RootElement;
+            return new ClassificationResult(
+                Classification: root.GetProperty("classification").GetString() ?? "unknown",
+                Confidence: root.GetProperty("confidence").GetDouble(),
+                Reason: root.GetProperty("reason").GetString() ?? ""
+            );
+        }
+        catch
+        {
+            return null;
+        }
+    }
+
+    [GeneratedRegex(@"```(?:json)?\s*([\s\S]*?)\s*```", RegexOptions.Compiled)]
+    private static partial Regex StripMarkdownFencing();
+}

src/SpamGuard/Services/ImapClientFactory.cs

@@ -0,0 +1,30 @@
+namespace SpamGuard.Services;
+
+using MailKit.Net.Imap;
+using MailKit.Security;
+using Microsoft.Extensions.Logging;
+using SpamGuard.Configuration;
+
+public sealed class ImapClientFactory
+{
+    private readonly ILogger<ImapClientFactory> _logger;
+
+    public ImapClientFactory(ILogger<ImapClientFactory> logger)
+    {
+        _logger = logger;
+    }
+
+    public async Task<ImapClient> CreateConnectedClientAsync(ImapOptions imap, CancellationToken ct = default)
+    {
+        var client = new ImapClient();
+
+        _logger.LogDebug("Connecting to {Host}:{Port} (SSL={UseSsl})", imap.Host, imap.Port, imap.UseSsl);
+
+        var secureSocketOptions = imap.UseSsl ? SecureSocketOptions.SslOnConnect : SecureSocketOptions.StartTlsWhenAvailable;
+        await client.ConnectAsync(imap.Host, imap.Port, secureSocketOptions, ct);
+        await client.AuthenticateAsync(imap.Username, imap.Password, ct);
+
+        _logger.LogDebug("Connected and authenticated as {Username}", imap.Username);
+        return client;
+    }
+}

src/SpamGuard/Services/InboxMonitorService.cs

@@ -0,0 +1,403 @@
+// src/SpamGuard/Services/InboxMonitorService.cs
+namespace SpamGuard.Services;
+
+using MailKit;
+using MailKit.Search;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using MimeKit;
+using SpamGuard.Configuration;
+using SpamGuard.Models;
+using SpamGuard.State;
+
+public sealed partial class InboxMonitorService : BackgroundService
+{
+    private readonly ImapClientFactory _imapFactory;
+    private readonly TrustedSenderStore _trustedSenders;
+    private readonly BlockedDomainStore _blockedDomains;
+    private readonly ProcessedUidStore _processedUids;
+    private readonly EmailClassifier _classifier;
+    private readonly ActivityLog _activityLog;
+    private readonly ImapOptions _imap;
+    private readonly MonitoringOptions _monitoring;
+    private readonly ILogger<InboxMonitorService> _logger;
+
+    private volatile bool _paused;
+    private uint _lastSeenUid;
+
+    public string AccountName => _imap.Name.Length > 0 ? _imap.Name : _imap.Username;
+    public bool IsPaused => _paused;
+    public void Pause() => _paused = true;
+    public void Resume() => _paused = false;
+
+    public InboxMonitorService(
+        ImapClientFactory imapFactory,
+        TrustedSenderStore trustedSenders,
+        BlockedDomainStore blockedDomains,
+        ProcessedUidStore processedUids,
+        EmailClassifier classifier,
+        ActivityLog activityLog,
+        ImapOptions imap,
+        MonitoringOptions monitoring,
+        ILogger<InboxMonitorService> logger)
+    {
+        _imapFactory = imapFactory;
+        _trustedSenders = trustedSenders;
+        _blockedDomains = blockedDomains;
+        _processedUids = processedUids;
+        _classifier = classifier;
+        _activityLog = activityLog;
+        _imap = imap;
+        _monitoring = monitoring;
+        _logger = logger;
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        _logger.LogInformation("InboxMonitorService started for {Account}", AccountName);
+
+        // Brief delay to let TrustedSenderService do its first scan
+        await Task.Delay(TimeSpan.FromSeconds(10), stoppingToken);
+
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            if (!_paused)
+            {
+                try
+                {
+                    await PollInboxAsync(stoppingToken);
+                    _processedUids.Prune(TimeSpan.FromDays(30));
+                    _processedUids.Save();
+                }
+                catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
+                {
+                    break;
+                }
+                catch (Exception ex)
+                {
+                    _logger.LogError(ex, "Error polling inbox");
+                    _activityLog.Add(new ActivityEntry
+                    {
+                        Timestamp = DateTime.UtcNow, Sender = "", Subject = "",
+                        Verdict = Verdict.Error, Reason = ex.Message, AccountName = AccountName
+                    });
+                }
+            }
+
+            await Task.Delay(TimeSpan.FromSeconds(_monitoring.PollIntervalSeconds), stoppingToken);
+        }
+    }
+
+    private async Task PollInboxAsync(CancellationToken ct)
+    {
+        var client = await _imapFactory.CreateConnectedClientAsync(_imap, ct);
+        try
+        {
+            var inbox = client.Inbox;
+            await inbox.OpenAsync(FolderAccess.ReadWrite, ct);
+
+            // Build search query: only fetch new messages
+            IList<UniqueId> uids;
+            if (_lastSeenUid > 0)
+            {
+                var range = new UniqueIdRange(new UniqueId(_lastSeenUid + 1), UniqueId.MaxValue);
+                uids = await inbox.SearchAsync(range, SearchQuery.All, ct);
+            }
+            else if (_processedUids.Count > 0)
+            {
+                // Resuming from persisted state -- scan recent messages only
+                uids = await inbox.SearchAsync(
+                    SearchQuery.DeliveredAfter(DateTime.UtcNow.AddDays(-1)), ct);
+            }
+            else
+            {
+                // First ever run -- initial scan window
+                uids = await inbox.SearchAsync(
+                    SearchQuery.DeliveredAfter(DateTime.UtcNow.AddDays(-_monitoring.InitialScanDays)), ct);
+            }
+            _logger.LogDebug("Found {Count} messages in inbox", uids.Count);
+
+            // Find the spam/junk folder
+            var spamFolder = await FindSpamFolderAsync(client, ct);
+
+            foreach (var uid in uids)
+            {
+                if (_processedUids.Contains(uid.Id))
+                {
+                    if (uid.Id > _lastSeenUid) _lastSeenUid = uid.Id;
+                    continue;
+                }
+
+                try
+                {
+                    await ProcessMessageAsync(inbox, uid, spamFolder, ct);
+                }
+                catch (OperationCanceledException) when (ct.IsCancellationRequested)
+                {
+                    throw;
+                }
+                catch (Exception ex)
+                {
+                    _logger.LogError(ex, "Error processing UID={Uid}", uid.Id);
+                    _activityLog.Add(new ActivityEntry
+                    {
+                        Timestamp = DateTime.UtcNow, Sender = "", Subject = $"UID {uid.Id}",
+                        Verdict = Verdict.Error, Reason = ex.Message,
+                        Uid = uid.Id, AccountName = AccountName
+                    });
+                    _processedUids.Add(uid.Id);
+
+                    // Reconnect if the server dropped the connection (e.g. unexpected response after MoveToAsync)
+                    if (!client.IsConnected || ex is MailKit.Net.Imap.ImapProtocolException)
+                    {
+                        _logger.LogWarning("IMAP connection lost for {Account}, reconnecting", AccountName);
+                        try { client.Dispose(); } catch { }
+                        client = await _imapFactory.CreateConnectedClientAsync(_imap, ct);
+                        inbox = client.Inbox;
+                        await inbox.OpenAsync(FolderAccess.ReadWrite, ct);
+                        spamFolder = await FindSpamFolderAsync(client, ct);
+                    }
+                }
+
+                if (uid.Id > _lastSeenUid) _lastSeenUid = uid.Id;
+            }
+
+            await client.DisconnectAsync(true, ct);
+        }
+        finally
+        {
+            client.Dispose();
+        }
+    }
+
+    private async Task ProcessMessageAsync(
+        IMailFolder inbox, UniqueId uid, IMailFolder? spamFolder, CancellationToken ct)
+    {
+        var message = await inbox.GetMessageAsync(uid, ct);
+        var from = message.From.Mailboxes.FirstOrDefault()?.Address ?? "unknown";
+        var subject = message.Subject ?? "(no subject)";
+        var bodySnippet = ExtractBodySnippet(message);
+
+        // Check trusted senders
+        if (_trustedSenders.IsTrusted(from))
+        {
+            _logger.LogDebug("UID={Uid} from trusted sender {From}, skipping", uid.Id, from);
+            _activityLog.Add(new ActivityEntry
+            {
+                Timestamp = DateTime.UtcNow, Sender = from, Subject = subject,
+                Verdict = Verdict.Trusted, Uid = uid.Id, AccountName = AccountName,
+                BodySnippet = bodySnippet
+            });
+            _processedUids.Add(uid.Id);
+            return;
+        }
+
+        // Check blocked domains
+        if (_blockedDomains.IsBlocked(from))
+        {
+            _logger.LogInformation("UID={Uid} from blocked domain {From}, marking as spam", uid.Id, from);
+            if (spamFolder != null)
+                await inbox.MoveToAsync(uid, spamFolder, ct);
+            else
+                await inbox.AddFlagsAsync(uid, MailKit.MessageFlags.Flagged, true, ct);
+
+            _activityLog.Add(new ActivityEntry
+            {
+                Timestamp = DateTime.UtcNow, Sender = from, Subject = subject,
+                Verdict = Verdict.Spam, Confidence = 1.0, Reason = "Blocked domain",
+                Uid = uid.Id, AccountName = AccountName, BodySnippet = bodySnippet
+            });
+            _processedUids.Add(uid.Id);
+            return;
+        }
+
+        var emailSummary = new EmailSummary(uid.Id, from, subject, bodySnippet, message.Date);
+
+        // Classify
+        var result = await _classifier.ClassifyAsync(emailSummary, ct);
+
+        if (result == null)
+        {
+            _activityLog.Add(new ActivityEntry
+            {
+                Timestamp = DateTime.UtcNow, Sender = from, Subject = subject,
+                Verdict = Verdict.Error, Reason = "Classification failed",
+                Uid = uid.Id, AccountName = AccountName, BodySnippet = bodySnippet
+            });
+            _processedUids.Add(uid.Id);
+            return;
+        }
+
+        if (result.IsSpam && result.Confidence >= _monitoring.SpamConfidenceThreshold)
+        {
+            if (spamFolder != null)
+            {
+                await inbox.MoveToAsync(uid, spamFolder, ct);
+                _logger.LogInformation("Moved UID={Uid} to spam: {Reason}", uid.Id, result.Reason);
+            }
+            else
+            {
+                _logger.LogWarning("Spam detected but no spam folder found, flagging instead");
+                await inbox.AddFlagsAsync(uid, MailKit.MessageFlags.Flagged, true, ct);
+            }
+
+            _activityLog.Add(new ActivityEntry
+            {
+                Timestamp = DateTime.UtcNow, Sender = from, Subject = subject,
+                Verdict = Verdict.Spam, Confidence = result.Confidence, Reason = result.Reason,
+                Uid = uid.Id, AccountName = AccountName, BodySnippet = bodySnippet
+            });
+        }
+        else if (result.IsSpam)
+        {
+            _activityLog.Add(new ActivityEntry
+            {
+                Timestamp = DateTime.UtcNow, Sender = from, Subject = subject,
+                Verdict = Verdict.Uncertain, Confidence = result.Confidence, Reason = result.Reason,
+                Uid = uid.Id, AccountName = AccountName, BodySnippet = bodySnippet
+            });
+        }
+        else
+        {
+            _activityLog.Add(new ActivityEntry
+            {
+                Timestamp = DateTime.UtcNow, Sender = from, Subject = subject,
+                Verdict = Verdict.Legitimate, Confidence = result.Confidence, Reason = result.Reason,
+                Uid = uid.Id, AccountName = AccountName, BodySnippet = bodySnippet
+            });
+        }
+
+        _processedUids.Add(uid.Id);
+    }
+
+    private static string ExtractBodySnippet(MimeMessage message)
+    {
+        var text = message.TextBody;
+
+        if (text == null && message.HtmlBody != null)
+        {
+            // Strip script and style blocks first, then remaining tags
+            text = StripScriptStyle().Replace(message.HtmlBody, " ");
+            text = StripHtmlTags().Replace(text, " ");
+            text = System.Net.WebUtility.HtmlDecode(text);
+            text = CollapseWhitespace().Replace(text, " ").Trim();
+        }
+
+        text ??= "";
+        return text.Length > 2000 ? text[..2000] : text;
+    }
+
+    [System.Text.RegularExpressions.GeneratedRegex(@"<(script|style)[^>]*>[\s\S]*?</\1>", System.Text.RegularExpressions.RegexOptions.IgnoreCase)]
+    private static partial System.Text.RegularExpressions.Regex StripScriptStyle();
+
+    [System.Text.RegularExpressions.GeneratedRegex(@"<[^>]+>")]
+    private static partial System.Text.RegularExpressions.Regex StripHtmlTags();
+
+    [System.Text.RegularExpressions.GeneratedRegex(@"\s{2,}")]
+    private static partial System.Text.RegularExpressions.Regex CollapseWhitespace();
+
+    public async Task MoveToSpamAsync(uint uid, CancellationToken ct = default)
+    {
+        using var client = await _imapFactory.CreateConnectedClientAsync(_imap, ct);
+        var inbox = client.Inbox;
+        await inbox.OpenAsync(FolderAccess.ReadWrite, ct);
+        var spamFolder = await FindSpamFolderAsync(client, ct);
+        if (spamFolder != null)
+            await inbox.MoveToAsync(new UniqueId(uid), spamFolder, ct);
+        else
+            await inbox.AddFlagsAsync(new UniqueId(uid), MailKit.MessageFlags.Flagged, true, ct);
+        await client.DisconnectAsync(true, ct);
+    }
+
+    public async Task MoveToInboxAsync(uint uid, CancellationToken ct = default)
+    {
+        using var client = await _imapFactory.CreateConnectedClientAsync(_imap, ct);
+
+        // Find the spam folder and open it
+        var spamFolder = await FindSpamFolderAsync(client, ct);
+        if (spamFolder == null)
+        {
+            _logger.LogWarning("Cannot move to inbox: spam folder not found");
+            return;
+        }
+
+        await spamFolder.OpenAsync(FolderAccess.ReadWrite, ct);
+        var inbox = client.Inbox;
+
+        // Search for the UID in the spam folder
+        var uids = await spamFolder.SearchAsync(SearchQuery.All, ct);
+        var target = uids.FirstOrDefault(u => u.Id == uid);
+        if (target.IsValid)
+            await spamFolder.MoveToAsync(target, inbox, ct);
+        else
+            _logger.LogWarning("UID={Uid} not found in spam folder", uid);
+
+        await client.DisconnectAsync(true, ct);
+    }
+
+    private async Task<IMailFolder?> FindSpamFolderAsync(MailKit.Net.Imap.ImapClient client, CancellationToken ct)
+    {
+        // 1. Try IMAP special-use \Junk attribute (most reliable when server advertises it)
+        try
+        {
+            var junk = client.GetFolder(MailKit.SpecialFolder.Junk);
+            if (junk != null)
+            {
+                _logger.LogDebug("Found spam folder via special-use attribute: {Full}", junk.FullName);
+                return junk;
+            }
+        }
+        catch (Exception ex)
+        {
+            _logger.LogDebug(ex, "Server does not advertise Junk special-use attribute");
+        }
+
+        // 2. Search by name — try configured name plus common variants, two levels deep
+        var candidates = new HashSet<string>(StringComparer.OrdinalIgnoreCase)
+        {
+            _monitoring.SpamFolderName, "Junk", "Spam", "Junk Email", "Junk E-mail", "Junk Mail", "Bulk Mail"
+        };
+
+        foreach (var ns in client.PersonalNamespaces)
+        {
+            IMailFolder root;
+            try { root = client.GetFolder(ns); }
+            catch { continue; }
+
+            IList<IMailFolder> topLevel;
+            try { topLevel = await root.GetSubfoldersAsync(false, ct); }
+            catch (Exception ex) { _logger.LogDebug(ex, "Could not list top-level folders"); continue; }
+
+            _logger.LogDebug("Folder list for {Account}: {Folders}",
+                AccountName, string.Join(", ", topLevel.Select(f => f.FullName)));
+
+            foreach (var folder in topLevel)
+            {
+                if (candidates.Contains(folder.Name))
+                {
+                    _logger.LogDebug("Found spam folder: {Full}", folder.FullName);
+                    return folder;
+                }
+
+                // One level deeper — catches [Gmail]/Spam, INBOX.Junk, etc.
+                try
+                {
+                    var sub = await folder.GetSubfoldersAsync(false, ct);
+                    if (sub.Count > 0)
+                        _logger.LogDebug("Subfolders of {Parent}: {Subs}",
+                            folder.FullName, string.Join(", ", sub.Select(f => f.FullName)));
+                    var match = sub.FirstOrDefault(f => candidates.Contains(f.Name));
+                    if (match != null)
+                    {
+                        _logger.LogDebug("Found nested spam folder: {Full}", match.FullName);
+                        return match;
+                    }
+                }
+                catch { /* skip non-enumerable folders */ }
+            }
+        }
+
+        _logger.LogWarning("Could not find spam/junk folder for account {Account} — will flag instead", AccountName);
+        return null;
+    }
+}

src/SpamGuard/Services/TrustedSenderService.cs

@@ -0,0 +1,137 @@
+// src/SpamGuard/Services/TrustedSenderService.cs
+namespace SpamGuard.Services;
+
+using MailKit;
+using MailKit.Search;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+using MimeKit;
+using SpamGuard.Configuration;
+using SpamGuard.State;
+
+public sealed class TrustedSenderService : BackgroundService
+{
+    private readonly ImapClientFactory _imapFactory;
+    private readonly TrustedSenderStore _store;
+    private readonly ImapOptions _imap;
+    private readonly MonitoringOptions _monitoring;
+    private readonly ILogger<TrustedSenderService> _logger;
+    private bool _initialScanDone;
+
+    public TrustedSenderService(
+        ImapClientFactory imapFactory,
+        TrustedSenderStore store,
+        ImapOptions imap,
+        MonitoringOptions monitoring,
+        ILogger<TrustedSenderService> logger)
+    {
+        _imapFactory = imapFactory;
+        _store = store;
+        _imap = imap;
+        _monitoring = monitoring;
+        _logger = logger;
+    }
+
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        _logger.LogInformation("TrustedSenderService started for {Account}", _imap.Username);
+
+        while (!stoppingToken.IsCancellationRequested)
+        {
+            try
+            {
+                await ScanSentFolderAsync(stoppingToken);
+                _store.Save();
+                _logger.LogInformation("Trusted sender scan complete. {Count} trusted senders", _store.Count);
+            }
+            catch (OperationCanceledException) when (stoppingToken.IsCancellationRequested)
+            {
+                break;
+            }
+            catch (Exception ex)
+            {
+                _logger.LogError(ex, "Error scanning sent folder");
+            }
+
+            await Task.Delay(TimeSpan.FromMinutes(_monitoring.TrustedSenderRefreshMinutes), stoppingToken);
+        }
+    }
+
+    private async Task ScanSentFolderAsync(CancellationToken ct)
+    {
+        using var client = await _imapFactory.CreateConnectedClientAsync(_imap, ct);
+
+        var sentFolder = await FindSentFolderAsync(client, ct)
+                         ?? throw new InvalidOperationException("Could not find Sent folder");
+
+        await sentFolder.OpenAsync(FolderAccess.ReadOnly, ct);
+
+        // After initial full scan, only check messages from the last refresh period
+        var query = _initialScanDone
+            ? SearchQuery.DeliveredAfter(DateTime.UtcNow.AddMinutes(-_monitoring.TrustedSenderRefreshMinutes))
+            : SearchQuery.All;
+
+        var uids = await sentFolder.SearchAsync(query, ct);
+        _logger.LogDebug("Found {Count} messages in Sent folder to scan", uids.Count);
+
+        var addresses = new List<string>();
+        foreach (var uid in uids)
+        {
+            var headers = await sentFolder.GetHeadersAsync(uid, ct);
+            ExtractAddresses(headers, addresses);
+        }
+
+        _store.AddRange(addresses);
+        _initialScanDone = true;
+        await client.DisconnectAsync(true, ct);
+    }
+
+    private static readonly string[] SentFolderNames = ["Sent", "Sent Items", "Sent Messages", "INBOX.Sent"];
+
+    private async Task<IMailFolder?> FindSentFolderAsync(MailKit.Net.Imap.ImapClient client, CancellationToken ct)
+    {
+        // Try special folder first (requires SPECIAL-USE or XLIST extension)
+        try
+        {
+            var sent = client.GetFolder(MailKit.SpecialFolder.Sent);
+            if (sent != null) return sent;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogDebug(ex, "SPECIAL-USE not supported, falling back to folder name lookup");
+        }
+
+        // Fall back to well-known folder names
+        try
+        {
+            var personal = client.GetFolder(client.PersonalNamespaces[0]);
+            var folders = await personal.GetSubfoldersAsync(false, ct);
+            return folders.FirstOrDefault(f =>
+                SentFolderNames.Any(name => f.Name.Equals(name, StringComparison.OrdinalIgnoreCase)));
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning(ex, "Could not enumerate folders to find Sent folder");
+        }
+
+        return null;
+    }
+
+    private static void ExtractAddresses(HeaderList headers, List<string> addresses)
+    {
+        foreach (var headerName in new[] { "To", "Cc" })
+        {
+            var value = headers[headerName];
+            if (string.IsNullOrEmpty(value)) continue;
+
+            if (InternetAddressList.TryParse(value, out var list))
+            {
+                foreach (var address in list.Mailboxes)
+                {
+                    if (!string.IsNullOrEmpty(address.Address))
+                        addresses.Add(address.Address);
+                }
+            }
+        }
+    }
+}

src/SpamGuard/SpamGuard.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
     <OutputType>WinExe</OutputType>
@@ -12,9 +12,18 @@
     <PackageReference Include="MailKit" Version="4.*" />
     <PackageReference Include="Anthropic" Version="12.*" />
     <PackageReference Include="Microsoft.Extensions.Hosting" Version="8.*" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.Json" Version="8.*" />
+    <PackageReference Include="Microsoft.Extensions.Configuration.EnvironmentVariables" Version="8.*" />
+    <PackageReference Include="Microsoft.Extensions.Http" Version="8.*" />
     <PackageReference Include="Serilog.Extensions.Hosting" Version="8.*" />
     <PackageReference Include="Serilog.Sinks.File" Version="5.*" />
     <PackageReference Include="Serilog.Sinks.Console" Version="5.*" />
   </ItemGroup>
 
+  <ItemGroup>
+    <None Update="appsettings.json">
+      <CopyToOutputDirectory>Always</CopyToOutputDirectory>
+    </None>
+  </ItemGroup>
+
 </Project>

src/SpamGuard/State/BlockedDomainStore.cs

@@ -0,0 +1,77 @@
+namespace SpamGuard.State;
+
+using System.Text.Json;
+
+public sealed class BlockedDomainStore
+{
+    private readonly string _filePath;
+    private readonly HashSet<string> _domains;
+    private readonly object _lock = new();
+
+    public BlockedDomainStore(string dataDirectory)
+    {
+        _filePath = Path.Combine(dataDirectory, "blocked-domains.json");
+        _domains = Load();
+    }
+
+    public int Count
+    {
+        get { lock (_lock) { return _domains.Count; } }
+    }
+
+    public bool IsBlocked(string email)
+    {
+        var domain = ExtractDomain(email);
+        if (string.IsNullOrEmpty(domain)) return false;
+
+        lock (_lock)
+        {
+            return _domains.Contains(domain);
+        }
+    }
+
+    public void Add(string domain)
+    {
+        lock (_lock)
+        {
+            _domains.Add(Normalize(domain));
+        }
+    }
+
+    public void Remove(string domain)
+    {
+        lock (_lock)
+        {
+            _domains.Remove(Normalize(domain));
+        }
+    }
+
+    public void Save()
+    {
+        lock (_lock)
+        {
+            var json = JsonSerializer.Serialize(_domains);
+            var tempPath = _filePath + ".tmp";
+            File.WriteAllText(tempPath, json);
+            File.Move(tempPath, _filePath, overwrite: true);
+        }
+    }
+
+    public static string ExtractDomain(string email)
+    {
+        var at = email.IndexOf('@');
+        return at >= 0 ? Normalize(email[(at + 1)..]) : "";
+    }
+
+    private static string Normalize(string domain) => domain.Trim().ToLowerInvariant();
+
+    private HashSet<string> Load()
+    {
+        if (!File.Exists(_filePath))
+            return new HashSet<string>();
+
+        var json = File.ReadAllText(_filePath);
+        return JsonSerializer.Deserialize<HashSet<string>>(json)
+               ?? new HashSet<string>();
+    }
+}

src/SpamGuard/State/OverrideStore.cs

@@ -0,0 +1,85 @@
+namespace SpamGuard.State;
+
+using System.Text;
+using System.Text.Json;
+
+public sealed record OverrideRecord(
+    DateTime Timestamp,
+    string Sender,
+    string Subject,
+    string? BodySnippet,
+    string UserVerdict,
+    string OriginalVerdict
+);
+
+public sealed class OverrideStore
+{
+    private readonly string _filePath;
+    private readonly List<OverrideRecord> _overrides;
+    private readonly object _lock = new();
+    private const int MaxOverrides = 50;
+
+    public OverrideStore(string dataDirectory)
+    {
+        _filePath = Path.Combine(dataDirectory, "overrides.json");
+        _overrides = Load();
+    }
+
+    public void Add(OverrideRecord record)
+    {
+        lock (_lock)
+        {
+            _overrides.Add(record);
+            while (_overrides.Count > MaxOverrides)
+                _overrides.RemoveAt(0);
+        }
+    }
+
+    public List<OverrideRecord> GetRecent(int count = 10)
+    {
+        lock (_lock)
+        {
+            return _overrides
+                .OrderByDescending(o => o.Timestamp)
+                .Take(count)
+                .ToList();
+        }
+    }
+
+    public string BuildFewShotText(int count = 10)
+    {
+        var recent = GetRecent(count);
+        if (recent.Count == 0)
+            return "";
+
+        var sb = new StringBuilder();
+        sb.AppendLine();
+        sb.AppendLine("The user has previously corrected these classifications:");
+        foreach (var o in recent)
+        {
+            sb.AppendLine($"- [From: {o.Sender}, Subject: {o.Subject}] was originally classified as {o.OriginalVerdict} but the user marked it as {o.UserVerdict}.");
+        }
+        return sb.ToString();
+    }
+
+    public void Save()
+    {
+        lock (_lock)
+        {
+            var json = JsonSerializer.Serialize(_overrides, new JsonSerializerOptions { WriteIndented = true });
+            var tempPath = _filePath + ".tmp";
+            File.WriteAllText(tempPath, json);
+            File.Move(tempPath, _filePath, overwrite: true);
+        }
+    }
+
+    private List<OverrideRecord> Load()
+    {
+        if (!File.Exists(_filePath))
+            return new List<OverrideRecord>();
+
+        var json = File.ReadAllText(_filePath);
+        return JsonSerializer.Deserialize<List<OverrideRecord>>(json)
+               ?? new List<OverrideRecord>();
+    }
+}

src/SpamGuard/State/ProcessedUidStore.cs

@@ -9,9 +9,10 @@ public sealed class ProcessedUidStore
     private readonly Dictionary<uint, DateTime> _uids;
     private readonly object _lock = new();
 
-    public ProcessedUidStore(string dataDirectory)
+    public ProcessedUidStore(string dataDirectory, string accountName)
     {
-        _filePath = Path.Combine(dataDirectory, "processed-uids.json");
+        var safeName = string.Concat(accountName.Select(c => Path.GetInvalidFileNameChars().Contains(c) ? '_' : c));
+        _filePath = Path.Combine(dataDirectory, $"processed-uids-{safeName}.json");
         _uids = Load();
     }
 
@@ -52,7 +53,9 @@ public sealed class ProcessedUidStore
         lock (_lock)
         {
             var json = JsonSerializer.Serialize(_uids);
-            File.WriteAllText(_filePath, json);
+            var tempPath = _filePath + ".tmp";
+            File.WriteAllText(tempPath, json);
+            File.Move(tempPath, _filePath, overwrite: true);
         }
     }
 

src/SpamGuard/State/TrustedSenderStore.cs

@@ -50,7 +50,9 @@ public sealed class TrustedSenderStore
         lock (_lock)
         {
             var json = JsonSerializer.Serialize(_senders);
-            File.WriteAllText(_filePath, json);
+            var tempPath = _filePath + ".tmp";
+            File.WriteAllText(tempPath, json);
+            File.Move(tempPath, _filePath, overwrite: true);
         }
     }
 

src/SpamGuard/Tray/ActivityLogForm.cs

@@ -0,0 +1,355 @@
+namespace SpamGuard.Tray;
+
+using SpamGuard.Models;
+using SpamGuard.Services;
+using SpamGuard.State;
+
+public sealed class ActivityLogForm : Form
+{
+    private readonly ActivityLog _activityLog;
+    private readonly IReadOnlyList<InboxMonitorService> _monitors;
+    private readonly TrustedSenderStore _trustedSenders;
+    private readonly BlockedDomainStore _blockedDomains;
+    private readonly OverrideStore _overrideStore;
+    private readonly DataGridView _grid;
+    private readonly ToolStrip _toolbar;
+    private readonly ContextMenuStrip _rowMenu;
+
+    private const int DisplayCount = 200;
+
+    public ActivityLogForm(
+        ActivityLog activityLog,
+        IReadOnlyList<InboxMonitorService> monitors,
+        TrustedSenderStore trustedSenders,
+        BlockedDomainStore blockedDomains,
+        OverrideStore overrideStore)
+    {
+        _activityLog = activityLog;
+        _monitors = monitors;
+        _trustedSenders = trustedSenders;
+        _blockedDomains = blockedDomains;
+        _overrideStore = overrideStore;
+
+        Text = "SpamGuard - Activity Log";
+        Size = new System.Drawing.Size(900, 550);
+        StartPosition = FormStartPosition.CenterScreen;
+        Icon = IconGenerator.Green;
+        KeyPreview = true;
+
+        // Toolbar
+        _toolbar = new ToolStrip();
+        var btnMarkSpam = new ToolStripButton("Mark Spam (S)")
+        {
+            ForeColor = System.Drawing.Color.Red,
+            Tag = "spam"
+        };
+        btnMarkSpam.Click += OnMarkSpam;
+
+        var btnMarkNotSpam = new ToolStripButton("Not Spam (H)")
+        {
+            ForeColor = System.Drawing.Color.Green,
+            Tag = "ham"
+        };
+        btnMarkNotSpam.Click += OnMarkNotSpam;
+
+        var btnBlockDomain = new ToolStripButton("Block Domain (D)")
+        {
+            ForeColor = System.Drawing.Color.DarkRed,
+            Tag = "block"
+        };
+        btnBlockDomain.Click += OnBlockDomain;
+
+        var btnAllowDomain = new ToolStripButton("Allow Domain")
+        {
+            ForeColor = System.Drawing.Color.DarkGreen,
+            Tag = "allow"
+        };
+        btnAllowDomain.Click += OnAllowDomain;
+
+        _toolbar.Items.AddRange(new ToolStripItem[]
+        {
+            btnMarkSpam,
+            btnMarkNotSpam,
+            new ToolStripSeparator(),
+            btnBlockDomain,
+            btnAllowDomain
+        });
+
+        // Context menu
+        _rowMenu = new ContextMenuStrip();
+        var ctxSpam = new ToolStripMenuItem("Mark as Spam (S)");
+        ctxSpam.Click += OnMarkSpam;
+        var ctxNotSpam = new ToolStripMenuItem("Mark as Not Spam (H)");
+        ctxNotSpam.Click += OnMarkNotSpam;
+        var ctxBlockDomain = new ToolStripMenuItem("Always Block Domain (D)");
+        ctxBlockDomain.Click += OnBlockDomain;
+        var ctxAllowDomain = new ToolStripMenuItem("Never Block Domain");
+        ctxAllowDomain.Click += OnAllowDomain;
+
+        _rowMenu.Items.AddRange(new ToolStripItem[]
+        {
+            ctxSpam, ctxNotSpam,
+            new ToolStripSeparator(),
+            ctxBlockDomain, ctxAllowDomain
+        });
+
+        // Grid
+        _grid = new DataGridView
+        {
+            Dock = DockStyle.Fill,
+            ReadOnly = true,
+            AllowUserToAddRows = false,
+            AllowUserToDeleteRows = false,
+            AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.Fill,
+            SelectionMode = DataGridViewSelectionMode.FullRowSelect,
+            BackgroundColor = System.Drawing.SystemColors.Window,
+            BorderStyle = BorderStyle.None,
+            ContextMenuStrip = _rowMenu
+        };
+
+        _grid.Columns.Add("Time", "Time");
+        _grid.Columns.Add("From", "From");
+        _grid.Columns.Add("Subject", "Subject");
+        _grid.Columns.Add("Verdict", "Verdict");
+        _grid.Columns.Add("Confidence", "Confidence");
+        _grid.Columns.Add("Reason", "Reason");
+        _grid.Columns.Add("Status", "");
+
+        _grid.Columns["Time"]!.Width = 70;
+        _grid.Columns["From"]!.Width = 150;
+        _grid.Columns["Verdict"]!.Width = 80;
+        _grid.Columns["Confidence"]!.Width = 80;
+        _grid.Columns["Status"]!.Width = 30;
+        _grid.Columns["Status"]!.AutoSizeMode = DataGridViewAutoSizeColumnMode.None;
+
+        Controls.Add(_grid);
+        Controls.Add(_toolbar);
+
+        // Subscribe to data changes — refresh only when something actually changes
+        _activityLog.EntryChanged += RefreshData;
+
+        RefreshData();
+    }
+
+    protected override bool ProcessCmdKey(ref Message msg, Keys keyData)
+    {
+        if (_grid.SelectedRows.Count == 0)
+            return base.ProcessCmdKey(ref msg, keyData);
+
+        switch (keyData)
+        {
+            case Keys.S:
+                OnMarkSpam(this, EventArgs.Empty);
+                return true;
+            case Keys.H:
+                OnMarkNotSpam(this, EventArgs.Empty);
+                return true;
+            case Keys.D:
+                OnBlockDomain(this, EventArgs.Empty);
+                return true;
+            default:
+                return base.ProcessCmdKey(ref msg, keyData);
+        }
+    }
+
+    private async void OnMarkSpam(object? sender, EventArgs e)
+    {
+        var entry = GetSelectedEntry();
+        if (entry == null || entry.Uid == 0) return;
+
+        var monitor = FindMonitor(entry.AccountName);
+        if (monitor == null) return;
+
+        try
+        {
+            await monitor.MoveToSpamAsync(entry.Uid);
+            RecordOverride(entry, "spam");
+            _activityLog.UpdateEntry(entry, Verdict.Spam, UserOverride.MarkedSpam);
+        }
+        catch (Exception ex)
+        {
+            MessageBox.Show($"Failed to move email: {ex.Message}", "Error",
+                MessageBoxButtons.OK, MessageBoxIcon.Error);
+        }
+    }
+
+    private async void OnMarkNotSpam(object? sender, EventArgs e)
+    {
+        var entry = GetSelectedEntry();
+        if (entry == null || entry.Uid == 0) return;
+
+        var monitor = FindMonitor(entry.AccountName);
+        if (monitor == null) return;
+
+        try
+        {
+            await monitor.MoveToInboxAsync(entry.Uid);
+            _trustedSenders.Add(entry.Sender);
+            _trustedSenders.Save();
+            RecordOverride(entry, "legitimate");
+            _activityLog.UpdateEntry(entry, Verdict.Legitimate, UserOverride.MarkedLegitimate);
+        }
+        catch (Exception ex)
+        {
+            MessageBox.Show($"Failed to move email: {ex.Message}", "Error",
+                MessageBoxButtons.OK, MessageBoxIcon.Error);
+        }
+    }
+
+    private void OnBlockDomain(object? sender, EventArgs e)
+    {
+        var entry = GetSelectedEntry();
+        if (entry == null || string.IsNullOrEmpty(entry.Sender)) return;
+
+        var domain = BlockedDomainStore.ExtractDomain(entry.Sender);
+        if (string.IsNullOrEmpty(domain)) return;
+
+        _blockedDomains.Add(domain);
+        _blockedDomains.Save();
+
+        OnMarkSpam(sender, e);
+    }
+
+    private void OnAllowDomain(object? sender, EventArgs e)
+    {
+        var entry = GetSelectedEntry();
+        if (entry == null || string.IsNullOrEmpty(entry.Sender)) return;
+
+        var domain = BlockedDomainStore.ExtractDomain(entry.Sender);
+        if (string.IsNullOrEmpty(domain)) return;
+
+        _blockedDomains.Remove(domain);
+        _blockedDomains.Save();
+
+        OnMarkNotSpam(sender, e);
+    }
+
+    private ActivityEntry? GetSelectedEntry()
+    {
+        if (_grid.SelectedRows.Count == 0) return null;
+        return _grid.SelectedRows[0].Tag as ActivityEntry;
+    }
+
+    private InboxMonitorService? FindMonitor(string accountName)
+    {
+        return _monitors.FirstOrDefault(m =>
+            m.AccountName.Equals(accountName, StringComparison.OrdinalIgnoreCase));
+    }
+
+    private void RecordOverride(ActivityEntry entry, string userVerdict)
+    {
+        var originalVerdict = entry.Verdict.ToString().ToLowerInvariant();
+        _overrideStore.Add(new OverrideRecord(
+            DateTime.UtcNow,
+            entry.Sender,
+            entry.Subject,
+            entry.BodySnippet,
+            userVerdict,
+            originalVerdict
+        ));
+        _overrideStore.Save();
+    }
+
+    public void RefreshData()
+    {
+        if (InvokeRequired)
+        {
+            Invoke(RefreshData);
+            return;
+        }
+
+        // Preserve selection and scroll position across refresh
+        var selectedEntry = GetSelectedEntry();
+        var selectedUid = selectedEntry?.Uid ?? 0;
+        var selectedTimestamp = selectedEntry?.Timestamp ?? default;
+        var firstVisible = _grid.FirstDisplayedScrollingRowIndex;
+
+        var entries = _activityLog.GetRecent(DisplayCount);
+
+        _grid.SuspendLayout();
+        _grid.Rows.Clear();
+
+        int restoreIndex = -1;
+
+        foreach (var entry in entries)
+        {
+            var overrideMarker = entry.Override switch
+            {
+                UserOverride.MarkedSpam => "\u2716",       // heavy X
+                UserOverride.MarkedLegitimate => "\u2714", // heavy checkmark
+                _ => ""
+            };
+
+            var rowIndex = _grid.Rows.Add(
+                entry.Timestamp.ToLocalTime().ToString("HH:mm:ss"),
+                entry.Sender,
+                entry.Subject,
+                entry.Verdict.ToString(),
+                entry.Confidence?.ToString("P0") ?? "--",
+                entry.Reason ?? "",
+                overrideMarker
+            );
+
+            var row = _grid.Rows[rowIndex];
+            row.Tag = entry;
+
+            row.DefaultCellStyle.ForeColor = entry.Verdict switch
+            {
+                Verdict.Spam => System.Drawing.Color.Red,
+                Verdict.Trusted => System.Drawing.Color.Green,
+                Verdict.Uncertain => System.Drawing.Color.Orange,
+                Verdict.Error => System.Drawing.Color.Gray,
+                _ => System.Drawing.SystemColors.ControlText
+            };
+
+            if (entry.Override != null)
+            {
+                row.DefaultCellStyle.Font = new System.Drawing.Font(
+                    _grid.DefaultCellStyle.Font ?? System.Drawing.SystemFonts.DefaultFont,
+                    System.Drawing.FontStyle.Bold);
+            }
+
+            if (restoreIndex < 0)
+            {
+                if (selectedUid != 0 && entry.Uid == selectedUid)
+                    restoreIndex = rowIndex;
+                else if (selectedUid == 0 && entry.Timestamp == selectedTimestamp)
+                    restoreIndex = rowIndex;
+            }
+        }
+
+        // Restore scroll position
+        if (_grid.RowCount > 0 && firstVisible >= 0)
+        {
+            var clampedFirst = Math.Min(firstVisible, _grid.RowCount - 1);
+            _grid.FirstDisplayedScrollingRowIndex = clampedFirst;
+        }
+
+        // Restore selection without triggering a scroll jump
+        _grid.ClearSelection();
+        if (restoreIndex >= 0)
+            _grid.Rows[restoreIndex].Selected = true;
+
+        _grid.ResumeLayout();
+    }
+
+    protected override void OnFormClosing(FormClosingEventArgs e)
+    {
+        if (e.CloseReason == CloseReason.UserClosing)
+        {
+            e.Cancel = true;
+            Hide();
+        }
+        else
+        {
+            base.OnFormClosing(e);
+        }
+    }
+
+    protected override void Dispose(bool disposing)
+    {
+        if (disposing)
+            _activityLog.EntryChanged -= RefreshData;
+        base.Dispose(disposing);
+    }
+}

src/SpamGuard/Tray/IconGenerator.cs

@@ -0,0 +1,39 @@
+namespace SpamGuard.Tray;
+
+using System.Drawing;
+using System.Drawing.Drawing2D;
+using System.Runtime.InteropServices;
+
+public static class IconGenerator
+{
+    private static readonly Lazy<Icon> _green = new(() => CreateCircleIcon(Color.FromArgb(76, 175, 80)));
+    private static readonly Lazy<Icon> _yellow = new(() => CreateCircleIcon(Color.FromArgb(255, 193, 7)));
+    private static readonly Lazy<Icon> _red = new(() => CreateCircleIcon(Color.FromArgb(244, 67, 54)));
+
+    public static Icon Green => _green.Value;
+    public static Icon Yellow => _yellow.Value;
+    public static Icon Red => _red.Value;
+
+    [DllImport("user32.dll", SetLastError = true)]
+    [return: MarshalAs(UnmanagedType.Bool)]
+    private static extern bool DestroyIcon(IntPtr handle);
+
+    private static Icon CreateCircleIcon(Color color, int size = 16)
+    {
+        using var bitmap = new Bitmap(size, size);
+        using var graphics = Graphics.FromImage(bitmap);
+        graphics.SmoothingMode = SmoothingMode.AntiAlias;
+        graphics.Clear(Color.Transparent);
+
+        using var brush = new SolidBrush(color);
+        graphics.FillEllipse(brush, 1, 1, size - 2, size - 2);
+
+        using var pen = new Pen(Color.FromArgb(100, 0, 0, 0), 1);
+        graphics.DrawEllipse(pen, 1, 1, size - 3, size - 3);
+
+        var hIcon = bitmap.GetHicon();
+        var icon = (Icon)Icon.FromHandle(hIcon).Clone();
+        DestroyIcon(hIcon);
+        return icon;
+    }
+}

src/SpamGuard/Tray/TrayApplicationContext.cs

@@ -0,0 +1,121 @@
+// src/SpamGuard/Tray/TrayApplicationContext.cs
+namespace SpamGuard.Tray;
+
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Hosting;
+using SpamGuard.Services;
+using SpamGuard.State;
+
+public sealed class TrayApplicationContext : ApplicationContext
+{
+    private readonly NotifyIcon _notifyIcon;
+    private readonly System.Windows.Forms.Timer _refreshTimer;
+    private readonly ActivityLog _activityLog;
+    private readonly IReadOnlyList<InboxMonitorService> _monitors;
+    private readonly TrustedSenderStore _trustedSenders;
+    private readonly BlockedDomainStore _blockedDomains;
+    private readonly OverrideStore _overrideStore;
+    private readonly IHost _host;
+    private ActivityLogForm? _logForm;
+    private readonly ToolStripMenuItem _pauseMenuItem;
+
+    private bool AllPaused => _monitors.All(m => m.IsPaused);
+
+    public TrayApplicationContext(IHost host)
+    {
+        _host = host;
+        _activityLog = host.Services.GetRequiredService<ActivityLog>();
+        _monitors = host.Services.GetServices<InboxMonitorService>().ToList();
+        _trustedSenders = host.Services.GetRequiredService<TrustedSenderStore>();
+        _blockedDomains = host.Services.GetRequiredService<BlockedDomainStore>();
+        _overrideStore = host.Services.GetRequiredService<OverrideStore>();
+
+        _pauseMenuItem = new ToolStripMenuItem("Pause", null, OnPauseResume);
+
+        var contextMenu = new ContextMenuStrip();
+        contextMenu.Items.Add("View Activity Log", null, OnViewLog);
+        contextMenu.Items.Add(_pauseMenuItem);
+        contextMenu.Items.Add(new ToolStripSeparator());
+        contextMenu.Items.Add("Quit", null, OnQuit);
+
+        _notifyIcon = new NotifyIcon
+        {
+            Icon = IconGenerator.Green,
+            Text = "SpamGuard - Starting...",
+            Visible = true,
+            ContextMenuStrip = contextMenu
+        };
+
+        _notifyIcon.DoubleClick += OnViewLog;
+
+        // Timer only updates tray tooltip and icon — form refresh is event-driven
+        _refreshTimer = new System.Windows.Forms.Timer { Interval = 5000 };
+        _refreshTimer.Tick += OnRefreshTick;
+        _refreshTimer.Start();
+    }
+
+    private void OnRefreshTick(object? sender, EventArgs e)
+    {
+        var checked_ = _activityLog.TodayChecked;
+        var spam = _activityLog.TodaySpam;
+        var tooltip = $"SpamGuard - {checked_} checked, {spam} spam caught today";
+        _notifyIcon.Text = tooltip.Length > 127 ? tooltip[..127] : tooltip;
+
+        if (!AllPaused)
+        {
+            var recent = _activityLog.GetRecent(1);
+            var hasRecentError = recent.Count > 0
+                && recent[0].Verdict == Models.Verdict.Error
+                && recent[0].Timestamp > DateTime.UtcNow.AddMinutes(-5);
+            _notifyIcon.Icon = hasRecentError ? IconGenerator.Red : IconGenerator.Green;
+        }
+
+        // Form refresh removed — ActivityLogForm subscribes to ActivityLog.EntryChanged directly
+    }
+
+    private void OnViewLog(object? sender, EventArgs e)
+    {
+        if (_logForm == null || _logForm.IsDisposed)
+        {
+            _logForm = new ActivityLogForm(
+                _activityLog, _monitors, _trustedSenders, _blockedDomains, _overrideStore);
+        }
+        _logForm.Show();
+        _logForm.BringToFront();
+    }
+
+    private void OnPauseResume(object? sender, EventArgs e)
+    {
+        if (AllPaused)
+        {
+            foreach (var m in _monitors) m.Resume();
+            _pauseMenuItem.Text = "Pause";
+            _notifyIcon.Icon = IconGenerator.Green;
+        }
+        else
+        {
+            foreach (var m in _monitors) m.Pause();
+            _pauseMenuItem.Text = "Resume";
+            _notifyIcon.Icon = IconGenerator.Yellow;
+        }
+    }
+
+    private async void OnQuit(object? sender, EventArgs e)
+    {
+        _notifyIcon.Visible = false;
+        _refreshTimer.Stop();
+        await _host.StopAsync();
+        Application.Exit();
+    }
+
+    protected override void Dispose(bool disposing)
+    {
+        if (disposing)
+        {
+            _refreshTimer.Dispose();
+            _notifyIcon.Dispose();
+            _logForm?.Dispose();
+        }
+        base.Dispose(disposing);
+    }
+}

src/SpamGuard/appsettings.json

@@ -1,15 +1,27 @@
 {
   "SpamGuard": {
-    "Imap": {
+    "Accounts": [
-      "Host": "imap.example.com",
+      {
-      "Port": 993,
+        "Name": "Work",
-      "UseSsl": true,
+        "Host": "imap.dynu.com",
-      "Username": "user@example.com",
+        "Port": 993,
-      "Password": ""
+        "UseSsl": true,
-    },
+        "Username": "peter.foster@ukdataservices.co.uk",
+        "Password": "Piglet69!"
+      },
+      {
+        "Name": "Personal",
+        "Host": "mail.hover.com",
+        "Port": 993,
+        "UseSsl": true,
+        "Username": "peter@foster.net",
+        "Password": "Piglet1969!!"
+      }
+    ],
     "Claude": {
-      "ApiKey": "",
+      "ApiKey": "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",
-      "Model": "claude-sonnet-4-6",
+      "BaseUrl": "https://openrouter.ai/api/",
+      "Model": "anthropic/claude-3.5-haiku",
       "MaxBodyLength": 2000
     },
     "Monitoring": {

src/SpamGuard/appsettings.template.json

@@ -0,0 +1,38 @@
+{
+  "SpamGuard": {
+    "Imap": {
+      "Host": "imap.example.com",
+      "Port": 993,
+      "UseSsl": true,
+      "Username": "user@example.com",
+      "Password": ""
+    },
+    "Claude": {
+      "ApiKey": "",
+      "Model": "claude-sonnet-4-6",
+      "MaxBodyLength": 2000
+    },
+    "Monitoring": {
+      "PollIntervalSeconds": 60,
+      "TrustedSenderRefreshMinutes": 60,
+      "SpamConfidenceThreshold": 0.7,
+      "SpamFolderName": "Junk",
+      "InitialScanDays": 7,
+      "MaxActivityLogEntries": 500
+    }
+  },
+  "Serilog": {
+    "MinimumLevel": "Information",
+    "WriteTo": [
+      { "Name": "Console" },
+      {
+        "Name": "File",
+        "Args": {
+          "path": "%APPDATA%/SpamGuard/logs/spamguard-.log",
+          "rollingInterval": "Day",
+          "retainedFileCountLimit": 7
+        }
+      }
+    ]
+  }
+}

tests/SpamGuard.Tests/Services/EmailClassifierTests.cs

@@ -0,0 +1,103 @@
+// tests/SpamGuard.Tests/Services/EmailClassifierTests.cs
+namespace SpamGuard.Tests.Services;
+
+using System.Net;
+using System.Text.Json;
+using Microsoft.Extensions.Logging.Abstractions;
+using Microsoft.Extensions.Options;
+using SpamGuard.Configuration;
+using SpamGuard.Models;
+using SpamGuard.Services;
+using SpamGuard.State;
+
+public class EmailClassifierTests
+{
+    private static SpamGuardOptions DefaultOptions => new()
+    {
+        Claude = new ClaudeOptions
+        {
+            ApiKey = "test-key",
+            Model = "claude-sonnet-4-6",
+            MaxBodyLength = 2000
+        }
+    };
+
+    private static EmailSummary SampleEmail => new(
+        Uid: 1,
+        From: "spammer@sketchy.com",
+        Subject: "Buy now! Limited offer!",
+        BodySnippet: "Click here to claim your prize...",
+        Date: DateTimeOffset.UtcNow
+    );
+
+    [Fact]
+    public void BuildPrompt_ContainsSenderAndSubjectAndBody()
+    {
+        var classifier = new EmailClassifier(
+            Options.Create(DefaultOptions),
+            new NullLogger<EmailClassifier>(),
+            new HttpClient(),
+            new OverrideStore(Path.GetTempPath())
+        );
+
+        var prompt = classifier.BuildPrompt(SampleEmail);
+
+        Assert.Contains("spammer@sketchy.com", prompt);
+        Assert.Contains("Buy now! Limited offer!", prompt);
+        Assert.Contains("Click here to claim your prize...", prompt);
+    }
+
+    [Fact]
+    public void BuildPrompt_TruncatesLongBody()
+    {
+        var longBody = new string('x', 5000);
+        var email = SampleEmail with { BodySnippet = longBody };
+
+        var classifier = new EmailClassifier(
+            Options.Create(DefaultOptions),
+            new NullLogger<EmailClassifier>(),
+            new HttpClient(),
+            new OverrideStore(Path.GetTempPath())
+        );
+
+        var prompt = classifier.BuildPrompt(email);
+
+        // Body in prompt should be truncated to MaxBodyLength
+        Assert.DoesNotContain(longBody, prompt);
+    }
+
+    [Fact]
+    public void ParseResponse_ValidJson_ReturnsResult()
+    {
+        var json = """{"classification": "spam", "confidence": 0.95, "reason": "Unsolicited marketing"}""";
+
+        var result = EmailClassifier.ParseResponse(json);
+
+        Assert.NotNull(result);
+        Assert.True(result.IsSpam);
+        Assert.Equal(0.95, result.Confidence);
+        Assert.Equal("Unsolicited marketing", result.Reason);
+    }
+
+    [Fact]
+    public void ParseResponse_InvalidJson_ReturnsNull()
+    {
+        var result = EmailClassifier.ParseResponse("not json at all");
+        Assert.Null(result);
+    }
+
+    [Fact]
+    public void ParseResponse_JsonWithMarkdownFencing_ReturnsResult()
+    {
+        var json = """
+            ```json
+            {"classification": "legitimate", "confidence": 0.85, "reason": "Normal business email"}
+            ```
+            """;
+
+        var result = EmailClassifier.ParseResponse(json);
+
+        Assert.NotNull(result);
+        Assert.False(result.IsSpam);
+    }
+}

tests/SpamGuard.Tests/State/ProcessedUidStoreTests.cs

@@ -12,7 +12,7 @@ public class ProcessedUidStoreTests : IDisposable
     {
         _tempDir = Path.Combine(Path.GetTempPath(), $"spamguard-test-{Guid.NewGuid()}");
         Directory.CreateDirectory(_tempDir);
-        _store = new ProcessedUidStore(_tempDir);
+        _store = new ProcessedUidStore(_tempDir, "TestAccount");
     }
 
     public void Dispose()
@@ -50,7 +50,7 @@ public class ProcessedUidStoreTests : IDisposable
         _store.Add(3);
         _store.Save();
 
-        var loaded = new ProcessedUidStore(_tempDir);
+        var loaded = new ProcessedUidStore(_tempDir, "TestAccount");
         Assert.True(loaded.Contains(1));
         Assert.True(loaded.Contains(2));
         Assert.True(loaded.Contains(3));

tests/SpamGuard.Tests/UnitTest1.cs

@@ -1,10 +0,0 @@
-namespace SpamGuard.Tests;
-
-public class UnitTest1
-{
-    [Fact]
-    public void Test1()
-    {
-
-    }
-}