Search newest Outlook mail first and let trusted providers continue chats

app/MindWork AI Studio/Tools/ToolCallingSystem/ToolCallingImplementations/OutlookMail/EwsMailClient.cs

@@ -1,3 +1,4 @@
+using System.Globalization;
 using System.Net;
 using System.Text;
 using System.Xml;
@@ -13,6 +14,7 @@ internal sealed class EwsMailClient : IDisposable
     private const int MAX_RESPONSE_BYTES = 2_000_000;
     private const int MAX_FOLDERS = 250;
     private const int FOLDER_PAGE_SIZE = 100;
+    private const int MAX_PARALLEL_FOLDER_SEARCHES = 4;
     internal const int MAX_RESULTS = 20;
     internal const int MAX_BODY_CHARACTERS = 20_000;
 
@@ -50,61 +52,88 @@ internal sealed class EwsMailClient : IDisposable
         using var deadline = CancellationTokenSource.CreateLinkedTokenSource(token);
         deadline.CancelAfter(TimeSpan.FromSeconds(90));
         var (folders, foldersPartial) = await this.FindFoldersAsync(deadline.Token);
+
+        //
+        // Recent mail is most often the mail the user means. Every folder is therefore asked for
+        // its newest matches, and the newest of all of them win. Stopping at the first folders
+        // with enough hits would return old mail from an archive and leave out yesterday's
+        // message in the inbox.
+        //
+        var resultLock = new Lock();
         var messages = new List<EwsMessage>();
         var partial = foldersPartial;
         var searchedFolders = false;
-        foreach (var folder in folders)
+        try
         {
-            if (messages.Count == MAX_RESULTS)
+            var options = new ParallelOptions { MaxDegreeOfParallelism = MAX_PARALLEL_FOLDER_SEARCHES, CancellationToken = deadline.Token };
+            await Parallel.ForEachAsync(folders, options, async (folder, folderToken) =>
             {
-                partial = true;
-                break;
-            }
-
-            try
-            {
-                var root = ResponseRoot(await this.SendAsync(BuildFindItem(folder, terms, MAX_RESULTS), deadline.Token), "FindItem");
-                var items = root.Element(T + "Items") ?? throw new EwsMailException("Exchange returned an incomplete search response.");
-                searchedFolders = true;
-                var added = 0;
-                foreach (var item in items.Elements(T + "Message"))
+                var folderResult = await this.SearchFolderAsync(folder, terms, folderToken);
+                lock (resultLock)
                 {
-                    if (RequiredId(item, "ParentFolderId") != folder)
-                    {
-                        partial = true;
-                        continue;
-                    }
-                    var id = RequiredId(item, "ItemId");
-                    var subject = Truncate(item.Element(T + "Subject")?.Value ?? string.Empty, 300);
-                    var mailbox = item.Element(T + "From")?.Element(T + "Mailbox");
-                    var sender = Truncate(mailbox?.Element(T + "EmailAddress")?.Value ?? mailbox?.Element(T + "Name")?.Value ?? string.Empty, 320);
-                    var date = Truncate(item.Element(T + "DateTimeReceived")?.Value ?? item.Element(T + "DateTimeSent")?.Value ?? string.Empty, 64);
-                    var excerpt = item.Element(T + "Preview")?.Value ?? item.Element(T + "Body")?.Value ?? string.Empty;
-                    var webPath = item.Element(T + "WebClientReadFormQueryString")?.Value;
-                    messages.Add(new EwsMessage(id, subject, sender, date, Truncate(excerpt, 500), webPath?.Length <= 2048 ? webPath : null));
-                    added++;
-                    if (messages.Count == MAX_RESULTS)
-                        break;
+                    messages.AddRange(folderResult.Messages);
+                    partial |= folderResult.Partial;
+                    searchedFolders |= folderResult.Searched;
                 }
-
-                if (root.Attribute("IncludesLastItemInRange")?.Value != "true" || items.Elements(T + "Message").Count() > added)
-                    partial = true;
-            }
-            catch (EwsMailException)
-            {
-                partial = true;
-            }
-            catch (OperationCanceledException) when (!token.IsCancellationRequested)
-            {
-                partial = true;
-                break;
-            }
+            });
+        }
+        catch (OperationCanceledException) when (!token.IsCancellationRequested)
+        {
+            partial = true;
         }
 
         if (!searchedFolders && folders.Count > 0)
             throw new EwsMailException("Exchange could not search the primary mailbox. Check the VPN connection and EWS access.");
 
-        return new EwsSearchResult(messages, partial);
+        if (messages.Count > MAX_RESULTS)
+            partial = true;
+
+        var newest = messages.OrderByDescending(message => message.ReceivedAt).Take(MAX_RESULTS).ToList();
+        return new EwsSearchResult(newest, partial);
+    }
+
+    private async Task<(List<EwsMessage> Messages, bool Partial, bool Searched)> SearchFolderAsync(string folder, string terms, CancellationToken token)
+    {
+        try
+        {
+            var root = ResponseRoot(await this.SendAsync(BuildFindItem(folder, terms, MAX_RESULTS), token), "FindItem");
+            var items = root.Element(T + "Items") ?? throw new EwsMailException("Exchange returned an incomplete search response.");
+            var partial = root.Attribute("IncludesLastItemInRange")?.Value != "true";
+            var returned = items.Elements(T + "Message").ToList();
+            if (returned.Count > MAX_RESULTS)
+                partial = true;
+
+            var messages = new List<EwsMessage>();
+            foreach (var item in returned.Take(MAX_RESULTS))
+            {
+                if (RequiredId(item, "ParentFolderId") != folder)
+                {
+                    partial = true;
+                    continue;
+                }
+
+                var id = RequiredId(item, "ItemId");
+                var subject = Truncate(item.Element(T + "Subject")?.Value ?? string.Empty, 300);
+                var mailbox = item.Element(T + "From")?.Element(T + "Mailbox");
+                var sender = Truncate(mailbox?.Element(T + "EmailAddress")?.Value ?? mailbox?.Element(T + "Name")?.Value ?? string.Empty, 320);
+                var rawDate = item.Element(T + "DateTimeReceived")?.Value ?? item.Element(T + "DateTimeSent")?.Value ?? string.Empty;
+                var receivedAt = DateTimeOffset.TryParse(rawDate, CultureInfo.InvariantCulture, DateTimeStyles.AssumeUniversal, out var parsedDate) ? parsedDate : DateTimeOffset.MinValue;
+                var excerpt = item.Element(T + "Preview")?.Value ?? item.Element(T + "Body")?.Value ?? string.Empty;
+                var webPath = item.Element(T + "WebClientReadFormQueryString")?.Value;
+                messages.Add(new EwsMessage(id, subject, sender, Truncate(rawDate, 64), Truncate(excerpt, 500), webPath?.Length <= 2048 ? webPath : null, receivedAt));
+            }
+
+            return (messages, partial, true);
+        }
+        catch (EwsMailException)
+        {
+            return ([], true, false);
+        }
+        catch (OperationCanceledException) when (!token.IsCancellationRequested)
+        {
+            // The per-request timeout of the HTTP client; the other folders are still searched.
+            return ([], true, false);
+        }
     }
 
     internal async Task<EwsReadResult> ReadAsync(string itemId, CancellationToken token)
@@ -250,8 +279,10 @@ internal sealed class EwsMailClient : IDisposable
         new XElement(M + "ItemShape", new XElement(T + "BaseShape", "IdOnly"),
             Properties("item:ParentFolderId", "item:Subject", "item:DateTimeReceived", "item:DateTimeSent", "item:Preview", "message:From", "item:WebClientReadFormQueryString")),
         new XElement(M + "IndexedPageItemView", new XAttribute("MaxEntriesReturned", pageSize), new XAttribute("Offset", 0), new XAttribute("BasePoint", "Beginning")),
-        new XElement(M + "QueryString", terms),
-        new XElement(M + "ParentFolderIds", new XElement(T + "FolderId", new XAttribute("Id", folderId)))));
+        new XElement(M + "SortOrder", new XElement(T + "FieldOrder", new XAttribute("Order", "Descending"), new XElement(T + "FieldURI", new XAttribute("FieldURI", "item:DateTimeReceived")))),
+        // The EWS schema requires this order: SortOrder, then ParentFolderIds, then QueryString.
+        new XElement(M + "ParentFolderIds", new XElement(T + "FolderId", new XAttribute("Id", folderId))),
+        new XElement(M + "QueryString", terms)));
 
     internal static XDocument BuildGetItem(string itemId) => Envelope(new XElement(M + "GetItem",
         new XElement(M + "ItemShape", new XElement(T + "BaseShape", "IdOnly"), new XElement(T + "BodyType", "Text"),
@@ -270,7 +301,7 @@ internal sealed class EwsMailClient : IDisposable
     public void Dispose() => this.client.Dispose();
 }
 
-internal sealed record EwsMessage(string Id, string Subject, string Sender, string Date, string Excerpt, string? WebPath);
+internal sealed record EwsMessage(string Id, string Subject, string Sender, string Date, string Excerpt, string? WebPath, DateTimeOffset ReceivedAt);
 internal sealed record EwsSearchResult(IReadOnlyList<EwsMessage> Messages, bool Partial);
 internal sealed record EwsReadResult(string Subject, string Body, bool Truncated, string? WebPath);
 internal sealed class EwsMailException(string message) : Exception(message);

app/MindWork AI Studio/Tools/ToolCallingSystem/ToolCallingImplementations/OutlookMail/OutlookMailTool.cs

@@ -40,7 +40,7 @@ public sealed class OutlookMailTool(PromptInjectionGuardService promptInjectionG
         Function = new()
         {
             Name = ToolSelectionRules.OUTLOOK_MAIL_TOOL_ID,
-            DescriptionForLLM = "Search the signed-in employee's primary Outlook mailbox or read one message from a previous search. Works through company Exchange without opening Outlook.",
+            DescriptionForLLM = "Search the signed-in employee's primary Outlook mailbox or read one message from a previous search. Search results are the newest matches first. Works through company Exchange without opening Outlook.",
             Parameters = ToolParameterSchemaBuilder.Create()
                 .RequiredEnum(OPERATION_ARGUMENT, "Search mail or read a message from a previous result.", "search", "read")
                 .OptionalString(TERMS_ARGUMENT, "Plain search terms, required for search.")
@@ -179,8 +179,10 @@ public sealed class OutlookMailTool(PromptInjectionGuardService promptInjectionG
         {
             foreach (var key in this.cachedIds.Where(entry => entry.Value.ExpiresAt <= DateTimeOffset.UtcNow).Select(entry => entry.Key).ToList())
                 this.cachedIds.Remove(key);
+            // Every ID lives equally long, so the earliest expiry is the oldest one. The order of
+            // the dictionary's keys says nothing about that once entries were removed.
             if (this.cachedIds.Count >= MAX_CACHED_IDS)
-                this.cachedIds.Remove(this.cachedIds.Keys.First());
+                this.cachedIds.Remove(this.cachedIds.MinBy(entry => entry.Value.ExpiresAt).Key);
             var id = Guid.NewGuid().ToString("N");
             this.cachedIds[id] = new CachedId(ewsId, endpoint.AbsoluteUri, DateTimeOffset.UtcNow.AddMinutes(15));
             return id;