Review fixes: telemetry session id per login; Framework number text

F1: the telemetry session id is new at every login. The original made one per
load of its assembly and its loader reloaded it at every login; the backend
counts new kills per (session id, character), so reusing one id across a
relog under-counted kills until the reset counter passed the old total.

F5/F6: .NET Framework never wrote a negative zero, and its fixed-point
formats (F7, F2, F0) rounded at fifteen significant digits, half away from
zero. Spawn and portal coordinates, kills_per_hour and the !report line now
format that way; the round-trip converter maps -0 to 0.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

src/OpenAC.MosswartMassacre/Backend/FrameworkNumberConverter.cs

@@ -58,9 +58,28 @@ internal sealed class FrameworkNumberConverter : JsonConverter
     public override object? ReadJson(JsonReader reader, Type objectType, object? existingValue, JsonSerializer serializer) =>
         throw new NotSupportedException();
 
+    /// <summary>
+    /// .NET Framework's fixed-point and number formats ("F7", "F2", "F0",
+    /// "N0" ...) for a double: the value taken to fifteen significant digits,
+    /// then rounded half away from zero to the format's decimals, and never a
+    /// negative zero. The decimal type formats exactly that way.
+    /// </summary>
+    internal static string FrameworkFixed(double value, string format, IFormatProvider provider)
+    {
+        if (!double.IsFinite(value))
+            return value.ToString(format, provider);
+        string digits = value.ToString("G15", CultureInfo.InvariantCulture);
+        return decimal.TryParse(digits, NumberStyles.Float, CultureInfo.InvariantCulture, out decimal exact)
+            ? exact.ToString(format, provider)
+            : value.ToString(format, provider);
+    }
+
     /// <summary>.NET Framework's "R" for a double: G15 if it reads back exactly, else G17.</summary>
     internal static string FrameworkRoundTrip(double value)
     {
+        // The Framework printed a negative zero as "0".
+        if (value == 0d)
+            value = 0d;
         string text = value.ToString("G15", CultureInfo.InvariantCulture);
         if (double.Parse(text, NumberStyles.Float, CultureInfo.InvariantCulture) == value)
             return text;
@@ -70,6 +89,8 @@ internal sealed class FrameworkNumberConverter : JsonConverter
     /// <summary>.NET Framework's "R" for a float: G7 if it reads back exactly, else G9.</summary>
     internal static string FrameworkRoundTrip(float value)
     {
+        if (value == 0f)
+            value = 0f;
         string text = value.ToString("G7", CultureInfo.InvariantCulture);
         if (float.Parse(text, NumberStyles.Float, CultureInfo.InvariantCulture) == value)
             return text;

src/OpenAC.MosswartMassacre/MmContext.cs

@@ -71,8 +71,13 @@ internal sealed class MmContext
     /// <summary>The character's vitae penalty in percent (0 when none), as the original's vitals frame carried it.</summary>
     public Func<int> Vitae { get; set; } = static () => 0;
 
-    /// <summary>The per-process id the original put in every telemetry frame.</summary>
-    public static string ProcessSessionId { get; } = Guid.NewGuid().ToString("N");
+    /// <summary>
+    /// The telemetry session id: a fresh GUID at every login. The original
+    /// made one per load of its assembly, and its loader reloaded the assembly
+    /// at every login; the backend counts new kills per (session id,
+    /// character), so a login that resets the kill counter needs a new id.
+    /// </summary>
+    public string TelemetrySessionId { get; set; } = Guid.NewGuid().ToString("N");
 
     /// <summary>
     /// Sees every frame the plugin hands to the socket, before the socket

src/OpenAC.MosswartMassacre/MosswartMassacrePlugin.cs

@@ -110,6 +110,7 @@ public sealed class MosswartMassacrePlugin : IAcDreamPlugin
 
         string name = _host.Automation.Character.Name;
         _context.CharacterName = name;
+        _context.TelemetrySessionId = Guid.NewGuid().ToString("N");
         _context.Settings.Load(name);
         _context.IsLoggedIn = true;
         _context.Chat.Write("Mosswart Massacre has started!");

src/OpenAC.MosswartMassacre/Streams/ChatRouter.cs

@@ -71,8 +71,11 @@ internal sealed class ChatRouter : IMmFeature
                 TimeSpan elapsed = _context.Clock.Now - _kills.StatsStartTime;
                 string report = string.Format(
                     CultureInfo.CurrentCulture,
-                    "Total Kills: {0}, Kills per Hour: {1:F2}, Elapsed Time: {2:dd\\.hh\\:mm\\:ss}, Rares Found: {3}",
-                    _kills.TotalKills, _kills.KillsPerHour, elapsed, _rares.RareCount);
+                    "Total Kills: {0}, Kills per Hour: {1}, Elapsed Time: {2:dd\\.hh\\:mm\\:ss}, Rares Found: {3}",
+                    _kills.TotalKills,
+                    FrameworkNumberConverter.FrameworkFixed(_kills.KillsPerHour, "F2", CultureInfo.CurrentCulture),
+                    elapsed,
+                    _rares.RareCount);
                 _context.Host.Log.Info($"[Mosswart Massacre] Reporting to allegiance: {report}");
                 _context.Automation.Chat.Submit($"/a {report}");
             }

src/OpenAC.MosswartMassacre/Streams/SpawnPortalStream.cs

@@ -102,9 +102,10 @@ internal sealed class SpawnPortalStream : IMmFeature
     private static (string Ns, string Ew, string Z) Format(in PluginNavigationPosition position)
     {
         const string fmt = "F7";
-        string ns = position.NorthSouth.ToString(fmt, CultureInfo.InvariantCulture);
-        string ew = position.EastWest.ToString(fmt, CultureInfo.InvariantCulture);
-        string z = ((float)(position.Elevation * 240d)).ToString("F2", CultureInfo.InvariantCulture);
+        string ns = FrameworkNumberConverter.FrameworkFixed(position.NorthSouth, fmt, CultureInfo.InvariantCulture);
+        string ew = FrameworkNumberConverter.FrameworkFixed(position.EastWest, fmt, CultureInfo.InvariantCulture);
+        // The original read the height as a float and formatted it widened to a double.
+        string z = FrameworkNumberConverter.FrameworkFixed((double)(float)(position.Elevation * 240d), "F2", CultureInfo.InvariantCulture);
         return (ns, ew, z);
     }
 }

src/OpenAC.MosswartMassacre/Streams/TelemetryStream.cs

@@ -64,13 +64,13 @@ internal sealed class TelemetryStream : IMmFeature, IBackendConnectionListener
             type = "telemetry",
             character_name = _context.CharacterName,
             char_tag = _context.Settings.Current.CharTag ?? "",
-            session_id = MmContext.ProcessSessionId,
+            session_id = _context.TelemetrySessionId,
             timestamp = Wire.Timestamp(_context.Clock),
             ew = coords.EW,
             ns = coords.NS,
             z = coords.Z,
             kills = kills.TotalKills,
-            kills_per_hour = kills.KillsPerHour.ToString("F0", CultureInfo.CurrentCulture),
+            kills_per_hour = FrameworkNumberConverter.FrameworkFixed(kills.KillsPerHour, "F0", CultureInfo.CurrentCulture),
             onlinetime = (_context.Clock.Now - kills.StatsStartTime).ToString(@"dd\.hh\:mm\:ss", CultureInfo.InvariantCulture),
             deaths = kills.SessionDeaths.ToString(CultureInfo.CurrentCulture),
             total_deaths = kills.TotalDeaths.ToString(CultureInfo.CurrentCulture),

tests/OpenAC.MosswartMassacre.Tests/Backend/WireNumberTests.cs

@@ -43,6 +43,25 @@ public sealed class WireNumberTests
     public void Floats_use_the_frameworks_round_trip_digits(float value, string expected) =>
         Assert.Equal("{\"v\":" + expected + "}", Wire.Serialize(new { v = value }));
 
+    [Fact]
+    public void Negative_zero_is_written_as_zero_as_the_framework_did()
+    {
+        Assert.Equal("{\"v\":0.0}", Wire.Serialize(new { v = Math.Round(-0.001, 2) }));
+        Assert.Equal("{\"v\":0.0}", Wire.Serialize(new { v = -0f }));
+    }
+
+    [Theory]
+    // Rounded half away from zero at fifteen significant digits, as the
+    // Framework did; the modern exact-binary rounding differs on these.
+    [InlineData(0.125, "F2", "0.13")]
+    [InlineData(2.675, "F2", "2.68")]
+    [InlineData(-0.001, "F2", "0.00")]
+    [InlineData(-0.0, "F7", "0.0000000")]
+    [InlineData(12.5, "F0", "13")]
+    [InlineData(33.650001525878906, "F7", "33.6500015")]
+    public void Fixed_formats_round_as_the_framework_did(double value, string format, string expected) =>
+        Assert.Equal(expected, FrameworkNumberConverter.FrameworkFixed(value, format, System.Globalization.CultureInfo.InvariantCulture));
+
     [Fact]
     public void Nulls_and_non_finite_values_keep_newtonsofts_handling()
     {

tests/OpenAC.MosswartMassacre.Tests/PluginLifecycleTests.cs

@@ -42,6 +42,21 @@ public sealed class PluginLifecycleTests
         Assert.Equal("Horan", harness.Context.Settings.CharacterName);
     }
 
+    [Fact]
+    public void Each_login_gets_a_new_telemetry_session_id()
+    {
+        // The backend counts new kills per (session id, character); the kill
+        // counter restarts at every login, so the id must too.
+        using var harness = new PluginHarness("Mossy");
+        harness.Login();
+        string first = harness.Context.TelemetrySessionId;
+
+        harness.Plugin.OnLogin();
+
+        Assert.NotEqual(first, harness.Context.TelemetrySessionId);
+        Assert.Equal(32, harness.Context.TelemetrySessionId.Length);
+    }
+
     [Fact]
     public void Mm_without_a_subcommand_prints_usage_and_unknown_is_reported()
     {

tests/OpenAC.MosswartMassacre.Tests/Streams/StreamGoldenTests.cs

@@ -142,7 +142,7 @@ public sealed class StreamGoldenTests
         Assert.Equal(expectedOrder, frame.Properties().Select(p => p.Name));
 
         string head = "{\"type\":\"telemetry\",\"character_name\":\"Mossy\",\"char_tag\":\"tank\",\"session_id\":\""
-            + MmContext.ProcessSessionId + "\",\"timestamp\":\"2026-09-25T10:00:15.1230000Z\","
+            + harness.Context.TelemetrySessionId + "\",\"timestamp\":\"2026-09-25T10:00:15.1230000Z\","
             + "\"ew\":" + D(33.65f) + ",\"ns\":" + D(42.55f) + ",\"z\":42.5,\"kills\":0,"
             + "\"kills_per_hour\":\"0\",\"onlinetime\":\"00.01:30:00\",\"deaths\":\"0\",\"total_deaths\":\"7\","
             + "\"prismatic_taper_count\":\"1234\",\"vt_state\":\"Combat\",\"mem_mb\":";

tools/FrameRecorder/Program.cs

@@ -59,6 +59,7 @@ static async Task<int> Record(int port, string outPath)
         {
             var buffer = new byte[65536];
             using var message = new MemoryStream();
+            string? name = null;
             try
             {
                 while (ws.WebSocket.State == WebSocketState.Open && !cts.IsCancellationRequested)
@@ -71,6 +72,7 @@ static async Task<int> Record(int port, string outPath)
                         continue;
                     string frame = Encoding.UTF8.GetString(message.ToArray());
                     message.SetLength(0);
+                    name = await Relay.Handle(frame, ws.WebSocket, name);
                     await writeLock.WaitAsync();
                     try
                     {
@@ -86,6 +88,7 @@ static async Task<int> Record(int port, string outPath)
             catch (Exception ex) when (ex is OperationCanceledException or WebSocketException)
             {
             }
+            Relay.Disconnected(name);
             Console.WriteLine("client disconnected");
         });
     }
@@ -170,3 +173,82 @@ static bool IsDataMap(string name) => name is "monsters" or "properties" or "ski
     or "vitals" or "IntValues" or "DoubleValues" or "BoolValues" or "StringValues" or "offense" or "defense";
 
 static bool LooksLikeData(string key) => key.Length > 0 && (char.IsDigit(key[0]) || key.Contains(' '));
+
+// The backend's vital-sharing relay: a client registers under its character
+// name; share_subscribe / share_unsubscribe opt it in and out; every other
+// share_* frame goes to every other opted-in client, unchanged.
+static class Relay
+{
+    private static readonly object Gate = new();
+    private static readonly Dictionary<string, WebSocket> Clients = new(StringComparer.Ordinal);
+    private static readonly HashSet<string> Subscribers = new(StringComparer.Ordinal);
+
+    public static async Task<string?> Handle(string frame, WebSocket socket, string? name)
+    {
+        string? type;
+        string? character;
+        try
+        {
+            using JsonDocument doc = JsonDocument.Parse(frame);
+            JsonElement root = doc.RootElement;
+            type = root.TryGetProperty("type", out JsonElement t) ? t.GetString() : null;
+            character = root.TryGetProperty("character_name", out JsonElement c) ? c.GetString()
+                : root.TryGetProperty("player_name", out JsonElement p) ? p.GetString() : null;
+        }
+        catch (JsonException)
+        {
+            return name;
+        }
+
+        List<WebSocket> targets = [];
+        lock (Gate)
+        {
+            if (type == "register" && character is not null)
+            {
+                Clients[character] = socket;
+                return character;
+            }
+            if (type == "share_subscribe" && character is not null)
+            {
+                Subscribers.Add(character);
+                return name;
+            }
+            if (type == "share_unsubscribe" && character is not null)
+            {
+                Subscribers.Remove(character);
+                return name;
+            }
+            if (type is null || !type.StartsWith("share_", StringComparison.Ordinal))
+                return name;
+            foreach ((string client, WebSocket other) in Clients)
+            {
+                if (client != character && Subscribers.Contains(client) && other.State == WebSocketState.Open)
+                    targets.Add(other);
+            }
+        }
+
+        byte[] bytes = Encoding.UTF8.GetBytes(frame);
+        foreach (WebSocket target in targets)
+        {
+            try
+            {
+                await target.SendAsync(bytes, WebSocketMessageType.Text, true, CancellationToken.None);
+            }
+            catch (WebSocketException)
+            {
+            }
+        }
+        return name;
+    }
+
+    public static void Disconnected(string? name)
+    {
+        if (name is null)
+            return;
+        lock (Gate)
+        {
+            Clients.Remove(name);
+            Subscribers.Remove(name);
+        }
+    }
+}