diff --git a/SVSim.BattleNode/Bridge/CardClass.cs b/SVSim.BattleNode/Bridge/CardClass.cs
new file mode 100644
index 0000000..c04b128
--- /dev/null
+++ b/SVSim.BattleNode/Bridge/CardClass.cs
@@ -0,0 +1,29 @@
+namespace SVSim.BattleNode.Bridge;
+
+/// <summary>
+/// A Shadowverse class (craft). The wire carries it as the stringified ordinal (<c>"1".."8"</c> on
+/// the <c>classId</c> field); this enum replaces that stringly-typed value on
+/// <see cref="MatchContext.ClassId"/> so the legal set lives in the type, not a trailing comment.
+/// <see cref="None"/> covers an unset / placeholder context. Use <see cref="CardClassWire.ToWireValue"/>
+/// to render the wire string.
+/// </summary>
+public enum CardClass
+{
+    None = 0,
+    Forestcraft = 1,
+    Swordcraft = 2,
+    Runecraft = 3,
+    Dragoncraft = 4,
+    Shadowcraft = 5,
+    Bloodcraft = 6,
+    Havencraft = 7,
+    Portalcraft = 8,
+}
+
+/// <summary>Wire rendering for <see cref="CardClass"/>.</summary>
+public static class CardClassWire
+{
+    /// <summary>The <c>classId</c> wire value — the class ordinal as a string (<c>"1".."8"</c>,
+    /// <c>"0"</c> for <see cref="CardClass.None"/>), matching what the client sends/expects.</summary>
+    public static string ToWireValue(this CardClass cardClass) => ((int)cardClass).ToString();
+}
diff --git a/SVSim.BattleNode/Bridge/CountryCodes.cs b/SVSim.BattleNode/Bridge/CountryCodes.cs
new file mode 100644
index 0000000..e4c7ae6
--- /dev/null
+++ b/SVSim.BattleNode/Bridge/CountryCodes.cs
@@ -0,0 +1,13 @@
+namespace SVSim.BattleNode.Bridge;
+
+/// <summary>
+/// Known values for <see cref="MatchContext.CountryCode"/>. NOT a closed set — the field is the
+/// account's region code copied verbatim from viewer data (any value, possibly empty), and the node
+/// never branches on it. These constants just name the values seen in the prod captures so test
+/// fixtures and docs aren't sprinkled with bare <c>"KOR"</c>/<c>"JPN"</c> literals.
+/// </summary>
+public static class CountryCodes
+{
+    public const string Korea = "KOR";
+    public const string Japan = "JPN";
+}
diff --git a/SVSim.BattleNode/Bridge/MatchContext.cs b/SVSim.BattleNode/Bridge/MatchContext.cs
index adb7098..da0a684 100644
--- a/SVSim.BattleNode/Bridge/MatchContext.cs
+++ b/SVSim.BattleNode/Bridge/MatchContext.cs
@@ -12,12 +12,25 @@ public sealed record MatchContext(
     IReadOnlyList<long> SelfDeckCardIds,
 
     // Player class + leader (BattleStartSelfInfo)
-    string ClassId,         // "1".."8"
-    string CharaId,         // "1".."8" — equals ClassId when no leader skin chosen
+
+    /// <summary>The player's class. Rendered onto the wire <c>classId</c> as <c>"1".."8"</c> via
+    /// <see cref="CardClassWire.ToWireValue"/>; a closed set, so it's typed, not stringly.</summary>
+    CardClass ClassId,
+
+    /// <summary>Leader/skin id on the wire <c>charaId</c>. FREE-FORM, not a class enum: it's the
+    /// equipped leader-skin id (e.g. <c>"5000123"</c>) when one is chosen, else the class ordinal
+    /// (<c>"1".."8"</c>). Passed through verbatim — the node never interprets it.</summary>
+    string CharaId,
+
     string CardMasterName,  // current card-master, e.g. "card_master_node_10015"
 
     // Player cosmetics (MatchedSelfInfo)
-    string CountryCode,     // "KOR", "JPN", ...
+
+    /// <summary>Account region code, wire <c>country_code</c>. OPEN-ENDED account data (any value,
+    /// possibly empty); the node never branches on it. <see cref="CountryCodes"/> names the values
+    /// seen in captures.</summary>
+    string CountryCode,
+
     string UserName,
     string SleeveId,
     string EmblemId,
diff --git a/SVSim.BattleNode/Lifecycle/ServerBattleFrames.cs b/SVSim.BattleNode/Lifecycle/ServerBattleFrames.cs
index 886c640..cfa83e1 100644
--- a/SVSim.BattleNode/Lifecycle/ServerBattleFrames.cs
+++ b/SVSim.BattleNode/Lifecycle/ServerBattleFrames.cs
@@ -59,7 +59,7 @@ public static class ServerBattleFrames
                 SelfInfo: new BattleStartSelfInfo(
                     Rank: BattleFrameDefaults.PlayerRank,
                     BattlePoint: BattleFrameDefaults.PlayerBattlePoint,
-                    ClassId: selfCtx.ClassId,
+                    ClassId: selfCtx.ClassId.ToWireValue(),
                     CharaId: selfCtx.CharaId,
                     CardMasterName: selfCtx.CardMasterName),
                 OppoInfo: new BattleStartOppoInfo(
@@ -69,7 +69,7 @@ public static class ServerBattleFrames
                     IsMasterRank: "0",
                     BattlePoint: 0,
                     MasterPoint: "0",
-                    ClassId: oppoCtx.ClassId,
+                    ClassId: oppoCtx.ClassId.ToWireValue(),
                     CharaId: oppoCtx.CharaId,
                     CardMasterName: oppoCtx.CardMasterName)));
 
diff --git a/SVSim.BattleNode/Sessions/Participants/NoOpBotParticipant.cs b/SVSim.BattleNode/Sessions/Participants/NoOpBotParticipant.cs
index f5e791a..70fb351 100644
--- a/SVSim.BattleNode/Sessions/Participants/NoOpBotParticipant.cs
+++ b/SVSim.BattleNode/Sessions/Participants/NoOpBotParticipant.cs
@@ -20,7 +20,7 @@ public sealed class NoOpBotParticipant : IBattleParticipant
     public long ViewerId => ServerBattleFrames.FakeOpponentViewerId;
     public MatchContext Context { get; } = new(
         SelfDeckCardIds: Array.Empty<long>(),
-        ClassId: "0", CharaId: "0", CardMasterName: BotCardMasterName,
+        ClassId: CardClass.None, CharaId: "0", CardMasterName: BotCardMasterName,
         CountryCode: "", UserName: "Bot", SleeveId: "0",
         EmblemId: "0", DegreeId: "0", FieldId: 0, IsOfficial: 0,
         BattleModeId: 0);
diff --git a/SVSim.EmulatedEntrypoint/Controllers/RankBattleController.cs b/SVSim.EmulatedEntrypoint/Controllers/RankBattleController.cs
index f2aaae7..2a88d00 100644
--- a/SVSim.EmulatedEntrypoint/Controllers/RankBattleController.cs
+++ b/SVSim.EmulatedEntrypoint/Controllers/RankBattleController.cs
@@ -183,7 +183,7 @@ public sealed class RankBattleController : ControllerBase
                 Seed = seed,
                 Rank = 0,
                 BattlePoint = 0,
-                ClassId = int.TryParse(selfCtx.ClassId, out var cId) ? cId : -1,
+                ClassId = (int)selfCtx.ClassId,
                 CharaId = int.TryParse(selfCtx.CharaId, out var chId) ? chId : -1,
                 IsMasterRank = 0,
                 MasterPoint = 0,
diff --git a/SVSim.EmulatedEntrypoint/Services/MatchContextBuilder.cs b/SVSim.EmulatedEntrypoint/Services/MatchContextBuilder.cs
index bb18a64..3be5fcc 100644
--- a/SVSim.EmulatedEntrypoint/Services/MatchContextBuilder.cs
+++ b/SVSim.EmulatedEntrypoint/Services/MatchContextBuilder.cs
@@ -54,7 +54,7 @@ public class MatchContextBuilder : IMatchContextBuilder
 
         return new MatchContext(
             SelfDeckCardIds: deck,
-            ClassId: run.ClassId.ToString(),
+            ClassId: (CardClass)run.ClassId,
             CharaId: charaId,
             // Hardcoded v1; see spec §Deferred plumbing.
             CardMasterName: "card_master_node_10015",
@@ -104,7 +104,7 @@ public class MatchContextBuilder : IMatchContextBuilder
 
         return new MatchContext(
             SelfDeckCardIds: deckCardIds,
-            ClassId: deck.Class.Id.ToString(),
+            ClassId: (CardClass)deck.Class.Id,
             CharaId: charaId,
             CardMasterName: "card_master_node_10015",
             CountryCode: viewer.Info.CountryCode ?? string.Empty,
diff --git a/SVSim.UnitTests/BattleNode/Bridge/MatchingBridgeTests.cs b/SVSim.UnitTests/BattleNode/Bridge/MatchingBridgeTests.cs
index e45faba..dfa99c1 100644
--- a/SVSim.UnitTests/BattleNode/Bridge/MatchingBridgeTests.cs
+++ b/SVSim.UnitTests/BattleNode/Bridge/MatchingBridgeTests.cs
@@ -93,8 +93,8 @@ public class MatchingBridgeTests
 
     private static MatchContext FixtureCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(i => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 }
diff --git a/SVSim.UnitTests/BattleNode/Hosting/WaitingRoomTests.cs b/SVSim.UnitTests/BattleNode/Hosting/WaitingRoomTests.cs
index 36456bc..acdefff 100644
--- a/SVSim.UnitTests/BattleNode/Hosting/WaitingRoomTests.cs
+++ b/SVSim.UnitTests/BattleNode/Hosting/WaitingRoomTests.cs
@@ -69,8 +69,8 @@ public class WaitingRoomTests
         var ws = new TestWebSocket();
         var ctx = new MatchContext(
             SelfDeckCardIds: Array.Empty<long>(),
-            ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-            CountryCode: "KOR", UserName: "Player", SleeveId: "0",
+            ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+            CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "0",
             EmblemId: "0", DegreeId: "0", FieldId: 0, IsOfficial: 0,
             BattleModeId: BattleModes.TakeTwo);
         return new RealParticipant(ws, viewerId, ctx, NullLogger<RealParticipant>.Instance);
diff --git a/SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs b/SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs
index 61d3689..8d0f42c 100644
--- a/SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs
+++ b/SVSim.UnitTests/BattleNode/Integration/BattleNodeFlowTests.cs
@@ -23,8 +23,8 @@ public class BattleNodeFlowTests
 
     internal static MatchContext FixtureCtx(IReadOnlyList<long>? deck = null) => new(
         SelfDeckCardIds: deck ?? Enumerable.Range(1, 30).Select(i => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 
diff --git a/SVSim.UnitTests/BattleNode/Lifecycle/ServerBattleFramesTests.cs b/SVSim.UnitTests/BattleNode/Lifecycle/ServerBattleFramesTests.cs
index c2cb3bc..7ebd857 100644
--- a/SVSim.UnitTests/BattleNode/Lifecycle/ServerBattleFramesTests.cs
+++ b/SVSim.UnitTests/BattleNode/Lifecycle/ServerBattleFramesTests.cs
@@ -82,7 +82,7 @@ public class ServerBattleFramesTests
     {
         var ctx = FixtureCtx() with
         {
-            ClassId = "7", CharaId = "5000123",
+            ClassId = CardClass.Havencraft, CharaId = "5000123",
             CardMasterName = "card_master_test_v2",
             BattleModeId = 42,
         };
@@ -168,8 +168,8 @@ public class ServerBattleFramesTests
 
     private static MatchContext FixtureCtx(IReadOnlyList<long>? deck = null) => new(
         SelfDeckCardIds: deck ?? Enumerable.Range(1, 30).Select(i => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 
@@ -177,8 +177,8 @@ public class ServerBattleFramesTests
     // helpers read from for the oppo half.
     private static MatchContext FakeOpponentCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 0L).ToList(),
-        ClassId: "8", CharaId: "8", CardMasterName: "card_master_node_10015",
-        CountryCode: "JPN", UserName: "Opponent", SleeveId: "704141010",
+        ClassId: CardClass.Portalcraft, CharaId: "8", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Japan, UserName: "Opponent", SleeveId: "704141010",
         EmblemId: "400001100", DegreeId: "120027", FieldId: 5, IsOfficial: 0,
         BattleModeId: 0);
 }
diff --git a/SVSim.UnitTests/BattleNode/Lifecycle/TypedBodyWireShapeTests.cs b/SVSim.UnitTests/BattleNode/Lifecycle/TypedBodyWireShapeTests.cs
index 3519e34..78352bc 100644
--- a/SVSim.UnitTests/BattleNode/Lifecycle/TypedBodyWireShapeTests.cs
+++ b/SVSim.UnitTests/BattleNode/Lifecycle/TypedBodyWireShapeTests.cs
@@ -155,8 +155,8 @@ public class TypedBodyWireShapeTests
     /// </summary>
     private static MatchContext FixtureCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 
@@ -166,8 +166,8 @@ public class TypedBodyWireShapeTests
     // signature change.
     private static MatchContext FakeOpponentCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 0L).ToList(),
-        ClassId: "8", CharaId: "8", CardMasterName: "card_master_node_10015",
-        CountryCode: "JPN", UserName: "Opponent", SleeveId: "704141010",
+        ClassId: CardClass.Portalcraft, CharaId: "8", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Japan, UserName: "Opponent", SleeveId: "704141010",
         EmblemId: "400001100", DegreeId: "120027", FieldId: 5, IsOfficial: 0,
         BattleModeId: 0);
 }
diff --git a/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchConcurrencyTests.cs b/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchConcurrencyTests.cs
index 87fe7eb..fd74293 100644
--- a/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchConcurrencyTests.cs
+++ b/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchConcurrencyTests.cs
@@ -62,14 +62,14 @@ public class BattleSessionDispatchConcurrencyTests
 
     private static MatchContext CtxA() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
-        ClassId: "3", CharaId: "3", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "PlayerA", SleeveId: "3000011",
+        ClassId: CardClass.Runecraft, CharaId: "3", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "PlayerA", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0, BattleModeId: BattleModes.TakeTwo);
 
     private static MatchContext CtxB() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 200_011_010L).ToList(),
-        ClassId: "5", CharaId: "5", CardMasterName: "card_master_node_10015",
-        CountryCode: "JPN", UserName: "PlayerB", SleeveId: "3000022",
+        ClassId: CardClass.Shadowcraft, CharaId: "5", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Japan, UserName: "PlayerB", SleeveId: "3000022",
         EmblemId: "701441022", DegreeId: "300004", FieldId: 44, IsOfficial: 0, BattleModeId: BattleModes.TakeTwo);
 
     /// <summary>Tracks the peak number of dispatches in flight at once. Records the count under a
diff --git a/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchTests.cs b/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchTests.cs
index d9cdd37..b1e35c8 100644
--- a/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchTests.cs
+++ b/SVSim.UnitTests/BattleNode/Sessions/BattleSessionDispatchTests.cs
@@ -892,7 +892,7 @@ public class BattleSessionDispatchTests
 
     private static MatchContext NoOpBotContext() => new(
         SelfDeckCardIds: Array.Empty<long>(),
-        ClassId: "0", CharaId: "0", CardMasterName: "card_master_node_10015",
+        ClassId: CardClass.None, CharaId: "0", CardMasterName: "card_master_node_10015",
         CountryCode: "", UserName: "Bot", SleeveId: "0",
         EmblemId: "0", DegreeId: "0", FieldId: 0, IsOfficial: 0, BattleModeId: 0);
 
@@ -1048,22 +1048,22 @@ public class BattleSessionDispatchTests
 
     private static MatchContext PlayerACtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
-        ClassId: "3", CharaId: "3", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "PlayerA", SleeveId: "3000011",
+        ClassId: CardClass.Runecraft, CharaId: "3", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "PlayerA", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 
     private static MatchContext PlayerBCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 200_011_010L).ToList(),
-        ClassId: "5", CharaId: "5", CardMasterName: "card_master_node_10015",
-        CountryCode: "JPN", UserName: "PlayerB", SleeveId: "3000022",
+        ClassId: CardClass.Shadowcraft, CharaId: "5", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Japan, UserName: "PlayerB", SleeveId: "3000022",
         EmblemId: "701441022", DegreeId: "300004", FieldId: 44, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 
     private static MatchContext FixtureCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 
diff --git a/SVSim.UnitTests/BattleNode/Sessions/BattleSessionStateTests.cs b/SVSim.UnitTests/BattleNode/Sessions/BattleSessionStateTests.cs
index 59a9711..1958ca9 100644
--- a/SVSim.UnitTests/BattleNode/Sessions/BattleSessionStateTests.cs
+++ b/SVSim.UnitTests/BattleNode/Sessions/BattleSessionStateTests.cs
@@ -22,8 +22,8 @@ public class BattleSessionStateTests
     }
 
     private static MatchContext Ctx(params long[] deck) => new(
-        SelfDeckCardIds: deck, ClassId: "1", CharaId: "1", CardMasterName: "cm",
-        CountryCode: "KOR", UserName: "P", SleeveId: "0", EmblemId: "0", DegreeId: "0",
+        SelfDeckCardIds: deck, ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "cm",
+        CountryCode: CountryCodes.Korea, UserName: "P", SleeveId: "0", EmblemId: "0", DegreeId: "0",
         FieldId: 0, IsOfficial: 0, BattleModeId: BattleModes.TakeTwo);
 
     [Test]
diff --git a/SVSim.UnitTests/BattleNode/Sessions/BattleSessionTerminateCascadeTests.cs b/SVSim.UnitTests/BattleNode/Sessions/BattleSessionTerminateCascadeTests.cs
index 7d2574d..9aec370 100644
--- a/SVSim.UnitTests/BattleNode/Sessions/BattleSessionTerminateCascadeTests.cs
+++ b/SVSim.UnitTests/BattleNode/Sessions/BattleSessionTerminateCascadeTests.cs
@@ -52,7 +52,7 @@ public class BattleSessionTerminateCascadeTests
 
     private static MatchContext MakeFakeContext() => new(
         SelfDeckCardIds: Array.Empty<long>(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
         CountryCode: "JP", UserName: "Test", SleeveId: "0",
         EmblemId: "0", DegreeId: "0", FieldId: 0, IsOfficial: 0, BattleModeId: BattleModes.TakeTwo);
 }
diff --git a/SVSim.UnitTests/BattleNode/Sessions/InMemoryBattleSessionStoreTests.cs b/SVSim.UnitTests/BattleNode/Sessions/InMemoryBattleSessionStoreTests.cs
index c7e8cf5..9f5b19e 100644
--- a/SVSim.UnitTests/BattleNode/Sessions/InMemoryBattleSessionStoreTests.cs
+++ b/SVSim.UnitTests/BattleNode/Sessions/InMemoryBattleSessionStoreTests.cs
@@ -45,8 +45,8 @@ public class InMemoryBattleSessionStoreTests
 
     private static MatchContext FixtureCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(i => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 }
diff --git a/SVSim.UnitTests/BattleNode/Sessions/Participants/RealParticipantHandEventTests.cs b/SVSim.UnitTests/BattleNode/Sessions/Participants/RealParticipantHandEventTests.cs
index 29ff307..ff1c5bd 100644
--- a/SVSim.UnitTests/BattleNode/Sessions/Participants/RealParticipantHandEventTests.cs
+++ b/SVSim.UnitTests/BattleNode/Sessions/Participants/RealParticipantHandEventTests.cs
@@ -147,8 +147,8 @@ public class RealParticipantHandEventTests
 
     private static MatchContext FixtureCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 }
diff --git a/SVSim.UnitTests/BattleNode/Sessions/Participants/RealParticipantTests.cs b/SVSim.UnitTests/BattleNode/Sessions/Participants/RealParticipantTests.cs
index dc6c366..e11a00d 100644
--- a/SVSim.UnitTests/BattleNode/Sessions/Participants/RealParticipantTests.cs
+++ b/SVSim.UnitTests/BattleNode/Sessions/Participants/RealParticipantTests.cs
@@ -171,8 +171,8 @@ public class RealParticipantTests
 
     private static MatchContext FixtureCtx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 
diff --git a/SVSim.UnitTests/Matching/BotRosterTests.cs b/SVSim.UnitTests/Matching/BotRosterTests.cs
index 900e0d5..2f0c583 100644
--- a/SVSim.UnitTests/Matching/BotRosterTests.cs
+++ b/SVSim.UnitTests/Matching/BotRosterTests.cs
@@ -10,9 +10,9 @@ namespace SVSim.UnitTests.Matching;
 [TestFixture]
 public class BotRosterTests
 {
-    private static MatchContext Ctx(string userName, string classId) => new(
+    private static MatchContext Ctx(string userName, CardClass classId) => new(
         SelfDeckCardIds: Array.Empty<long>(),
-        ClassId: classId, CharaId: classId, CardMasterName: "card_master_node_10015",
+        ClassId: classId, CharaId: classId.ToWireValue(), CardMasterName: "card_master_node_10015",
         CountryCode: "JP", UserName: userName, SleeveId: "0",
         EmblemId: "0", DegreeId: "0", FieldId: 0, IsOfficial: 0, BattleModeId: BattleModes.TakeTwo);
 
@@ -30,7 +30,7 @@ public class BotRosterTests
         using var factory = new SVSimTestFactory();
         var roster = await NewRosterAsync(factory);
 
-        var bot = await roster.PickAsync(Ctx("PlayerA", "1"), "123456789012");
+        var bot = await roster.PickAsync(Ctx("PlayerA", CardClass.Forestcraft), "123456789012");
 
         // Series-1 enemy_ai_id values from data_dumps/client-assets/rm_ai_setting.csv —
         // one per class (1=Forest, 2=Sword, 3=Rune, 4=Dragon, 5=Shadow, 6=Blood, 7=Haven, 8=Portal).
@@ -44,7 +44,7 @@ public class BotRosterTests
         using var factory = new SVSimTestFactory();
         var roster = await NewRosterAsync(factory);
 
-        var bot = await roster.PickAsync(Ctx("PlayerA", "1"), "123456789012");
+        var bot = await roster.PickAsync(Ctx("PlayerA", CardClass.Forestcraft), "123456789012");
 
         Assert.That(bot.ClassId, Is.InRange(1, 8));
         Assert.That(bot.CharaId, Is.InRange(1, 8));
@@ -57,7 +57,7 @@ public class BotRosterTests
     {
         using var factory = new SVSimTestFactory();
         var roster = await NewRosterAsync(factory);
-        var ctx = Ctx("PlayerA", "3");
+        var ctx = Ctx("PlayerA", CardClass.Runecraft);
 
         var a = await roster.PickAsync(ctx, "999888777666");
         var b = await roster.PickAsync(ctx, "999888777666");
@@ -70,7 +70,7 @@ public class BotRosterTests
     {
         using var factory = new SVSimTestFactory();
         var roster = await NewRosterAsync(factory);
-        var ctx = Ctx("PlayerA", "3");
+        var ctx = Ctx("PlayerA", CardClass.Runecraft);
 
         var seen = new HashSet<int>();
         for (var i = 0; i < 20; i++)
@@ -91,7 +91,7 @@ public class BotRosterTests
         var globals = scope.ServiceProvider.GetRequiredService<IGlobalsRepository>();
         var roster = new BotRoster(globals);
 
-        Assert.That(async () => await roster.PickAsync(Ctx("PlayerA", "1"), "000000000001"),
+        Assert.That(async () => await roster.PickAsync(Ctx("PlayerA", CardClass.Forestcraft), "000000000001"),
             Throws.InvalidOperationException);
     }
 }
diff --git a/SVSim.UnitTests/Matching/InProcessPairUpRankFallbackTests.cs b/SVSim.UnitTests/Matching/InProcessPairUpRankFallbackTests.cs
index ad27463..bb66808 100644
--- a/SVSim.UnitTests/Matching/InProcessPairUpRankFallbackTests.cs
+++ b/SVSim.UnitTests/Matching/InProcessPairUpRankFallbackTests.cs
@@ -45,7 +45,7 @@ public class InProcessPairUpRankFallbackTests
 
     private static BattlePlayer Player(long id) =>
         new(id, new MatchContext(
-            SelfDeckCardIds: Array.Empty<long>(), ClassId: "0", CharaId: "0",
+            SelfDeckCardIds: Array.Empty<long>(), ClassId: CardClass.None, CharaId: "0",
             CardMasterName: "card_master_node_10015",
             CountryCode: "JP", UserName: $"P{id}", SleeveId: "0",
             EmblemId: "0", DegreeId: "0", FieldId: 0, IsOfficial: 0, BattleModeId: BattleModes.TakeTwo));
diff --git a/SVSim.UnitTests/Matching/InProcessPairUpTests.cs b/SVSim.UnitTests/Matching/InProcessPairUpTests.cs
index d43b360..f163e4d 100644
--- a/SVSim.UnitTests/Matching/InProcessPairUpTests.cs
+++ b/SVSim.UnitTests/Matching/InProcessPairUpTests.cs
@@ -91,8 +91,8 @@ public class InProcessPairUpTests
 
     private static MatchContext Ctx() => new(
         SelfDeckCardIds: Enumerable.Range(1, 30).Select(_ => 100_011_010L).ToList(),
-        ClassId: "1", CharaId: "1", CardMasterName: "card_master_node_10015",
-        CountryCode: "KOR", UserName: "Player", SleeveId: "3000011",
+        ClassId: CardClass.Forestcraft, CharaId: "1", CardMasterName: "card_master_node_10015",
+        CountryCode: CountryCodes.Korea, UserName: "Player", SleeveId: "3000011",
         EmblemId: "701441011", DegreeId: "300003", FieldId: 43, IsOfficial: 0,
         BattleModeId: BattleModes.TakeTwo);
 }
diff --git a/SVSim.UnitTests/Matching/MatchingResolverTests.cs b/SVSim.UnitTests/Matching/MatchingResolverTests.cs
index fb2f6db..4929227 100644
--- a/SVSim.UnitTests/Matching/MatchingResolverTests.cs
+++ b/SVSim.UnitTests/Matching/MatchingResolverTests.cs
@@ -28,7 +28,7 @@ public class MatchingResolverTests
 
     private static BattlePlayer Player(long vid = 1) =>
         new(vid, new MatchContext(
-            SelfDeckCardIds: Array.Empty<long>(), ClassId: "0", CharaId: "0",
+            SelfDeckCardIds: Array.Empty<long>(), ClassId: CardClass.None, CharaId: "0",
             CardMasterName: "card_master_node_10015",
             CountryCode: "JP", UserName: $"P{vid}", SleeveId: "0",
             EmblemId: "0", DegreeId: "0", FieldId: 0, IsOfficial: 0, BattleModeId: BattleModes.TakeTwo));
diff --git a/SVSim.UnitTests/Services/MatchContextBuilderTests.cs b/SVSim.UnitTests/Services/MatchContextBuilderTests.cs
index ad8228d..9aaa69b 100644
--- a/SVSim.UnitTests/Services/MatchContextBuilderTests.cs
+++ b/SVSim.UnitTests/Services/MatchContextBuilderTests.cs
@@ -57,7 +57,7 @@ public class MatchContextBuilderTests
         var ctx = await builder.BuildForTwoPickAsync(vid);
 
         Assert.That(ctx.SelfDeckCardIds, Is.EqualTo(deck));
-        Assert.That(ctx.ClassId, Is.EqualTo("5"));
+        Assert.That(ctx.ClassId, Is.EqualTo(CardClass.Shadowcraft));
         Assert.That(ctx.CharaId, Is.EqualTo("5000001"));      // LeaderSkinId set
         Assert.That(ctx.CountryCode, Is.EqualTo("KOR"));
         Assert.That(ctx.UserName, Is.EqualTo("Drafter"));
@@ -132,7 +132,7 @@ public class MatchContextBuilderTests
 
         Assert.That(ctx.UserName, Is.EqualTo("Ranker"));
         Assert.That(ctx.BattleModeId, Is.EqualTo(BattleModes.TakeTwo), "rank-battle carries the same mode id as TK2 on the wire.");
-        Assert.That(ctx.ClassId, Is.Not.Null.And.Not.Empty, "ClassId from the selected deck's class.");
+        Assert.That(ctx.ClassId, Is.Not.EqualTo(CardClass.None), "ClassId from the selected deck's class.");
         Assert.That(ctx.CardMasterName, Is.EqualTo("card_master_node_10015"));
         Assert.That(ctx.FieldId, Is.EqualTo(43));
     }
@@ -198,8 +198,8 @@ public class MatchContextBuilderTests
         var deck1Ctx = await builder.BuildForRankBattleAsync(viewerId, Format.Unlimited, deckNo: 1);
         var deck5Ctx = await builder.BuildForRankBattleAsync(viewerId, Format.Unlimited, deckNo: 5);
 
-        Assert.That(deck1Ctx.ClassId, Is.EqualTo("1"), "deckNo=1 → class 1.");
-        Assert.That(deck5Ctx.ClassId, Is.EqualTo("6"), "deckNo=5 → class 6 (the wire-bug case).");
+        Assert.That(deck1Ctx.ClassId, Is.EqualTo(CardClass.Forestcraft), "deckNo=1 → class 1.");
+        Assert.That(deck5Ctx.ClassId, Is.EqualTo(CardClass.Bloodcraft), "deckNo=5 → class 6 (the wire-bug case).");
     }
 
     [Test]