diff --git a/Assets/Scripts/Network/NetworkApplication/SyncSequenceTracker.cs b/Assets/Scripts/Network/NetworkApplication/SyncSequenceTracker.cs
index 5aa0404..3006472 100644
--- a/Assets/Scripts/Network/NetworkApplication/SyncSequenceTracker.cs
+++ b/Assets/Scripts/Network/NetworkApplication/SyncSequenceTracker.cs
@@ -41,7 +41,7 @@ namespace Network.NetworkApplication
                 case MessageType.MoveInput:
                 {
                     var input = MoveInput.Parser.ParseFrom(payload);
-                    streamKey = $"input:{Normalize(sender)}:{input.PlayerId}";
+                    streamKey = $"input:{input.PlayerId}";
                     sequence = input.Tick;
                     return true;
                 }
diff --git a/Assets/Scripts/Network/NetworkHost/ServerAuthoritativeCombatCoordinator.cs b/Assets/Scripts/Network/NetworkHost/ServerAuthoritativeCombatCoordinator.cs
index 3fab8ff..fde9bc0 100644
--- a/Assets/Scripts/Network/NetworkHost/ServerAuthoritativeCombatCoordinator.cs
+++ b/Assets/Scripts/Network/NetworkHost/ServerAuthoritativeCombatCoordinator.cs
@@ -42,6 +42,29 @@ namespace Network.NetworkHost
             }
         }
 
+        public void BootstrapState(IPEndPoint remoteEndPoint, string playerId, int hp, bool isDead)
+        {
+            if (remoteEndPoint == null || string.IsNullOrWhiteSpace(playerId))
+            {
+                return;
+            }
+
+            var key = Normalize(remoteEndPoint).ToString();
+            lock (gate)
+            {
+                if (statesByPeer.ContainsKey(key))
+                {
+                    return;
+                }
+
+                statesByPeer.Add(key, new ServerAuthoritativeCombatState(
+                    Normalize(remoteEndPoint),
+                    playerId,
+                    hp,
+                    isDead));
+            }
+        }
+
         public Task HandleShootInputAsync(byte[] payload, IPEndPoint sender)
         {
             if (payload == null || sender == null)
@@ -95,7 +118,7 @@ namespace Network.NetworkHost
                 EventType = CombatEventType.Hit,
                 AttackerId = attackerState.PlayerId,
                 TargetId = targetState.PlayerId,
-                Damage = 0,
+                Damage = configuration.DamagePerShot,
                 HitPosition = hitPosition
             }, MessageType.CombatEvent);
 
diff --git a/Assets/Scripts/Network/NetworkHost/ServerNetworkHost.cs b/Assets/Scripts/Network/NetworkHost/ServerNetworkHost.cs
index 947e259..7517944 100644
--- a/Assets/Scripts/Network/NetworkHost/ServerNetworkHost.cs
+++ b/Assets/Scripts/Network/NetworkHost/ServerNetworkHost.cs
@@ -284,6 +284,7 @@ namespace Network.NetworkHost
             RememberPlayerId(remoteEndPoint, playerId);
             SessionCoordinator.NotifyLoginSucceeded(remoteEndPoint);
             BootstrapAuthoritativeMovementState(remoteEndPoint, speed);
+            BootstrapAuthoritativeCombatState(remoteEndPoint, playerId);
             PublishMetricsSessionSnapshot(remoteEndPoint);
         }
 
@@ -382,6 +383,21 @@ namespace Network.NetworkHost
             authoritativeMovementCoordinator.EnsureState(remoteEndPoint, playerId, speed, out _);
         }
 
+        private void BootstrapAuthoritativeCombatState(IPEndPoint remoteEndPoint, string playerId)
+        {
+            if (!TryGetKnownPlayerId(remoteEndPoint, out var resolvedPlayerId))
+            {
+                return;
+            }
+
+            if (!authoritativeMovementCoordinator.TryGetState(remoteEndPoint, out var movementState))
+            {
+                return;
+            }
+
+            authoritativeCombatCoordinator.BootstrapState(remoteEndPoint, resolvedPlayerId, movementState.Hp, movementState.IsDead);
+        }
+
         private void RememberPlayerId(IPEndPoint remoteEndPoint, string playerId)
         {
             if (remoteEndPoint == null || string.IsNullOrWhiteSpace(playerId))
diff --git a/openspec/specs/network-gameplay-message-types/spec.md b/openspec/specs/network-gameplay-message-types/spec.md
index b165fae..5ef905a 100644
--- a/openspec/specs/network-gameplay-message-types/spec.md
+++ b/openspec/specs/network-gameplay-message-types/spec.md
@@ -17,26 +17,26 @@ The repository SHALL keep the source protobuf schema that defines gameplay netwo
 - **THEN** the checked-in generated code matches the schema contract used by client and server hosts
 
 ### Requirement: Gameplay messages expose explicit MVP payload fields
-The shared networking contract SHALL define the MVP payload fields for gameplay messages explicitly in the source protobuf schema and generated C# messages. `MoveInput` MUST expose `playerId`, `tick`, `moveX`, and `moveY`; `ShootInput` MUST expose `playerId`, `tick`, `dirX`, `dirY`, and an optional `targetId`; `PlayerState` MUST expose `playerId`, `tick`, `acknowledgedMoveTick`, `position`, `rotation`, `hp`, and an optional `velocity`; `CombatEvent` MUST expose `tick`, `eventType`, `attackerId`, `targetId`, `damage`, and an optional `hitPosition`. The shared contract MUST also provide `CombatEventType` so combat results use explicit event categories rather than ad hoc integer payload conventions.
+The shared networking contract SHALL define the MVP payload fields for gameplay messages explicitly in the source protobuf schema and generated C# messages. `MoveInput` MUST expose `player_id`, `tick`, `turn_input`, and `throttle_input`; `ShootInput` MUST expose `player_id`, `tick`, `dir_x`, `dir_y`, and an optional `target_id`; `PlayerState` MUST expose `player_id`, `tick`, `acknowledged_move_tick`, `position`, `rotation`, `hp`, and `velocity`; `CombatEvent` MUST expose `tick`, `event_type`, `attacker_id`, `target_id`, `damage`, and an optional `hit_position`. The shared contract MUST also provide `CombatEventType` so combat results use explicit event categories rather than ad hoc integer payload conventions.
 
 #### Scenario: Movement input carries explicit movement fields
 - **WHEN** client or server code constructs or parses `MoveInput`
-- **THEN** the message exposes `playerId`, `tick`, `moveX`, and `moveY`
+- **THEN** the message exposes `player_id`, `tick`, `turn_input`, and `throttle_input`
 - **THEN** movement intent does not rely on an overloaded payload extension
 
 #### Scenario: Shooting input carries explicit aim fields
 - **WHEN** client or server code constructs or parses `ShootInput`
-- **THEN** the message exposes `playerId`, `tick`, `dirX`, `dirY`, and `targetId`
+- **THEN** the message exposes `player_id`, `tick`, `dir_x`, `dir_y`, and `target_id`
 - **THEN** shooting direction and optional target selection are represented directly in the message contract
 
 #### Scenario: Authoritative player state carries explicit gameplay state fields
 - **WHEN** client or server code constructs or parses `PlayerState`
-- **THEN** the message exposes `playerId`, `tick`, `acknowledgedMoveTick`, `position`, `rotation`, `hp`, and `velocity`
+- **THEN** the message exposes `player_id`, `tick`, `acknowledged_move_tick`, `position`, `rotation`, `hp`, and `velocity`
 - **THEN** snapshot ordering and acknowledged-input reconciliation are both expressed without ad hoc payload extensions or overloaded tick semantics
 
 #### Scenario: Combat events carry explicit result fields and event categories
 - **WHEN** client or server code constructs or parses `CombatEvent`
-- **THEN** the message exposes `tick`, `eventType`, `attackerId`, `targetId`, `damage`, and `hitPosition`
+- **THEN** the message exposes `tick`, `event_type`, `attacker_id`, `target_id`, `damage`, and `hit_position`
 - **THEN** `CombatEventType` provides explicit combat-result categories for interpreting that event payload
 
 ### Requirement: Client gameplay actions use split gameplay messages directly