diff --git a/internal/agent/loop.go b/internal/agent/loop.go
index a334934c..5de90bb1 100644
--- a/internal/agent/loop.go
+++ b/internal/agent/loop.go
@@ -34,6 +34,7 @@ func (l *Loop) runLoop(ctx context.Context, req RunRequest) (*RunResult, error)
 		event.UserID = req.UserID
 		event.Channel = req.Channel
 		event.ChatID = req.ChatID
+		event.SessionKey = req.SessionKey
 		event.TenantID = l.tenantID
 		l.emit(event)
 	}
diff --git a/internal/agent/loop_run.go b/internal/agent/loop_run.go
index 051774f2..03e53756 100644
--- a/internal/agent/loop_run.go
+++ b/internal/agent/loop_run.go
@@ -29,6 +29,7 @@ func (l *Loop) Run(ctx context.Context, req RunRequest) (*RunResult, error) {
 		event.UserID = req.UserID
 		event.Channel = req.Channel
 		event.ChatID = req.ChatID
+		event.SessionKey = req.SessionKey
 		event.TenantID = store.TenantIDFromContext(ctx)
 		l.emit(event)
 	}
diff --git a/internal/agent/loop_types.go b/internal/agent/loop_types.go
index 7ce12bf1..e7765a32 100644
--- a/internal/agent/loop_types.go
+++ b/internal/agent/loop_types.go
@@ -160,10 +160,11 @@ type AgentEvent struct {
 	TeamTaskID    string `json:"teamTaskId,omitempty"`
 	ParentAgentID string `json:"parentAgentId,omitempty"`
 
-	// Routing context (helps WS clients filter by user/channel)
-	UserID  string `json:"userId,omitempty"`
-	Channel string `json:"channel,omitempty"`
-	ChatID  string `json:"chatId,omitempty"`
+	// Routing context (helps WS clients filter by user/channel/session)
+	UserID     string `json:"userId,omitempty"`
+	Channel    string `json:"channel,omitempty"`
+	ChatID     string `json:"chatId,omitempty"`
+	SessionKey string `json:"sessionKey,omitempty"`
 
 	// TenantID scopes this event to a specific tenant for filtering (not serialized).
 	TenantID uuid.UUID `json:"-"`
diff --git a/ui/web/src/pages/chat/hooks/use-chat-messages.ts b/ui/web/src/pages/chat/hooks/use-chat-messages.ts
index e86c1e1b..26ff3157 100644
--- a/ui/web/src/pages/chat/hooks/use-chat-messages.ts
+++ b/ui/web/src/pages/chat/hooks/use-chat-messages.ts
@@ -34,6 +34,8 @@ export function useChatMessages(sessionKey: string, agentId: string) {
   const toolStreamRef = useRef<ToolStreamEntry[]>([]);
   const agentIdRef = useRef(agentId);
   agentIdRef.current = agentId;
+  const sessionKeyRef = useRef(sessionKey);
+  sessionKeyRef.current = sessionKey;
   const activityRef = useRef<RunActivity | null>(null);
   const blockRepliesRef = useRef<ChatMessage[]>([]);
   const rafPendingRef = useRef(false);
@@ -155,6 +157,15 @@ export function useChatMessages(sessionKey: string, agentId: string) {
       const event = payload as AgentEventPayload;
       if (!event) return;
 
+      // Only process events from WS channel targeting the active session.
+      // Delegations/announces (runKind set) are allowed regardless of channel.
+      if (event.channel && event.channel !== "ws" && !event.runKind) {
+        return;
+      }
+      if (event.sessionKey && event.sessionKey !== sessionKeyRef.current) {
+        return;
+      }
+
       // Capture run.started when we are expecting a run for this agent,
       // OR when an announce run starts (leader summarising team results).
       if (event.type === "run.started" && event.agentId === agentIdRef.current) {
diff --git a/ui/web/src/types/chat.ts b/ui/web/src/types/chat.ts
index c720e656..fb82abbb 100644
--- a/ui/web/src/types/chat.ts
+++ b/ui/web/src/types/chat.ts
@@ -52,6 +52,8 @@ export interface AgentEventPayload {
   agentId: string;
   runId: string;
   runKind?: string; // "delegation" | "announce" — omitted for user-initiated runs
+  channel?: string; // "ws", "telegram", "cron", etc.
+  sessionKey?: string; // session this event belongs to
   payload?: {
     content?: string;
     name?: string;