diff --git a/backend/mpc-system/services/account/adapters/input/http/account_handler.go b/backend/mpc-system/services/account/adapters/input/http/account_handler.go
index b389f723..3de31549 100644
--- a/backend/mpc-system/services/account/adapters/input/http/account_handler.go
+++ b/backend/mpc-system/services/account/adapters/input/http/account_handler.go
@@ -814,7 +814,8 @@ func (h *AccountHTTPHandler) CreateSigningSession(c *gin.Context) {
 		logger.Info("Calling CreateSigningSession via gRPC (auto party selection)",
 			zap.String("username", req.Username),
 			zap.Int("threshold_t", accountOutput.Account.ThresholdT),
-			zap.Int("available_parties", len(partyIDs)))
+			zap.Int("available_parties", len(partyIDs)),
+			zap.String("keygen_session_id", accountOutput.Account.KeygenSessionID.String()))
 	}
 
 	resp, err := h.sessionCoordinatorClient.CreateSigningSessionAuto(
@@ -835,7 +836,9 @@ func (h *AccountHTTPHandler) CreateSigningSession(c *gin.Context) {
 
 	logger.Info("gRPC CreateSigningSession succeeded",
 		zap.String("session_id", resp.SessionID),
-		zap.Int("num_parties", len(resp.SelectedParties)))
+		zap.Int("num_parties", len(resp.SelectedParties)),
+		zap.String("keygen_session_id", accountOutput.Account.KeygenSessionID.String()),
+		zap.Strings("selected_parties", resp.SelectedParties))
 
 	// Record session_created event for sign
 	signSessionID, _ := uuid.Parse(resp.SessionID)
diff --git a/backend/mpc-system/services/message-router/adapters/input/grpc/message_grpc_handler.go b/backend/mpc-system/services/message-router/adapters/input/grpc/message_grpc_handler.go
index 97ad374c..b1e41943 100644
--- a/backend/mpc-system/services/message-router/adapters/input/grpc/message_grpc_handler.go
+++ b/backend/mpc-system/services/message-router/adapters/input/grpc/message_grpc_handler.go
@@ -532,11 +532,16 @@ func (s *MessageRouterServer) JoinSession(
 		}
 	}
 
+	keygenSessionID := ""
+	if resp.SessionInfo != nil {
+		keygenSessionID = resp.SessionInfo.KeygenSessionId
+	}
 	logger.Info("Proxied JoinSession to coordinator",
 		zap.String("session_id", req.SessionId),
 		zap.String("party_id", req.PartyId),
 		zap.Int32("party_index", resp.PartyIndex),
-		zap.Bool("success", resp.Success))
+		zap.Bool("success", resp.Success),
+		zap.String("keygen_session_id", keygenSessionID))
 
 	return resp, nil
 }
diff --git a/backend/mpc-system/services/server-party/adapters/output/grpc/message_router_client.go b/backend/mpc-system/services/server-party/adapters/output/grpc/message_router_client.go
index 40ece983..116123a2 100644
--- a/backend/mpc-system/services/server-party/adapters/output/grpc/message_router_client.go
+++ b/backend/mpc-system/services/server-party/adapters/output/grpc/message_router_client.go
@@ -685,7 +685,10 @@ func (c *MessageRouterClient) JoinSession(
 		logger.Info("Joined session via Message Router",
 			zap.String("session_id", sessionID.String()),
 			zap.String("party_id", partyID),
-			zap.String("session_type", sessionInfo.SessionType))
+			zap.String("session_type", sessionInfo.SessionType),
+			zap.String("keygen_session_id", sessionInfo.KeygenSessionID.String()),
+			zap.Int("threshold_n", sessionInfo.ThresholdN),
+			zap.Int("threshold_t", sessionInfo.ThresholdT))
 
 		return sessionInfo, nil
 	})
diff --git a/backend/mpc-system/services/session-coordinator/adapters/input/grpc/session_grpc_handler.go b/backend/mpc-system/services/session-coordinator/adapters/input/grpc/session_grpc_handler.go
index 3ec512d0..08714587 100644
--- a/backend/mpc-system/services/session-coordinator/adapters/input/grpc/session_grpc_handler.go
+++ b/backend/mpc-system/services/session-coordinator/adapters/input/grpc/session_grpc_handler.go
@@ -203,7 +203,9 @@ func (s *SessionCoordinatorServer) CreateSession(
 
 	logger.Info("gRPC CreateSession completed successfully",
 		zap.String("session_id", output.SessionID.String()),
-		zap.Int("num_join_tokens", len(output.JoinTokens)))
+		zap.Int("num_join_tokens", len(output.JoinTokens)),
+		zap.String("keygen_session_id", inputData.KeygenSessionID.String()),
+		zap.String("session_type", req.SessionType))
 
 	// Load session to get delegate party ID
 	session, err := s.sessionRepo.FindByUUID(ctx, output.SessionID)
@@ -288,6 +290,15 @@ func (s *SessionCoordinatorServer) JoinSession(
 		keygenSessionIDStr = output.SessionInfo.KeygenSessionID.String()
 	}
 
+	logger.Info("gRPC JoinSession completed",
+		zap.String("session_id", output.SessionInfo.SessionID.String()),
+		zap.String("party_id", req.PartyId),
+		zap.Int("party_index", output.PartyIndex),
+		zap.String("keygen_session_id", keygenSessionIDStr),
+		zap.String("session_type", output.SessionInfo.SessionType),
+		zap.Int("threshold_n", output.SessionInfo.ThresholdN),
+		zap.Int("threshold_t", output.SessionInfo.ThresholdT))
+
 	return &pb.JoinSessionResponse{
 		Success: output.Success,
 		SessionInfo: &pb.SessionInfo{