diff --git a/internal/database/monitor.go b/internal/database/monitor.go
index c9f27f08..102980f6 100644
--- a/internal/database/monitor.go
+++ b/internal/database/monitor.go
@@ -267,7 +267,8 @@ type ToolStatsSummaryResult struct {
 	TopTools []*mcp.ToolStats
 }
 
-// LoadToolStatsSummary 聚合统计信息，仅返回汇总与 Top N 工具（避免全量 map 传输）
+// LoadToolStatsSummary 聚合统计信息，仅返回汇总与 Top N 工具（避免全量 map 传输）。
+// 监控页的失败口径只包含真实失败/异常终止；用户主动取消的 cancelled 保留在总调用中，不计入失败。
 func (db *DB) LoadToolStatsSummary(topN int) (*ToolStatsSummaryResult, error) {
 	if topN <= 0 {
 		topN = 6
@@ -282,19 +283,19 @@ func (db *DB) LoadToolStatsSummary(topN int) (*ToolStatsSummaryResult, error) {
 
 	summaryQuery := `
 		SELECT COUNT(*),
-			COALESCE(SUM(total_calls), 0),
-			COALESCE(SUM(success_calls), 0),
-			COALESCE(SUM(failed_calls), 0),
-			MAX(last_call_time)
-		FROM tool_stats
+			COALESCE(SUM(CASE WHEN status = 'completed' THEN 1 ELSE 0 END), 0),
+			COALESCE(SUM(CASE WHEN status IN ('failed', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END), 0),
+			MAX(start_time),
+			COUNT(DISTINCT tool_name)
+		FROM tool_executions
 	`
 	var lastCallRaw sql.NullString
 	err := db.QueryRow(summaryQuery).Scan(
-		&result.Summary.ToolCount,
 		&result.Summary.TotalCalls,
 		&result.Summary.SuccessCalls,
 		&result.Summary.FailedCalls,
 		&lastCallRaw,
+		&result.Summary.ToolCount,
 	)
 	if err != nil {
 		return nil, err
@@ -310,9 +311,13 @@ func (db *DB) LoadToolStatsSummary(topN int) (*ToolStatsSummaryResult, error) {
 	}
 
 	topQuery := `
-		SELECT tool_name, total_calls, success_calls, failed_calls, last_call_time
-		FROM tool_stats
-		WHERE total_calls > 0
+		SELECT tool_name,
+			COUNT(*) AS total_calls,
+			SUM(CASE WHEN status = 'completed' THEN 1 ELSE 0 END) AS success_calls,
+			SUM(CASE WHEN status IN ('failed', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END) AS failed_calls,
+			MAX(start_time) AS last_call_time
+		FROM tool_executions
+		GROUP BY tool_name
 		ORDER BY total_calls DESC, tool_name ASC
 		LIMIT ?
 	`
@@ -324,7 +329,7 @@ func (db *DB) LoadToolStatsSummary(topN int) (*ToolStatsSummaryResult, error) {
 
 	for rows.Next() {
 		var stat mcp.ToolStats
-		var lastCallTime sql.NullTime
+		var lastCallTime sql.NullString
 		if err := rows.Scan(
 			&stat.ToolName,
 			&stat.TotalCalls,
@@ -336,7 +341,8 @@ func (db *DB) LoadToolStatsSummary(topN int) (*ToolStatsSummaryResult, error) {
 			continue
 		}
 		if lastCallTime.Valid {
-			stat.LastCallTime = &lastCallTime.Time
+			parsed := parseDBTime(lastCallTime.String)
+			stat.LastCallTime = &parsed
 		}
 		result.TopTools = append(result.TopTools, &stat)
 	}
@@ -359,7 +365,7 @@ func (db *DB) LoadToolStatsSummaryForAccess(topN int, access RBACListAccess) (*T
 	var lastCall sql.NullString
 	err := db.QueryRow(`SELECT COUNT(*),
 		COALESCE(SUM(CASE WHEN status = 'completed' THEN 1 ELSE 0 END), 0),
-		COALESCE(SUM(CASE WHEN status IN ('failed', 'cancelled', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END), 0),
+		COALESCE(SUM(CASE WHEN status IN ('failed', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END), 0),
 		MAX(start_time), COUNT(DISTINCT tool_name)`+fromSQL, args...).Scan(
 		&result.Summary.TotalCalls, &result.Summary.SuccessCalls, &result.Summary.FailedCalls,
 		&lastCall, &result.Summary.ToolCount,
@@ -373,7 +379,7 @@ func (db *DB) LoadToolStatsSummaryForAccess(topN int, access RBACListAccess) (*T
 	}
 	rows, err := db.Query(`SELECT tool_name, COUNT(*),
 		SUM(CASE WHEN status = 'completed' THEN 1 ELSE 0 END),
-		SUM(CASE WHEN status IN ('failed', 'cancelled', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END), MAX(start_time)`+
+		SUM(CASE WHEN status IN ('failed', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END), MAX(start_time)`+
 		fromSQL+` GROUP BY tool_name ORDER BY COUNT(*) DESC, tool_name ASC LIMIT ?`, append(args, topN)...)
 	if err != nil {
 		return nil, err
@@ -815,7 +821,7 @@ func (db *DB) PurgeToolExecutionsBefore(cutoff time.Time) (int64, error) {
 		}
 		delta.totalCalls += count
 		switch status {
-		case "failed", "cancelled", "hard_timeout", "orphaned":
+		case "failed", "hard_timeout", "orphaned":
 			delta.failedCalls += count
 		case "completed":
 			delta.successCalls += count
@@ -971,7 +977,7 @@ func (db *DB) LoadCallsTimeline(since time.Time, dailyBuckets bool) ([]CallsTime
 		query = `
 			SELECT date(start_time, 'localtime') AS bucket,
 				COUNT(*) AS total,
-				SUM(CASE WHEN status IN ('failed', 'cancelled', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END) AS failed
+				SUM(CASE WHEN status IN ('failed', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END) AS failed
 			FROM tool_executions
 			WHERE start_time >= ?
 			GROUP BY bucket
@@ -981,7 +987,7 @@ func (db *DB) LoadCallsTimeline(since time.Time, dailyBuckets bool) ([]CallsTime
 		query = `
 			SELECT strftime('%Y-%m-%d %H:00:00', start_time, 'localtime') AS bucket,
 				COUNT(*) AS total,
-				SUM(CASE WHEN status IN ('failed', 'cancelled', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END) AS failed
+				SUM(CASE WHEN status IN ('failed', 'hard_timeout', 'orphaned') THEN 1 ELSE 0 END) AS failed
 			FROM tool_executions
 			WHERE start_time >= ?
 			GROUP BY bucket
diff --git a/internal/database/monitor_summary_test.go b/internal/database/monitor_summary_test.go
index 7c162aed..f7fcbf4d 100644
--- a/internal/database/monitor_summary_test.go
+++ b/internal/database/monitor_summary_test.go
@@ -84,3 +84,49 @@ func TestLoadToolStatsSummaryAndListPage(t *testing.T) {
 		}
 	}
 }
+
+func TestLoadToolStatsSummaryDoesNotCountCancelledAsFailed(t *testing.T) {
+	dbPath := filepath.Join(t.TempDir(), "monitor-cancelled-summary.db")
+	db, err := NewDB(dbPath, zap.NewNop())
+	if err != nil {
+		t.Fatalf("NewDB: %v", err)
+	}
+	defer db.Close()
+
+	now := time.Now()
+	for i, status := range []string{"completed", "cancelled", "failed"} {
+		exec := &mcp.ToolExecution{
+			ID:        fmt.Sprintf("exec-%d", i),
+			ToolName:  "exec",
+			Arguments: map[string]interface{}{},
+			Status:    status,
+			StartTime: now.Add(time.Duration(i) * time.Second),
+		}
+		end := exec.StartTime.Add(time.Second)
+		exec.EndTime = &end
+		exec.Duration = time.Second
+		if err := db.SaveToolExecution(exec); err != nil {
+			t.Fatalf("SaveToolExecution(%s): %v", status, err)
+		}
+	}
+
+	summary, err := db.LoadToolStatsSummary(1)
+	if err != nil {
+		t.Fatalf("LoadToolStatsSummary: %v", err)
+	}
+	if summary.Summary.TotalCalls != 3 {
+		t.Fatalf("totalCalls = %d, want 3", summary.Summary.TotalCalls)
+	}
+	if summary.Summary.SuccessCalls != 1 {
+		t.Fatalf("successCalls = %d, want 1", summary.Summary.SuccessCalls)
+	}
+	if summary.Summary.FailedCalls != 1 {
+		t.Fatalf("failedCalls = %d, want 1", summary.Summary.FailedCalls)
+	}
+	if len(summary.TopTools) != 1 {
+		t.Fatalf("top tools = %d, want 1", len(summary.TopTools))
+	}
+	if summary.TopTools[0].FailedCalls != 1 {
+		t.Fatalf("top tool failedCalls = %d, want 1", summary.TopTools[0].FailedCalls)
+	}
+}
diff --git a/internal/mcp/external_manager.go b/internal/mcp/external_manager.go
index ca9913fd..c6bd9b53 100644
--- a/internal/mcp/external_manager.go
+++ b/internal/mcp/external_manager.go
@@ -745,7 +745,7 @@ func (m *ExternalMCPManager) CallTool(ctx context.Context, toolName string, args
 			return result, callErr
 		},
 		OnDone: func(exec *ToolExecution) {
-			failed := exec != nil && exec.Status != ToolExecutionStatusCompleted
+			failed := exec != nil && exec.Status != ToolExecutionStatusCompleted && exec.Status != ToolExecutionStatusCancelled
 			m.recordExternalMCPResult(mcpName, failed)
 			m.updateStats(toolName, failed)
 		},
diff --git a/internal/mcp/server.go b/internal/mcp/server.go
index d2838db5..2bf2c8ec 100644
--- a/internal/mcp/server.go
+++ b/internal/mcp/server.go
@@ -602,13 +602,13 @@ func (s *Server) handleCallTool(requestCtx context.Context, msg *Message) *Messa
 		st, msg := executionStatusAndMessage(err)
 		execution.Status = st
 		execution.Error = msg
-		failed = true
+		failed = st != "cancelled"
 	} else if result != nil && result.IsError {
 		if cancelledWithUserNote {
 			execution.Status = "cancelled"
 			execution.Error = ""
 			execution.Result = result
-			failed = true
+			failed = false
 		} else {
 			execution.Status = "failed"
 			if len(result.Content) > 0 {
@@ -930,7 +930,7 @@ func (s *Server) CallTool(ctx context.Context, toolName string, args map[string]
 			return handler(runCtx, args)
 		},
 		OnDone: func(exec *ToolExecution) {
-			failed := exec != nil && exec.Status != ToolExecutionStatusCompleted
+			failed := exec != nil && exec.Status != ToolExecutionStatusCompleted && exec.Status != ToolExecutionStatusCancelled
 			s.updateStats(toolName, failed)
 		},
 	})