diff --git a/docs/feature/rest-error-empty-results.md b/docs/feature/rest-error-empty-results.md
index dbc650c0..aea7c924 100644
--- a/docs/feature/rest-error-empty-results.md
+++ b/docs/feature/rest-error-empty-results.md
@@ -20,3 +20,11 @@
 ## F3：实施计划
 
 改动 c2.go 的 DeleteProfile、webshell.go 的 DeleteConnection、database/vulnerability.go 的列表初始化、batch_task_manager.go 的 ListQueuesForAccess 初始化。添加独立 HTTP 合同测试，临时数据库验证缺失、成功删除和重复删除、真实 SQL 失败、空库、筛选无匹配及有结果列表；批量列表含内存路径。运行针对性测试及 handler/database 包测试、git diff --check。更新 changelog 与验证记录。回退使用本分支修复提交的 revert。
+
+## F4：实施结果
+
+- C2 Profile 删除将 sql.ErrNoRows 映射为 404；真实错误写内部日志，对外通用 500 文案。
+- WebShell 删除使用 errors.Is 识别缺失，对外数据库错误改为通用 500 文案，底层已有日志保留。
+- 漏洞数据库列表、批量队列业务列表初始化为空切片，成功的无记录查询序列化为 []；后者同时覆盖数据库与内存路径。
+- 独立 httptest 回归覆盖缺失、成功删除、重复删除、SQL 错误脱敏、两类空列表、非空结果和批量内存分支。
+- 修复前回归按预期失败，明确捕获原行为；修复后 `go test ./internal/handler -run '^TestREST(Delete|VulnerabilityList|BatchList)Semantics$' -count=1` 通过。
diff --git a/internal/database/vulnerability.go b/internal/database/vulnerability.go
index b0a33da2..8c7e827f 100644
--- a/internal/database/vulnerability.go
+++ b/internal/database/vulnerability.go
@@ -258,7 +258,7 @@ func (db *DB) ListVulnerabilitiesForAccess(limit, offset int, filter Vulnerabili
 	}
 	defer rows.Close()
 
-	var vulnerabilities []*Vulnerability
+	vulnerabilities := make([]*Vulnerability, 0)
 	for rows.Next() {
 		var vuln Vulnerability
 		err := rows.Scan(
diff --git a/internal/handler/batch_task_manager.go b/internal/handler/batch_task_manager.go
index 7343dec7..e9b17007 100644
--- a/internal/handler/batch_task_manager.go
+++ b/internal/handler/batch_task_manager.go
@@ -442,7 +442,7 @@ func (m *BatchTaskManager) ListQueues(limit, offset int, status, keyword string)
 }
 
 func (m *BatchTaskManager) ListQueuesForAccess(limit, offset int, status, keyword, userID, scope string) ([]*BatchTaskQueue, int, error) {
-	var queues []*BatchTaskQueue
+	queues := make([]*BatchTaskQueue, 0)
 	var total int
 
 	// 如果数据库可用，从数据库查询
diff --git a/internal/handler/c2.go b/internal/handler/c2.go
index c20f3343..af228eaf 100644
--- a/internal/handler/c2.go
+++ b/internal/handler/c2.go
@@ -1092,7 +1092,12 @@ func (h *C2Handler) UpdateProfile(c *gin.Context) {
 func (h *C2Handler) DeleteProfile(c *gin.Context) {
 	id := c.Param("id")
 	if err := h.mgr().DB().DeleteC2Profile(id); err != nil {
-		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		if errors.Is(err, sql.ErrNoRows) {
+			c.JSON(http.StatusNotFound, gin.H{"error": "profile not found"})
+			return
+		}
+		h.logger.Error("删除 C2 Profile 失败", zap.Error(err), zap.String("id", id))
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to delete profile"})
 		return
 	}
 	c.JSON(http.StatusOK, gin.H{"deleted": true})
diff --git a/internal/handler/rest_semantics_test.go b/internal/handler/rest_semantics_test.go
new file mode 100644
index 00000000..a92801ac
--- /dev/null
+++ b/internal/handler/rest_semantics_test.go
@@ -0,0 +1,153 @@
+package handler
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/http/httptest"
+	"path/filepath"
+	"testing"
+	"time"
+
+	"cyberstrike-ai/internal/c2"
+	"cyberstrike-ai/internal/database"
+	"github.com/gin-gonic/gin"
+	"go.uber.org/zap"
+)
+
+func newRESTSemanticsDB(t *testing.T) *database.DB {
+	t.Helper()
+	db, err := database.NewDB(filepath.Join(t.TempDir(), "rest.db"), zap.NewNop())
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Cleanup(func() { _ = db.Close() })
+	return db
+}
+
+func restSemanticsRequest(r http.Handler, method, path string) *httptest.ResponseRecorder {
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, httptest.NewRequest(method, path, nil))
+	return w
+}
+
+func TestRESTDeleteSemantics(t *testing.T) {
+	for _, module := range []string{"profile", "webshell"} {
+		t.Run(module, func(t *testing.T) {
+			db := newRESTSemanticsDB(t)
+			r := gin.New()
+			table, missing, failure, success := "c2_profiles", "profile not found", "failed to delete profile", `{"deleted":true}`
+			if module == "profile" {
+				h := NewC2Handler(c2.NewManager(db, zap.NewNop(), t.TempDir()), zap.NewNop())
+				r.DELETE("/objects/:id", h.DeleteProfile)
+				if err := db.CreateC2Profile(&database.C2Profile{ID: "existing", Name: "test", CreatedAt: time.Now()}); err != nil {
+					t.Fatal(err)
+				}
+			} else {
+				table, missing, failure, success = "webshell_connections", "connection not found", "failed to delete connection", `{"ok":true}`
+				h := NewWebShellHandler(zap.NewNop(), db)
+				r.DELETE("/objects/:id", h.DeleteConnection)
+				if err := db.CreateWebshellConnection(&database.WebShellConnection{ID: "existing", URL: "https://example.invalid", CreatedAt: time.Now()}); err != nil {
+					t.Fatal(err)
+				}
+			}
+			for _, tc := range []struct {
+				id   string
+				code int
+				body string
+			}{
+				{"missing", http.StatusNotFound, `{"error":"` + missing + `"}`},
+				{"existing", http.StatusOK, success},
+				{"existing", http.StatusNotFound, `{"error":"` + missing + `"}`},
+			} {
+				w := restSemanticsRequest(r, http.MethodDelete, "/objects/"+tc.id)
+				if w.Code != tc.code || w.Body.String() != tc.body {
+					t.Fatalf("delete %s: %d %s, want %d %s", tc.id, w.Code, w.Body.String(), tc.code, tc.body)
+				}
+			}
+			// Break only the temporary database: genuine SQL failures must remain 500,
+			// with no table name or driver error in the HTTP response.
+			if _, err := db.Exec("DROP TABLE " + table); err != nil {
+				t.Fatal(err)
+			}
+			w := restSemanticsRequest(r, http.MethodDelete, "/objects/missing")
+			if w.Code != http.StatusInternalServerError || w.Body.String() != `{"error":"`+failure+`"}` {
+				t.Fatalf("SQL failure: %d %s", w.Code, w.Body.String())
+			}
+		})
+	}
+}
+
+func assertRESTList(t *testing.T, r http.Handler, path, field string, count int) {
+	t.Helper()
+	w := restSemanticsRequest(r, http.MethodGet, path)
+	if w.Code != http.StatusOK {
+		t.Fatalf("%s: %d %s", path, w.Code, w.Body.String())
+	}
+	var body map[string]json.RawMessage
+	if err := json.Unmarshal(w.Body.Bytes(), &body); err != nil {
+		t.Fatal(err)
+	}
+	var items []json.RawMessage
+	if err := json.Unmarshal(body[field], &items); err != nil || items == nil || len(items) != count {
+		t.Fatalf("%s: %s=%s, want array of length %d (err=%v)", path, field, body[field], count, err)
+	}
+	var total int
+	if err := json.Unmarshal(body["total"], &total); err != nil || total != count {
+		t.Fatalf("%s: total=%s, want %d", path, body["total"], count)
+	}
+}
+
+func TestRESTVulnerabilityListSemantics(t *testing.T) {
+	db := newRESTSemanticsDB(t)
+	h := NewVulnerabilityHandler(db, zap.NewNop())
+	r := gin.New()
+	r.GET("/api/vulnerabilities", h.ListVulnerabilities)
+	assertRESTList(t, r, "/api/vulnerabilities", "vulnerabilities", 0)
+	if _, err := db.CreateVulnerability(&database.Vulnerability{Title: "test finding", Status: "open", Severity: "low"}); err != nil {
+		t.Fatal(err)
+	}
+	assertRESTList(t, r, "/api/vulnerabilities?status=__none__", "vulnerabilities", 0)
+	assertRESTList(t, r, "/api/vulnerabilities?status=open", "vulnerabilities", 1)
+	if _, err := db.Exec("DROP TABLE vulnerabilities"); err != nil {
+		t.Fatal(err)
+	}
+	w := restSemanticsRequest(r, http.MethodGet, "/api/vulnerabilities")
+	if w.Code != http.StatusInternalServerError {
+		t.Fatalf("SQL failure became empty success: %d %s", w.Code, w.Body.String())
+	}
+}
+
+func TestRESTBatchListSemantics(t *testing.T) {
+	for _, withDB := range []bool{true, false} {
+		name := "memory"
+		if withDB {
+			name = "database"
+		}
+		t.Run(name, func(t *testing.T) {
+			m := NewBatchTaskManager(zap.NewNop())
+			var db *database.DB
+			if withDB {
+				db = newRESTSemanticsDB(t)
+				m.SetDB(db)
+			}
+			h := &AgentHandler{batchTaskManager: m, logger: zap.NewNop()}
+			r := gin.New()
+			r.GET("/api/batch-tasks", h.ListBatchQueues)
+			assertRESTList(t, r, "/api/batch-tasks", "queues", 0)
+			if _, err := m.CreateBatchQueue("test queue", "", "eino_single", "manual", "", "", nil, 1, []string{"test"}); err != nil {
+				t.Fatal(err)
+			}
+			assertRESTList(t, r, "/api/batch-tasks?status=__none__", "queues", 0)
+			assertRESTList(t, r, "/api/batch-tasks", "queues", 1)
+			if withDB {
+				if _, err := db.Exec("DROP TABLE batch_task_queues"); err != nil {
+					t.Fatal(err)
+				}
+				w := restSemanticsRequest(r, http.MethodGet, "/api/batch-tasks")
+				if w.Code != http.StatusInternalServerError {
+					t.Fatalf("SQL failure became empty success: %d %s", w.Code, w.Body.String())
+				}
+			}
+		})
+	}
+}
diff --git a/internal/handler/webshell.go b/internal/handler/webshell.go
index 61711174..c23e7404 100644
--- a/internal/handler/webshell.go
+++ b/internal/handler/webshell.go
@@ -6,6 +6,7 @@ import (
 	"database/sql"
 	"encoding/base64"
 	"encoding/json"
+	"errors"
 	"io"
 	"net/http"
 	"net/url"
@@ -552,11 +553,11 @@ func (h *WebShellHandler) DeleteConnection(c *gin.Context) {
 		return
 	}
 	if err := h.db.DeleteWebshellConnection(id); err != nil {
-		if err == sql.ErrNoRows {
+		if errors.Is(err, sql.ErrNoRows) {
 			c.JSON(http.StatusNotFound, gin.H{"error": "connection not found"})
 			return
 		}
-		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to delete connection"})
 		return
 	}
 	if h.audit != nil {