diff --git a/openspec/specs/backend-code-quality/spec.md b/openspec/specs/backend-code-quality/spec.md
index 187e6fb..a1d73ef 100644
--- a/openspec/specs/backend-code-quality/spec.md
+++ b/openspec/specs/backend-code-quality/spec.md
@@ -94,6 +94,40 @@
 - **WHEN** 输入包含不同 intervalMs 值的多个 target
 - **THEN** `groupBy(targets, t => t.intervalMs)` SHALL 返回 key 为 intervalMs 值的分组对象，值为对应 target 数组
 
+### Requirement: 使用原生 API 进行数组类型判断
+系统 SHALL 使用原生 `Array.isArray()` 替代 `es-toolkit/compat` 的 `isArray`，用于 checker 模块中所有数组类型判断场景。
+
+#### Scenario: 数组值判定为数组
+- **WHEN** 校验值为数组（如 `[1, 2, 3]`）
+- **THEN** `Array.isArray(value)` SHALL 返回 true
+
+#### Scenario: 非数组值判定为非数组
+- **WHEN** 校验值为对象 `{}`、字符串 `"abc"`、数字 `123`、null 等
+- **THEN** `Array.isArray(value)` SHALL 返回 false
+
+### Requirement: 使用原生 API 进行对象类型判断
+系统 SHALL 使用原生 `typeof x === 'object' && x !== null` 替代 `es-toolkit/compat` 的 `isObject`，用于 checker 模块中需要判断值为对象类型（排除 null）的场景。
+
+#### Scenario: 普通对象判定为对象
+- **WHEN** 值为普通对象 `{ key: "val" }`
+- **THEN** `typeof value === 'object' && value !== null` SHALL 返回 true
+
+#### Scenario: 数组判定为对象
+- **WHEN** 值为数组 `[1, 2, 3]`
+- **THEN** `typeof value === 'object' && value !== null` SHALL 返回 true
+
+#### Scenario: Headers 实例判定为对象
+- **WHEN** 值为 `Headers` 实例
+- **THEN** `typeof value === 'object' && value !== null` SHALL 返回 true
+
+#### Scenario: null 判定为非对象
+- **WHEN** 值为 null
+- **THEN** `typeof value === 'object' && value !== null` SHALL 返回 false
+
+#### Scenario: 原始值判定为非对象
+- **WHEN** 值为字符串、数字、布尔值、undefined
+- **THEN** `typeof value === 'object' && value !== null` SHALL 返回 false
+
 ### Requirement: 使用 Bun 内置 API 进行 Headers 转换
 系统 SHALL 使用 `Object.fromEntries(headers)` 标准 Web API 替代手写的 `headersToRecord` 函数，用于将 Fetch API 的 Headers 对象转换为键值对。
 
diff --git a/src/server/checker/config-loader.ts b/src/server/checker/config-loader.ts
index 2a99c1c..1c6afec 100644
--- a/src/server/checker/config-loader.ts
+++ b/src/server/checker/config-loader.ts
@@ -1,5 +1,4 @@
 import { isNumber, isPlainObject, isString } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 import { dirname, resolve } from "node:path";
 
 import type { ConfigValidationIssue } from "./schema/issues";
@@ -151,7 +150,7 @@ function resolveTarget(
 
 function validateConfig(config: RawProbeConfig): ConfigValidationIssue[] {
   const issues: ConfigValidationIssue[] = [];
-  if (!isArray(config.targets) || config.targets.length === 0) {
+  if (!Array.isArray(config.targets) || config.targets.length === 0) {
     issues.push(issue("required", "targets", "配置文件必须包含至少一个 target"));
     return issues;
   }
diff --git a/src/server/checker/expect/content.ts b/src/server/checker/expect/content.ts
index 083e877..237f81b 100644
--- a/src/server/checker/expect/content.ts
+++ b/src/server/checker/expect/content.ts
@@ -1,6 +1,5 @@
 import { DOMParser } from "@xmldom/xmldom";
 import * as cheerio from "cheerio";
-import { isArray } from "es-toolkit/compat";
 import * as xpath from "xpath";
 
 import type { CheckFailure } from "../types";
@@ -165,7 +164,7 @@ function parseJsonSource(source: unknown): ParsedJsonResult {
 }
 
 function xpathValue(result: unknown): unknown {
-  if (!isArray(result)) return result;
+  if (!Array.isArray(result)) return result;
   if (result.length === 0) return undefined;
 
   const node = (result as unknown[])[0]!;
diff --git a/src/server/checker/expect/failure.ts b/src/server/checker/expect/failure.ts
index 95b542a..3723633 100644
--- a/src/server/checker/expect/failure.ts
+++ b/src/server/checker/expect/failure.ts
@@ -1,5 +1,4 @@
 import { isString } from "es-toolkit";
-import { isObject } from "es-toolkit/compat";
 
 import type { CheckFailure } from "../types";
 
@@ -32,7 +31,7 @@ export function mismatchFailure(
 export function truncateActual(value: unknown, maxLen = 200): unknown {
   if (value === undefined || value === null) return value;
 
-  const str = isString(value) ? value : isObject(value) ? JSON.stringify(value) : undefined;
+  const str = isString(value) ? value : typeof value === "object" && value !== null ? JSON.stringify(value) : undefined;
   if (str === undefined) return value;
   if (str.length <= maxLen) return value;
   return `${str.slice(0, maxLen)}…(共 ${str.length} 字符)`;
diff --git a/src/server/checker/expect/matcher.ts b/src/server/checker/expect/matcher.ts
index 89180c2..da783b3 100644
--- a/src/server/checker/expect/matcher.ts
+++ b/src/server/checker/expect/matcher.ts
@@ -1,5 +1,4 @@
 import { isEmptyObject, isEqual, isNil, isPlainObject } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 
 import type { CheckFailure, JsonValue } from "../types";
 import type { ExpectResult, ValueMatcher } from "./types";
@@ -98,7 +97,7 @@ export function evaluateJsonPath(json: unknown, path: string): unknown {
       if (current === null || current === undefined) return undefined;
       current = (current as Record<string, unknown>)[bracketMatch[1]!];
       const idx = parseInt(bracketMatch[2]!, 10);
-      if (!isArray(current) || idx >= current.length) return undefined;
+      if (!Array.isArray(current) || idx >= current.length) return undefined;
       current = current[idx];
     } else {
       if (current === null || current === undefined) return undefined;
@@ -123,7 +122,7 @@ function compareNumber(
 }
 
 function isEmptyValue(value: unknown): boolean {
-  return isNil(value) || value === "" || (isArray(value) && value.length === 0) || isEmptyObject(value);
+  return isNil(value) || value === "" || (Array.isArray(value) && value.length === 0) || isEmptyObject(value);
 }
 
 function stringValue(actual: unknown, options: { stringifyNonString?: boolean }): string {
diff --git a/src/server/checker/expect/validate-matcher.ts b/src/server/checker/expect/validate-matcher.ts
index 73b82fe..2b56a5e 100644
--- a/src/server/checker/expect/validate-matcher.ts
+++ b/src/server/checker/expect/validate-matcher.ts
@@ -1,6 +1,5 @@
 import { DOMParser } from "@xmldom/xmldom";
 import { isBoolean, isNumber, isPlainObject, isString } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 import * as xpath from "xpath";
 
 import type { ConfigValidationIssue } from "../schema/issues";
@@ -19,7 +18,7 @@ export function isJsonValue(value: unknown): value is JsonValue {
   if (value === null) return true;
   if (isString(value) || isBoolean(value)) return true;
   if (isNumber(value)) return Number.isFinite(value);
-  if (isArray(value)) return value.every(isJsonValue);
+  if (Array.isArray(value)) return value.every(isJsonValue);
   if (isPlainObject(value)) return Object.values(value).every(isJsonValue);
   return false;
 }
@@ -29,7 +28,7 @@ export function isPlainRecord(value: unknown): value is Record<string, unknown>
 }
 
 export function validateContentRules(rules: unknown, path: string, targetName?: string): ConfigValidationIssue[] {
-  if (!isArray(rules)) return [issue("invalid-type", path, "必须为数组", targetName)];
+  if (!Array.isArray(rules)) return [issue("invalid-type", path, "必须为数组", targetName)];
   return rules.flatMap((rule, index) => validateContentRule(rule, `${path}[${index}]`, targetName));
 }
 
diff --git a/src/server/checker/runner/db/execute.ts b/src/server/checker/runner/db/execute.ts
index b5fd958..35a1e86 100644
--- a/src/server/checker/runner/db/execute.ts
+++ b/src/server/checker/runner/db/execute.ts
@@ -1,6 +1,5 @@
 import { SQL } from "bun";
 import { isError } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 
 import type { CheckResult, RawTargetConfig } from "../../types";
 import type { CheckerContext, CheckerDefinition, CheckerValidationInput, ResolveContext } from "../types";
@@ -126,7 +125,7 @@ export class DbChecker implements CheckerDefinition<ResolvedDbTarget> {
           durationMs,
           failure: durationResult.failure,
           matched: false,
-          statusDetail: `${isArray(rows) ? rows.length : 0} rows`,
+          statusDetail: `${Array.isArray(rows) ? rows.length : 0} rows`,
           targetId: t.id,
           timestamp,
         };
@@ -134,13 +133,13 @@ export class DbChecker implements CheckerDefinition<ResolvedDbTarget> {
 
       // rowCount 断言
       if (t.expect?.rowCount) {
-        const rowCountResult = checkRowCount(isArray(rows) ? rows.length : 0, t.expect.rowCount);
+        const rowCountResult = checkRowCount(Array.isArray(rows) ? rows.length : 0, t.expect.rowCount);
         if (!rowCountResult.matched) {
           return {
             durationMs,
             failure: rowCountResult.failure,
             matched: false,
-            statusDetail: `${isArray(rows) ? rows.length : 0} rows`,
+            statusDetail: `${Array.isArray(rows) ? rows.length : 0} rows`,
             targetId: t.id,
             timestamp,
           };
@@ -155,7 +154,7 @@ export class DbChecker implements CheckerDefinition<ResolvedDbTarget> {
             durationMs,
             failure: rowsResult.failure,
             matched: false,
-            statusDetail: `${isArray(rows) ? rows.length : 0} rows`,
+            statusDetail: `${Array.isArray(rows) ? rows.length : 0} rows`,
             targetId: t.id,
             timestamp,
           };
@@ -163,7 +162,7 @@ export class DbChecker implements CheckerDefinition<ResolvedDbTarget> {
       }
 
       if (t.expect?.result && t.expect.result.length > 0) {
-        const rowCount = isArray(rows) ? rows.length : 0;
+        const rowCount = Array.isArray(rows) ? rows.length : 0;
         const resultCheck = checkContentRules({ rowCount, rows }, t.expect.result, { path: "result", phase: "result" });
         if (!resultCheck.matched) {
           return {
@@ -181,7 +180,7 @@ export class DbChecker implements CheckerDefinition<ResolvedDbTarget> {
         durationMs,
         failure: null,
         matched: true,
-        statusDetail: `${isArray(rows) ? rows.length : 0} rows`,
+        statusDetail: `${Array.isArray(rows) ? rows.length : 0} rows`,
         targetId: t.id,
         timestamp,
       };
diff --git a/src/server/checker/runner/db/expect.ts b/src/server/checker/runner/db/expect.ts
index 6177a86..7e7707c 100644
--- a/src/server/checker/runner/db/expect.ts
+++ b/src/server/checker/runner/db/expect.ts
@@ -1,5 +1,4 @@
 import { isPlainObject } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 
 import type { ExpectResult, KeyValueExpect, ValueMatcher } from "../../expect/types";
 
@@ -16,7 +15,7 @@ export function checkRowCount(actual: number, matcher: ValueMatcher): ExpectResu
 }
 
 export function checkRows(rows: unknown, rules: KeyValueExpect[]): ExpectResult {
-  if (!isArray(rows)) {
+  if (!Array.isArray(rows)) {
     return {
       failure: mismatchFailure("row", "rows", rules, rows, "查询结果不是数组"),
       matched: false,
diff --git a/src/server/checker/runner/db/validate.ts b/src/server/checker/runner/db/validate.ts
index 2450117..e403b0b 100644
--- a/src/server/checker/runner/db/validate.ts
+++ b/src/server/checker/runner/db/validate.ts
@@ -1,5 +1,4 @@
 import { isPlainObject, isString } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 
 import type { ConfigValidationIssue } from "../../schema/issues";
 import type { CheckerValidationInput } from "../types";
@@ -54,7 +53,7 @@ function validateDbExpect(target: Record<string, unknown>, path: string): Config
   }
 
   if (expect["rows"] !== undefined) {
-    if (!isArray(expect["rows"])) {
+    if (!Array.isArray(expect["rows"])) {
       issues.push(issue("invalid-type", joinPath(expectPath, "rows"), "必须为数组", targetName));
     } else {
       issues.push(...collectRowExpects(expect["rows"], joinPath(expectPath, "rows"), targetName));
diff --git a/src/server/checker/runner/http/execute.ts b/src/server/checker/runner/http/execute.ts
index 1d3083d..c0d1242 100644
--- a/src/server/checker/runner/http/execute.ts
+++ b/src/server/checker/runner/http/execute.ts
@@ -1,5 +1,4 @@
 import { isError } from "es-toolkit";
-import { isObject } from "es-toolkit/compat";
 
 import type { CheckResult, RawTargetConfig } from "../../types";
 import type { CheckerContext, CheckerDefinition, CheckerValidationInput, ResolveContext } from "../types";
@@ -161,7 +160,10 @@ function buildRedirectInit(init: RequestInit, statusCode: number, fromUrl: strin
   const method = init.method?.toUpperCase();
 
   if (statusCode === 303 || ((statusCode === 301 || statusCode === 302) && method === "POST")) {
-    const headers = isObject(init.headers) ? { ...(init.headers as Record<string, string>) } : undefined;
+    const headers =
+      typeof init.headers === "object" && init.headers !== null
+        ? { ...(init.headers as Record<string, string>) }
+        : undefined;
     if (headers) {
       for (const key of Object.keys(headers)) {
         const lower = key.toLowerCase();
@@ -176,7 +178,7 @@ function buildRedirectInit(init: RequestInit, statusCode: number, fromUrl: strin
   try {
     const fromOrigin = new URL(fromUrl).origin;
     const toOrigin = new URL(toUrl).origin;
-    if (fromOrigin !== toOrigin && isObject(newInit.headers)) {
+    if (fromOrigin !== toOrigin && typeof newInit.headers === "object" && newInit.headers !== null) {
       const headers = { ...(newInit.headers as Record<string, string>) };
       for (const key of Object.keys(headers)) {
         if (SENSITIVE_HEADERS.has(key.toLowerCase())) {
diff --git a/src/server/checker/runner/http/validate.ts b/src/server/checker/runner/http/validate.ts
index b2c5628..c8cf80f 100644
--- a/src/server/checker/runner/http/validate.ts
+++ b/src/server/checker/runner/http/validate.ts
@@ -1,5 +1,4 @@
 import { isNumber, isString } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 
 import type { ConfigValidationIssue } from "../../schema/issues";
 import type { CheckerValidationInput } from "../types";
@@ -76,7 +75,7 @@ function validateHttpExpect(target: Record<string, unknown>, path: string): Conf
     issues.push(...validateContentRules(expect["body"], joinPath(expectPath, "body"), targetName));
   }
 
-  if (isArray(expect["status"])) {
+  if (Array.isArray(expect["status"])) {
     issues.push(...validateStatusValues(expect["status"], joinPath(expectPath, "status"), targetName));
   }
 
diff --git a/src/server/checker/runner/llm/validate.ts b/src/server/checker/runner/llm/validate.ts
index 9a663c9..b4b92db 100644
--- a/src/server/checker/runner/llm/validate.ts
+++ b/src/server/checker/runner/llm/validate.ts
@@ -1,5 +1,4 @@
 import { isBoolean, isNumber, isString } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 
 import type { ConfigValidationIssue } from "../../schema/issues";
 import type { CheckerValidationInput } from "../types";
@@ -73,7 +72,7 @@ function validateLlmExpect(
   const issues: ConfigValidationIssue[] = [];
   const expectPath = joinPath(path, "expect");
 
-  if (isArray(expect["status"])) {
+  if (Array.isArray(expect["status"])) {
     issues.push(...validateStatusValues(expect["status"], joinPath(expectPath, "status"), targetName));
   }
   if (expect["headers"] !== undefined) {
@@ -144,7 +143,7 @@ function validateLlmOptions(options: unknown, path: string, targetName?: string)
   }
 
   if (options["stopSequences"] !== undefined) {
-    if (!isArray(options["stopSequences"])) {
+    if (!Array.isArray(options["stopSequences"])) {
       issues.push(issue("invalid-type", joinPath(path, "stopSequences"), "必须为字符串数组", targetName));
     } else {
       for (let i = 0; i < options["stopSequences"].length; i++) {
diff --git a/src/server/checker/schema/validate.ts b/src/server/checker/schema/validate.ts
index ac5a4bc..33fc18c 100644
--- a/src/server/checker/schema/validate.ts
+++ b/src/server/checker/schema/validate.ts
@@ -2,7 +2,6 @@ import type { ErrorObject } from "ajv";
 
 import Ajv from "ajv";
 import { isPlainObject, isString } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 
 import type { CheckerRegistry } from "../runner/registry";
 import type { ConfigValidationIssue } from "./issues";
@@ -34,7 +33,7 @@ export function validateProbeConfigContract(
   if (isPlainObject(config)) {
     const configRecord = config as Record<string, unknown>;
     const targetsValue: unknown = configRecord["targets"];
-    if (!isArray(targetsValue))
+    if (!Array.isArray(targetsValue))
       return issues.length > 0 ? { config: null, issues } : { config: config as RawProbeConfig, issues: [] };
     const targets = targetsValue;
     for (let i = 0; i < targets.length; i++) {
@@ -142,7 +141,7 @@ function targetDisplayNameFromPath(root: unknown, path: string): string | undefi
   if (!match || !isPlainObject(root)) return undefined;
   const rootRecord = root as Record<string, unknown>;
   const targetsValue: unknown = rootRecord["targets"];
-  if (!isArray(targetsValue)) return undefined;
+  if (!Array.isArray(targetsValue)) return undefined;
   const target: unknown = targetsValue[Number(match[1])];
   if (!isPlainObject(target)) return undefined;
   const targetRecord = target as Record<string, unknown>;
diff --git a/src/server/checker/variables.ts b/src/server/checker/variables.ts
index c369c33..0c2dd8d 100644
--- a/src/server/checker/variables.ts
+++ b/src/server/checker/variables.ts
@@ -1,5 +1,4 @@
 import { isBoolean, isNumber, isPlainObject, isString } from "es-toolkit";
-import { isArray } from "es-toolkit/compat";
 
 import type { ConfigValidationIssue } from "./schema/issues";
 import type { VariableValue } from "./types";
@@ -66,7 +65,7 @@ export function resolveVariables(config: unknown): { config: unknown; issues: Co
   }
   const configRecord = config as Record<string, unknown>;
   const rawTargets: unknown = configRecord["targets"];
-  if (!isArray(rawTargets)) {
+  if (!Array.isArray(rawTargets)) {
     return { config, issues };
   }
 
@@ -76,7 +75,7 @@ export function resolveVariables(config: unknown): { config: unknown; issues: Co
 
 function describeInvalidVariableValue(value: unknown): string {
   if (value === null) return "null";
-  if (isArray(value)) return "array";
+  if (Array.isArray(value)) return "array";
   return typeof value;
 }
 
@@ -156,7 +155,7 @@ function resolveValue(
   if (isString(value)) {
     return replaceStringValue(value, variables, issues, { ...context, path });
   }
-  if (isArray(value)) {
+  if (Array.isArray(value)) {
     return value.map((item, index) =>
       resolveValue(item, `${path}[${index}]`, variables, issues, { ...context, path: `${path}[${index}]` }),
     );