diff --git a/apps/api/src/judge/ast.ts b/apps/api/src/judge/ast.ts
index 2f55fff..f245ea7 100644
--- a/apps/api/src/judge/ast.ts
+++ b/apps/api/src/judge/ast.ts
@@ -1,4 +1,10 @@
-import type { AstRule } from "@oj2/contract"
+import {
+  astRuleSchema,
+  AST_NODE_TARGET_LABELS,
+  type AstRequirement,
+  type AstRequirements,
+  type AstRule,
+} from "@oj2/contract"
 import { Language, Parser, type Node } from "web-tree-sitter"
 // 语法 wasm 内嵌成资源。原来是 `Bun.resolveSync(pkg + "/" + name, import.meta.dir)`，
 // 编译成单二进制后 import.meta.dir 是 /$bunfs/root，解析不到 node_modules。见 vendor/jieba.ts
@@ -90,16 +96,87 @@ function hasNode(root: Node, type: string): boolean {
 }
 
 function targetName(rule: AstRule) {
-  return rule.label || rule.target || "指定语法"
+  const target = rule.target ?? ""
+  return rule.label || AST_NODE_TARGET_LABELS[target] || target || "指定语法"
 }
 
-function rangeDescription(subject: string, rule: AstRule) {
+function countPhrase(verb: string, rule: AstRule) {
+  if (rule.exact !== undefined) return `${verb} ${rule.exact} 次`
+  if (rule.min !== undefined && rule.max !== undefined)
+    return `${verb} ${rule.min}～${rule.max} 次`
+  if (rule.min !== undefined) return `至少${verb} ${rule.min} 次`
+  if (rule.max !== undefined) return `至多${verb} ${rule.max} 次`
+  return ""
+}
+
+/**
+ * 一条规则的中文描述。判题结果（statistic_info.ast_results）和题目页的「要求」
+ * 用的是同一份 —— 原来前端 ProblemContent.vue 里另有一份几乎一样的实现，
+ * 只有 min/max 同时给出时的措辞不一样（生产库里没有这种规则）。
+ */
+export function describeAstRule(rule: AstRule): string {
   if (rule.message) return rule.message
-  if (rule.exact !== undefined) return `${subject} 出现 ${rule.exact} 次`
-  const parts: string[] = []
-  if (rule.min !== undefined) parts.push(`至少 ${rule.min} 次`)
-  if (rule.max !== undefined) parts.push(`至多 ${rule.max} 次`)
-  return `${subject} ${parts.join("、")}`.trim()
+  const name = targetName(rule)
+  const target = rule.target ?? ""
+  switch (rule.engine) {
+    case "must_exist_node":
+      return `必须使用 ${name}`
+    case "must_not_exist_node":
+      return `不能使用 ${name}`
+    case "count_node":
+      return `${name} ${countPhrase("出现", rule)}`.trim()
+    case "must_call_function":
+      return `必须调用 ${target}()`
+    case "must_not_call_function":
+      return `不能调用 ${target}()`
+    case "count_function_call":
+      return `${target}() ${countPhrase("调用", rule)}`.trim()
+    case "must_call_method":
+      return `必须调用 .${target}()`
+    case "must_not_call_method":
+      return `不能调用 .${target}()`
+    case "must_use_operator":
+      return `必须使用 ${target} 运算符`
+    case "must_have_nesting": {
+      const outer = rule.outer ?? ""
+      const inner = rule.inner ?? ""
+      return outer === inner
+        ? `必须使用 ${outer} 嵌套`
+        : `必须在 ${outer} 中嵌套使用 ${inner}`
+    }
+  }
+}
+
+/** 标签配色用的粗分类，见契约 astRequirementSchema */
+function requirementKind(engine: AstRule["engine"]): AstRequirement["kind"] {
+  if (engine.startsWith("must_not")) return "forbid"
+  if (engine.startsWith("count")) return "count"
+  return "require"
+}
+
+/**
+ * 把规则原文投影成下发给学生的「代码要求」。规则里的 engine / target 不出现在
+ * 响应里 —— 阶段 3 泄露评审收掉 ast_rules 时要的就是这个，见契约的注释。
+ */
+export function astRequirements(value: unknown): AstRequirements | null {
+  const grouped = value && typeof value === "object" && !Array.isArray(value)
+    ? (value as Record<string, unknown>)
+    : null
+  if (!grouped) return null
+  const out: AstRequirements = {}
+  for (const [language, rules] of Object.entries(grouped)) {
+    if (!Array.isArray(rules)) continue
+    const items = rules.flatMap((rule) => {
+      const parsed = astRuleSchema.safeParse(rule)
+      if (!parsed.success) return []
+      return [{
+        description: describeAstRule(parsed.data),
+        kind: requirementKind(parsed.data.engine),
+      }]
+    })
+    if (items.length > 0) out[language] = items
+  }
+  return Object.keys(out).length > 0 ? out : null
 }
 
 function rangePassed(count: number, rule: AstRule) {
@@ -140,51 +217,51 @@ function evaluateRule(
   switch (rule.engine) {
     case "must_exist_node":
       return {
-        description: rule.message || `必须使用 ${targetName(rule)}`,
+        description: describeAstRule(rule),
         passed: hasNode(root, nodeType),
       }
     case "must_not_exist_node":
       return {
-        description: rule.message || `不能使用 ${targetName(rule)}`,
+        description: describeAstRule(rule),
         passed: !hasNode(root, nodeType),
       }
     case "count_node": {
       const count = collectNodes(root, nodeType).length
       return {
-        description: rangeDescription(targetName(rule), rule),
+        description: describeAstRule(rule),
         passed: rangePassed(count, rule),
       }
     }
     case "must_call_function":
       return {
-        description: rule.message || `必须调用 ${target}()`,
+        description: describeAstRule(rule),
         passed: functionCalls(root, target, language).length > 0,
       }
     case "must_not_call_function":
       return {
-        description: rule.message || `不能调用 ${target}()`,
+        description: describeAstRule(rule),
         passed: functionCalls(root, target, language).length === 0,
       }
     case "count_function_call": {
       const count = functionCalls(root, target, language).length
       return {
-        description: rangeDescription(`${target}()`, rule),
+        description: describeAstRule(rule),
         passed: rangePassed(count, rule),
       }
     }
     case "must_call_method":
       return {
-        description: rule.message || `必须调用 .${target}()`,
+        description: describeAstRule(rule),
         passed: methodCalls(root, target, language).length > 0,
       }
     case "must_not_call_method":
       return {
-        description: rule.message || `不能调用 .${target}()`,
+        description: describeAstRule(rule),
         passed: methodCalls(root, target, language).length === 0,
       }
     case "must_use_operator":
       return {
-        description: rule.message || `必须使用 ${target} 运算符`,
+        description: describeAstRule(rule),
         passed: hasNode(root, nodeType),
       }
     case "must_have_nesting": {
@@ -195,14 +272,7 @@ function evaluateRule(
       const passed = collectNodes(root, outerType).some((node) =>
         node.children.some((child) => hasNode(child, innerType)),
       )
-      return {
-        description:
-          rule.message ||
-          (outer === inner
-            ? `必须使用 ${outer} 嵌套`
-            : `必须在 ${outer} 中嵌套使用 ${inner}`),
-        passed,
-      }
+      return { description: describeAstRule(rule), passed }
     }
     default:
       return null
diff --git a/apps/api/src/routes/contest.ts b/apps/api/src/routes/contest.ts
index 9b24edf..b13ba91 100644
--- a/apps/api/src/routes/contest.ts
+++ b/apps/api/src/routes/contest.ts
@@ -14,6 +14,7 @@ import { Hono } from "hono"
 import { optionalAuth, requireAuth } from "../auth/middleware"
 import { setContestPassword } from "../auth/session"
 import { db, schema } from "../db"
+import { astRequirements } from "../judge/ast"
 import { failure, success } from "../http"
 import {
   canAccessContest,
@@ -180,6 +181,8 @@ contestRoutes.get("/contests/:id/problems/:displayId", optionalAuth, requireCont
     flowchartHint: row.problem.flowchartHint,
     sqlConfig: row.problem.sqlConfig ? objectValue(row.problem.sqlConfig) : null,
     sqlDisplay: row.problem.sqlDisplay ? objectValue(row.problem.sqlDisplay) : null,
+    // 代码要求：只给渲染好的文案，规则原文不下发给学生
+    astRequirements: astRequirements(row.problem.astRules),
   }))
 })
 
diff --git a/apps/api/src/routes/problem.ts b/apps/api/src/routes/problem.ts
index 117352f..0743cf9 100644
--- a/apps/api/src/routes/problem.ts
+++ b/apps/api/src/routes/problem.ts
@@ -25,6 +25,7 @@ import { Hono } from "hono"
 
 import { optionalAuth, type AppEnv } from "../auth/middleware"
 import { db, schema } from "../db"
+import { astRequirements } from "../judge/ast"
 import { failure, success } from "../http"
 import { JudgeStatus } from "../judge/status"
 import { objectValue as toObject, queryInteger, sampleUser } from "./helpers"
@@ -319,6 +320,8 @@ problemRoutes.get("/problems/:displayId", optionalAuth, async (c) => {
 		flowchartHint: row.problem.flowchartHint,
 		sqlConfig: row.problem.sqlConfig ? objectValue(row.problem.sqlConfig) : null,
 		sqlDisplay: row.problem.sqlDisplay ? objectValue(row.problem.sqlDisplay) : null,
+		// 代码要求：只给渲染好的文案，规则原文不下发给学生
+		astRequirements: astRequirements(row.problem.astRules),
 	})
 
 	return success(c, data)
diff --git a/apps/web/src/admin/problem/components/AstRulesEditor.vue b/apps/web/src/admin/problem/components/AstRulesEditor.vue
index caf906b..7268d4e 100644
--- a/apps/web/src/admin/problem/components/AstRulesEditor.vue
+++ b/apps/web/src/admin/problem/components/AstRulesEditor.vue
@@ -1,4 +1,5 @@
 <script setup lang="ts">
+import { AST_NODE_TARGET_LABELS } from "@oj2/contract"
 import type { AstRule, AstRules, LANGUAGE } from "utils/types"
 
 interface Props {
@@ -51,23 +52,11 @@ const ENGINE_OPTIONS: SelectOption[] = [
   },
 ]
 
-const NODE_TARGET_OPTIONS: SelectOption[] = [
-  { label: "for 循环", value: "for_loop" },
-  { label: "while 循环", value: "while_loop" },
-  { label: "if 条件", value: "if_statement" },
-  { label: "else 子句", value: "else_clause" },
-  { label: "函数定义", value: "function_definition" },
-  { label: "return 语句", value: "return" },
-  { label: "break 语句", value: "break" },
-  { label: "continue 语句", value: "continue" },
-  { label: "列表推导式", value: "list_comprehension" },
-  { label: "列表", value: "list_literal" },
-  { label: "字典", value: "dict_literal" },
-  { label: "集合", value: "set_literal" },
-  { label: "f-string", value: "f_string" },
-  { label: "try-except", value: "try_except" },
-  { label: "类定义", value: "class_definition" },
-]
+// 选项从契约的 AST_NODE_TARGET_LABELS 生成 —— 这 15 条原来在这里和
+// ProblemContent.vue 各手抄一份
+const NODE_TARGET_OPTIONS: SelectOption[] = Object.entries(
+  AST_NODE_TARGET_LABELS,
+).map(([value, label]) => ({ label, value }))
 
 const OPERATOR_TARGET_OPTIONS: SelectOption[] = [
   { label: "+", value: "+" },
diff --git a/apps/web/src/oj/problem/components/ProblemContent.vue b/apps/web/src/oj/problem/components/ProblemContent.vue
index f34e14f..3df5476 100644
--- a/apps/web/src/oj/problem/components/ProblemContent.vue
+++ b/apps/web/src/oj/problem/components/ProblemContent.vue
@@ -6,7 +6,7 @@ import { useCodeStore } from "oj/store/code"
 import { useProblemStore } from "oj/store/problem"
 import { createTestSubmission } from "utils/judge"
 import { DIFFICULTY } from "utils/constants"
-import type { AstRule, Problem, ProblemStatus } from "utils/types"
+import type { Problem, ProblemStatus } from "utils/types"
 import Copy from "shared/components/Copy.vue"
 import { useDark } from "@vueuse/core"
 import { MdPreview } from "md-editor-v3"
@@ -97,80 +97,18 @@ const samples = ref<Sample[]>(
   })),
 )
 
-const NODE_TARGET_LABELS: Record<string, string> = {
-  for_loop: "for 循环",
-  while_loop: "while 循环",
-  if_statement: "if 条件",
-  else_clause: "else 子句",
-  function_definition: "函数定义",
-  return: "return 语句",
-  break: "break 语句",
-  continue: "continue 语句",
-  list_comprehension: "列表推导式",
-  list_literal: "列表",
-  dict_literal: "字典",
-  set_literal: "集合",
-  f_string: "f-string",
-  try_except: "try-except",
-  class_definition: "类定义",
-}
+// 文案和配色分类都由后端生成 —— 原来这里有一份 NODE_TARGET_LABELS +
+// ruleDescription + ruleTagType，和判题机那份几乎一模一样，见契约
+// astRequirementSchema。规则原文（engine / target）不下发给学生。
+const KIND_TAG_TYPE = {
+  require: "success",
+  forbid: "error",
+  count: "info",
+} as const
 
-function ruleDescription(rule: AstRule): string {
-  if (rule.message) return rule.message
-  const target = rule.target || ""
-  const targetLabel = rule.label || NODE_TARGET_LABELS[target] || target
-  const countDesc = () => {
-    if (rule.exact !== undefined) return `出现 ${rule.exact} 次`
-    if (rule.min !== undefined && rule.max !== undefined)
-      return `出现 ${rule.min}～${rule.max} 次`
-    if (rule.min !== undefined) return `至少出现 ${rule.min} 次`
-    if (rule.max !== undefined) return `至多出现 ${rule.max} 次`
-    return ""
-  }
-  const callDesc = () => {
-    if (rule.exact !== undefined) return `调用 ${rule.exact} 次`
-    if (rule.min !== undefined && rule.max !== undefined)
-      return `调用 ${rule.min}～${rule.max} 次`
-    if (rule.min !== undefined) return `至少调用 ${rule.min} 次`
-    if (rule.max !== undefined) return `至多调用 ${rule.max} 次`
-    return ""
-  }
-  switch (rule.engine) {
-    case "must_exist_node":
-      return `必须使用 ${targetLabel}`
-    case "must_not_exist_node":
-      return `不能使用 ${targetLabel}`
-    case "count_node":
-      return `${targetLabel} ${countDesc()}`
-    case "must_call_function":
-      return `必须调用 ${target}()`
-    case "must_not_call_function":
-      return `不能调用 ${target}()`
-    case "count_function_call":
-      return `${target}() ${callDesc()}`
-    case "must_call_method":
-      return `必须调用 .${target}()`
-    case "must_not_call_method":
-      return `不能调用 .${target}()`
-    case "must_use_operator":
-      return `必须使用 ${target} 运算符`
-    default:
-      return rule.engine
-  }
-}
-
-function ruleTagType(engine: string): "error" | "success" | "info" {
-  if (engine.startsWith("must_not")) return "error"
-  if (engine.startsWith("must")) return "success"
-  return "info"
-}
-
-const astRulesForDisplay = computed(() => {
-  if (!problem.value?.astRules) return []
-  return Object.entries(problem.value.astRules).filter(
-    ([, rules]) => rules.length > 0,
-  )
-})
+const astRequirements = computed(() =>
+  Object.entries(problem.value?.astRequirements ?? {}),
+)
 
 async function test(sample: Sample, index: number) {
   samples.value = samples.value.map((sample) => {
@@ -360,27 +298,20 @@ function type(status: ProblemStatus) {
     </div>
 
     <!-- 代码要求（AST 规则） -->
-    <div v-if="astRulesForDisplay.length > 0">
+    <div v-if="astRequirements.length > 0">
       <p class="title" :style="style">
         <n-flex align="center">
           <Icon icon="streamline-ultimate-color:check-button"></Icon>
           要求
         </n-flex>
       </p>
-      <div v-for="[lang, rules] in astRulesForDisplay" :key="lang">
-        <p v-if="astRulesForDisplay.length > 1" class="lang-label">
+      <div v-for="[lang, rules] in astRequirements" :key="lang">
+        <p v-if="astRequirements.length > 1" class="lang-label">
           {{ lang }}
         </p>
         <n-list bordered style="margin-bottom: 8px">
           <n-list-item v-for="(rule, i) in rules" :key="i">
-            <n-flex align="center">
-              <n-tag :type="ruleTagType(rule.engine)">
-                {{ ruleDescription(rule) }}
-              </n-tag>
-              <span v-if="rule.message" class="rule-message">{{
-                rule.message
-              }}</span>
-            </n-flex>
+            <n-tag :type="KIND_TAG_TYPE[rule.kind]">{{ rule.description }}</n-tag>
           </n-list-item>
         </n-list>
       </div>
@@ -520,11 +451,6 @@ function type(status: ProblemStatus) {
   margin: 8px 0 4px;
 }
 
-.rule-message {
-  font-size: 13px;
-  opacity: 0.65;
-}
-
 .sqlTableName {
   font-weight: 600;
   margin: 8px 0 4px;
diff --git a/apps/web/src/utils/types.ts b/apps/web/src/utils/types.ts
index be8fd41..2975c97 100644
--- a/apps/web/src/utils/types.ts
+++ b/apps/web/src/utils/types.ts
@@ -116,7 +116,7 @@ export type { ProblemTestCaseScore as Testcase } from "@oj2/contract"
 export type Problem = Omit<ProblemDetail, "languages" | "template"> & {
   languages: LANGUAGE[]
   template: { [key in LANGUAGE]?: string }
-  astRules?: AstRules | null
+  // oj 侧不下发 astRules 原文，只有 astRequirements（契约里就有）
   hasAstRules?: boolean
   visible?: boolean
   answers?: { language: LANGUAGE; code: string }[]
diff --git a/packages/contract/src/admin.ts b/packages/contract/src/admin.ts
index fdac6f3..75a0416 100644
--- a/packages/contract/src/admin.ts
+++ b/packages/contract/src/admin.ts
@@ -4,7 +4,12 @@ import { achievementRaritySchema } from "./achievement"
 import { rankProfileSchema } from "./account"
 import { paginatedSchema, sampleUserSchema } from "./common"
 import { reactionKeySchema } from "./content"
-import { problemDifficultySchema, sqlConfigSchema, sqlDisplaySchema } from "./problem"
+import {
+  astRulesSchema,
+  problemDifficultySchema,
+  sqlConfigSchema,
+  sqlDisplaySchema,
+} from "./problem"
 
 /**
  * 后台侧的契约。与 oj 侧分开放：同一张表在两侧下发的字段集通常不同
@@ -43,9 +48,6 @@ export const createAnnouncementRequestSchema = z.object({
 
 export const updateAnnouncementRequestSchema = createAnnouncementRequestSchema
 
-export type AstRuleEngine = z.infer<typeof astRuleEngineSchema>
-export type AstRule = z.infer<typeof astRuleSchema>
-export type AstRules = z.infer<typeof astRulesSchema>
 export type ProblemSample = z.infer<typeof problemSampleSchema>
 export type ProblemAnswer = z.infer<typeof problemAnswerSchema>
 export type ProblemTestCaseScore = z.infer<typeof problemTestCaseScoreSchema>
@@ -569,49 +571,6 @@ export const problemTestCaseScoreSchema = z.object({
   score: z.coerce.number().int().min(0),
 })
 
-/**
- * AST 代码要求。同一个形状原来在**三个地方**各写了一份，三份都不一样：
- * apps/api/src/judge/ast.ts 的 AstRule（判题机真读的那份，九个字段）、
- * apps/web/src/utils/types.ts 的 AstRules（少了 label / exact / outer / inner）、
- * AstRulesEditor.vue 里的本地 AstRule（少了 outer / inner）。
- * 编辑器写得出 label / exact，题目类型却描述不了它们。现在以这里为准。
- *
- * 除 engine 外全部可选：判题机每条规则只读自己那几个字段
- * （见 ast.ts 的 evaluateRule），缺了就走默认文案。
- */
-export const astRuleEngineSchema = z.enum([
-  "must_exist_node",
-  "must_not_exist_node",
-  "count_node",
-  "must_call_function",
-  "must_not_call_function",
-  "count_function_call",
-  "must_call_method",
-  "must_not_call_method",
-  "must_use_operator",
-  // 判题机实现了，但后台编辑器还没有对应的选项，目前只能手工造数据用上
-  "must_have_nesting",
-])
-
-export const astRuleSchema = z.object({
-  engine: astRuleEngineSchema,
-  /** 检查目标：节点类型 / 函数名 / 方法名 / 运算符，按 engine 而定 */
-  target: z.string().optional(),
-  /** must_have_nesting 专用：外层、内层节点 */
-  outer: z.string().optional(),
-  inner: z.string().optional(),
-  /** 展示用的中文名，缺省回落到 target */
-  label: z.string().optional(),
-  /** 自定义提示。生产库里存的是空串而不是缺键，判题机按 `||` 回落到默认文案 */
-  message: z.string().optional(),
-  /** count_* 引擎的次数约束 */
-  exact: z.number().int().optional(),
-  min: z.number().int().optional(),
-  max: z.number().int().optional(),
-})
-
-/** 按语言分组：`{ Python3: [...], C: [...] }`，键是 languages 里的语言名 */
-export const astRulesSchema = z.record(z.string(), z.array(astRuleSchema))
 
 /** 后台题目详情：包含 oj 侧永不下发的 answers / testCase* / astRules */
 export const adminProblemSchema = z.object({
diff --git a/packages/contract/src/problem.ts b/packages/contract/src/problem.ts
index 7e261de..f095df8 100644
--- a/packages/contract/src/problem.ts
+++ b/packages/contract/src/problem.ts
@@ -55,6 +55,94 @@ export const sqlDisplaySchema = z.object({
   ]),
 })
 
+/**
+ * AST 代码要求。同一个形状原来在**三个地方**各写了一份，三份都不一样：
+ * apps/api/src/judge/ast.ts 的 AstRule（判题机真读的那份，九个字段）、
+ * apps/web/src/utils/types.ts 的 AstRules（少了 label / exact / outer / inner）、
+ * AstRulesEditor.vue 里的本地 AstRule（少了 outer / inner）。
+ * 编辑器写得出 label / exact，题目类型却描述不了它们。现在以这里为准。
+ *
+ * 除 engine 外全部可选：判题机每条规则只读自己那几个字段
+ * （见 ast.ts 的 evaluateRule），缺了就走默认文案。
+ */
+export const astRuleEngineSchema = z.enum([
+  "must_exist_node",
+  "must_not_exist_node",
+  "count_node",
+  "must_call_function",
+  "must_not_call_function",
+  "count_function_call",
+  "must_call_method",
+  "must_not_call_method",
+  "must_use_operator",
+  // 判题机实现了，但后台编辑器还没有对应的选项，目前只能手工造数据用上
+  "must_have_nesting",
+])
+
+export const astRuleSchema = z.object({
+  engine: astRuleEngineSchema,
+  /** 检查目标：节点类型 / 函数名 / 方法名 / 运算符，按 engine 而定 */
+  target: z.string().optional(),
+  /** must_have_nesting 专用：外层、内层节点 */
+  outer: z.string().optional(),
+  inner: z.string().optional(),
+  /** 展示用的中文名，缺省回落到 target */
+  label: z.string().optional(),
+  /** 自定义提示。生产库里存的是空串而不是缺键，判题机按 `||` 回落到默认文案 */
+  message: z.string().optional(),
+  /** count_* 引擎的次数约束 */
+  exact: z.number().int().optional(),
+  min: z.number().int().optional(),
+  max: z.number().int().optional(),
+})
+
+/** 按语言分组：`{ Python3: [...], C: [...] }`，键是 languages 里的语言名 */
+export const astRulesSchema = z.record(z.string(), z.array(astRuleSchema))
+
+/**
+ * 节点类型的中文名。后台编辑器的下拉选项、后端生成要求文案都要用它 ——
+ * 原来在 AstRulesEditor.vue（下拉 options）和 ProblemContent.vue
+ * （NODE_TARGET_LABELS）各存了一份同样的 15 条。
+ */
+export const AST_NODE_TARGET_LABELS: Record<string, string> = {
+  for_loop: "for 循环",
+  while_loop: "while 循环",
+  if_statement: "if 条件",
+  else_clause: "else 子句",
+  function_definition: "函数定义",
+  return: "return 语句",
+  break: "break 语句",
+  continue: "continue 语句",
+  list_comprehension: "列表推导式",
+  list_literal: "列表",
+  dict_literal: "字典",
+  set_literal: "集合",
+  f_string: "f-string",
+  try_except: "try-except",
+  class_definition: "类定义",
+}
+
+/**
+ * 下发给**学生**的代码要求。只有渲染要用的两个字段 —— 文案由后端生成，
+ * engine / target 这些内部字段不出现在响应里。
+ *
+ * 旧后端的 ProblemSerializer 没排掉 ast_rules，学生拿到的是规则原文；阶段 3
+ * 泄露评审刻意收掉了它，同时写明「前端要读具体内容的话得补个专门的字段」——
+ * 就是这个。收紧保留，展示恢复。
+ */
+export const astRequirementSchema = z.object({
+  /** 已经渲染好的中文文案，例如「if 条件 出现 2 次」 */
+  description: z.string(),
+  /** 标签配色：必须做 / 不能做 / 次数约束 */
+  kind: z.enum(["require", "forbid", "count"]),
+})
+
+/** 按语言分组，与 astRulesSchema 同一套键 */
+export const astRequirementsSchema = z.record(
+  z.string(),
+  z.array(astRequirementSchema),
+)
+
 export const problemDetailSchema = z.object({
   id: z.number().int(),
   _id: z.string(),
@@ -98,6 +186,8 @@ export const problemDetailSchema = z.object({
   flowchartHint: z.string().nullable(),
   sqlConfig: sqlConfigSchema.nullable(),
   sqlDisplay: sqlDisplaySchema.nullable(),
+  // 代码要求（AST 规则的展示投影）。规则原文不下发给学生，见 astRequirementSchema
+  astRequirements: astRequirementsSchema.nullable(),
 })
 
 export type ProblemDetail = z.infer<typeof problemDetailSchema>
@@ -138,6 +228,11 @@ export const yearlyAcSchema = z.object({
   acRate: z.number(),
 })
 
+export type AstRuleEngine = z.infer<typeof astRuleEngineSchema>
+export type AstRule = z.infer<typeof astRuleSchema>
+export type AstRules = z.infer<typeof astRulesSchema>
+export type AstRequirement = z.infer<typeof astRequirementSchema>
+export type AstRequirements = z.infer<typeof astRequirementsSchema>
 export type ProblemDifficulty = z.infer<typeof problemDifficultySchema>
 export type ProblemListItem = z.infer<typeof problemListItemSchema>
 export type ProblemList = z.infer<typeof problemListSchema>