diff --git a/backend/app/api/action_plans.py b/backend/app/api/action_plans.py
index 8123edf0..694995f6 100644
--- a/backend/app/api/action_plans.py
+++ b/backend/app/api/action_plans.py
@@ -262,7 +262,8 @@ def update_plan(
         if data["kr_id"] is None:
             plan.kr_id = None
         else:
-            kr_ent = db.query(KR).filter(KR.id == data["kr_id"]).first()
+            # 账套隔离: KR 必须属于当前企业（对齐同文件 create_plan:158 既有写法；2026-09-18 batch3）
+            kr_ent = db.query(KR).filter(KR.id == data["kr_id"], KR.entity_id == entity_id).first()
             if not kr_ent:
                 raise HTTPException(404, "关联KR不存在")
             plan.kr_id = kr_ent.id
@@ -299,9 +300,19 @@ def delete_plan(plan_id: int, db: Session = Depends(get_db), entity_id: int = De
 
 
 @router.get("/stats")
-def plan_stats(db: Session = Depends(get_db), current_user: User = Depends(require_auth)):
-    """行动计划统计"""
-    query = db.query(ActionPlan)
+def plan_stats(db: Session = Depends(get_db), current_user: User = Depends(require_auth),
+               entity_id: int = Depends(get_entity_id)):
+    """行动计划统计（账套隔离: join KPI 按企业过滤, 2026-09-18 batch3）
+
+    口径说明（为何改）：本端点原为全局统计（仅 business 角色按 assignee 过滤）→ 非 e1 账套
+    用户看到的是含其它账套计划的合计，与同文件列表端点 list_plans（join KPIDefinition 按账套）
+    的可见集不一致。现按同文件既有先例（update_plan/delete_plan 的 join(KPIDefinition)）过滤，
+    保证「统计数 = 列表可见行数」。数据侧存在 action_plans 行 entity_id 与 KPI 归属不一致的
+    存量行（batch2 报告 §六.2），统一以 KPI 归属为准与列表口径一致。
+    """
+    query = (db.query(ActionPlan)
+             .join(KPIDefinition, KPIDefinition.id == ActionPlan.kpi_id)
+             .filter(KPIDefinition.entity_id == entity_id))
     if current_user.role == "business":
         query = query.filter(
             (ActionPlan.assignee == current_user.username) |
diff --git a/backend/app/api/cost.py b/backend/app/api/cost.py
index 4acbc63d..960bfc76 100644
--- a/backend/app/api/cost.py
+++ b/backend/app/api/cost.py
@@ -180,6 +180,12 @@ def create_actual_cost(data: dict, db: Session = Depends(get_db),
 #   GET /abc/activities 原为全表取（生产 10 行全属 entity2）→ 酣客会话可见博海 ABC 作业中心；
 #   现按会话账套过滤（AbcActivity.entity_id）。
 #   OpenCode 多租户审查 2026-09-07 的「单实体演示数据暂不强制隔离」豁免就此撤销。
+# 账套隔离（2026-09-18，project-20260918-entity-isolation-batch3）：batch2 同族残留收口
+#   - POST /abc/activities  原签名无账套依赖、不写归属 → 落模型默认 entity_id=1；现按会话账套写入
+#   - POST /abc/allocate    原无账套依赖、activity_id 不校验归属、分配记录落默认 1；
+#                           现校验 activity_id 归属本账套（跨账套 → 404，文案对齐同文件先例）
+#                           并把 entity_id 透传 cost_engine.allocate_cost 显式写入 AbcAllocation
+#   - GET  /abc/allocations 原查询只按 period/product_code → 现加 entity_id 过滤（读型同族）
 # ============================================================
 
 @router.get("/abc/activities")
@@ -193,9 +199,11 @@ def list_abc_activities(db: Session = Depends(get_db), entity_id: int = Depends(
 
 
 @router.post("/abc/activities")
-def create_abc_activity(data: dict, db: Session = Depends(get_db)):
-    """创建ABC作业中心"""
+def create_abc_activity(data: dict, db: Session = Depends(get_db),
+    entity_id: int = Depends(get_entity_id)):
+    """创建ABC作业中心（账套隔离：按会话账套写入归属）"""
     act = AbcActivity(
+        entity_id=entity_id,
         activity_code=data["activity_code"],
         activity_name=data["activity_name"],
         activity_desc=data.get("activity_desc"),
@@ -211,14 +219,21 @@ def create_abc_activity(data: dict, db: Session = Depends(get_db)):
 
 
 @router.post("/abc/allocate")
-def do_allocate(data: dict, db: Session = Depends(get_db)):
-    """执行ABC成本分配"""
+def do_allocate(data: dict, db: Session = Depends(get_db),
+    entity_id: int = Depends(get_entity_id)):
+    """执行ABC成本分配（账套隔离：activity_id 须属本账套，跨账套 → 404）"""
+    act = (db.query(AbcActivity)
+           .filter(AbcActivity.id == data["activity_id"], AbcActivity.entity_id == entity_id)
+           .first())
+    if not act:
+        raise HTTPException(404, "作业中心不存在")
     result = allocate_cost(
         activity_id=data["activity_id"],
         period=data.get("period", datetime.now().strftime("%Y-%m")),
         product_code=data["product_code"],
         product_name=data.get("product_name", ""),
         driver_consumed=data["driver_consumed"],
+        entity_id=entity_id,
     )
     return result
 
@@ -226,9 +241,10 @@ def do_allocate(data: dict, db: Session = Depends(get_db)):
 @router.get("/abc/allocations")
 def list_allocations(period: Optional[str] = Query(None),
                       product_code: Optional[str] = Query(None),
-                      db: Session = Depends(get_db)):
-    """查询ABC分配记录"""
-    query = db.query(AbcAllocation)
+                      db: Session = Depends(get_db),
+    entity_id: int = Depends(get_entity_id)):
+    """查询ABC分配记录（账套隔离：只返回本账套）"""
+    query = db.query(AbcAllocation).filter(AbcAllocation.entity_id == entity_id)
     if period:
         query = query.filter(AbcAllocation.period == period)
     if product_code:
diff --git a/backend/app/utils/cost_engine.py b/backend/app/utils/cost_engine.py
index 0fece6e5..056f414f 100644
--- a/backend/app/utils/cost_engine.py
+++ b/backend/app/utils/cost_engine.py
@@ -158,11 +158,21 @@ def calc_driver_rate(activity_id: int) -> dict:
 
 
 def allocate_cost(activity_id: int, period: str, product_code: str,
-                  product_name: str, driver_consumed: float) -> dict:
-    """按动因分配成本到产品"""
+                  product_name: str, driver_consumed: float,
+                  entity_id: Optional[int] = None) -> dict:
+    """按动因分配成本到产品
+
+    账套隔离（2026-09-18，project-20260918-entity-isolation-batch3）：
+      - entity_id 非 None 时，作业中心查询按本账套过滤（跨账套 activity_id 查不到 → 返回错误字典，
+        端点侧已先行 404）；
+      - 新建 AbcAllocation 显式写入 entity_id（不传则维持原语义：不写归属，落模型默认）。
+    """
     db = get_session_local()()
     try:
-        act = db.query(AbcActivity).filter(AbcActivity.id == activity_id).first()
+        q_act = db.query(AbcActivity).filter(AbcActivity.id == activity_id)
+        if entity_id is not None:
+            q_act = q_act.filter(AbcActivity.entity_id == entity_id)
+        act = q_act.first()
         if not act or act.driver_rate == 0:
             # 自动计算分配率
             if act and act.driver_volume > 0:
@@ -171,7 +181,7 @@ def allocate_cost(activity_id: int, period: str, product_code: str,
         if not act or act.driver_rate == 0:
             return {"error": "分配率未设置"}
         allocated = round(driver_consumed * act.driver_rate, 2)
-        alloc = AbcAllocation(
+        alloc_kwargs = dict(
             period=period,
             activity_id=activity_id,
             product_code=product_code,
@@ -179,6 +189,9 @@ def allocate_cost(activity_id: int, period: str, product_code: str,
             driver_consumed=driver_consumed,
             allocated_cost=allocated,
         )
+        if entity_id is not None:
+            alloc_kwargs["entity_id"] = entity_id
+        alloc = AbcAllocation(**alloc_kwargs)
         db.add(alloc)
         db.commit()
         return {
diff --git a/backend/tests/test_cross_entity_isolation_batch3_20260918.py b/backend/tests/test_cross_entity_isolation_batch3_20260918.py
new file mode 100644
index 00000000..f2390f52
--- /dev/null
+++ b/backend/tests/test_cross_entity_isolation_batch3_20260918.py
@@ -0,0 +1,412 @@
+"""CMA 跨实体隔离收口（第三批）账套隔离回归测试 — 2026-09-18
+
+任务：project-20260918-entity-isolation-batch3（项目Bot 派单）
+缺陷（本单范围，均与 batch2 同类残留）：
+
+A. 写型未接账套
+   1. POST /api/cma/cost/abc/activities  函数签名无 get_entity_id 依赖；AbcActivity(...) 不写归属
+                                          → 落模型默认 entity_id=1（非 e1 账套新建的作业中心落进 e1）
+   2. POST /api/cma/cost/abc/allocate    无账套依赖；cost_engine.allocate_cost() 内 AbcAllocation(...)
+                                          不写 entity_id → 分配记录全落 e1；activity_id 也不校验归属
+
+B. 读型未接账套
+   3. GET  /api/cma/cost/abc/allocations 查询只按 period/product_code 过滤 → 跨账套读泄漏
+                                          （与 batch2 已修的 GET /abc/activities 同族）
+   4. GET  /api/cma/action-plans/stats   统计 db.query(ActionPlan) 无账套过滤
+                                          → 非 e1 账套用户统计数含其它账套计划（同文件既有先例=join KPIDefinition）
+
+C. 归属校验缺失（写型）
+   5. PUT  /api/cma/action-plans/{plan_id}  plan_id 已按账套校验（batch2），但 kr_id 分支
+                                          db.query(KR).filter(KR.id == data["kr_id"]) 无账套校验
+                                          → 可把本账套计划挂到对端账套的 KR（同文件 create_plan:158 有先例）
+
+本用例覆盖（每条均双向 + 同账套正对照；改前必失败条目见回报 §三 RED 原文）：
+- 写型：会话账套新建 ABC 作业中心 → 库内该行 entity_id = 会话账套；对端账套看不到；
+- 写型：本账套 activity_id 分配 → 200 且新建 abc_allocations 行 entity_id = 会话账套；
+        对端 activity_id → 404 且不产生任何分配行；
+- 读型：GET /abc/allocations 只返回本账套行；
+- 归属：PUT /{plan_id} 传对端 kr_id → 404 且对端 KR/本账套计划均未被改动；同账套改挂 → 200；
+- 统计：GET /action-plans/stats 只统计本账套计划；
+- 鉴权底线：无 token → 401（改前改后都应通过）。
+"""
+import pytest
+from fastapi.testclient import TestClient
+from sqlalchemy.orm import Session
+
+from app.models import (
+    AbcActivity,
+    AbcAllocation,
+    ActionPlan,
+    Entity,
+    KR,
+    KPIDefinition,
+    Objective,
+)
+from tests.conftest import TEST_USER_PASSWORD, auth_header, create_test_user
+
+COST = "/api/cma/cost"
+PLANS = "/api/cma/action-plans"
+
+# 账套 1/2 各自的资源编码前缀（activity_code 库内唯一）
+E1_KPI = "ZZ_B3_E1_KPI_001"
+E2_KPI = "ZZ_B3_E2_KPI_001"
+E1_ACT = "ZZ_B3_E1_ACT_001"
+E2_ACT = "ZZ_B3_E2_ACT_001"
+
+
+# ──────────────────────────────────────────────
+# 夹具
+# ──────────────────────────────────────────────
+
+def _ensure_entity(db: Session, eid: int, name: str) -> Entity:
+    ent = db.query(Entity).filter(Entity.id == eid).first()
+    if not ent:
+        ent = Entity(id=eid, name=name, short_name=name, status="active")
+        db.add(ent)
+        db.commit()
+        db.refresh(ent)
+    return ent
+
+
+def _mk_kpi(db: Session, code: str, eid: int) -> KPIDefinition:
+    kpi = KPIDefinition(
+        entity_id=eid,
+        kpi_code=code,
+        kpi_name=f"{code}-名称",
+        dimension="finance",
+        category="revenue_growth",
+        formula="-",
+        data_source_type="excel",
+        data_source="Excel导入",
+        data_owner="财务部",
+        frequency="monthly",
+        unit="元",
+        target_value=0,
+        kpi_level="operational",
+        status="active",
+    )
+    db.add(kpi)
+    db.commit()
+    db.refresh(kpi)
+    return kpi
+
+
+def _login(client: TestClient, entity_id: int) -> str:
+    resp = client.post("/api/cma/auth/login", json={
+        "username": "testadmin",
+        "password": TEST_USER_PASSWORD,
+        "entity_id": entity_id,
+    })
+    assert resp.status_code == 200, f"登录 entity{entity_id} 失败: {resp.text[:300]}"
+    return resp.json()["token"]
+
+
+def _mk_activity(db: Session, code: str, eid: int) -> AbcActivity:
+    """直插作业中心（显式 entity_id，用于构造「对端账套既有数据」）"""
+    act = AbcActivity(
+        entity_id=eid, activity_code=code, activity_name=f"{code}-作业",
+        cost_driver="动因", driver_unit="次", total_cost=1000.0, driver_volume=10,
+        driver_rate=100.0, status="active",
+    )
+    db.add(act)
+    db.commit()
+    db.refresh(act)
+    return act
+
+
+def _mk_allocation(db: Session, activity: AbcActivity, eid: int, product_code: str) -> AbcAllocation:
+    alloc = AbcAllocation(
+        entity_id=eid, period="2026-06", activity_id=activity.id,
+        product_code=product_code, product_name=f"{product_code}-产品",
+        driver_consumed=3, allocated_cost=300.0,
+    )
+    db.add(alloc)
+    db.commit()
+    db.refresh(alloc)
+    return alloc
+
+
+def _mk_plan(db: Session, kpi_id: int, eid: int, title: str, **kw) -> ActionPlan:
+    plan = ActionPlan(entity_id=eid, kpi_id=kpi_id, title=title,
+                      assignee=kw.get("assignee", "张三"), priority="medium",
+                      status=kw.get("status", "pending"), progress=0)
+    db.add(plan)
+    db.commit()
+    db.refresh(plan)
+    return plan
+
+
+def _mk_objective_kr(db: Session, eid: int, title: str) -> KR:
+    obj = Objective(entity_id=eid, title=f"{title}-目标", quarter="2026Q3", status="active")
+    db.add(obj)
+    db.commit()
+    db.refresh(obj)
+    kr = KR(entity_id=eid, objective_id=obj.id, title=title, operator=">=",
+            weight=50, target_value=100)
+    db.add(kr)
+    db.commit()
+    db.refresh(kr)
+    return kr
+
+
+def _seed_two_entities(db: Session):
+    _ensure_entity(db, 1, "酣客")
+    _ensure_entity(db, 2, "博海")
+    create_test_user(db)
+    k1 = _mk_kpi(db, E1_KPI, 1)
+    k2 = _mk_kpi(db, E2_KPI, 2)
+    return k1, k2
+
+
+# ──────────────────────────────────────────────
+# A1. 写型：POST /cost/abc/activities 按会话账套写入
+# ──────────────────────────────────────────────
+
+def test_create_abc_activity_writes_session_entity(client: TestClient, db: Session):
+    """博海(e2)会话新建作业中心 → 库内该行 entity_id=2；酣客(e1)会话看不到它"""
+    _seed_two_entities(db)
+
+    token2 = _login(client, 2)
+    r = client.post(f"{COST}/abc/activities", headers=auth_header(token2), json={
+        "activity_code": E2_ACT,
+        "activity_name": "e2 新建作业",
+        "cost_driver": "动因",
+        "driver_unit": "次",
+        "total_cost": 2000.0,
+        "driver_volume": 20,
+    })
+    assert r.status_code == 200, r.text
+    new_id = r.json()["id"]
+
+    db.expire_all()
+    row = db.query(AbcActivity).filter(AbcActivity.id == new_id).first()
+    assert row is not None, "作业中心未落库"
+    assert row.entity_id == 2, (
+        f"会话账套=2 新建的作业中心落库归属 entity_id={row.entity_id}（缺陷：未写归属→模型默认 1）"
+    )
+
+    # e1 会话看不到 e2 的作业中心；e2 会话能看到
+    codes1 = _abc_codes(client, _login(client, 1))
+    codes2 = _abc_codes(client, _login(client, 2))
+    assert E2_ACT not in codes1, f"酣客(e1)会话看到了博海(e2)新建的作业中心: {sorted(codes1)}"
+    assert E2_ACT in codes2, f"博海(e2)会话看不到自己新建的作业中心: {sorted(codes2)}"
+
+
+def test_create_abc_activity_e1_still_defaults_to_own_entity(client: TestClient, db: Session):
+    """酣客(e1)会话新建 → entity_id=1 且对端(e2)看不到（同账套正对照，防「一律写死某账套」）"""
+    _seed_two_entities(db)
+
+    token1 = _login(client, 1)
+    r = client.post(f"{COST}/abc/activities", headers=auth_header(token1), json={
+        "activity_code": E1_ACT,
+        "activity_name": "e1 新建作业",
+        "cost_driver": "动因",
+        "driver_unit": "次",
+        "total_cost": 1000.0,
+        "driver_volume": 10,
+    })
+    assert r.status_code == 200, r.text
+    new_id = r.json()["id"]
+
+    db.expire_all()
+    row = db.query(AbcActivity).filter(AbcActivity.id == new_id).first()
+    assert row.entity_id == 1, f"会话账套=1 新建行归属 {row.entity_id}"
+
+    codes2 = _abc_codes(client, _login(client, 2))
+    assert E1_ACT not in codes2, f"博海(e2)会话看到了酣客(e1)作业中心: {sorted(codes2)}"
+
+
+def _abc_codes(client: TestClient, token: str) -> set:
+    r = client.get(f"{COST}/abc/activities", headers=auth_header(token))
+    assert r.status_code == 200, r.text
+    return {row["activity_code"] for row in r.json()["data"]}
+
+
+# ──────────────────────────────────────────────
+# A2. 写型：POST /cost/abc/allocate 按会话账套 + activity_id 归属校验
+# ──────────────────────────────────────────────
+
+def test_allocate_cross_entity_activity_rejected(client: TestClient, db: Session):
+    """酣客(e1)会话用博海(e2)的 activity_id 分配 → 404，且不产生任何分配行"""
+    _seed_two_entities(db)
+    other = _mk_activity(db, E2_ACT, 2)
+    token1 = _login(client, 1)
+
+    r = client.post(f"{COST}/abc/allocate", headers=auth_header(token1), json={
+        "activity_id": other.id,
+        "period": "2026-06",
+        "product_code": "ZZ_B3_E1_PROD",
+        "product_name": "跨账套产品",
+        "driver_consumed": 5,
+    })
+    assert r.status_code == 404, (
+        f"跨账套 allocate 应 404，实际 {r.status_code} {r.text[:200]}"
+    )
+
+    db.expire_all()
+    assert db.query(AbcAllocation).count() == 0, "跨账套 allocate 竟写入了分配记录"
+    # 对端作业中心未被改动（分配率计算会回写 driver_rate）
+    db.refresh(other)
+    assert other.driver_rate == 100.0, "跨账套 allocate 竟改动了对端作业中心"
+
+
+def test_allocate_writes_session_entity(client: TestClient, db: Session):
+    """双向：e1/e2 各自用本账套 activity_id 分配 → 200 且新建行 entity_id = 会话账套"""
+    _seed_two_entities(db)
+    act1 = _mk_activity(db, E1_ACT, 1)
+    act2 = _mk_activity(db, E2_ACT, 2)
+
+    # e2 会话分配本账套作业中心
+    token2 = _login(client, 2)
+    r = client.post(f"{COST}/abc/allocate", headers=auth_header(token2), json={
+        "activity_id": act2.id,
+        "period": "2026-06",
+        "product_code": "ZZ_B3_E2_PROD",
+        "product_name": "e2 产品",
+        "driver_consumed": 4,
+    })
+    assert r.status_code == 200, f"同账套 allocate 应 200，实际 {r.status_code} {r.text[:200]}"
+    assert r.json()["allocated_cost"] == 400.0  # 4 × 100.0
+
+    db.expire_all()
+    row2 = (db.query(AbcAllocation)
+            .filter(AbcAllocation.product_code == "ZZ_B3_E2_PROD").first())
+    assert row2 is not None, "e2 会话分配未落库"
+    assert row2.entity_id == 2, (
+        f"e2 会话分配行归属 entity_id={row2.entity_id}（缺陷：AbcAllocation 未写归属→默认 1）"
+    )
+
+    # e1 会话分配本账套作业中心（反向对照）
+    token1 = _login(client, 1)
+    r = client.post(f"{COST}/abc/allocate", headers=auth_header(token1), json={
+        "activity_id": act1.id,
+        "period": "2026-06",
+        "product_code": "ZZ_B3_E1_PROD",
+        "product_name": "e1 产品",
+        "driver_consumed": 2,
+    })
+    assert r.status_code == 200, r.text
+
+    db.expire_all()
+    row1 = (db.query(AbcAllocation)
+            .filter(AbcAllocation.product_code == "ZZ_B3_E1_PROD").first())
+    assert row1 is not None and row1.entity_id == 1, f"e1 分配行归属异常: {row1.entity_id if row1 else None}"
+
+
+# ──────────────────────────────────────────────
+# B3. 读型：GET /cost/abc/allocations 按会话账套
+# ──────────────────────────────────────────────
+
+def _alloc_products(client: TestClient, token: str) -> set:
+    r = client.get(f"{COST}/abc/allocations", headers=auth_header(token))
+    assert r.status_code == 200, r.text
+    return {row["product_code"] for row in r.json()["data"]}
+
+
+def test_allocations_list_isolated_by_entity(client: TestClient, db: Session):
+    """酣客(e1)会话只返本账套分配行，不含博海(e2)行；e2 会话同理（双向）"""
+    _seed_two_entities(db)
+    act1 = _mk_activity(db, E1_ACT, 1)
+    act2 = _mk_activity(db, E2_ACT, 2)
+    _mk_allocation(db, act1, 1, "ZZ_B3_E1_ALLOC")
+    _mk_allocation(db, act2, 2, "ZZ_B3_E2_ALLOC")
+
+    prods1 = _alloc_products(client, _login(client, 1))
+    prods2 = _alloc_products(client, _login(client, 2))
+
+    assert prods1 == {"ZZ_B3_E1_ALLOC"}, f"e1 会话分配记录集应为本账套，实际 {sorted(prods1)}"
+    assert prods2 == {"ZZ_B3_E2_ALLOC"}, f"e2 会话分配记录集应为本账套，实际 {sorted(prods2)}"
+
+
+# ──────────────────────────────────────────────
+# C5. PUT /action-plans/{plan_id} 的 kr_id 归属校验
+# ──────────────────────────────────────────────
+
+def test_update_plan_kr_id_cross_entity_404(client: TestClient, db: Session):
+    """酣客(e1)计划改挂博海(e2)KR → 404，且计划 kr_id 未变、对端 KR 未被改动"""
+    k1, k2 = _seed_two_entities(db)
+    mine = _mk_plan(db, k1.id, 1, "e1 计划")
+    kr2 = _mk_objective_kr(db, 2, "e2 KR")
+    token1 = _login(client, 1)
+
+    r = client.put(f"{PLANS}/{mine.id}", headers=auth_header(token1),
+                   json={"kr_id": kr2.id})
+    assert r.status_code == 404, (
+        f"跨账套 kr_id 应 404，实际 {r.status_code} {r.text[:200]}"
+    )
+
+    db.expire_all()
+    after = db.query(ActionPlan).filter(ActionPlan.id == mine.id).first()
+    assert after.kr_id is None, f"跨账套 kr_id 竟被写入: kr_id={after.kr_id}"
+    assert after.objective_id is None, f"跨账套改挂竟改动了 objective_id={after.objective_id}"
+
+    db.refresh(kr2)
+    assert kr2.entity_id == 2 and kr2.title == "e2 KR", "对端 KR 被改动"
+
+
+def test_update_plan_kr_id_same_entity_200(client: TestClient, db: Session):
+    """同账套正对照：酣客(e1)计划改挂本账套 KR → 200 且 kr_id/objective_id 生效"""
+    k1, _ = _seed_two_entities(db)
+    mine = _mk_plan(db, k1.id, 1, "e1 计划")
+    kr1 = _mk_objective_kr(db, 1, "e1 KR")
+    token1 = _login(client, 1)
+
+    r = client.put(f"{PLANS}/{mine.id}", headers=auth_header(token1),
+                   json={"kr_id": kr1.id})
+    assert r.status_code == 200, f"同账套 kr_id 应 200，实际 {r.status_code} {r.text[:200]}"
+    body = r.json()
+    assert body["kr_id"] == kr1.id
+    assert body["objective_id"] == kr1.objective_id
+
+
+# ──────────────────────────────────────────────
+# B4. GET /action-plans/stats 按会话账套
+# ──────────────────────────────────────────────
+
+def _stats(client: TestClient, token: str) -> dict:
+    r = client.get(f"{PLANS}/stats", headers=auth_header(token))
+    assert r.status_code == 200, r.text
+    return r.json()
+
+
+def test_plan_stats_isolated_by_entity(client: TestClient, db: Session):
+    """酣客(e1)会话统计只含本账套计划（e2 造 2 条做对照）"""
+    k1, k2 = _seed_two_entities(db)
+    _mk_plan(db, k1.id, 1, "e1 待开始")
+    _mk_plan(db, k1.id, 1, "e1 已完成", status="completed")
+    _mk_plan(db, k2.id, 2, "e2 待开始")
+    _mk_plan(db, k2.id, 2, "e2 进行中", status="in_progress")
+
+    s1 = _stats(client, _login(client, 1))
+    assert s1["total"] == 2, f"e1 统计应只含本账套 2 条，实际 {s1}"
+    assert s1["pending"] == 1 and s1["completed"] == 1 and s1["in_progress"] == 0
+
+
+def test_plan_stats_reverse_direction(client: TestClient, db: Session):
+    """博海(e2)会话统计只含本账套计划（防止「一律统计 e1」或全局口径）"""
+    k1, k2 = _seed_two_entities(db)
+    _mk_plan(db, k1.id, 1, "e1 待开始")
+    _mk_plan(db, k1.id, 1, "e1 待开始2")
+    _mk_plan(db, k2.id, 2, "e2 待开始")
+
+    s2 = _stats(client, _login(client, 2))
+    assert s2["total"] == 1, f"e2 统计应只含本账套 1 条，实际 {s2}"
+    assert s2["pending"] == 1
+
+
+# ──────────────────────────────────────────────
+# 鉴权底线（改前改后都应通过）
+# ──────────────────────────────────────────────
+
+def test_batch3_endpoints_without_token_401(client: TestClient, db: Session):
+    """无 Bearer token → 401（四个端点鉴权底线不变）"""
+    _seed_two_entities(db)
+    assert client.post(f"{COST}/abc/activities", json={
+        "activity_code": "ZZ_B3_NOTOKEN", "activity_name": "x",
+        "cost_driver": "d", "total_cost": 1, "driver_volume": 1,
+    }).status_code == 401
+    assert client.post(f"{COST}/abc/allocate", json={
+        "activity_id": 1, "product_code": "p", "driver_consumed": 1,
+    }).status_code == 401
+    assert client.get(f"{COST}/abc/allocations").status_code == 401
+    assert client.get(f"{PLANS}/stats").status_code == 401