diff --git a/backend/app/api/alerts.py b/backend/app/api/alerts.py
index bd81fba..5368a66 100644
--- a/backend/app/api/alerts.py
+++ b/backend/app/api/alerts.py
@@ -1,5 +1,6 @@
-from fastapi import APIRouter, HTTPException, Query
+from fastapi import APIRouter, Query
 
+from app.core.errors import NOT_FOUND, equipment_not_found
 from app.schemas.alert import AlertOut
 from app.services import alert_service, equipment_service
 
@@ -7,12 +8,14 @@
 
 
 @router.get("", response_model=list[AlertOut], summary="Список последних алертов")
-def list_alerts(limit: int = Query(50, ge=1, le=500)):
+def list_alerts(limit: int = Query(50, ge=1, le=500, description="Максимум записей")):
     return alert_service.list_alerts(limit=limit)
 
 
-@router.get("/{equipment_id}", response_model=list[AlertOut], summary="Алерты по оборудованию")
-def alerts_by_equipment(equipment_id: int, limit: int = Query(50, ge=1, le=500)):
+@router.get("/{equipment_id}", response_model=list[AlertOut], responses=NOT_FOUND,
+            summary="Алерты по конкретному оборудованию")
+def alerts_by_equipment(equipment_id: int,
+                        limit: int = Query(50, ge=1, le=500, description="Максимум записей")):
     if equipment_service.get_equipment(equipment_id) is None:
-        raise HTTPException(status_code=404, detail="Оборудование не найдено")
+        raise equipment_not_found(equipment_id)
     return alert_service.list_alerts(equipment_id, limit)
diff --git a/backend/app/api/equipment.py b/backend/app/api/equipment.py
index 673f7c1..41c0d1f 100644
--- a/backend/app/api/equipment.py
+++ b/backend/app/api/equipment.py
@@ -1,14 +1,15 @@
 from fastapi import APIRouter, HTTPException, Query
 
+from app.core.errors import NOT_FOUND, equipment_not_found
 from app.schemas.equipment import EquipmentOut, ForecastOut, ReadingOut, StatusOut
 from app.services import equipment_service
 
 router = APIRouter(prefix="/equipment", tags=["Оборудование"])
 
 
-def _or_404(value):
+def _found(value, equipment_id: int):
     if value is None:
-        raise HTTPException(status_code=404, detail="Оборудование не найдено")
+        raise equipment_not_found(equipment_id)
     return value
 
 
@@ -17,25 +18,30 @@ def list_equipment():
     return equipment_service.list_equipment()
 
 
-@router.get("/{equipment_id}", response_model=EquipmentOut, summary="Информация об одной единице")
+@router.get("/{equipment_id}", response_model=EquipmentOut, responses=NOT_FOUND,
+            summary="Информация об одной единице")
 def get_equipment(equipment_id: int):
-    return _or_404(equipment_service.get_equipment(equipment_id))
+    return _found(equipment_service.get_equipment(equipment_id), equipment_id)
 
 
-@router.get("/{equipment_id}/status", response_model=StatusOut, summary="Текущее состояние")
+@router.get("/{equipment_id}/status", response_model=StatusOut, responses=NOT_FOUND,
+            summary="Текущее состояние: статус, RUL, вероятность дефекта, невязка")
 def get_status(equipment_id: int):
-    return _or_404(equipment_service.get_status(equipment_id))
+    return _found(equipment_service.get_status(equipment_id), equipment_id)
 
 
-@router.get("/{equipment_id}/history", response_model=list[ReadingOut],
-            summary="История показаний датчиков")
+@router.get("/{equipment_id}/history", response_model=list[ReadingOut], responses=NOT_FOUND,
+            summary="История показаний датчиков за период")
 def get_history(equipment_id: int,
-                from_cycle: int | None = Query(None, ge=0),
-                to_cycle: int | None = Query(None, ge=0),
-                limit: int = Query(500, ge=1, le=5000)):
-    return _or_404(equipment_service.get_history(equipment_id, from_cycle, to_cycle, limit))
+                from_cycle: int | None = Query(None, ge=0, description="С какого цикла (включительно)"),
+                to_cycle: int | None = Query(None, ge=0, description="По какой цикл (включительно)"),
+                limit: int = Query(500, ge=1, le=5000, description="Максимум записей (берутся последние)")):
+    if from_cycle is not None and to_cycle is not None and from_cycle > to_cycle:
+        raise HTTPException(status_code=400, detail="from_cycle не может быть больше to_cycle")
+    return _found(equipment_service.get_history(equipment_id, from_cycle, to_cycle, limit), equipment_id)
 
 
-@router.get("/{equipment_id}/forecast", response_model=ForecastOut, summary="Прогноз деградации")
+@router.get("/{equipment_id}/forecast", response_model=ForecastOut, responses=NOT_FOUND,
+            summary="Прогноз деградации: RUL по будущим циклам с доверительным интервалом")
 def get_forecast(equipment_id: int):
-    return _or_404(equipment_service.get_forecast(equipment_id))
+    return _found(equipment_service.get_forecast(equipment_id), equipment_id)
diff --git a/backend/app/api/predict.py b/backend/app/api/predict.py
index 312cd59..8def7ab 100644
--- a/backend/app/api/predict.py
+++ b/backend/app/api/predict.py
@@ -1,5 +1,6 @@
-from fastapi import APIRouter, HTTPException
+from fastapi import APIRouter
 
+from app.core.errors import NOT_FOUND, equipment_not_found
 from app.schemas.equipment import StatusOut
 from app.schemas.predict import PredictIn
 from app.services import predict_service
@@ -7,9 +8,9 @@
 router = APIRouter(prefix="/predict", tags=["Прогнозирование"])
 
 
-@router.post("", response_model=StatusOut, summary="Ручной запрос инференса")
+@router.post("", response_model=StatusOut, responses=NOT_FOUND, summary="Ручной запрос инференса")
 def predict(body: PredictIn):
     result = predict_service.run_prediction(body.equipment_id)
     if result is None:
-        raise HTTPException(status_code=404, detail="Оборудование не найдено")
+        raise equipment_not_found(body.equipment_id)
     return result
diff --git a/backend/app/core/errors.py b/backend/app/core/errors.py
new file mode 100644
index 0000000..bc59196
--- /dev/null
+++ b/backend/app/core/errors.py
@@ -0,0 +1,8 @@
+from fastapi import HTTPException
+
+
+def equipment_not_found(equipment_id: int) -> HTTPException:
+    return HTTPException(status_code=404, detail=f"Оборудование с id={equipment_id} не найдено")
+
+
+NOT_FOUND = {404: {"description": "Оборудование не найдено"}}
diff --git a/backend/app/schemas/equipment.py b/backend/app/schemas/equipment.py
index a7f16cb..b3b79e4 100644
--- a/backend/app/schemas/equipment.py
+++ b/backend/app/schemas/equipment.py
@@ -1,6 +1,6 @@
 from typing import Literal
 
-from pydantic import BaseModel
+from pydantic import BaseModel, Field
 
 Status = Literal["normal", "warning", "critical"]
 
@@ -12,33 +12,33 @@ class EquipmentOut(BaseModel):
     unit_number: int
     current_cycle: int
     status: Status
-    predicted_rul: float
+    predicted_rul: float = Field(description="Прогноз остаточного ресурса, циклов")
 
 
 class StatusOut(BaseModel):
     equipment_id: int
-    status: Status
+    status: Status = Field(description="normal: RUL > 75, warning: 31–75, critical: ≤ 30 циклов")
     current_cycle: int
-    predicted_rul: float
-    defect_probability: float
-    residual: float
+    predicted_rul: float = Field(description="Прогноз остаточного ресурса, циклов")
+    defect_probability: float = Field(ge=0, le=1, description="Вероятность дефекта, 0–1")
+    residual: float = Field(description="Невязка: отклонение от физически ожидаемого поведения")
 
 
 class ReadingOut(BaseModel):
     cycle: int
-    sensors: dict[str, float]
+    sensors: dict[str, float] = Field(description="Показания 14 рабочих датчиков: код → значение")
 
 
 class ForecastPoint(BaseModel):
     cycle: int
-    rul: float
-    rul_low: float
-    rul_high: float
+    rul: float = Field(description="Ожидаемый остаточный ресурс на этом цикле")
+    rul_low: float = Field(description="Нижняя граница доверительного интервала")
+    rul_high: float = Field(description="Верхняя граница доверительного интервала")
 
 
 class ForecastOut(BaseModel):
     equipment_id: int
     current_cycle: int
     predicted_rul: float
-    predicted_failure_cycle: int
-    points: list[ForecastPoint]
+    predicted_failure_cycle: int = Field(description="Цикл, на котором ожидается отказ")
+    points: list[ForecastPoint] = Field(description="От текущего цикла до ожидаемого отказа, шаг — 1 цикл")
diff --git a/backend/app/services/equipment_service.py b/backend/app/services/equipment_service.py
index 3297815..51a1331 100644
--- a/backend/app/services/equipment_service.py
+++ b/backend/app/services/equipment_service.py
@@ -38,10 +38,10 @@ def get_forecast(equipment_id: int) -> dict | None:
     if e is None:
         return None
     rul, cycle = e["predicted_rul"], e["current_cycle"]
-    horizon = round(rul)
+    horizon = int(rul) 
     points = []
     for k in range(horizon + 1):
-        value, spread = rul - k, 2 + 0.12 * k
+        value, spread = rul - k, 2 + 0.12 * k  
         points.append({"cycle": cycle + k, "rul": round(value, 1),
                        "rul_low": round(max(0.0, value - spread), 1), "rul_high": round(value + spread, 1)})
     return {"equipment_id": equipment_id, "current_cycle": cycle, "predicted_rul": rul,
diff --git a/backend/app/services/mock_data.py b/backend/app/services/mock_data.py
index 2163c94..bad233b 100644
--- a/backend/app/services/mock_data.py
+++ b/backend/app/services/mock_data.py
@@ -34,7 +34,7 @@ def _build() -> None:
     now = datetime.now(UTC)
     for i in range(1, 13):
         life = _rnd.randint(130, 300)                  
-        cut = int(life * _rnd.uniform(0.35, 0.97))     
+        cut = int(life * _rnd.uniform(0.35, 0.97))    
         READINGS[i] = [
             {"cycle": c, "sensors": {
                 code: round(base + trend * std * 3 * (c / life) ** 2 + _rnd.gauss(0, std * 0.4), 4)