diff --git a/backend/app/api/v1/parcels.py b/backend/app/api/v1/parcels.py
index 25f718a0..f5cab072 100644
--- a/backend/app/api/v1/parcels.py
+++ b/backend/app/api/v1/parcels.py
@@ -42,6 +42,9 @@ from app.services.site_finder.quarter_dump_lookup import (
     make_empty_result,
 )
 from app.services.site_finder.velocity import compute_velocity
+from app.services.site_finder.weight_profiles import (
+    _SYSTEM_POI_WEIGHTS as _POI_WEIGHTS,
+)
 from app.services.site_finder.weight_profiles import (
     ALLOWED_CATEGORIES as _ALLOWED_CATEGORIES,
 )
@@ -298,21 +301,6 @@ def _confidence_label(c: float) -> str:
     return "low"
 
 
-# Веса POI-категорий для scoring (Максим: трамвай = минус)
-_POI_WEIGHTS: dict[str, float] = {
-    "school": 1.5,
-    "kindergarten": 1.5,
-    "pharmacy": 0.8,
-    "hospital": 0.6,
-    "shop_mall": 1.2,
-    "shop_supermarket": 1.0,
-    "shop_small": 0.5,
-    "park": 1.8,
-    "bus_stop": 0.3,
-    "metro_stop": 1.5,
-    "tram_stop": -0.5,  # негативный вес — шум / вибрация
-}
-
 # Человеко-читаемые имена категорий для verbal breakdown (X1).
 _POI_CATEGORY_RU: dict[str, str] = {
     "school": "Школа",
@@ -1255,7 +1243,9 @@ def analyze_parcel(
                 ),
             )
         out_of_range = {
-            k: v for k, v in _inline_weights.items() if v < _MIN_WEIGHT or v > _MAX_WEIGHT
+            k: v
+            for k, v in _inline_weights.items()
+            if not math.isfinite(v) or v < _MIN_WEIGHT or v > _MAX_WEIGHT
         }
         if out_of_range:
             raise HTTPException(
diff --git a/backend/app/services/site_finder/weight_profiles.py b/backend/app/services/site_finder/weight_profiles.py
index 7f3f0ad2..12259896 100644
--- a/backend/app/services/site_finder/weight_profiles.py
+++ b/backend/app/services/site_finder/weight_profiles.py
@@ -17,6 +17,7 @@ from __future__ import annotations
 
 import json
 import logging
+import math
 from datetime import datetime
 from typing import Any
 
@@ -25,7 +26,7 @@ from sqlalchemy import text
 
 logger = logging.getLogger(__name__)
 
-# Allowed POI categories — mirrors _POI_WEIGHTS keys in api/v1/parcels.py
+# Allowed POI categories — single source of truth; imported by api/v1/parcels.py
 ALLOWED_CATEGORIES: set[str] = {
     "school",
     "kindergarten",
@@ -44,7 +45,7 @@ ALLOWED_CATEGORIES: set[str] = {
 MIN_WEIGHT: float = -2.0
 MAX_WEIGHT: float = 3.0
 
-# System defaults — keep in sync with _POI_WEIGHTS in parcels.py
+# System defaults — single source of truth; imported as _POI_WEIGHTS by api/v1/parcels.py
 _SYSTEM_POI_WEIGHTS: dict[str, float] = {
     "school": 1.5,
     "kindergarten": 1.5,
@@ -115,7 +116,7 @@ def _validate_weights_dict(v: dict[str, float]) -> dict[str, float]:
     for k, w in v.items():
         if not isinstance(w, int | float):
             raise ValueError(f"Weight for '{k}' must be number, got {type(w).__name__}")
-        if w < MIN_WEIGHT or w > MAX_WEIGHT:
+        if not math.isfinite(w) or w < MIN_WEIGHT or w > MAX_WEIGHT:
             raise ValueError(f"Weight for '{k}' = {w} out of bounds [{MIN_WEIGHT}, {MAX_WEIGHT}]")
     return v
 
diff --git a/backend/tests/api/v1/test_analyze_inline_weights.py b/backend/tests/api/v1/test_analyze_inline_weights.py
index d4fcdcc4..80a1a9d6 100644
--- a/backend/tests/api/v1/test_analyze_inline_weights.py
+++ b/backend/tests/api/v1/test_analyze_inline_weights.py
@@ -277,6 +277,31 @@ def test_analyze_weight_out_of_range_returns_422() -> None:
         _stop_patches()
 
 
+def test_inline_weights_rejects_nan() -> None:
+    """NaN weight должен вернуть 422, а не propagate в score."""
+    from app.core.db import get_db
+
+    db = _make_db_for_analyze()
+    app.dependency_overrides[get_db] = _override_db(db)
+    _start_patches()
+    try:
+        client = TestClient(app)
+        # Отправляем raw JSON с NaN — httpx.Client не умеет encode float('nan'),
+        # поэтому используем content= с явным bytes-телом.
+        raw_body = b'{"weights": {"school": NaN}}'
+        resp = client.post(
+            f"/api/v1/parcels/{_CAD}/analyze",
+            content=raw_body,
+            headers={"Content-Type": "application/json"},
+        )
+        assert (
+            resp.status_code == 422
+        ), f"Ожидали 422 для NaN-weight, получили {resp.status_code}: {resp.text}"
+    finally:
+        app.dependency_overrides.clear()
+        _stop_patches()
+
+
 def test_analyze_inline_weights_beats_profile_id() -> None:
     """body.weights + profile_id → body.weights имеет приоритет (source = 'inline')."""
     from app.core.db import get_db