diff --git a/server/static/app.js b/server/static/app.js
index 1c96fc3..03f5a0e 100644
--- a/server/static/app.js
+++ b/server/static/app.js
@@ -1873,6 +1873,91 @@ function renderApiDebugViewshedLayer(geojson) {
   });
 }
 
+function fitApiDebugLayer(layer) {
+  const bounds = layer?.getBounds?.();
+  if (bounds?.isValid?.()) {
+    setMapViewProgrammatically(() => map.fitBounds(bounds, { padding: [40, 40], maxZoom: 16 }));
+  }
+}
+
+function renderApiDebugFresnelSlice(data) {
+  clearApiDebugCoverage();
+  clearApiDebugBeam();
+  const layers = [];
+  const pathLayer = data?.path_geojson ? L.geoJSON(data.path_geojson, {
+    style: { color: '#4fc3f7', weight: 3, opacity: 0.95 }
+  }) : null;
+  const fresnelLayer = data?.fresnel_geojson ? L.geoJSON(data.fresnel_geojson, {
+    style: {
+      color: '#ffd54f',
+      weight: 2,
+      opacity: 0.95,
+      fillColor: '#ffd54f',
+      fillOpacity: 0.2
+    }
+  }) : null;
+  const buildingsLayer = data?.buildings_geojson ? L.geoJSON(data.buildings_geojson, {
+    style: {
+      color: '#ff1744',
+      weight: 1.5,
+      opacity: 0.95,
+      fillColor: '#ff1744',
+      fillOpacity: 0.3
+    },
+    onEachFeature: (feature, layer) => {
+      const p = feature.properties || {};
+      const parts = [];
+      if (p.height_m != null) parts.push(`height ${fmtNum(p.height_m, 1, ' m')}`);
+      if (p.intersection_area_m2 != null) parts.push(`пересечение ${fmtNum(p.intersection_area_m2, 1, ' m²')}`);
+      if (p.building_type) parts.push(escapeHtml(p.building_type));
+      if (parts.length) layer.bindPopup(parts.join(' · '));
+    }
+  }) : null;
+  [fresnelLayer, buildingsLayer, pathLayer].forEach(layer => {
+    if (layer) layers.push(layer);
+  });
+  if (!layers.length) {
+    apiDebugSetSummary('Ответ fresnel-slice не содержит GeoJSON слоёв.');
+    return;
+  }
+  apiDebugCoverageLayer = L.featureGroup(layers).addTo(map);
+  fitApiDebugLayer(apiDebugCoverageLayer);
+  const buildings = data?.buildings_geojson?.features?.length ?? 0;
+  const profilePoints = data?.profile?.length ?? 0;
+  apiDebugSetSummary(
+    `<b>Срез зоны Френеля:</b> ${profilePoints} точек профиля · ${buildings} зданий пересекают область<br>` +
+    `Жёлтая область — горизонтальный срез 60% зоны Френеля, красные полигоны — пересекающие здания.` +
+    formatDataSourcesLine(data?.data_sources)
+  );
+}
+
+function renderApiDebugBuildings(data) {
+  const features = data?.features?.length ?? 0;
+  const rendered = renderApiDebugGeoJsonLayer(data, {
+    style: {
+      color: '#ff1744',
+      weight: 1.3,
+      opacity: 0.95,
+      fillColor: '#ff1744',
+      fillOpacity: 0.22
+    },
+    onEachFeature: (feature, layer) => {
+      const p = feature.properties || {};
+      const parts = [];
+      if (p.height_m != null) parts.push(`height ${fmtNum(p.height_m, 1, ' m')}`);
+      if (p.levels != null) parts.push(`${p.levels} эт.`);
+      if (p.building_type) parts.push(escapeHtml(p.building_type));
+      if (p.source) parts.push(escapeHtml(p.source));
+      if (parts.length) layer.bindPopup(parts.join(' · '));
+    }
+  });
+  apiDebugSetSummary(
+    rendered
+      ? `<b>Здания вдоль линии:</b> ${features} объектов в буфере 50 m${formatDataSourcesLine(data?.data_sources)}`
+      : 'Ответ buildings/query не содержит GeoJSON features.'
+  );
+}
+
 async function fetchApiDebugJobArtifact(jobId) {
   const f = apiDebugReadForm();
   const url = `${f.base}/api/v1/jobs/${encodeURIComponent(jobId)}/artifact`;
@@ -2221,6 +2306,23 @@ function buildApiDebugRequest(kind) {
       }
     };
   }
+  if (kind === 'fresnelSlice') {
+    return {
+      method: 'POST',
+      path: '/api/v1/terrain/fresnel-slice',
+      body: {
+        tx,
+        rx,
+        frequency_mhz: f.frequency,
+        fresnel_fraction: 0.6,
+        include_buildings: true,
+        include_canopy: f.includeCanopy,
+        k_factor: 1.333,
+        samples: f.samples,
+        building_limit: 5000
+      }
+    };
+  }
   if (kind === 'budget') {
     return {
       method: 'POST',
@@ -2237,6 +2339,22 @@ function buildApiDebugRequest(kind) {
       }
     };
   }
+  if (kind === 'buildings') {
+    return {
+      method: 'POST',
+      path: '/api/v1/buildings/query',
+      body: {
+        path: {
+          type: 'LineString',
+          coordinates: [
+            [f.tx.lon, f.tx.lat],
+            [f.rx.lon, f.rx.lat]
+          ]
+        },
+        buffer_m: 50
+      }
+    };
+  }
   if (kind === 'landcover') {
     return {
       method: 'POST',
@@ -2429,7 +2547,9 @@ async function runApiDebugDemo(kind) {
     }
     if (kind === 'profile') renderApiDebugProfile(data, null, null);
     else if (kind === 'los') renderApiDebugProfile(null, data, null);
+    else if (kind === 'fresnelSlice') renderApiDebugFresnelSlice(data);
     else if (kind === 'budget') apiDebugSetSummary(formatApiDebugBudgetSummary(data));
+    else if (kind === 'buildings') renderApiDebugBuildings(data);
     else if (kind === 'landcover') apiDebugSetSummary(formatApiDebugLandcoverSummary(data));
     else if (kind === 'elevation') apiDebugSetSummary(formatApiDebugPointSummary(data));
     else if (kind === 'beam') renderApiDebugBeam(data);
diff --git a/server/static/index.html b/server/static/index.html
index d313763..5a99363 100644
--- a/server/static/index.html
+++ b/server/static/index.html
@@ -71,7 +71,9 @@
             <button type="button" data-api-demo="elevation">Высота TX</button>
             <button type="button" data-api-demo="profile">Только профиль</button>
             <button type="button" data-api-demo="los">Только LOS/Френель</button>
+            <button type="button" data-api-demo="fresnelSlice">Срез Френеля</button>
             <button type="button" data-api-demo="budget">Только link budget</button>
+            <button type="button" data-api-demo="buildings">Здания вдоль линии</button>
             <button type="button" data-api-demo="landcover">Landcover path</button>
             <button type="button" data-api-demo="beam">Сектор антенны</button>
           </div>