diff --git a/src/tools/gpfWfsGetFeatures/compile.ts b/src/helpers/wfs_internal/compile.ts
similarity index 96%
rename from src/tools/gpfWfsGetFeatures/compile.ts
rename to src/helpers/wfs_internal/compile.ts
index 50b26d0..d4440f3 100644
--- a/src/tools/gpfWfsGetFeatures/compile.ts
+++ b/src/helpers/wfs_internal/compile.ts
@@ -602,19 +602,35 @@ export function getSpatialFilter(input: GpfWfsGetFeaturesInput): SpatialFilter |
 }
 
 /**
- * Builds the list of non-geometric properties to request from the WFS layer.
+ * Build the list of property names to return in the WFS response according to the `select` and `result_type` input parameters.
  *
+ * Note that :
+ * - When `select` is omitted and `result_type` is `results`, all non-geometric properties are returned.
+ * - When `select` is provided, the specified properties are validated according to the featureType from the Catalog.
+ *  
  * @param featureType Feature type definition loaded from the embedded catalog.
  * @param geometryProperty Geometry property already resolved for the feature type.
  * @param input Normalized tool input.
- * @returns The list of selected property names, or every non-geometric property when `select` is omitted.
+ * @returns The list of non-geometric property names to include in the WFS `propertyName` parameter, or an empty list to include all properties.
+*
  */
 function buildSelectList(featureType: Collection, geometryProperty: CollectionProperty, input: GpfWfsGetFeaturesInput) {
-  return input.select && input.select.length > 0
-    ? input.select.map((propertyName) => compileSelectProperty(featureType, geometryProperty, propertyName))
-    : featureType.properties
+  // if `select` is specified, we only return the requested properties (after validation)
+  if (input.select && input.select.length > 0) {
+    return input.select.map((propertyName) => compileSelectProperty(featureType, geometryProperty, propertyName));
+  }
+
+  // if `select` is omitted and result_type is `results`,
+  // we return every non-geometric property 
+  if (input.result_type === "results") {
+    return featureType.properties
       .filter((property) => !property.defaultCrs)
       .map((property) => property.name);
+  }
+
+  // if `select` is omitted and result_type is `hits` or `request`
+  // we don't specify any propertyName
+  return [];
 }
 
 // --- Query Compilation ---
diff --git a/src/tools/gpfWfsGetFeatures/request.ts b/src/helpers/wfs_internal/request.ts
similarity index 100%
rename from src/tools/gpfWfsGetFeatures/request.ts
rename to src/helpers/wfs_internal/request.ts
diff --git a/src/tools/gpfWfsGetFeatures/response.ts b/src/helpers/wfs_internal/response.ts
similarity index 100%
rename from src/tools/gpfWfsGetFeatures/response.ts
rename to src/helpers/wfs_internal/response.ts
diff --git a/src/tools/gpfWfsGetFeatures/schema.ts b/src/helpers/wfs_internal/schema.ts
similarity index 100%
rename from src/tools/gpfWfsGetFeatures/schema.ts
rename to src/helpers/wfs_internal/schema.ts
diff --git a/src/tools/GpfWfsGetFeaturesTool.ts b/src/tools/GpfWfsGetFeaturesTool.ts
index fbbd269..284cbe3 100644
--- a/src/tools/GpfWfsGetFeaturesTool.ts
+++ b/src/tools/GpfWfsGetFeaturesTool.ts
@@ -5,16 +5,16 @@ import { wfsClient } from "../gpf/wfs.js";
 import { fetchJSONPost } from "../helpers/http.js";
 import logger from "../logger.js";
 import { READ_ONLY_OPEN_WORLD_TOOL_ANNOTATIONS } from "../helpers/toolAnnotations.js";
-import { compileQueryParts, geometryToEwkt, getGeometryProperty, getSpatialFilter } from "./gpfWfsGetFeatures/compile.js";
-import { buildMainRequest, buildReferenceGeometryRequest, type CompiledRequest } from "./gpfWfsGetFeatures/request.js";
-import { transformFeatureCollectionResponse } from "./gpfWfsGetFeatures/response.js";
+import { compileQueryParts, geometryToEwkt, getGeometryProperty, getSpatialFilter } from "../helpers/wfs_internal/compile.js";
+import { buildMainRequest, buildReferenceGeometryRequest, type CompiledRequest } from "../helpers/wfs_internal/request.js";
+import { transformFeatureCollectionResponse } from "../helpers/wfs_internal/response.js";
 import {
   gpfWfsGetFeaturesHitsOutputSchema,
   gpfWfsGetFeaturesInputSchema,
   type GpfWfsGetFeaturesInput,
   gpfWfsGetFeaturesPublishedInputSchema,
   gpfWfsGetFeaturesRequestOutputSchema,
-} from "./gpfWfsGetFeatures/schema.js";
+} from "../helpers/wfs_internal/schema.js";
 
 class GpfWfsGetFeaturesTool extends MCPTool<GpfWfsGetFeaturesInput> {
   name = "gpf_wfs_get_features";
diff --git a/test/gpfWfsGetFeatures/compile.test.ts b/test/helpers/wfs_internal/compile.test.ts
similarity index 95%
rename from test/gpfWfsGetFeatures/compile.test.ts
rename to test/helpers/wfs_internal/compile.test.ts
index c1f85e8..2ed7735 100644
--- a/test/gpfWfsGetFeatures/compile.test.ts
+++ b/test/helpers/wfs_internal/compile.test.ts
@@ -1,7 +1,7 @@
 import type { Collection } from "@ignfab/gpf-schema-store";
 
-import { compileQueryParts, geometryToEwkt } from "../../src/tools/gpfWfsGetFeatures/compile";
-import type { GpfWfsGetFeaturesInput } from "../../src/tools/gpfWfsGetFeatures/schema";
+import { compileQueryParts, geometryToEwkt } from "../../../src/helpers/wfs_internal/compile";
+import type { GpfWfsGetFeaturesInput } from "../../../src/helpers/wfs_internal/schema";
 
 describe("gpfWfsGetFeatures/compile", () => {
   const featureType: Collection = {
@@ -119,4 +119,5 @@ describe("gpfWfsGetFeatures/compile", () => {
     expect(geometryToEwkt({ type: "MultiPoint", coordinates: [[2.3, 48.8], [2.4, 48.9]] })).toEqual("SRID=4326;MULTIPOINT((2.3 48.8),(2.4 48.9))");
     expect(geometryToEwkt({ type: "LineString", coordinates: [[2.3, 48.8], [2.4, 48.9]] })).toEqual("SRID=4326;LINESTRING(2.3 48.8,2.4 48.9)");
   });
+
 });