Update Image segmentation description (#23261)

* Update Image segmentation description

* prompt -> label

src/transformers/tools/image_segmentation.py

@@ -28,10 +28,9 @@ if is_vision_available():
 
 class ImageSegmentationTool(PipelineTool):
     description = (
-        "This is a tool that creates a segmentation mask identifiying elements inside an image according to a prompt. "
-        "It takes two arguments named `image` which should be the original image, and `prompt` which should be a text "
-        "describing the elements what should be identified in the segmentation mask. The tool returns the mask as a "
-        "black-and-white image."
+        "This is a tool that creates a segmentation mask of an image according to a label. It cannot create an image."
+        "It takes two arguments named `image` which should be the original image, and `label` which should be a text "
+        "describing the elements what should be identified in the segmentation mask. The tool returns the mask."
     )
     default_checkpoint = "CIDAS/clipseg-rd64-refined"
     name = "image_segmenter"
@@ -44,9 +43,9 @@ class ImageSegmentationTool(PipelineTool):
         requires_backends(self, ["vision"])
         super().__init__(*args, **kwargs)
 
-    def encode(self, image: "Image", prompt: str):
+    def encode(self, image: "Image", label: str):
         self.pre_processor.image_processor.size = {"width": image.size[0], "height": image.size[1]}
-        return self.pre_processor(text=[prompt], images=[image], padding=True, return_tensors="pt")
+        return self.pre_processor(text=[label], images=[image], padding=True, return_tensors="pt")
 
     def forward(self, inputs):
         with torch.no_grad():