[MCP] better tiny-agents CLI help (#3105)

* nit

* better cli help

Author: hanouticelina

src/huggingface_hub/inference/_mcp/cli.py

@@ -134,9 +134,10 @@ def run(
         None,
         help=(
             "Path to a local folder containing an agent.json file or a built-in agent "
-            "stored in a Hugging Face dataset (default: "
-            "https://huggingface.co/datasets/tiny-agents/tiny-agents)"
+            "stored in the 'tiny-agents/tiny-agents' Hugging Face dataset "
+            "(https://huggingface.co/datasets/tiny-agents/tiny-agents)"
         ),
+        show_default=False,
     ),
 ):
     try: