langchain/tools/plugin.py/AIPluginTool/from_plugin_url
class AIPluginTool:    def from_plugin_url(cls, url: str) -> AIPluginTool:
        plugin = AIPlugin.from_url(url)
        description = (
            f"Call this tool to get the OpenAPI spec (and usage guide) "
            f"for interacting with the {plugin.name_for_human} API. "
            f"You should only call this ONCE! What is the "
            f"{plugin.name_for_human} API useful for? "
        ) + plugin.description_for_human
        open_api_spec_str = requests.get(plugin.api.url).text
        open_api_spec = marshal_spec(open_api_spec_str)
        api_spec = (
            f"Usage Guide: {plugin.description_for_model}\n\n"
            f"OpenAPI Spec: {open_api_spec}"
        )

        return cls(
            name=plugin.name_for_model,
            description=description,
            plugin=plugin,
            api_spec=api_spec,
        )