docs: added toolbox-core to toolbox documentation (#424)

docs/en/getting-started/introduction/_index.md

@@ -108,6 +108,26 @@ Once your server is up and running, you can load the tools into your
 application. See below the list of Client SDKs for using various frameworks:
 
 {{< tabpane text=true persist=header >}}
+{{% tab header="Core" lang="en" %}}
+
+Once you've installed the [Toolbox Core
+SDK](https://pypi.org/project/toolbox-core/), you can load
+tools:
+
+{{< highlight python >}}
+from toolbox_core import ToolboxClient
+
+# update the url to point to your server
+client = ToolboxClient("http://127.0.0.1:5000")
+
+# these tools can be passed to your application! 
+tools = await client.load_toolset("toolset_name")
+{{< /highlight >}}
+
+For more detailed instructions on using the Toolbox Core SDK, see the
+[project's README](https://github.com/googleapis/mcp-toolbox-sdk-python/blob/main/packages/toolbox-core/README.md).
+
+{{% /tab %}}
 {{% tab header="LangChain" lang="en" %}}
 
 Once you've installed the [Toolbox LangChain