public static final com.google.protobuf.Descriptors.Descriptor getDescriptor() {
      return com.google.cloud.vertexai.api.ToolProto
          .internal_static_google_cloud_vertexai_v1_Retrieval_descriptor;
    }
<pre>
Defines a retrieval tool that model can call to access external knowledge.
</pre>

Protobuf type {@code google.cloud.vertexai.v1.Retrieval}
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/Retrieval.java