public Builder setRetrievalConfig(
        com.google.cloud.vertexai.api.RetrievalConfig.Builder builderForValue) {
      if (retrievalConfigBuilder_ == null) {
        retrievalConfig_ = builderForValue.build();
      } else {
        retrievalConfigBuilder_.setMessage(builderForValue.build());
      }
      bitField0_ |= 0x00000002;
      onChanged();
      return this;
    }
<pre>
Optional. Retrieval config.
</pre>

<code>
.google.cloud.vertexai.v1.RetrievalConfig retrieval_config = 2 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/ToolConfig.java