public Builder removeTools(int index) {
      if (toolsBuilder_ == null) {
        ensureToolsIsMutable();
        tools_.remove(index);
        onChanged();
      } else {
        toolsBuilder_.remove(index);
      }
      return this;
    }
<pre>
Optional. A list of `Tools` the model may use to generate the next
response.

A `Tool` is a piece of code that enables the system to interact with
external systems to perform an action, or set of actions, outside of
knowledge and scope of the model.
</pre>

<code>
repeated .google.cloud.vertexai.v1.Tool tools = 6 [(.google.api.field_behavior) = OPTIONAL];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/CountTokensRequest.java