public Builder addTools(com.google.cloud.vertexai.api.Tool value) {
      if (toolsBuilder_ == null) {
        if (value == null) {
          throw new NullPointerException();
        }
        ensureToolsIsMutable();
        tools_.add(value);
        onChanged();
      } else {
        toolsBuilder_.addMessage(value);
      }
      return this;
    }
<pre>
Optional. Input only. Immutable. A list of `Tools` the model may use to
generate the next response
</pre>

<code>
repeated .google.cloud.vertexai.v1.Tool tools = 5 [(.google.api.field_behavior) = OPTIONAL, (.google.api.field_behavior) = IMMUTABLE, (.google.api.field_behavior) = INPUT_ONLY];
</code>
java-vertexai/proto-google-cloud-vertexai-v1/src/main/java/com/google/cloud/vertexai/api/CachedContent.java