"Item": {
                    "title": "Item",
                    "required": ["data"],
                    "type": "object",
                    "properties": {"data": {"title": "Data", "type": "string"}},
                },
                "ValidationError": {
                    "title": "ValidationError",
                    "required": ["loc", "msg", "type"],
                    "type": "object",

 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,

 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the

 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the

    /** The protocol scheme for file access (maximum 10 characters). */
    @Size(max = 10)
    public String protocolScheme;

    /** The username for file authentication (required, maximum 100 characters). */
    @Required
    @Size(max = 100)
    public String username;

    /** The password for file authentication (maximum 100 characters). */
    @Size(max = 100)
    public String password;

                    "title": "ResponseMessage",
                    "required": ["message"],
                    "type": "object",
                    "properties": {"message": {"title": "Message", "type": "string"}},
                },
                "User": {
                    "title": "User",
                    "required": ["username", "email"],
                    "type": "object",

        - binary
    validations:
      required: true

  - type: input
    id: tfversion
    attributes:
      label: TensorFlow version
      placeholder: e.g., tf 2.8
    validations:
      required: true
  - type: dropdown
    id: Code
    attributes:
      label: Custom code
      options:
        - "Yes"
        - "No"
    validations:
      required: true
  - type: input
    id: OS

     * Channel binding is disabled
     */
    public static final int CHANNEL_BINDING_DISABLED = 0;

    /**
     * Channel binding is preferred but not required
     */
    public static final int CHANNEL_BINDING_PREFERRED = 1;

    /**
     * Channel binding is required
     */
    public static final int CHANNEL_BINDING_REQUIRED = 2;

    /**
     * Default maximum number of channels per session
     */

                    },
                    "summary": "Read Items",
                    "operationId": "read_items_items__get",
                    "parameters": [
                        {
                            "required": False,
                            "schema": {
                                "anyOf": [
                                    {
                                        "type": "string",

The way to describe this in OpenAPI, is to mark that field as **required**, because it will always be there.

Because of that, the JSON Schema for a model can be different depending on if it's used for **input or output**:

* for **input** the `description` will **not be required**
* for **output** it will be **required** (and possibly `None`, or in JSON terms, `null`)