---
title: "Changes to Create a Message"
method: POST
path: "/v1/messages"
---

# Changes to Create a Message

`POST /v1/messages`

> Every recorded change to this operation, newest first.

## Timeline

Changed in 1 of 2 revisions.

- **2026-11-03** `0dfd8d5c3b27`: 7 breaking, 27 info

## Changes

- **2026-11-03** `0dfd8d5c3b27`: 7 breaking, 27 info
  - added the new required request property `max_tokens`
  - the request's body type changed from no type to `object`
  - the request property `messages` became required
  - the request property `model` became required
  - the `messages` request property type changed from no type to `array`
  - added `#/components/schemas/AnthropicMessageStartEvent, #/components/schemas/AnthropicMessageDeltaEvent, #/components/schemas/AnthropicMessageStopEvent, #/components/schemas/AnthropicContentBlockStartEvent, #/components/schemas/AnthropicContentBlockDeltaEvent, #/components/schemas/AnthropicContentBlockStopEvent` to the response body `oneOf` list for the response status `200` (media type: text/event-stream)
  - the response's body type changed from no type to `object` for status `200` (media type: application/json)
  - added the new optional request property `cache_control`
  - added the new optional request property `container`
  - added the new optional request property `inference_geo`
  - added the new optional request property `metadata`
  - added the new optional request property `output_config`
  - added the new optional request property `service_tier`
  - added the new optional request property `stop_sequences`
  - added the new optional request property `stream`
  - added the new optional request property `system`
  - added the new optional request property `temperature`
  - added the new optional request property `thinking`
  - added the new optional request property `tool_choice`
  - added the new optional request property `tools`
  - added the new optional request property `top_k`
  - added the new optional request property `top_p`
  - added `subschema #1, subschema #2, subschema #3, subschema #4, subschema #5, subschema #6, subschema #7, subschema #8, subschema #9, subschema #10, subschema #11, subschema #12, subschema #13, subschema #14, subschema #15, subschema #16, subschema #17, subschema #18, subschema #19` to the `model` request property `anyOf` list
  - added response discriminator for the response status `200` (media type: text/event-stream)
  - added the required property `container` to the response with the `200` status (media type: application/json)
  - added the required property `content` to the response with the `200` status (media type: application/json)
  - added the required property `id` to the response with the `200` status (media type: application/json)
  - added the required property `model` to the response with the `200` status (media type: application/json)
  - added the required property `role` to the response with the `200` status (media type: application/json)
  - added the required property `stop_details` to the response with the `200` status (media type: application/json)
  - added the required property `stop_reason` to the response with the `200` status (media type: application/json)
  - added the required property `stop_sequence` to the response with the `200` status (media type: application/json)
  - added the required property `type` to the response with the `200` status (media type: application/json)
  - added the required property `usage` to the response with the `200` status (media type: application/json)

---

[Operation](https://skmtc.dev/aihubmix/apis/aihubmix-gateway-api/docs/v1/messages/post.md) - [API](https://skmtc.dev/aihubmix/apis/aihubmix-gateway-api.md) - [Page](https://skmtc.dev/aihubmix/apis/aihubmix-gateway-api/changes/v1/messages/post)