---
title: "Changes to Create an Anthropic message"
method: POST
path: "/messages"
---

# Changes to Create an Anthropic message

`POST /messages`

> Every recorded change to this operation, newest first.

## Timeline

Changed in 1 of 2 revisions.

- **2026-11-03** `d63ac1749ae7`: 1 breaking, 40 warning, 22 info

## Changes

- **2026-11-03** `d63ac1749ae7`: 1 breaking, 40 warning, 22 info
  - removed the enum value `priority` of the request property `metadata/completion_window`
  - removed the optional property `error/code` from the response with the `400` status
  - removed the optional property `error/code` from the response with the `401` status
  - removed the optional property `error/code` from the response with the `500` status
  - removed the optional property `error/param` from the response with the `400` status
  - removed the optional property `error/param` from the response with the `401` status
  - removed the optional property `error/param` from the response with the `500` status
  - added the new `api_error` enum value to the `error/type` response property for the response status `400`
  - added the new `api_error` enum value to the `error/type` response property for the response status `401`
  - added the new `api_error` enum value to the `error/type` response property for the response status `500`
  - added the new `authentication_error` enum value to the `error/type` response property for the response status `400`
  - added the new `authentication_error` enum value to the `error/type` response property for the response status `401`
  - added the new `authentication_error` enum value to the `error/type` response property for the response status `500`
  - added the new `billing_error` enum value to the `error/type` response property for the response status `400`
  - added the new `billing_error` enum value to the `error/type` response property for the response status `401`
  - added the new `billing_error` enum value to the `error/type` response property for the response status `500`
  - added the new `conflict_error` enum value to the `error/type` response property for the response status `400`
  - added the new `conflict_error` enum value to the `error/type` response property for the response status `401`
  - added the new `conflict_error` enum value to the `error/type` response property for the response status `500`
  - added the new `invalid_request_error` enum value to the `error/type` response property for the response status `400`
  - added the new `invalid_request_error` enum value to the `error/type` response property for the response status `401`
  - added the new `invalid_request_error` enum value to the `error/type` response property for the response status `500`
  - added the new `model_context_window_exceeded` enum value to the `stop_reason` response property for the response status `200` (media type: application/json)
  - added the new `not_found_error` enum value to the `error/type` response property for the response status `400`
  - added the new `not_found_error` enum value to the `error/type` response property for the response status `401`
  - added the new `not_found_error` enum value to the `error/type` response property for the response status `500`
  - added the new `overloaded_error` enum value to the `error/type` response property for the response status `400`
  - added the new `overloaded_error` enum value to the `error/type` response property for the response status `401`
  - added the new `overloaded_error` enum value to the `error/type` response property for the response status `500`
  - added the new `permission_error` enum value to the `error/type` response property for the response status `400`
  - added the new `permission_error` enum value to the `error/type` response property for the response status `401`
  - added the new `permission_error` enum value to the `error/type` response property for the response status `500`
  - added the new `rate_limit_error` enum value to the `error/type` response property for the response status `400`
  - added the new `rate_limit_error` enum value to the `error/type` response property for the response status `401`
  - added the new `rate_limit_error` enum value to the `error/type` response property for the response status `500`
  - added the new `request_too_large` enum value to the `error/type` response property for the response status `400`
  - added the new `request_too_large` enum value to the `error/type` response property for the response status `401`
  - added the new `request_too_large` enum value to the `error/type` response property for the response status `500`
  - added the new `timeout_error` enum value to the `error/type` response property for the response status `400`
  - added the new `timeout_error` enum value to the `error/type` response property for the response status `401`
  - …23 more

---

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