---
title: "Changes to Chat Completions"
method: POST
path: "/v1/chat/completions"
---

# Changes to Chat Completions

`POST /v1/chat/completions`

> Every recorded change to this operation, newest first.

## Timeline

Changed in 3 of 6 revisions.

- **2026-09-24** `0e5e86e2bae5`: 4 warning, 2 info
- **2026-09-24** `1cffaad2a921`: 3 warning, 2 info
- **2026-08-04** `60b6b70202c9`: 8 info

## Changes

- **2026-09-24** `0e5e86e2bae5`: 4 warning, 2 info
  - removed the request property `effort`
  - removed the request property `models`
  - removed the optional property `x_pioneer` from the response with the `200` status (media type: application/json)
  - removed the optional property `x_pioneer` from the response with the `200` status (media type: text/event-stream)
  - added the optional property `x_fastino` to the response with the `200` status (media type: application/json)
  - added the optional property `x_fastino` to the response with the `200` status (media type: text/event-stream)
- **2026-09-24** `1cffaad2a921`: 3 warning, 2 info
  - the `temperature/anyOf[subschema #1]/` request property's max was set to `2.00`
  - the `temperature/anyOf[subschema #1]/` request property's min was set to `0.00`
  - removed the optional property `detail` from the response with the `422` status
  - added the new optional request property `threshold`
  - added the required property `error` to the response with the `422` status
- **2026-08-04** `60b6b70202c9`: 8 info
  - added the new optional request property `effort`
  - added the new optional request property `messages/items/reasoning_content`
  - added the new optional request property `models`
  - added the new optional request property `system`
  - added the optional property `x_pioneer/anyOf[subschema #1: PioneerExtension]/routed_model` to the response with the `200` status (media type: application/json)
  - added the optional property `x_pioneer/anyOf[subschema #1: PioneerExtension]/routed_model` to the response with the `200` status (media type: text/event-stream)
  - added the optional property `x_pioneer/anyOf[subschema #1: PioneerExtension]/savings` to the response with the `200` status (media type: application/json)
  - added the optional property `x_pioneer/anyOf[subschema #1: PioneerExtension]/savings` to the response with the `200` status (media type: text/event-stream)

---

[Operation](https://skmtc.dev/pioneer/apis/brain-api/docs/v1/chat/completions/post.md) - [API](https://skmtc.dev/pioneer/apis/brain-api.md) - [Page](https://skmtc.dev/pioneer/apis/brain-api/changes/v1/chat/completions/post)