---
title: "Changes to Chat Completion"
method: POST
path: "/openai/deployments/{model}/chat/completions"
---

# Changes to Chat Completion

`POST /openai/deployments/{model}/chat/completions`

> Every recorded change to this operation, newest first.

## Timeline

Changed in 1 of 95 revisions.

- **2026-09-18** `082b5fabd909`: 1 breaking, 3 warning, 14 info

## Changes

- **2026-09-18** `082b5fabd909`: 1 breaking, 3 warning, 14 info
  - the `messages/items/anyOf[subschema #3: ChatCompletionToolMessage]/content/anyOf[subschema #2]/items/` request property type changed from `object` to no type
  - removed the request property `messages/items/anyOf[subschema #3: ChatCompletionToolMessage]/content/anyOf[subschema #2]/items/cache_control`
  - removed the request property `messages/items/anyOf[subschema #3: ChatCompletionToolMessage]/content/anyOf[subschema #2]/items/text`
  - removed the request property `messages/items/anyOf[subschema #3: ChatCompletionToolMessage]/content/anyOf[subschema #2]/items/type`
  - added the new optional request property `messages/items/anyOf[subschema #1: ChatCompletionUserMessage]/cache_control/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #1: ChatCompletionUserMessage]/content/anyOf[subschema #2]/items/anyOf[subschema #1: ChatCompletionTextObject]/cache_control/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #2: ChatCompletionAssistantMessage]/cache_control/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #2: ChatCompletionAssistantMessage]/content/anyOf[subschema #2]/items/anyOf[subschema #1: ChatCompletionTextObject]/cache_control/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #2: ChatCompletionAssistantMessage]/content/anyOf[subschema #2]/items/anyOf[subschema #2: ChatCompletionThinkingBlock]/cache_control/anyOf[subschema #2: ChatCompletionCachedContent]/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #2: ChatCompletionAssistantMessage]/content/anyOf[subschema #2]/items/anyOf[subschema #3: ChatCompletionRedactedThinkingBlock]/cache_control/anyOf[subschema #2: ChatCompletionCachedContent]/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #2: ChatCompletionAssistantMessage]/thinking_blocks/anyOf[subschema #1]/items/anyOf[subschema #1: ChatCompletionThinkingBlock]/cache_control/anyOf[subschema #2: ChatCompletionCachedContent]/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #2: ChatCompletionAssistantMessage]/thinking_blocks/anyOf[subschema #1]/items/anyOf[subschema #2: ChatCompletionRedactedThinkingBlock]/cache_control/anyOf[subschema #2: ChatCompletionCachedContent]/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #4: ChatCompletionSystemMessage]/cache_control/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #5: ChatCompletionFunctionMessage]/content/anyOf[subschema #2]/items/cache_control/ttl`
  - added the new optional request property `messages/items/anyOf[subschema #6: ChatCompletionDeveloperMessage]/cache_control/ttl`
  - added `#/components/schemas/ChatCompletionTextObject, #/components/schemas/ChatCompletionImageObject, #/components/schemas/ChatCompletionToolReferenceObject` to the `messages/items/anyOf[subschema #3: ChatCompletionToolMessage]/content/anyOf[subschema #2]/items/` request property `anyOf` list
  - request property `messages/items/anyOf[subschema #2: ChatCompletionAssistantMessage]/content/anyOf[subschema #2]/items/anyOf[subschema #2: ChatCompletionThinkingBlock]/signature` list-of-types was widened by adding types `null` to media type `application/json`
  - request property `messages/items/anyOf[subschema #2: ChatCompletionAssistantMessage]/thinking_blocks/anyOf[subschema #1]/items/anyOf[subschema #1: ChatCompletionThinkingBlock]/signature` list-of-types was widened by adding types `null` to media type `application/json`

---

[Operation](https://skmtc.dev/flock/apis/litellm-api/docs/openai/deployments/:model/chat/completions/post.md) - [API](https://skmtc.dev/flock/apis/litellm-api.md) - [Page](https://skmtc.dev/flock/apis/litellm-api/changes/openai/deployments/:model/chat/completions/post)