---
title: "Changes to Create assistant"
method: POST
path: "/assistants"
---

# Changes to Create assistant

`POST /assistants`

> Every recorded change to this endpoint, newest first.

## Timeline

Changed in 16 of 163 revisions.

- **2026-09-03** `9430b00d75b4` — 1 info
- **2026-08-14** `6ac2618eefd7` — 1 info
- **2026-08-05** `ab0c5306e390` — 1 info
- **2026-05-13** `74cbcf73838f` — 26 breaking, 4 warning, 27 info
- **2025-04-29** `6a6c681b1820` — 6 info
- **2025-03-11** `6ab43fe7798e` — 2 breaking, 1 warning, 5 info
- **2025-02-11** `96060afbb5b9` — 1 breaking, 2 info
- **2025-01-31** `fc164a27fdb9` — 3 breaking, 3 info
- **2025-01-31** `15156e46769c` — 2 breaking, 1 warning, 3 info
- **2025-01-22** `bdebcdfcbbde` — 3 breaking, 2 info
- **2024-12-04** `223e7c033ac6` — 1 info
- **2024-09-13** `4c9e3967c707` — 1 breaking, 1 info
- **2024-08-23** `5856f8b0c850` — 2 info
- **2024-08-06** `8eca3b09b705` — 3 breaking, 7 info
- **2024-07-17** `12529f330aab` — 2 breaking
- **2024-07-15** `493a67abde1a` — 2 info

## Changes

- **2026-09-03** `9430b00d75b4` — 1 info
  - added the optional property `error/misalignment` to the response with the `429` status
- **2026-08-14** `6ac2618eefd7` — 1 info
  - added the non-success response with the status `429`
- **2026-08-05** `ab0c5306e390` — 1 info
  - added the new `max` enum value to the request property `reasoning_effort/anyOf[subschema #1]/`
- **2026-05-13** `74cbcf73838f` — 26 breaking, 4 warning, 27 info
  - the request property `description` became not nullable
  - the request property `instructions` became not nullable
  - the request property `metadata` became not nullable
  - the request property `name` became not nullable
  - the request property `reasoning_effort` became not nullable
  - the request property `response_format` became not nullable
  - the request property `temperature` became not nullable
  - the request property `tool_resources` became not nullable
  - the request property `tools/items/oneOf[subschema #3: Function tool]/function/strict` became not nullable
  - the request property `top_p` became not nullable
  - removed the enum value `high` of the request property `reasoning_effort`
  - removed the enum value `low` of the request property `reasoning_effort`
  - removed the enum value `medium` of the request property `reasoning_effort`
  - removed `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` from the `response_format` request property `oneOf` list
  - the `tool_resources` request property type changed from `object` to no type
  - response property `description` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
  - response property `instructions` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
  - response property `metadata` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
  - response property `name` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
  - response property `temperature` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
  - response property `tools/items/oneOf[subschema #3: Function tool]/function/strict` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
  - response property `top_p` list-of-types was widened by adding types `null` to media type `application/json` of response `200`
  - the `description` response property's maxLength was unset from `512` for the response status `200`
  - the `instructions` response property's maxLength was unset from `256000` for the response status `200`
  - the `name` response property's maxLength was unset from `256` for the response status `200`
  - the `tool_resources` response's property type changed from `object` to no type for status `200`
  - removed the request property `tool_resources/code_interpreter`
  - removed the request property `tool_resources/file_search`
  - removed the optional property `tool_resources/code_interpreter` from the response with the `200` status
  - removed the optional property `tool_resources/file_search` from the response with the `200` status
  - endpoint deprecated
  - added `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` to the `response_format` request property `anyOf` list
  - added `subschema #1, subschema #2` to the `tool_resources` request property `anyOf` list
  - the `reasoning_effort` request property default value `medium` was removed
  - the `strict` request property default value `false` was removed
  - the `temperature` request property default value `1` was removed
  - the `top_p` request property default value `1` was removed
  - added the new `gpt-5` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added the new `gpt-5-2025-08-07` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added the new `gpt-5-mini` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - …17 more
- **2025-04-29** `6a6c681b1820` — 6 info
  - added the new `gpt-4.1` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added the new `gpt-4.1-2025-04-14` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added the new `gpt-4.1-mini` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added the new `gpt-4.1-mini-2025-04-14` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added the new `gpt-4.1-nano` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added the new `gpt-4.1-nano-2025-04-14` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
- **2025-03-11** `6ab43fe7798e` — 2 breaking, 1 warning, 5 info
  - the response property `response_format` became nullable for the status `200`
  - added `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` to the `response_format` response property `oneOf` list for the response status `200`
  - removed `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` from the `response_format` request property `allOf` list
  - the request property `response_format` became nullable
  - added the new `gpt-4.5-preview` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added the new `gpt-4.5-preview-2025-02-27` enum value to the request property `model/anyOf[#/components/schemas/AssistantSupportedModels]/`
  - added `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` to the `response_format` request property `oneOf` list
  - removed `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` from the `response_format` response property `allOf` list for the response status `200`
- **2025-02-11** `96060afbb5b9` — 1 breaking, 2 info
  - removed `subschema #2` from the `model` request property `anyOf` list
  - added the new optional request property `reasoning_effort`
  - added `#/components/schemas/AssistantSupportedModels` to the `model` request property `anyOf` list
- **2025-01-31** `fc164a27fdb9` — 3 breaking, 3 info
  - added `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` to the `response_format` request property `allOf` list
  - the request property `response_format` became not nullable
  - removed `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` from the `response_format` request property `oneOf` list
  - the request property `tool_resources/file_search/vector_stores/items/metadata` became nullable
  - added `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` to the `response_format` response property `allOf` list for the response status `200`
  - removed `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` from the `response_format` response property `oneOf` list for the response status `200`
- **2025-01-31** `15156e46769c` — 2 breaking, 1 warning, 3 info
  - the response property `response_format` became nullable for the status `200`
  - added `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` to the `response_format` response property `oneOf` list for the response status `200`
  - removed `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` from the `response_format` request property `allOf` list
  - the request property `response_format` became nullable
  - added `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` to the `response_format` request property `oneOf` list
  - removed `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` from the `response_format` response property `allOf` list for the response status `200`
- **2025-01-22** `bdebcdfcbbde` — 3 breaking, 2 info
  - added `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` to the `response_format` request property `allOf` list
  - the request property `response_format` became not nullable
  - removed `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` from the `response_format` request property `oneOf` list
  - added `#/components/schemas/AssistantsApiResponseFormatOption, subschema #2` to the `response_format` response property `allOf` list for the response status `200`
  - removed `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema, subschema #1` from the `response_format` response property `oneOf` list for the response status `200`
- **2024-12-04** `223e7c033ac6` — 1 info
  - added the new `gpt-4o-2024-11-20` enum value to the request property `model/anyOf[subschema #2]/`
- **2024-09-13** `4c9e3967c707` — 1 breaking, 1 info
  - the request property `tools/items/oneOf[subschema #2: FileSearch tool]/file_search/ranking_options/score_threshold` became required
  - the response property `tools/items/oneOf[subschema #2: FileSearch tool]/file_search/ranking_options/score_threshold` became required for the status `200`
- **2024-08-23** `5856f8b0c850` — 2 info
  - added the new optional request property `tools/items/oneOf[subschema #2: FileSearch tool]/file_search/ranking_options`
  - added the optional property `tools/items/oneOf[subschema #2: FileSearch tool]/file_search/ranking_options` to the response with the `200` status
- **2024-08-06** `8eca3b09b705` — 3 breaking, 7 info
  - removed the enum value `none` of the request property `response_format/oneOf[subschema #1]/`
  - removed `#/components/schemas/AssistantsApiResponseFormat` from the `response_format` request property `oneOf` list
  - added `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema` to the `response_format` response property `oneOf` list for the response status `200`
  - added the new optional request property `tools/items/oneOf[subschema #3: Function tool]/function/strict`
  - added the new `gpt-4o-2024-08-06` enum value to the request property `model/anyOf[subschema #2]/`
  - added the new `gpt-4o-2024-08-06` enum value to the request property `model/anyOf[subschema #2]/`
  - added `#/components/schemas/ResponseFormatText, #/components/schemas/ResponseFormatJsonObject, #/components/schemas/ResponseFormatJsonSchema` to the `response_format` request property `oneOf` list
  - added the optional property `tools/items/oneOf[subschema #3: Function tool]/function/strict` to the response with the `200` status
  - removed the `none` enum value from the `response_format/oneOf[subschema #1]/` response property for the response status `200`
  - removed `#/components/schemas/AssistantsApiResponseFormat` from the `response_format` response property `oneOf` list for the response status `200`
- **2024-07-17** `12529f330aab` — 2 breaking
  - removed the enum value `gpt-4o-mini` of the request property `model/anyOf[subschema #2]/`
  - removed the enum value `gpt-4o-mini-2024-07-18` of the request property `model/anyOf[subschema #2]/`
- **2024-07-15** `493a67abde1a` — 2 info
  - added the new `gpt-4o-mini` enum value to the request property `model/anyOf[subschema #2]/`
  - added the new `gpt-4o-mini-2024-07-18` enum value to the request property `model/anyOf[subschema #2]/`

---

[Operation](https://skmtc.dev/openai/apis/openapi/docs/assistants/post.md) · [API](https://skmtc.dev/openai/apis/openapi.md) · [Page](https://skmtc.dev/openai/apis/openapi/changes/assistants/post)