Create assistant

POSThttps:/api.openai.com/v1/assistants

Create an assistant with a model and instructions.

Request body

model
string
ID of the model to use. You can use the List models API to see all of your available models, or see our Model overview for descriptions of them.
- model
  string
  Required
- model
  string
  Required
  gpt-4.1
  string
  gpt-4.1-mini
  string
  gpt-4.1-nano
  string
  gpt-4.1-2025-04-14
  string
  gpt-4.1-mini-2025-04-14
  string
  gpt-4.1-nano-2025-04-14
  string
  o3-mini
  string
  o3-mini-2025-01-31
  string
  o1
  string
  o1-2024-12-17
  string
  gpt-4o
  string
  gpt-4o-2024-11-20
  string
  gpt-4o-2024-08-06
  string
  gpt-4o-2024-05-13
  string
  gpt-4o-mini
  string
  gpt-4o-mini-2024-07-18
  string
  gpt-4.5-preview
  string
  gpt-4.5-preview-2025-02-27
  string
  gpt-4-turbo
  string
  gpt-4-turbo-2024-04-09
  string
  gpt-4-0125-preview
  string
  gpt-4-turbo-preview
  string
  gpt-4-1106-preview
  string
  gpt-4-vision-preview
  string
  gpt-4
  string
  gpt-4-0314
  string
  gpt-4-0613
  string
  gpt-4-32k
  string
  gpt-4-32k-0314
  string
  gpt-4-32k-0613
  string
  gpt-3.5-turbo
  string
  gpt-3.5-turbo-16k
  string
  gpt-3.5-turbo-0613
  string
  gpt-3.5-turbo-1106
  string
  gpt-3.5-turbo-0125
  string
  gpt-3.5-turbo-16k-0613
  string
name
string or null
The name of the assistant. The maximum length is 256 characters.
description
string or null
The description of the assistant. The maximum length is 512 characters.
instructions
string or null
The system instructions that the assistant uses. The maximum length is 256,000 characters.
reasoning_effort
string or null
Defaults: medium
o-series models only
Constrains effort on reasoning for reasoning models. Currently supported values are low, medium, and high. Reducing reasoning effort can result in faster responses and fewer tokens used on reasoning in a response.
- low
  string
- medium
  string
- high
  string
tools
array
Defaults:
A list of tool enabled on the assistant. There can be a maximum of 128 tools per assistant. Tools can be of types code_interpreter, file_search, or function.
- Code interpreter tool
  object
  type
  string
  Required
  The type of tool being defined: code_interpreter
  code_interpreter
  string
- FileSearch tool
  object
  type
  string
  Required
  The type of tool being defined: file_search
  file_search
  string
  file_search
  object
  Overrides for the file search tool.
  max_num_results
  integer
  The maximum number of results the file search tool should output. The default is 20 for gpt-4* models and 5 for gpt-3.5-turbo. This number should be between 1 and 50 inclusive.
  Note that the file search tool may output fewer than max_num_results results. See the file search tool documentation for more information.
  ranking_options
  object
  The ranking options for the file search. If not specified, the file search tool will use the auto ranker and a score_threshold of 0.
  See the file search tool documentation for more information.
  ranker
  string
  The ranker to use for the file search. If not specified will use the auto ranker.
  auto
  string
  default_2024_08_21
  string
  score_threshold
  number
  Required
  The score threshold for the file search. All values must be a floating point number between 0 and 1.
- Function tool
  object
  type
  string
  Required
  The type of tool being defined: function
  function
  string
  function
  object
  Required
  description
  string
  A description of what the function does, used by the model to choose when and how to call the function.
  name
  string
  Required
  The name of the function to be called. Must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64.
  parameters
  object
  The parameters the functions accepts, described as a JSON Schema object. See the guide for examples, and the JSON Schema reference for documentation about the format.
  Omitting parameters defines a function with an empty parameter list.
  strict
  boolean or null
  Defaults: false
  Whether to enable strict schema adherence when generating the function call. If set to true, the model will follow the exact schema defined in the parameters field. Only a subset of JSON Schema is supported when strict is true. Learn more about Structured Outputs in the .
tool_resources
object or null
A set of resources that are used by the assistant's tools. The resources are specific to the type of tool. For example, the code_interpreter tool requires a list of file IDs, while the file_search tool requires a list of vector store IDs.
- code_interpreter
  object
  file_ids
  array
  Defaults:
  A list of file IDs made available to the code_interpreter tool. There can be a maximum of 20 files associated with the tool.
  items
  string
- file_search
  object
  file_search
  object
  file_search
  object
metadata
object or null
Set of 16 key-value pairs that can be attached to an object. This can be useful for storing additional information about the object in a structured format, and querying for objects via API or the dashboard. Keys are strings with a maximum length of 64 characters. Values are strings with a maximum length of 512 characters.
temperature
number or null
Defaults: 1
What sampling temperature to use, between 0 and 2. Higher values like 0.8 will make the output more random, while lower values like 0.2 will make it more focused and deterministic.
top_p
number or null
Defaults: 1
An alternative to sampling with temperature, called nucleus sampling, where the model considers the results of the tokens with top_p probability mass. So 0.1 means only the tokens comprising the top 10% probability mass are considered. We generally recommend altering this or temperature but not both.
response_format
string or object
Specifies the format that the model must output. Compatible with GPT-4o, GPT-4 Turbo, and all GPT-3.5 Turbo models since gpt-3.5-turbo-1106.
Setting to enables Structured Outputs which ensures the model will match your supplied JSON schema. Learn more in the Structured Outputs guide.
Setting to enables JSON mode, which ensures the message the model generates is valid JSON.
Important: when using JSON mode, you must also instruct the model to produce JSON yourself via a system or user message. Without this, the model may generate an unending stream of whitespace until the generation reaches the token limit, resulting in a long-running and seemingly "stuck" request. Also note that the message content may be partially cut off if finish_reason="length", which indicates the generation exceeded max_tokens or the conversation exceeded the max context length.
- response_format
  string
  auto is the default value
  auto
  string
- Text
  object
  Default response format. Used to generate text responses.
  type
  string
  Required
  The type of response format being defined. Always text.
  text
  string
- JSON object
  object
  JSON object response format. An older method of generating JSON responses. Using json_schema is recommended for models that support it. Note that the model will not generate JSON without a system or user message instructing it to do so.
  type
  string
  Required
  The type of response format being defined. Always json_object.
  json_object
  string
- JSON schema
  object
  JSON Schema response format. Used to generate structured JSON responses. Learn more about Structured Outputs.
  type
  string
  Required
  The type of response format being defined. Always json_schema.
  json_schema
  string
  json_schema
  object
  Required
  Structured Outputs configuration options, including a JSON Schema.
  description
  string
  A description of what the response format is for, used by the model to determine how to respond in the format.
  name
  string
  Required
  The name of the response format. Must be a-z, A-Z, 0-9, or contain underscores and dashes, with a maximum length of 64.
  schema
  object
  The schema for the response format, described as a JSON Schema object. Learn how to build JSON schemas here.
  strict
  boolean or null
  Defaults: false
  Whether to enable strict schema adherence when generating the output. If set to true, the model will always follow the exact schema defined in the schema field. Only a subset of JSON Schema is supported when strict is true. To learn more, read the Structured Outputs guide.

Response

Example request

1curl "https://api.openai.com/v1/assistants" \
2  -H "Content-Type: application/json" \
3  -H "Authorization: Bearer $OPENAI_API_KEY" \
4  -H "OpenAI-Beta: assistants=v2" \
5  -d '{
6    "instructions": "You are a personal math tutor. When asked a question, write and run Python code to answer the question.",
7    "name": "Math Tutor",
8    "tools": [{"type": "code_interpreter"}],
9    "model": "gpt-4o"
10  }'

Example response

1{
2  "id": "asst_abc123",
3  "object": "assistant",
4  "created_at": 1698984975,
5  "name": "Math Tutor",
6  "description": null,
7  "model": "gpt-4o",
8  "instructions": "You are a personal math tutor. When asked a question, write and run Python code to answer the question.",
9  "tools": [
10    {
11      "type": "code_interpreter"
12    }
13  ],
14  "metadata": {},
15  "top_p": 1.0,
16  "temperature": 1.0,
17  "response_format": "auto"
18}

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