OpenAI

Use OpenAI GPT and o1 models with Kern agents.

The GPT models are the best in class LLMs and used as the default LLM by Agents. OpenAI supports a variety of world-class models. See their models here.

We recommend experimenting to find the best-suited model for your use-case. Here are some general recommendations:

gpt-5-mini is good for most general use-cases.
gpt-5-nano model is good for smaller tasks and faster inference.
o1 models are good for complex reasoning and multi-step tasks.
gpt-5-mini is a strong reasoning model with support for tool-calling and structured outputs, but at a much lower cost.

OpenAI have tier based rate limits. See the docs for more information.

Authentication

Set your OPENAI_API_KEY environment variable. You can get one from OpenAI here.

1export OPENAI_API_KEY=sk-***

1setx OPENAI_API_KEY sk-***

Example

Use OpenAIChat with your Agent:

1from kern.agent import Agent
2from kern.models.openai import OpenAIResponses
3
4agent = Agent(
5    model=OpenAIResponses(id="gpt-5.2"),
6    markdown=True
7)
8
9# Print the response in the terminal
10agent.print_response("Share a 2 sentence horror story.")

Prompt caching

Prompt caching will happen automatically using our OpenAIChat model. You can read more about how OpenAI handle caching in their docs.

Note View more examples here.

Parameters

For more information, please refer to the OpenAI docs as well.

Parameter	Type	Default	Description
`id`	`str`	`"gpt-4o"`	The id of the OpenAI model to use
`name`	`str`	`"OpenAIChat"`	The name of the model
`provider`	`str`	`"OpenAI"`	The provider of the model
`store`	`Optional[bool]`	`None`	Whether to store the conversation for training purposes
`reasoning_effort`	`Optional[str]`	`None`	The reasoning effort level for o1 models ("low", "medium", "high")
`verbosity`	`Optional[Literal["low", "medium", "high"]]`	`None`	Controls verbosity level of reasoning models
`metadata`	`Optional[Dict[str, Any]]`	`None`	Developer-defined metadata to associate with the completion
`frequency_penalty`	`Optional[float]`	`None`	Penalizes new tokens based on their frequency in the text so far (-2.0 to 2.0)
`logit_bias`	`Optional[Any]`	`None`	Modifies the likelihood of specified tokens appearing in the completion
`logprobs`	`Optional[bool]`	`None`	Whether to return log probabilities of the output tokens
`top_logprobs`	`Optional[int]`	`None`	Number of most likely tokens to return log probabilities for (0 to 20)
`max_tokens`	`Optional[int]`	`None`	Maximum number of tokens to generate (deprecated, use max_completion_tokens)
`max_completion_tokens`	`Optional[int]`	`None`	Maximum number of completion tokens to generate
`modalities`	`Optional[List[str]]`	`None`	List of modalities to use ("text" and/or "audio")
`audio`	`Optional[Dict[str, Any]]`	`None`	Audio configuration (e.g., `{"voice": "alloy", "format": "wav"}`)
`presence_penalty`	`Optional[float]`	`None`	Penalizes new tokens based on whether they appear in the text so far (-2.0 to 2.0)
`seed`	`Optional[int]`	`None`	Random seed for deterministic sampling
`stop`	`Optional[Union[str, List[str]]]`	`None`	Up to 4 sequences where the API will stop generating further tokens
`temperature`	`Optional[float]`	`None`	Controls randomness in the model's output (0.0 to 2.0)
`user`	`Optional[str]`	`None`	A unique identifier representing your end-user
`top_p`	`Optional[float]`	`None`	Controls diversity via nucleus sampling (0.0 to 1.0)
`service_tier`	`Optional[str]`	`None`	Service tier to use ("auto", "default", "flex", "priority")
`strict_output`	`bool`	`True`	Controls schema adherence for structured outputs
`extra_headers`	`Optional[Any]`	`None`	Additional headers to include in requests
`extra_query`	`Optional[Any]`	`None`	Additional query parameters to include in requests
`extra_body`	`Optional[Any]`	`None`	Additional body parameters to include in requests
`request_params`	`Optional[Dict[str, Any]]`	`None`	Additional parameters to include in the request
`role_map`	`Optional[Dict[str, str]]`	`None`	Mapping of message roles to OpenAI roles
`api_key`	`Optional[str]`	`None`	The API key for authenticating with OpenAI (defaults to OPENAI_API_KEY env var)
`organization`	`Optional[str]`	`None`	The organization ID to use for requests
`base_url`	`Optional[Union[str, httpx.URL]]`	`None`	The base URL for the OpenAI API
`timeout`	`Optional[float]`	`None`	Request timeout in seconds
`max_retries`	`Optional[int]`	`None`	Maximum number of retries for failed requests
`default_headers`	`Optional[Any]`	`None`	Default headers to include in all requests
`default_query`	`Optional[Any]`	`None`	Default query parameters to include in all requests
`http_client`	`Optional[Union[httpx.Client, httpx.AsyncClient]]`	`None`	HTTP client instance for making requests
`client_params`	`Optional[Dict[str, Any]]`	`None`	Additional parameters for client configuration

OpenAIChat is a subclass of the Model class and has access to the same params.