OpenAI Compatibility | ASI:One Documentation

Overview

ASI:One implements both of OpenAI’s request formats, so you can use the existing OpenAI client libraries and change only the base URL:

/v1/chat/completions - the Chat Completions format. The default, and what every example in these docs uses unless it says otherwise.
/v1/responses - the Responses format, including retrieving, chaining, cancelling and deleting a response by id.

Each endpoint supports its own OpenAI parameter set. Where they differ, the sections below say which endpoint to use.

API compatibility

Standard OpenAI parameters

These take the same values on /v1/chat/completions as they do on OpenAI’s API:

Parameter	What it does
`model`	The ASI:One model to use. See Models.
`messages`	The conversation so far.
`temperature`	Sampling temperature, `0` to `2`.
`top_p`	Nucleus sampling probability mass.
`max_tokens`	Upper bound on the tokens generated.
`stop`	Up to four strings that end generation when produced.
`stream`	Stream the reply as server-sent events.
`tools`, `tool_choice`	See Tool Calling.
`parallel_tool_calls`	Whether the model may call several tools in one turn.
`response_format`	See Structured Data.
`reasoning_effort`	How deeply the model reasons, on `/v1/chat/completions`. See Reasoning.
`web_search_options`	Gives the model live web search, on `/v1/chat/completions`. See Web Search.

On /v1/responses the same set applies, with input in place of messages and max_output_tokens in place of max_tokens, plus store, metadata, background and reasoning. stop, reasoning_effort and web_search_options belong to /v1/chat/completions alone. On /v1/responses the depth goes in the nested reasoning.effort, and a top-level reasoning_effort there is rejected with a 400; search is the hosted web_search tool instead. See Responses API.

Structured output is the one parameter that changes shape between the two: response_format on /v1/chat/completions, text.format on /v1/responses. Structured Data shows both.

Each model is tuned for the sampling values it was evaluated at, so send temperature and top_p only when you have a reason to move them. See Sampling defaults for the values and for when deviating helps.

Unrecognized parameters

A request carrying a top-level field the endpoint does not recognize is rejected with a 400, and the error names the field:

{
  "error": {
    "message": "unknown parameter: max_token",
    "type": "invalid_request_error",
    "code": "unknown_parameter",
    "param": "max_token",
    "status": 400
  }
}

This is deliberate. A misspelled max_token fails immediately and tells you what to fix, rather than being dropped and leaving you to work out why the reply ignored your limit.

In planner mode the planner manages its own model calls and takes temperature alone.

Custom parameters

These are specific to ASI:One and have no OpenAI equivalent.

Parameter	Endpoint	What it does
`planner_mode`	`/v1/chat/completions`	Routes the request to the planner. See Planner Mode.
`agents`	`/v1/chat/completions`	Agentverse addresses the planner may use. See Planner Mode.
`enable_thinking`	Both	Whether the model reasons first. See Reasoning.
`thinking_budget`	Both	The older way to size reasoning, superseded by `reasoning_effort`. See Reasoning.

All four are top-level fields. With the OpenAI SDK, pass them through extra_body so they land at the top level of the request body. reasoning_effort is not one of them: it is a standard OpenAI field, so the SDK sends it directly.

Next steps

Chat Completions API - The default endpoint in full, including streaming
Responses API - The stateful endpoint, with retrieve and chaining
Reasoning - The ASI:One parameters alongside OpenAI’s reasoning object
Planner Mode - Multi-step work against Agentverse agents and tools