/v1/responses).
Key Capabilities
- Responses API — Uses the new
/v1/responsesendpoint, replacingmessageswithinput - Reasoning control — Configurable reasoning effort (minimal / low / medium / high) and summary
- Verbosity control — Set response verbosity to low, medium, or high
- Streaming — Real-time token streaming via SSE
- Tool calling — Supports function calling and tool use
Quick Example
Parameters
| Parameter | Type | Required | Description |
|---|---|---|---|
model | string | Yes | Fixed value: gpt-5.2-codex |
input | array | Yes | Array of { role, content } objects |
stream | boolean | No | Enable SSE streaming, default false |
temperature | float | No | 0–2, controls randomness, default 1 |
top_p | float | No | Nucleus sampling threshold, default 1 |
max_output_tokens | integer | No | Maximum output tokens |
stop | string / array | No | Sequences where generation stops |
reasoning | object | No | { effort, summary } — Controls reasoning depth |
text | object | No | { format, verbosity } — Controls output format and verbosity |
tools | array | No | List of tools the model can call |
store | boolean | No | Store response for later retrieval, default true |
API Reference
View the interactive API Playground for GPT-5.2 Codex.

