# OpenAI introduces o3 and o4-mini

> OpenAI released o3 and o4-mini as reasoning models that could use ChatGPT tools including web search, file analysis, Python, and image generation. The announcement also described custom-tool access through function calling in the API and reported results from its evaluation and safety programs at launch.

Canonical: https://hypler.com/ai-news/openai-o3-o4-mini-2025
Hypler publication: 2026-10-06
Original source date: 2025-04-16
Publisher: OpenAI
Article kind: source-briefing
Category: Models
Tags: reasoning, tool use, OpenAI

## Engineering relevance

Tool-capable reasoning models widen a system's action surface. Hypler should bind every external tool to least privilege, approval boundaries, logs, and test cases for errors and refusals.

## Original source

- [OpenAI](https://openai.com/index/introducing-o3-and-o4-mini/)

## Image provenance

### Primary image

![Generated illustration of branching reasoning paths through a layered model architecture.](https://hypler.com/assets/news/reasoning-models.webp)

generated illustration. Credit: Hypler / AI-generated editorial illustration. Hypler editorial asset; not vendor or event photography.
- [Image source](https://hypler.com/ai-news/media.md)

### Supporting image

![Generated illustration of inference compute and memory hardware; not a specific commercial chipset.](https://hypler.com/assets/news/local-inference.webp)

generated illustration. Credit: Hypler / AI-generated editorial illustration. Hypler editorial asset; not vendor or event photography.
- [Image source](https://hypler.com/ai-news/media.md)

## Reading boundary

Historical source briefing, not current availability, compliance advice, partnership, or proof of Hypler deployment. Generated artwork is not event photography. Public reading grants no private access or execution authority.