OpenAI o3-mini

OpenAI released o3-mini on Jan 31, 2025 across ChatGPT and the API, raising Plus and Team limits from 50 to 150 messages per day versus o1-mini. The post confirms function calling, Structured Outputs, developer messages, streaming, and low/medium/high reasoning effort, but no vision; API access starts with usage tiers 3-5, and Enterprise arrives in February. The key signal is cost-performance: testers preferred o3-mini over o1-mini 56% of the time, with 39% fewer major errors on hard real-world questions; the page references Codeforces and other evals, but the provided body is truncated so not all scores are disclosed.

Why it matters: OpenAI o3-mini is a same-day, official model release, so it lands in the must-write band. HKR-H/K/R all pass: new model hook, concrete usage and benchmark deltas, and clear relevance to cost-sensitive coding and reasoning workflows.