OpenAI AI Updates: October 3, 2026

1. OpenAI Publishes a Model Guide for Building With the GPT-6 Family

OpenAI. OpenAI published a practical guide aimed at startups building on the GPT-6 family, which includes GPT-6 Astra, GPT-6 Sol, and GPT-6 Luna. The guide covers how to choose between the models, tune the reasoning effort setting, improve prompts and skills, coordinate tool calls, and prepare agent workflows for production. Source

2. Chatham Financial Cuts Trade Validation From 30 Minutes to Under 4 With Codex

OpenAI. In a new customer story, OpenAI describes how Chatham Financial, a capital markets advisory firm, uses Codex and GPT-5.6 to build internal technology and redesign workflows. OpenAI reports that the work cut Chatham’s trade validation time from 30 minutes to under 4 minutes. Source