Notes from building AI systems.

Greptile takes bug detection beyond code review with GPT-6 Astra

How Greptile uses GPT-6 Astra to test user workflows, Daybreak to strengthen security, and Codex to reduce rework.

Working with academic communities to build scientific understanding

OpenAI shares model results on the Kakeya conjecture, Exponential Time Hypothesis, and quantum chromodynamics—and how researchers can verify and build on them.

GPT-6.1 Sol helps CodeRabbit strengthen security across complex codebases

CodeRabbit uses GPT-6.1 Sol to investigate security risks across complex codebases. Its security agent helps developers review findings and proposed fixes.

ChatGPT’s expanding world of work

Explore OpenAI Signals data on 165 work activities across nearly 100 countries, revealing how people use ChatGPT for work and how usage changes over time.

How Fanatics and OpenAI streamline the fan experience

Fanatics uses OpenAI to help fans complete their game-day outfits with Shop the Look. Testing across roughly 30,000 MLB products showed 10% higher engagement.

How Ultrafast cut incident investigation from hours to minutes at OpenAI

See how OpenAI engineers use Codex Ultrafast to investigate incidents in minutes. Explore faster security analysis, code refactoring, and daily workflows.

Introducing GPT-6.1 Terra

Bringing fast and capable computer use to everyone

TCSP3.0: Template-Based Crystal Structure Prediction with Coefficient-Preserving Element Substitution and Structural Diversity

When Does GEPA Merge Help? A Mechanism-Level Diagnostic