New AI models for coding: OpenAI’s GPT-6 and Anthropic’s Claude Opus 5.5

Just yesterday, both OpenAI and Anthropic launched new versions of their latest AI models, and interestingly, both on the same day. You can read more about GPT-6 Sol and Luna here and Claude Opus 5.5 here. September 22's launches were following OpenAI's flagship model announcement earlier this month with the GPT-6 Astra model.

Both of these models are impressive, and both companies say they are cheaper than they (or their previous model) used to be. But overall, prices have gone up: just about a year ago, there was almost an unlimited amount of free or almost free usage. That's no longer the case.

It's also interesting to see which models dominate the Vellum AI leaderboard. I wanted to take a moment to record this point in time. It will be interesting to return to this in, say, a year, then five, and ten years. It will look very different.