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OpenAI launches GPT-4.1 model lineup featuring 1M-token context window
“Yeah, I'll just say we released three new models today, GPT-Fort.one, GPT-Fort.one mini, and GPT-Fort.one data, and the real focus on these were just making the models that were great for developers so we improved instruction following, coding, and shipped our…”
GPT-4.1 reduces extraneous edit rate to 2%, down from GPT-4o's 9%
“And we found that from four O, which got nine percent, which is pretty crazy, nine percent of the time making an extraneous edit is a lot. 4.1 is at two percent, so it's a pretty big improvement.”
OpenAI increases prompt caching discount from 50% to 75% on GPT-4.1
“We've increased our prompt caching discount from 50% to 75% on these models.”
Structured response format is limited to GPT-4o and GPT-4o mini
“Actually, the new response format is only available on two models. It's Foro Mini and the new Foro. So the old Foro doesn't have the new response format. However, for function calling, we were able to enable it for all models that support function calling, and…”
OpenAI Structured Outputs enforces schemas in one shot without retries
“We are not retrying, you know, we're doing it in one shot and this is how you save on latency and cost.”
OpenAI's seed parameter is best-effort and not fully deterministic
“Yeah, the seed parameter is not fully deterministic, and it's kind of a best effort thing. So you'll notice there's more determinism in the first few tokens. That's kind of the current implementation.”
OpenAI stealth-tested GPT-4.1 models on OpenRouter before official release
“Yeah yeah, we really wanted to get as much developer feedback as possible on this model to make sure it worked well in the real world, and so we tested it kind of through Open Router and it was super cool to see people latch on to the names and get the theorie…”
OpenAI currently restricts reinforcement fine-tuning exclusively to its reasoning models
“No, that's reinforcement fine tuning is only for reasoning models.”
OpenAI will cover inference costs for developers who share custom evaluation data
“You can upload an eval and opt in such that we'll pay for the inference, inference costs if we can also use the eval.”
Structured Outputs prevent models from hallucinating invalid tools
“The model before was able to hallucinate a tool, but now it's it can't when you're using structured outputs.”
Structured Outputs supports recursive schemas for generating dynamic UIs
“The schemas, we support recursive schemas, and this allows you to do really cool stuff, like, you know, every UI is a nested tree that has children, and so I thought that was super cool. You can use one schema and generate, like, tons of UIs.”
OpenAI's Assistants API increased its file limit to 10,000 files
“Before, we only supported, I think, like, 20 files per assistant, and the way we used those files was, like, less effective. Basically, the model would decide, based on the file name, whether to search a file, and there's, like, not a ton of information in the…”