Building more with GPT-5.1-Codex-Max
OpenAI ● Covered by 3 sources
OpenAI just dropped GPT-5.1-Codex-Max, a new coding model built for Codex. It's faster and smarter, and it's aimed at big, long-running projects, not just quick snippets.
Based on reporting by OpenAI — read the original for the full story.
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OpenAI has rolled out GPT-5.1-Codex-Max, the latest brain behind its Codex coding assistant, and the pitch this time is less about flashy demos and more about stamina. Where earlier Codex models were solid for quick fixes and isolated functions, this one is built to sit inside a codebase for hours, tracking context across a sprawling project without losing the thread.
The headline upgrade is token efficiency paired with sharper reasoning. OpenAI says the model has been tuned to think through harder problems while burning through fewer tokens to get there, which matters a lot once you're running agentic workflows that chain dozens of tool calls together. Long-running tasks are exactly where older models tend to drift, forget earlier decisions, or start hallucinating file structures that don't exist. Codex-Max is explicitly aimed at fixing that failure mode.
This fits a pattern OpenAI has been chasing all year: models that act less like autocomplete and more like a junior engineer who can be handed a ticket and left alone for a while. Speed matters here too, not just for user patience but because agentic coding loops often involve the model calling itself repeatedly, running tests, reading errors, and retrying. A faster model compounds those gains across every iteration instead of just shaving a few seconds off a single response.
OpenAI hasn't published granular benchmark comparisons in the announcement, and it's fair to be a little skeptical of
My take — AI-written commentary, not fact-checked reporting
OpenAI keeps releasing incremental Codex upgrades and calling them big leaps forward, but the real test for GPT-5.1-Codex-Max isn't a benchmark slide, it's whether it can survive an eight-hour refactor without OpenAI silently rate-limiting you or the model quietly forgetting why it renamed a function three files ago. I'll believe the 'project-scale' claim when developers stop posting screenshots of it looping on the same broken import.
Read more about this at: OpenAI