Introducing GPT-5.1 for developers

Today we’re releasing GPT‑5.1 in the API platform, the next model in the GPT‑5 series that balances intelligence and speed for a wide range of agentic and coding tasks. GPT‑5.1 dynamically adapts how much time it spends thinking based on the complexity of the task, making the model significantly faster and more token-efficient on simpler everyday tasks. The model also features a “no reasoning” mode to respond faster on tasks that don’t require deep thinking, while maintaining the frontier intelligence of GPT‑5.1.

To make GPT‑5.1 even more efficient, we’re releasing extended prompt caching for up to 24 hour cache retention, driving faster responses for follow-up questions at a lower cost. Our Priority Processing⁠(opens in a new window) customers will also experience noticeably faster performance with GPT‑5.1 over GPT‑5.

On coding, we’ve worked closely with startups like Cursor, Cognition, Augment Code, Factory, and Warp to improve GPT‑5.1’s coding personality, steerability, and code quality. In general, GPT‑5.1 feels more intuitive to use for coding and more communicative with user-facing updates as it completes tasks.

Finally, we’re introducing two new tools with GPT‑5.1: an apply_patch tool designed to edit code more reliably and a shell tool to let the model run shell commands.

GPT‑5.1 is the next advancement in the GPT‑5 series, and we plan to continue to invest in more intelligent and capable models to help developers build reliable agentic workflows.

Efficient reasoning across tasks

Adaptive reasoning

To make GPT‑5.1 faster, we overhauled the way we trained it to think. On straightforward tasks, GPT‑5.1 spends fewer tokens thinking, enabling snappier product experiences and lower token bills. On difficult tasks that require extra thinking, GPT‑5.1 remains persistent, exploring options and checking its work in order to maximize reliability.

New “no reasoning” mode

Extended prompt caching

Coding

—Denis Shiryaev, Head of AI DevTools Ecosystem, JetBrains