Models

GPT-5.4 Pro

OpenAI · March 2026

Thinks for longer before answering, over very long documents. Built for hard problems, not chat or code.

Best for
Deep reasoning
Superseded by
GPT-5.5 Pro

  • Context window

    1,050,000 tokens

    ≈ 788,000 words · about 3,150 pages

  • Max output

    128,000 tokens

    ≈ 96,000 words in a single answer

  • Knowledge cutoff

    August 2025

    its training cutoff

Modalities

  • TextInput and output
  • ImageInput only
  • AudioNot supported
  • VideoNot supported

Reasoning effort

Default: Medium.

  • Medium

  • High

  • X-High

Features

  • StreamingNot supported
  • Function callingSupported
  • Structured outputsNot supported
  • Fine-tuningNot supported

Tools

  • Web searchSupported
  • File searchSupported
  • Image generationSupported
  • Code interpreterNot supported
  • Hosted shellNot supported
  • Apply patchSupported
  • SkillsNot supported
  • Computer useSupported
  • MCPSupported
  • Tool searchSupported

Ready to try it?

Polymeti is currently invite-only.

Log in

Request an invitation

Bring your own API key · Your chats stay in your browser