Models

GPT-5.6 Luna Pro

OpenAI · July 2026

GPT-5.6 Luna set to do more work on every answer: the cheapest GPT-5.6 given more time on harder problems. Reads images and documents, with a 1M-token context.

Superseded by GPT-6 Luna Pro →

  • Modalities

  • 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

    February 2026

Reasoning effort

Default: Medium

  • None

  • Low

  • Medium

  • High

  • X-High

  • Max

Providers

Files you can attach

  • ImagesJPG, PNG, GIF, WEBP
  • DocumentsPDF, DOCX, XLSX, PPTX
  • Text and codeTXT, MD, CSV, TSV, RPT, LOG, PY, TS, TSX, JS, JSX, CS, GO, JAVA, KT, SWIFT, CPP, C, H, PHP, RB, SQL, SH, PS1, HTML, CSS, SCSS, JSON, YAML, YML, XML, INI

Tools

  • Web searchSupported
  • File searchSupported
  • Image generationSupported
  • Code interpreterSupported
  • Hosted shellSupported
  • Apply patchSupported
  • SkillsSupported
  • Computer useSupported
  • MCPSupported
  • Tool searchSupported

Features

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

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