GPT-5.5 Pro
The newest of the Pro models. Thinks for longer before answering, over very long documents; built for hard problems, not chat or code.
Use instead GPT-5.6 Sol →
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
December 2025
Reasoning effort
Default: High
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 patchNot supported
- SkillsNot supported
- Computer useNot supported
- MCPSupported
- Tool searchNot supported
Features
- StreamingNot supported
- Function callingSupported
- Structured outputsSupported
- Fine-tuningNot supported