OpenAI GPT-6 Astra is OpenAI's most capable model, built for the hardest end-to-end work — complex reasoning, coding, computer use, research, and document creation — with a 1,050,000-token context window and up to 128,000 tokens of output. Stronger reasoning, coding, multimodal understanding, and long-form writing than GPT-5.6 Sol. Supports text and image input, web search, and reasoning effort (five levels from low to max; this model has no 'none' setting) / summary display options. Best for large codebases, cross-document research, professional reports, and multi-step reasoning; it costs more than GPT-5.6 Sol, so for everyday tasks GPT-5.6 Terra or Luna is cheaper. If you need to search the web for information, please turn on the "Web Search" switch. Maximum context window (input and output combined): about 1,050,000 tokens. Maximum total input per request (including history): 922,000 tokens. Maximum output per reply: about 128,000 tokens (model reasoning, if any, counts toward this limit). Maximum total upload size per request: 256MB (all files and message content combined). Accepted document formats: pdf, docx, xlsx, pptx, txt, csv (file content is provided to the model as extracted text). Accepted image formats: gif, jpeg, jpg, png, webp. Maximum number of images: 1500. Maximum size per image: 50MB. Maximum total image size per message: 384MB (text and history share the same request size limit; uploads close to the limit may still be rejected). Image dimensions: 200 to 8,000 pixels per side. Maximum image resolution: 36,000,000 pixels in total. Output content formats: Text/Image This module supports continuous conversations. AI can make mistakes. Please verify important information.