Highest-accuracy GPT-5.5 tier for slower, precision-heavy reasoning and coding
Details
| Field | Value |
|---|---|
| id | openai-gpt-55-pro |
| family | gpt |
| modality | text+image->text |
| context_length | 1000000 |
| max_input_tokens | 922000 |
| max_output_tokens | 128000 |
| knowledge_cutoff | 2025-12-01 |
| release_date | 2026-04-24 |
| is_open_weights | no |
| supports_tool_call | yes |
| supports_reasoning | yes |
| supports_structured_output | yes |
| supports_attachment | yes |
| input_modalities | text, image |
| output_modalities | text |