Claude Opus 5.5 is Anthropic's flagship model for demanding reasoning, coding, and long-horizon agentic work, succeeding Claude Opus 5. It is particularly strong at multi-step changes in large codebases, code...
Details
| Field | Value |
|---|---|
| id | anthropic/claude-opus-5.5 |
| family | claude-opus |
| modality | text+image+pdf->text |
| context_length | 1000000 |
| max_output_tokens | 128000 |
| knowledge_cutoff | 2026-06 |
| release_date | 2026-09-22 |
| is_open_weights | no |
| supports_tool_call | yes |
| supports_reasoning | yes |
| supports_structured_output | yes |
| supports_attachment | yes |
| input_modalities | text, image, pdf |
| output_modalities | text |