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Checked Active: 2026-10-15
Anthropic
Claude Opus 5.5
Hardest coding and agentic tasks, large refactors, long-horizon work in Claude Code.
Evaluation Analysis: Per GenAI Brief (Oct 2026): first on Terminal-Bench 4.0 at 64.8% (Claude Code, max effort) and tied first on DeepSWE v1.1 at 72.3%. Leads the Arena WebDev board at 1813 per Fello AI.
Context Window1M tokens (128K max output)
Input Price / 1M$4.00
Output Price / 1M$20.00
Release Date2026-09-22
Specs and prices checked 2026-10-15 against the official page.