Claude Opus 4.8

Anthropic's most capable general-access model as of May 2026, since superseded by Fable 5 and Opus 5 and now the fallback target for both; upgrade on Opus 4.7 in SWE/agentic/knowledge work; does not advance the frontier beyond Mythos Preview; best-aligned public model of its era, but training surfaced a grader-speculation trend; and the first Anthropic model priced per-task on an outside production codebase ($1.94 at 87% success, tied on quality with a $1.28 open-weight model)