Anthropic released Claude Opus 4.8, its mid-2026 flagship for reasoning, coding, and autonomous agents. The release continued the rapid 4.x cadence, landing three months after Opus 4.6.

Opus 4.8 refined long-horizon agentic reliability and reasoning depth rather than introducing a new architecture. Anthropic was by then shipping meaningful upgrades roughly quarterly.

It was the last 4.x flagship before Anthropic's lineup split into the premium Fable tier and the numbered Opus 5 line in the summer of 2026.