What's new in Opus 4.8?

A 1M-token context, 128K output, effort control, a Dynamic Workflows preview and a ~2.5× fast mode, plus stated coding gains — per Anthropic. Released 28 May 2026.

Is it a big upgrade over 4.7?

Incremental on benchmarks (agentic coding 64.3%→69.2%, per Anthropic), but the fast mode and long context are the practical wins, and it claims ~4× fewer missed code flaws.

AI models

Anthropic ships Claude Opus 4.8 with a 1M-token context

Six weeks after 4.7, a faster, longer-memory Claude.

The FeaturedDaily Desk28 May 2026Verified June 2026

Anthropic released Claude Opus 4.8 on 28 May 2026, about 42 days after Opus 4.7.

What happened. On 28 May 2026 Anthropic released Claude Opus 4.8 (claude-opus-4-8), about 42 days after 4.7, across claude.ai, the API and Claude Code.

The specs. A 1M-token context and 128K max output, plus effort control, a Dynamic Workflows research preview in Claude Code (orchestrates parallel subagents) and a cheaper fast mode (~2.5× quicker).

The claims. Anthropic's own figures: agentic coding 64.3%→69.2%, and ~4× less likely than 4.7 to let flaws in its own code pass unremarked. Treat as vendor figures.

Sources

Claude Opus 4.8 — Anthropic, 28 May 2026
Anthropic's Opus release and the 'Mythos' tease — Axios, 28 May 2026
Claude Opus 4.8 — Simon Willison, 28 May 2026

Anthropic ships Claude Opus 4.8 with a 1M-token context

Sources

More from AI models

Anthropic ships Fable 5 — its most powerful public model yet

xAI ships Grok Imagine 1.5: a still photo becomes video

Google ships Gemini 3.5 Flash at I/O; the Pro stays unreleased