Anthropic: Claude Opus 4.8 arrives with 1M token context and adaptive thinking
Claude Opus 4.8 is Anthropic's new most capable generally available model, launched on May 28, 2026. It brings a one-million (1M) token context window by default on the Claude API, Amazon Bedrock and Vertex AI, 128k maximum output tokens, and adaptive thinking that triggers reasoning only when needed.