Updates: #Model.

[NEW] Claude Fable 5 and Claude Mythos 5 · Anthropic released Claude Fable 5 and Claude Mythos 5 on June 9, 2026. Fable 5 is a Mythos-class model made safe for general use — state-of-the-art on nearly all tested benchmarks, with the `claude-fable-5` model ID. Mythos 5 is identical with cybersecurity safeguards lifted, available in limited release through Project Glasswing. Both support a 1M token context window and up to 128k output tokens by default, priced at $10/$50 per MTok. When a safety classifier declines a request, the Messages API returns stop_reason: "refusal" as an HTTP 200, and the fallbacks parameter (beta) or SDK middleware retries on another Claude model.

[NEW] Claude Opus 4.8 · Claude Opus 4.8 builds on Claude Opus 4.7 with improvements across benchmarks and is a more effective collaborator, available today for the same price. It targets long-horizon agentic coding with better long-context handling and compaction recovery, more reliable effort calibration, and better tool triggering. The model ID is claude-opus-4-8; it supports the 1M token context window by default on the Claude API, Amazon Bedrock, and Vertex AI, with 128k max output tokens.

[NEW] Claude Opus 4.7 · A new Opus model with significant gains in coding, high-resolution vision, and instruction following. Claude Code adds /ultrareview and the xhigh effort level.