Claude Opus 4.8
Hybrid reasoning model built for serious coding and AI agents, featuring a 1M context window
Claude Opus 4.8 is an Anthropic Claude Opus model release announced on May 28, 2026, positioned as an upgrade over Opus 4.7 for coding, agentic tasks, reasoning, and professional knowledge work. Anthropic states developers can use it via the Claude API as `claude-opus-4-8`, with a 1M-token context window noted on the Claude Opus product page.
Pricing
Official table also lists 5-minute cache writes at $6.25/MTok and 1-hour cache writes at $10/MTok. MTok = million tokens.
Anthropic's official Claude Platform Docs pricing page lists Claude Opus 4.8 at $5 per million base input tokens and $25 per million output tokens, with cache hits/refreshes at $0.50 per million tokens.
Model Intelligence
Recent stories
Anthropic said a US government directive forced it to disable Fable 5 and Mythos 5 across Claude products and APIs. The change also pushed Build Day and downstream tooling to Opus 4.8, breaking active Fable sessions and triggering fallbacks in tools like Linear Agent.
Anthropic said flagged Fable 5 requests will now visibly fall back to Opus 4.8, and API refusals will return reasons instead of silently degrading output. The update matters because users were reporting sudden quality drops, opaque refusals, and quota-burn confusion around Mythos-class safeguards.
Creators shared browser-game workflows that pair Magnific asset generation or single Claude prompts with playable HTML demos. The examples matter because they turn vibe-coded mini-games into short, template-driven production recipes rather than one-off experiments.
Fresh Hacker News comments and user posts report 400 errors tied to modified thinking blocks, short cache TTLs, and behavior some testers call a regression from 4.7. The issue matters because the same model is also powering one-prompt sites and games, so quota burn and client breakage are showing up alongside stronger creative output.