Update: Claude Opus 5 expected today; Opus 4.8 still the latest live
Polymarket and multiple outlets expect Anthropic's next flagship to land today — the same day DeepSeek's legacy endpoints shut off at 15:59 UTC.
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The tell: Polymarket ~88%, docs still at 4.8
Polymarket's odds on an Opus 5 debut today spiked to ~88% on Jul 23 ET, and multiple outlets expect a Jul 24 unveiling — yet Anthropic's model docs still list Opus 4.8 ($5/$25 per M tokens, 1M context) as the newest live model. Nothing to call in the API yet.
What's rumored: cheaper long-horizon agents
Reporting frames Opus 5 around cost efficiency and reliability for agents running over extended sessions, not just benchmark gains. If it holds, that targets the exact multi-hour agent loops builders run on Opus 4.8 today. Treat specifics as unconfirmed until Anthropic ships.
Also today: DeepSeek's legacy endpoints go dark
Same-day housekeeping: deepseek-chat and deepseek-reasoner stop responding at 15:59 UTC on Jul 24 — hard errors, no redirects. Repoint to deepseek-v4-flash (add thinking:{type:'enabled'} to replace the reasoner) before the cutoff; V4-Flash runs $0.14/$0.28 per M.