Claude Opus 5 is limited to a 0.2M token context window by default
Opus 4.8 and earlier use a 1M token context window (on any paid plan, at least). So it’s surprising that Anthropic quietly reduced this by 80% with Opus 5. You can get the 1M token context window back, though – you just have to enable Usage Credits. You don’t have to pay for any usage… Read more