claude-opus-4-5 — pricing, context window and limits

Still active, and the first Opus with effort control at all

Opus 4.5 was the generation that introduced the effort parameter to the Opus line, though only at three levels rather than the fuller range later generations support — both the highest tier and the one below it are unavailable here and error if requested. It remains an active, supported model rather than a deprecated one, distinct from the older, genuinely retiring generations further back in the lineup.

Where this sits relative to the current top tier

Compared to Opus 5, this generation carries the older, opt-in-only thinking behaviour and a narrower effort range, at a matching sticker price — which makes the newer generation's expanded range close to a straightforward upgrade for teams already comfortable spending at this tier.

Why teams still on this generation tend to stay a while

Because it's still fully active rather than deprecated, there's no forcing function pushing a migration off this model the way there is for a genuinely retiring one — which means it's worth periodically re-asking whether the newer generation's wider effort range and different thinking default would actually change your outcomes, rather than letting "it still works" substitute for a deliberate decision to stay.

Related

See what actually changed from Opus 4.6 to Opus 5 for the fuller picture of what's changed since this generation, even though that guide is framed against 4.6 specifically.