Claude Sonnet 4.5 vs Laguna XS.2

Pick Claude Sonnet 4.5 if you want the stronger benchmark profile. Laguna XS.2 only becomes the better choice if you want the cheaper token bill or you want the stronger reasoning-first profile.

Claude Sonnet 4.5 is clearly ahead on the provisional aggregate, 66 to 32. The gap is large enough that you do not need to squint at the spreadsheet to see the difference.

Claude Sonnet 4.5's sharpest advantage is in agentic, where it averages 55.3 against 30.1. The single biggest benchmark swing on the page is Terminal-Bench 2.0, 50% to 30.1%.

Claude Sonnet 4.5 is also the more expensive model on tokens at $3.00 input / $15.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for Laguna XS.2. That is roughly Infinityx on output cost alone. Laguna XS.2 is the reasoning model in the pair, while Claude Sonnet 4.5 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use. Claude Sonnet 4.5 gives you the larger context window at 200K, compared with 131K for Laguna XS.2.