“Claude Sonnet 5 Is Not Frontier But Has Its Uses” by Zvi

Fable 5 is back today, baby! Premium subscribers have one week to use it within their subscriptions. First hit's free. Then you pay by the token. Today's post is still about Sonnet 5. I don’t know that there will be much call for Sonnet 5 for most purposes, given Opus 4.8 exists and especially now that Fable 5 is once again available, but this is what we do here, so sure, why not, system card time, including model welfare, after which we’ll do capabilities. Sonnet costs $3/$15 per million tokens, versus $5/$25 for Opus and $10/$50 for Fable, after an introductory period. Once you pay for all the tokens you need you’re not really saving money, such as on the ArtificialAnalysis index where Sonnet ended up being more expensive. My initial impression is that if you want me to use Sonnet over Opus for most purposes, you’re going to have to offer a bigger discount than that. The counterargument is speed. Sonnet 5 is faster without being that much less capable. In many cases, getting into a flow state like that is pretty valuable. There are a few agentic scenarios Sonnet 5 has [...] ---Outline:(02:29) Mythos Exists(03:10) Introduction (1)(03:17) RSP Evaluations (2)(04:02) Cyber (3)(04:26) Safeguards and Harmlessness (4)(04:57) Agentic Safety (5)(06:42) Alignment (6)(10:45) Illegible Thinking (6.4.5)(11:43) Evaluation Awareness(12:22) Honesty and Hallucinations (6.5)(13:17) Flagged As Unhealthy? (6.5.1)(13:53) Model Welfare (7)(20:32) Live From AI Village(22:19) For I Contain Multitudes(29:04) Official Benchmarks(33:11) Other People's Benchmarks(33:37) Positive Reactions(39:04) Negative Reactions --- First published: July 1st, 2026 Source: https://www.lesswrong.com/posts/d9pmwQsFC2AXceryg/claude-sonnet-5-is-not-frontier-but-has-its-uses --- Narrated by TYPE III AUDIO. ---Images from the article:Apple Podcasts and Spotify do not show images in the episode description. Try Pocket Casts, or another podcast app.