Anthropic Launches Claude Sonnet 5 as Testers Report Higher Costs Per Solved Task
Anthropic launched Claude Sonnet 5, positioning it as the most agentic version of its Sonnet series to date. The model is now the default for Anthropic’s free and Pro tier users and carries a promotional price of $2 per million input tokens and $10 per million output tokens through August 31, before settling at standard rates of $3 and $15 respectively. Despite the discounted rate, early benchmark testing shows Sonnet 5 is more expensive per completed task than Anthropic’s Opus 4.8, primarily because it consumes significantly more tokens to solve the same problems.
Sonnet 5 relies on a new tokenizer that increases performance for English and Spanish but drives output token usage up by roughly 40% compared to Sonnet 4.6, according to testing by AI measurement firms. The model also posted lower scores on cybersecurity benchmarks like CyberGym, landing at 52.7% compared to 65.2% for its predecessor. Anthropic stated this is because Sonnet 5 was not specifically optimized for vulnerability discovery, but instead targets general agentic coding and economic tasks, where it slightly surpassed Opus 4.8 on the GDPval benchmark while maintaining a low lying rate under evaluation pressure.
From the sources (25 posts)
@apples_jimmyFable 5 spotted again! and with identify verification 👮♂️
@andrewcurran_It's unfortunate, but user identity verification may be one of the things that the administration is asking for in order to free Fable.
@mweinbachI called this within 40 minutes of Fable and Mythos getting banned Seems like the only path forward, similar to getting a gun license Given how the government seems to view these models, I think that's a fair comparison
@mattparlmerI’m fine with but not enthused by the KYC crap as long as most of the restrictions are dropped, what’s really obnoxious here is the off-plan billing, enormous incentive to just go to OpenRouter if I need to throw tokens at a problem
@wesrothRT @WesRoth: Claude Fable 5 could return as soon as this coming week, according to a new report. The Trump administration is reportedly cl…
@mark_kWould you agree to a forced identity verification to get access to Fable 5? Because that's what @AnthropicAI has planned for you. Every step will be watched and recorded. Don't don't anything naughty or else it's off to the permanent under
@jukan05RT @M1Astra: Exclusive: New Claude app strings tie Fable 5 usage credits to identity verification. The strings show Fable 5 is being put b…
@testingcatalogANTHROPIC 🔥: Claude Fable 5 is being prepared to run on usage credits that would also require identity verification. Sonnet 5 is being prepared for the release as well. > Your credits will be added once your identity is verified. > Fable
@synthwavedd🚨 SCOOP: Claude Sonnet 5 is releasing later today: - Knowledge cutoff January 2026 - Launching at $2/$10 per Mtok promotional rate* - 1M context variant available *Some changes have been made behind the scenes to prepare for a promo price
@synthwaveddUpdate: - The promotion will run until August 31st - "xhigh" effort added - First Sonnet w/ high-res vision - New tokenizer - Marketed as Sonnet price for "near-Opus" performance
@lentils80🚨 Breaking: Claude Sonnet 5 appears in the latest Claude Code CLI build!
@andrewcurran_
@andrewcurran_New tokenizer, and Sonnet 5 has 'near Opus performance'. Their answer to GLM-5.2.
@kimmonismusSonnet 5 already in the model selector. Release is imminent.
@kimmonismusEvery day, I think I could not appreciate open source any more than I already do. And then something new happens, like ID verification, and I am simply glad that I can run increasingly better models locally as well.
@scaling01its already live in claude code 2.1.197
@scaling01get ready for Sonnet 5 bois
@kimmonismusSonnet 5 incoming today per leaker @synthwavedd - Knowledge cutoff January 2026 - Launching at $2/$10 per Mtok promotional rate* - 1M context variant available I assume we at least (!) get also fable 5 news.
@kimmonismusI have no idea if this is a legitimate leak. But a *Sonnet 5* release today would surely go hand in hand with a *Fable 5* re-release.
@kimmonismusRumors about Sonnet 5 have been circulating for a long time. Now it looks like Sonnet 5 will be released alongside the re-release of Fable 5 (presumably with ID verification). This leaves a bad taste in my mouth, because it raises the pos
@andrewcurran_Leo is reliable, and Sonnet 5 has been due for a while, get ready for a release day.
@mweinbachClaude Sonnet 5 is live
@scaling01Sonnet 5 on Anthropic GitHub
@andrewcurran_Sonnet 5 is live for me now.
@kimmonismusSonnet 5 released for me!!