Breaking News: The "Worker's Edition" Claude 5 Is Here, Everyone Can Use It
BREAKING: Claude Sonnet 5, dubbed "Fennec," is now the default model for all Free and Pro users. This mid-tier model boasts the strongest Agent capabilities in the Sonnet line yet, with performance rivaling the flagship Opus 4.8. It features autonomous planning and can utilize browser and terminal tools—capabilities previously exclusive to costly, large models.
Key benchmarks highlight significant gains over its predecessor, Sonnet 4.6, in reasoning, tool use, coding, and knowledge work. Sonnet 5 scores 63.2% on SWE-bench Pro (surpassing GPT-5.5's 58.6%), 80.4% on Terminal-Bench 2.1, and 57.4% on Humanity's Last Exam (just 0.5% behind Opus 4.8). It even slightly outperforms Opus 4.8 in some knowledge tasks. Anthropic positions it as delivering ~90% of Opus's capability at a fraction of the cost.
Pricing is aggressive: a limited-time promotional rate of $2 per million input tokens and $10 per million output tokens (reverting to $3/$15 after August 31). This undercuts Opus 4.8 ($5/$25) and GPT-5.5 ($5/$30). However, a new tokenizer may increase token counts by 1.0-1.35x, affecting final costs post-promotion.
Notably, Sonnet 5 excels in security, with a mere 0.93% browser injection attack success rate, outperforming Mythos 5 and Opus 4.8. Its prompt injection defense matches Opus 4.8 at 0.19%.
Launching amid uncertainty around the region-restricted Fable 5, Sonnet 5 is globally available. It targets the mid-market, offering near-flagship performance at a competitive price, effectively lowering the barrier for multi-Agent development and presenting a compelling alternative for cost-conscious developers.
marsbit07/01 07:47
