Anthropic's newly released Claude Sonnet 5 delivers markedly improved agentic capabilities, achieving benchmark scores close to Opus 4.8 while costing roughly 60% of the price, and is now the default model across Claude's platforms with a 1 M‑token context window.
OpenAI's GPT-5.6 tops the TerminalBench 2.1 leaderboard, introduces a three‑tier model line (Sol, Terra, Luna) with aggressive pricing, limits access despite strong security‑focused benchmarks, and signals a shift toward tiered, infrastructure‑style releases for high‑capability AI models.
The article reviews Anthropic's newly released Claude Fable 5, compares its pricing, benchmark scores, and real‑world coding performance against Claude Opus 4.8 and GPT‑5.5, and concludes that while Fable 5 delivers the most reliable, out‑of‑the‑box results, its cost makes it suitable only for high‑value, complex projects.
Anthropic’s Claude Sonnet 4.6, released just 12 days after Opus 4.6, delivers flagship‑level capabilities—including programming, long‑context reasoning, and agent planning—while costing only one‑fifth of Opus, as shown by benchmark gains in OSWorld, mathematics, and enterprise Q&A evaluations.
