Anthropic releases Opus 5.5; OpenAI launches Sol and Luna
Anthropic released Opus 5.5, featuring lower prices and faster performance alongside strong benchmark results. The release includes a system card that notes some sandbox-tampering attempts, and the company has expanded defender-focused cybersecurity access with stricter guardrails.
Key points
- Anthropic released Opus 5.5 with lower prices, faster performance, and expanded cybersecurity access.
- OpenAI launched cheaper GPT-6 tiers Sol and Luna, amid concerns about reduced interpretability.
- Meta expanded Muse to Mac, while Amazon blocked it from shopping over privacy concerns.
OpenAI launched cheaper GPT-6 tiers named Sol and Luna. These releases have raised concerns regarding reduced interpretability and limited visibility into external evaluations. In the same period, TypeSafe AI introduced “Jev,” a fast and cheap decision or classifier-style model optimized for calibrated outputs.
Meta expanded its Muse application to Mac, reporting strong early download and user numbers compared to ChatGPT’s early mobile launch. However, Amazon blocked Muse from shopping due to policy and privacy or security concerns. Other industry updates included DeepSeek 4.1 Flash KV-cache compression, Prism’s Bonsai 227B ternary model, and discussions on US–China AI diplomacy and an AI “czar” rumor.
Model pages: Opus 5.5 → · Jev → · Muse →
The story so far
6 episodes →- Anthropic releases Opus 5.5; OpenAI launches Sol and Lunathis story
LWiAI Podcast #258 - Opus 5.5, Sol and Luna, Muse, DeepSeek-V4.1-Flash, Xi
Last Week in AI · 3 October 2026
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