Simon Willison’s Weblog

2nd September 2026

Release llm-anthropic 0.28 — LLM access to models by Anthropic, including the Claude series

Claude Fable 5.1, reasoning traces are now displayed by default for models that support them, plus a new llm_anthropic.ClaudeRefusal exception for when Claude throws a refusal.

Posted 2nd September 2026 at 5:59 pm

Recent articles

2026 in LLMs (so far) - 27th September 2026
Claude Opus 5.5, GPT-6 Sol, GPT-6 Luna, and a new price war - 22nd September 2026
Jev introduces a new shape of LLM - System One, aka Decision Models - 21st September 2026

This is a beat by Simon Willison, posted on 2nd September 2026.

llm 635 anthropic 341 claude 313 claude-mythos-fable 41

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