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

Hello Python 3.15, goodbye 3.10, and now I can use 3.11 - 12th October 2026
A new feature for my blog, built using my voice - 9th October 2026
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We're going to need default hard budget caps on pretty much everything - 3rd October 2026

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

llm 639 anthropic 350 claude 319 claude-mythos-fable 41

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