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llm-anthropic 0.31

Simon Willison released llm-anthropic 0.31, adding Anthropic's newly released Fable 5.2 and Mythos 5.2 models to the LLM command-line tool. Testing the models on an SVG pelican prompt across all five reasoning levels (low, medium, high, xhigh, max), Willison found that max effort failed to return an image at all, exhausting 128,000 tokens on reasoning — the same over-thinking bug he saw with Opus 5.5, but new to the Fable series since Fable 5 and Fable 5.1 returned max-effort pelicans successfully.

read1 min views1 publishedNov 9, 2026

Release: llm-anthropic 0.31

Anthropic released Fable 5.2 and Mythos 5.2 today. I've added them to llm-anthropic, so you can now run prompts through Fable 5.2 like this:

uv tool install llm
llm install llm-anthropic
llm keys set anthropic
llm -m claude-fable-5.2 "Generate an SVG of a pelican riding a bicycle"

I ran pelicans at all five reasoning levels - low, medium, high, xhigh, and max. You can see them all here - here's the best result I got, from xhigh:

max failed to return an image at all, running out of tokens after spending 128,000 thinking about them. That's the same bug that I saw with Opus 5.5 - but it's new for the Fable series, both Fable 5 and Fable 5.1 returned max effort pelicans just fine.

Tags: llm, anthropic, claude, generative-ai, pelican-riding-a-bicycle, ai, llms, claude-mythos-fable

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