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.

Release: llm-anthropic 0.31 https://github.com/simonw/llm-anthropic/releases/tag/0.31 Anthropic released Fable 5.2 and Mythos 5.2 https://www.anthropic.com/claude-fable-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 paste key here 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 https://tools.simonwillison.net/markdown-svg-renderer?url=https%3A%2F%2Fgist.github.com%2Fsimonw%2Fbcd1a1bf38b929b0bbbae2e38b808e97 - 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 https://tools.simonwillison.net/markdown-svg-renderer?url=https%3A%2F%2Fgist.github.com%2Fsimonw%2Fbcd1a1bf38b929b0bbbae2e38b808e97 reasoning-2 . That's the same bug that I saw with Opus 5.5 https://simonwillison.net/2026/Sep/22/opus-and-sol-and-luna/ claude-opus-5-5-max-over-thinks-to-the-point-of-breaking - but it's new for the Fable series, both Fable 5 https://simonwillison.net/2026/Jun/9/claude-fable-5/ and-some-pelicans and Fable 5.1 https://simonwillison.net/2026/Sep/1/claude-fable-5-1/ max returned max effort pelicans just fine. Tags: llm https://simonwillison.net/tags/llm , anthropic https://simonwillison.net/tags/anthropic , claude https://simonwillison.net/tags/claude , generative-ai https://simonwillison.net/tags/generative-ai , pelican-riding-a-bicycle https://simonwillison.net/tags/pelican-riding-a-bicycle , ai https://simonwillison.net/tags/ai , llms https://simonwillison.net/tags/llms , claude-mythos-fable https://simonwillison.net/tags/claude-mythos-fable