llm-anthropic 0.31 released: adds support for Claude Fable 5.2 and Mythos 5.2
Simon Willison released llm-anthropic 0.31, adding support for Fable 5.2 and Mythos 5.2, which Anthropic launched the same day; they can be invoked via `llm -m claude-fable-5.2`. In tests across five reasoning-effort levels from low to max, the max level exhausted 128,000 tokens without returning an image, the same old issue as with Opus 5.5, whereas the max level of Fable 5 and 5.1 had previously worked normally.
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9th November 2026
Release llm-anthropic 0.31 — LLM access to models by Anthropic, including the Claude series
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 # 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 - 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.
Posted 9th November 2026 at 11:58 pm
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This is a beat by Simon Willison, posted on 9th November 2026.
pelican-riding-a-bicycle 156
claude-mythos-fable 45
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