---
title: "Claude Fable 5.1 made me a really nice animated pelican"
type: signal
url: https://frontiernewswire.com/s/claude-fable-5-1-made-me-a-really-nice-animated-pelican-v6cb14383
published: 2026-09-01T23:57:28.000Z
byline: "Source: Simon Willison"
---

# Claude Fable 5.1 made me a really nice animated pelican

Source: Simon Willison · Published 2026-09-01 · Canonical: https://frontiernewswire.com/s/claude-fable-5-1-made-me-a-really-nice-animated-pelican-v6cb14383

Today is Claude Fable (and Mythos) 5.1 day . Anthropic say that Fable 5.1 "sets a new standard for coding, knowledge work, and long-running problem-solving tasks". Their announcement spends a notable amount of time on scientific research, boasting of a 52.6% score on the brand new Terminal-Bench-Science 0.1 benchmark (first announced on August 27th ), up from 24.7% for Fable 5, 29.0% for Opus 5 and 22.4% for GPT-5.6 Sol. Other benchmarks show slightly improved scores, but none as impressive as the Science one. But how well can it pelican? Back in July I wrote about how I was losing faith in the pelican benchmark - its connection to how good the models were at other tasks didn't seem to hold as strongly as it did back in 2025 . The most interesting insights I get from it now are comparisons within model families, and particularly comparisons for the same prompt at different reasoning effort levels. Fable 5.1 has five reasoning levels: low, medium, high, xhigh, max - and no option to tur

In this story: [GPT-5.6 Sol](https://frontiernewswire.com/models/gpt-5-6-sol), [Claude Opus 5](https://frontiernewswire.com/models/claude-opus-5), [Claude Fable 5.1](https://frontiernewswire.com/models/claude-fable-5-1), [Fable 5](https://frontiernewswire.com/models/fable-5), [Mythos 5.1](https://frontiernewswire.com/models/mythos-5-1)

## Sources

- [Read the original at Simon Willison](https://simonwillison.net/2026/Sep/1/claude-fable-5-1/)

## Related on Frontier

- [LifeVal](https://frontiernewswire.com/s/lifeval-bd447fb4)

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