
“Claude Fable 5 and Mythos 5: The System Card” by Zvi
From LessWrong (30+ Karma) by LessWrong
June 12, 2026 · 60 min
About this episode
Zvi discusses the capabilities and limitations of the new AI model Claude Fable 5 compared to previous models.
First things first: Claude Fable 5 is the new best publicly available model. I have noticed a step change, where Fable can suddenly help me in ways that previous models were not worth bothering to query. Almost everything it has noticed in one of my drafts so far has been spot on and it is downright scary. Suddenly I am motivated to once again continue improving my Chrome extension. I only ask for things I actually want or am curious about, and it has nailed every question I have asked it. That does not mean it is the right tool for every job. There are four good reasons to often not use Fable. Speed and price. Fable is importantly slower and more expensive than Opus 4.8, and often you will not need to make this trade. After the 22nd, when Fable may no longer be included in subscription plans if demand is too high, we may have to all pay by the token outside our subscriptions (although I suspect subscribers will get at least some credits to help with this), which could add up fast. Relative strengths. Capabilities are jagged. There will still [...] --- Outline: (02:05) Another Week Another Giant System Card (03:02) How To Tell A Fable (08:33) Why They Did That In That Way (10:14)…
People in this episode
Host: Zvi
Topics covered
- AI models
- technology
- product evaluation
- Chrome extension
- alignment risk
Keywords
- Claude Fable 5
- Opus 4.8
- AI research
- Chrome extension
- alignment risk
Mentioned in this episode
Products: Claude Fable 5, Opus 4.8
More episodes of LessWrong (30+ Karma)
- “The Uncertainty That Matters Isn’t Fundamental” by jimmy · June 13, 2026 · 22 min
- [Linkpost] “US government directive to suspend access to Fable 5 and Mythos 5” by Capybasilisk · June 13, 2026 · 0 min
- “Simulating Simulators” by kromem · June 12, 2026 · 27 min
- “Citations Needed: Magic Encyclopedias to Save the World” by Oliver Sourbut · June 12, 2026 · 10 min
- “Implications of Continual Learning for LLM Agents: Introduction” by RohanS, Rauno Arike, Owen Terry, Achu Menon, Zhijing Jin, Francis Rhys Ward, Seth Herd · June 12, 2026 · 14 min
- “Reward Hacking at the 1937 World’s Fair” by frmsaul · June 12, 2026 · 6 min
Explore listener stats, chart rankings, contacts and more on the LessWrong (30+ Karma) podcast page.