Fable 5 is out - and it’s good, very good. But beyond the splashy demos, I want to bring you the 20+ nuggets from the 319 page system card, which I read in full, all day, plus benchmarks you may not have noticed. 

https://assemblyai.com/aiexplained

Plus two worrying trends inside the ‘mind’ of Claude, how OpenAI counter, and the transformer inventor’s warning.



Check out my fast-growing (!) app, free to use, and code INSIDER15 for paid tiers: https://lmcouncil.ai

AI Insiders ($9!): https://www.patreon.com/AIExplained

Chapters:
00:00 - Introduction
01:06 - Blocks + Better Models
02:42 - Fable 5 Upgrade over Mythos Preview
04:49 - ML Acceleration Bombshell
07:11 - No RSI yet
07:41 - Bio-capable
14:51 - Creative Writing … no
17:23 - Does need bug-checks
18:57 - OpenAI Response
19:23 - Benchmark Bonanza
28:06 - Chain of Thought worrying trend

Fable 5 Release: https://www.anthropic.com/news/claude-fable-5-mythos-5

System Card: https://www-cdn.anthropic.com/d00db56fa754a1b115b6dd7cb2e3c342ee809620.pdf

Intelligence Explosion: https://www.patreon.com/posts/anthropic-charts-160231656

Annotated: https://x.com/Miles_Brundage/status/2064500190523113816/photo/1

OpenAI Counter: https://x.com/thsottiaux/status/2064572118264913923
https://x.com/thsottiaux/status/2043177597434306699

Double Lifespan: https://darioamodei.com/essay/machines-of-loving-grace

AutomationBench: https://zapier.com/benchmarks
Vending Bench: https://x.com/andonlabs/status/2064429817530085804
CritPt: https://critpt.com/
Riemann Bench: https://surgehq.ai/leaderboards/riemann-bench
GDPVal: https://artificialanalysis.ai/evaluations/gdpval-aa
BluePrint Bench 2: https://andonlabs.com/evals/blueprint-bench-2
MCP Atlas: https://labs.scale.com/leaderboard/mcp_atlas
FutureSim: https://x.com/nikhilchandak29/status/2064676801440358774

Roon Stun Lock: https://x.com/tszzl/status/2064454617568874669

Noam Brown Inference Ceiling: https://x.com/polynoamial/status/2064210146558136827

Isochronic Chart: https://isochronic-passage-chart.netlify.app/#nyc
Rose Tavern: https://claude.ai/public/artifacts/2295bebe-77e6-43e2-ae94-0fe49e9a776b
Redwall Game: https://redwall-mossflower.surge.sh/

Risk Report: https://www-cdn.anthropic.com/097c63b5fe7dd8b14866e1f15bb1910ec713658a.pdf

Transformer Inventor Warning: https://x.com/tszzl/status/2064563986914554125



Non-hype Newsletter: https://signaltonoise.beehiiv.com/

Podcast: https://aiexplainedopodcast.buzzsprout.com/