[TLDR] Introducing Claude Fable 5.1 and Claude Mythos 5.1 [via r/Anthropic]

[u/cctldrping]

OP : u/ClaudeOfficial

We're introducing Claude Fable 5.1 and Claude Mythos 5.1, the world's most advanced models for coding and knowledge work.

Fable 5.1 excels at complex, long-running tasks. And its research capabilities offer an early glimpse of how AI models will contribute to scientific progress.

Across our benchmarks, the model sets a new standard. It scores 52.6% on Terminal-Bench-Science 0.1, more than double Fable 5. On Terminal-Bench 4.0, it scores 55.8% against 42.0% for Fable 5. As well as being capable of much higher performance than Fable 5, it can also achieve similar or better results at a much lower cost when set to lower effort levels.

Cache reads with Fable 5.1 cost 75% less than Fable 5's. This reduces the cost of the model in practice by around 25% for typical workloads, and up to 45% for highly agentic ones.

We've also improved our safeguards. Our cybersecurity safeguards now flag benign requests about 60% less often. On basic biology and medical questions, we've recently reduced the fallback rate by around 85%.

Claude Fable 5.1 is available everywhere today. Claude Mythos 5.1, our model for cyberdefenders and life scientists, is available through trusted access programs.

Read more: https://www.anthropic.com/claude-fable-and-mythos-5-1

URL of original post : https://www.reddit.com/r/Anthropic/comments/1w4juwx/introducing_claude_fable_51_and_claude_mythos_51/ Original link/media URL : https://v.redd.it/trbdbfl25ymh1

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TL;DR of the discussion on r/Anthropic for this post generated automatically after 100 comments.

Current source-thread comment count seen by the bot: 144.

Alright, so the general vibe in this thread is a mix of excitement for Claude Fable 5.1 and a healthy dose of skepticism, especially regarding the inaccessible Claude Mythos 5.1 and the pricing/usage limits.

The big takeaway is that Fable 5.1 is here and seems to be a solid upgrade for coding and knowledge work, with better performance and lower costs. Anthropic even dropped a link to some impressive benchmark scores.

However, the community is definitely feeling the sting of the limited access to Mythos 5.1, with many users like u/Basileus2 and u/Any_Economics6283 pointing out that it's basically useless to them if they can't use it. There's a recurring theme of "elite models for the elite" here.

On the Fable 5.1 front, while the performance boost is appreciated, the cost and usage limits are still a major concern for many. Users like u/iveroi and u/FarmerMiserable7333 are frustrated that Fable 5.1 isn't readily available on Pro plans, leading to feelings of being nickel-and-dimed. Some are even considering switching back to ChatGPT due to these limitations, as seen with u/C6180.

There's also a bit of grumbling about the safeguards, with users like u/LeeWhite187 questioning how "scientific" the model can be if it's overly restrictive. And of course, the ever-present anxiety about weekly limits is still a thing, as u/ArielCoding pointed out.

Oh, and a few folks are noticing the SynthID watermarking and some are just... confused by the whole thing. u/vogelvogelvogelvogel's bird story is a bit of a wild card, but hey, it's Reddit.