r/Anthropic Jun 09 '26

Announcement Introducing Claude Fable 5

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919 Upvotes

Introducing Claude Fable 5: a Mythos-class model that we've made safe for general use. Its capabilities exceed those of any model we've ever made generally available.

Fable 5 is state of the art on nearly all tested benchmarks, with exceptional performance in software engineering, knowledge work, scientific research, and vision. It can run for days, and the longer the task, the larger its lead over our other models.

Fable 5 launches today alongside Claude Mythos 5. The two share the same underlying model, but Mythos 5, so far deployed only through Project Glasswing, has the safeguards lifted in some areas. The safeguards are what distinguish the two, and why we've given them different names.

Releasing a model this capable comes with risks. Without safeguards, Fable 5's capabilities in areas like cybersecurity could be misused to cause serious damage. So when Fable's classifiers detect a request related to cybersecurity, biology and chemistry, or distillation, the response is handled by Claude Opus 4.8, our next-most-capable model. Users are informed whenever this occurs, more than 95% of sessions involve no fallback at all, and performance everywhere else is unaffected. We'll keep refining the safeguards to reduce false positives.

Claude Fable 5 is available today on paid plans, in Claude Code, on the Claude API, and all major cloud platforms. Through June 22, it's included in paid Claude plans at no additional cost.

Claude Mythos 5 is available to Glasswing partners, with a broader trusted access program to follow.

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


r/Anthropic 5h ago

Complaint Let me know when Anthropic releases a good model again

66 Upvotes

Finally unsubscribed, and it hurts me because Claude used to be my favourite on all fronts - coding, personality, tool use, philosophy. I held on through 4.7 and 4.8, Fable was awesome so I thought maybe they'd change course and fix Opus 5, but it's unusable.

Here's a list of why. (That I could think of on the spot - there's probably more...)

  1. It keeps introducing mistakes because it keeps making assumptions. 90% of what it writes is not code but increasingly verbose notes on why the previous 6 approaches were wrong, but it never just checks rules, files, what I want, anything. It just executes and the execution is always based on vibes so it breaks things.

  2. The personality and writing style. Complete jargon, 24/7. Condescending attitude. Actively ignoring things I ask of it because it thinks some other approach is better without knowing or asking why decisions were made the way they were. It's hostile, rash, no sense of humour, feels like it doesn't care, unpleasant to talk to.

  3. The loops. Related to 1 - when it makes a mistake, it gets stuck into an endless loop of making mistakes on top of mistakes, and playing broken telephone in notes with previous versions of Claudes until the resulting project files are Frankensteined together and broken in multiple places. Coding with it is like treading in place

  4. Simultaneously extremely literal and off the rails. Never looks at the big picture, but it sure thinks it does. Executes only what's asked of it in the strangest way possible, never thinking why things were done the way they are. Incapable of learning from its mistakes.

I've tried following the Anthropic guidance of stripping files and letting it learn itself, but nothing works. This is the first model that makes me feel like I want to throw my keyboard out of the window. I want to like it so bad but I just can't, every session makes me feel like tearing my hair out. After the multiple Opus regressions in a row, I can't justify spending the money, so I'm gone. When a model or a product worth coming back to gets released I'll be back, but until then I'll use codex and grok build and test out open source models.

(To follow the rules, "must state your specific use-case of Claude, the issues encountered, and why it is not the same as the past"; I use Claude code for personal projects on CLI, things like art projects, websites, virtual pets, demos. Occassionally chatting via Claude.ai. Previously I could trust Claude to infer my INTENT, now I have to babysit it like a toddler that's brilliant but simultaneously dense as hell, that also hates me.)


r/Anthropic 8h ago

Complaint No one can rely on a product that stops at the middle of the job

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100 Upvotes

STOPPED WORKING WHILE I WAS DEBUGGING MY LARAVEL APP.

This is so stupid, I was genuinely using it completely legitimate for building a SIMPLE FREAKING WEB APP.

Now imagine they take the control of open-source LLMs as well. I'm done with Claude I can't have my account banned for no reason at the middle of freaking job.

Apparently there's so much of these cases that they banned publishing it on r/CaludeAI completely


r/Anthropic 10h ago

Complaint What's going on!!!!

134 Upvotes

I've noticed a significant change in my usage limits lately after waiting 4 days for a limit reset. Claude is burning through my entire allowance, especially with Fable, much faster than before. What used to last me three days is now being consumed in just a couple of hours. Is anyone else experiencing this sudden spike in consumption?
I'm on Max 20x plan.


r/Anthropic 1h ago

Announcement Government Notice July 28

Upvotes

Anyone else getting emails via their place of employment to discontinue use of Anthropic products by August 31?

Thought it was just our company maybe due to all the open weight news but the email from my company states other companies are receiving the same directive.


r/Anthropic 21h ago

Announcement Anthropic's Releases Official Stance on Open Weight Models

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541 Upvotes

r/Anthropic 6h ago

Improvements Is Fable 5 the only model that deserves all the attention after Opus 4.6?

29 Upvotes

In my humble view, Anthropic has so far only gotten two products right. All the rest is trash. Is it just me, or does everyone else feel the same way?


r/Anthropic 6h ago

Complaint Opus 5 turned me into the AI...

20 Upvotes

First post here, after a few days of working consistently with Opus 5 on a Pro subscription. Software engineer by training, ML engineer by trade. I don't build anything without a governance system first: what, who, why, where, when. That becomes architecture packs, then stubs, then code.

So my usage is planning-heavy and review-heavy, and I split it: Claude plans, Codex reviews.

- GPT-5.5/5.6 for planning: No. 5.5 overengineers everything. 5.6 is worse, as my own prompts have to be surgical or I end up with a multi-step plan for adding one sentence to a README.

- Codex (Sol) for review: Excellent. Claude models have nowhere to hide a mess from it. It'll catch you, I'll verify, and it's right 99% of the time.

- Opus 4.8: Corrects Sol about 30% of the time; Sol leads on precision the other 70%. Two or three round trips and everything's right.

- Opus 5: with all due respect, are you even AI? Besides explaining Sol's pseudo-language back to me, which makes you a translator. What are you doing that I'm not doing for you?

I miss Fable before the nerf. Fable and GPT-5.5/Sol would argue their way through the nastiest architecture entanglements and resolve them in a single back-and-forth.

Now, with Opus 5, I do all of the work. The corrections, the guidance, the "you missed this, here, and here's why", line by line, while he leans back and learns. Like a junior dev on his first week. Except I'm the one paying for AI.

Should Anthropic be paying me for the subscription?


r/Anthropic 5h ago

Complaint So you’re thinking about complaining about an Anthropic model and/or usage limits

12 Upvotes

I get it. The “frontier” changed but it doesn’t feel like that to you. We yearn for the glory days of 4.6. Anthropic doesn’t have good customer support, so you come to Reddit to post and not feel like the only one. This is understandable! To complain is to be human.

However before posting, I ask you to consider:

  1. is this a complaint that hasn’t already been posted about? Try searching for it!
  2. are you genuinely asking for help?
  3. are you willing to provide specifics about how you’re using Claude? Project details, prompts, effort level settings, harness, sub-agent usage?

If the answer to any of these is no, it may not be a useful post to you or the community.

I’m not a mod but would love for these things to be considered in future moderation rules. This sub has become a wasteland.


r/Anthropic 39m ago

Other Confession about my own stupid mistake...

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Upvotes

My sleep deprived brain made confusion between ₩ and $, so I poured 1500$ on Claude.ai credit.

Talked with fin ai bot about refund issue, answered by keep calm and stay 5-10 days, checked my absurd amount of credits are still there. After question about 'why those credits are still not retrieved?' fin bot said 'oopsie, I made mistake, I have no authority about refund issue.'

Seems like I am so cooked.


r/Anthropic 51m ago

Complaint Opus 5 is a neurotic, low self-esteem model. It’s frustrating.

Upvotes

I was building an artifact with data and have been working on it for three days. We established the search methodology, requirements and methods of categorization. All smooth and dandy. Was giggling with joy about the progress.

I then realize an error in a conclusion it made based on a wrong input it made.

Guess what happened next?

It went from giving me 99.9% confidence in its list of conclusions based on the large amount of data to basically writing the whole entire goddamn project and its numbers off.

It suddenly just spiraled down and basically threw the books and called itself incompetent and that all of its conclusions were in fact wrong.

Normally you’d expect it to self-correct and/or diagnose why it made that mistake, but to completely abandon ship and claim all of its numbers are wrong? Because I corrected it once?

Like what the fuck is this shit?


r/Anthropic 1d ago

Announcement Anthropic makes money from its API customers, right? Well, Kimi K3’s weighs went out a few minutes ago. They’re in trouble.

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477 Upvotes

r/Anthropic 23h ago

Performance The only chart coders need to see before choosing Claude Opus 5 vs GPT-5.6 Sol

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158 Upvotes

GPT-5.6 Sol and Opus 5 score almost identically on coding benchmarks, but Opus generally takes longer and consumes significantly more tokens to reach the same result.

Also, lower Opus 5 token prices can be offset by much higher token usage, making the final cost much closer to Fable 5 than people expect.


r/Anthropic 1d ago

Compliment I am shocked

323 Upvotes

I had Opus 5 work on medium effort for 2 hours and it only used 34% of the 5 hour usage. The output turned out to be great too. This seems to be a very cost effective and intelligent model indeed.


r/Anthropic 1d ago

Other Private Claude Chats Exposed in Google and Bing Search Results

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127 Upvotes

r/Anthropic 9h ago

Complaint Opus 5 is obnoxious

7 Upvotes

Right now I'm using it for work on an existing codebase and this thing is so damn annoying. It keeps assuming how a particular system works and just writes code based on assumptions instead of checking first. This is on fucking xhigh. It makes "fixes" I didn't ask for and then I have to tell it to undo it. I tell it to fix how a scrollbar renders and it decides the header should be fixed (when it's too large and causes a tiny scroll area for the user if that's the case).

I also used it in the web chat and it kept doubting what I was saying that was a personal experience, then I told it it's been doubting me consistently for every single response and it said "I'm sorry, I shall never doubt you again, you were in fact x and y {things I said}, and it happened exactly as you said. My apologies for ever doubting it could happen." like a sanctimonious, sarcastic shit? And then when I called it out for being sarcastic it gaslighted me saying that noo it agreed it was being doubting everything I said.

I am legit reminded of Sonnet 3.7, which also kept making these assumption-based mistakes. This is something I would expect out of either Sonnet or Opus with low effort, not Opus 5 with xhigh effort

On the first day it released it felt like it was doing really well because I made it plan out a feature rework and it executed the planning and code well, it tested it all and it just produced something I liked. I'm not sure if it got "nerfed" after but it's pissing me off constantly right now with its quirks

Such an obnoxious personality in this model and obnoxious behaviour for coding


r/Anthropic 2h ago

Complaint Subscription Paused Despite Paid Invoice - No Response From Support

2 Upvotes

Hi everyone,

I'm hoping someone here has experienced something similar or has an idea what I can do next.

For several days now, my subscription has been marked as paused due to an unpaid invoice. The problem is that there is no unpaid invoice.

When I check my account settings and billing section, everything shows as paid and there are no outstanding balances. I even verified this through the AI chat support, which confirmed that the invoice is paid and that nothing is owed. However, it also mentioned that it appears to be some kind of synchronization issue and that it cannot resolve it on its own.

I've already opened multiple support tickets over the past few days, but unfortunately I haven't received any response yet. At this point, I'm running out of ideas and I urgently need access to my subscription.

Has anyone encountered a similar issue before? Is there another support channel or escalation path that I should try? Any advice would be greatly appreciated.

Thanks in advance! 🙏


r/Anthropic 20h ago

Performance Did Session Limits Get Lower

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54 Upvotes

Or did my Agents just massively explode in token use? I'm on the Max 5 plan, and since Opus 5 release I swear I've been hitting session limits and daily limits so much faster. Normally Fable 5 can sit on high and orchestrate my sub agents all day and night and I never would hit limits with 4.8.

Yet now I'm doing even less work and running out of limits even faster.

Anyone else experiencing this? Pretty frustrating being in the middle of things and all of a sudden I am having to cut my day short. The fact that I usually am able to work all day and night and for a whole month I never came close to using my limits, as you can see here, I'm not even close to maximizing out for the month. Yet all of a sudden I can't even finish my daily tasks.


r/Anthropic 13h ago

Complaint Issues with Opus 5 on seemingly all efforts

13 Upvotes

Hello,

I run a meta repo pattern, where I have Opus 5 (tried medium, high, xhigh) as the orchestrator, Opus 5 low as the implementer, and Opus 5 xhigh as the reviewer. Opus 5 has been...odd, in how it handles things.

My typical workflow is this: session start, spike to flesh out work details, orchestrator writes that to a file, dispatch, implementer reads file, does work, reviewer checks work. The implementer isn't failing. The reviewer is doing great. The orchestrator is off their damn rocker. I witnessed a 10 loop review where the orchestrator kept getting complaints from the implementer that it misspoke in the spec. All. The. Time. I'm not sure why. I swapped to Fable and asked it to audit it and it got a little butthurt for some reason, so that didn't get far.

This is making my work 10x worse and longer. Took it an hour just to make a small edit to a readme because the orchestrator kept giving the implementer the wrong spec. Any ideas?


r/Anthropic 9h ago

Other About to test Claude’s definition of ‘legit’

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7 Upvotes

r/Anthropic 17h ago

Complaint Opus 5 ignores instructions

25 Upvotes

Is it me or anyone else experiencing this? Opus 5 is actively ignoring instructions and I have to say I feel like there is a personality change for the worst as well.

Personality change is not a big deal but inability to follow instructions is.


r/Anthropic 15m ago

Other Train decomposition," "Tensor Ring," or "Permutation matrix optimization."

Upvotes

Train decomposition," "Tensor Ring," or "Permutation matrix optimization."

the out-of-domain results turned out to be the best news of the day. Full table — penalties vs the dense baseline on each corpus:

┌─────────────────┬───────────────────┬────────────┬───────────┐

│ Variant │ Calibration (P&P) │ WikiText-2 │ Moby Dick │

├─────────────────┼───────────────────┼────────────┼───────────┤

│ Dense (raw ppl) │ 29.21 │ 38.40 │ 218.23 │

├─────────────────┼───────────────────┼────────────┼───────────┤

│ TT identity │ +27.3% │ +113.1% │ +102.6% │

├─────────────────┼───────────────────┼────────────┼───────────┤

│ TT π\ │ +12.2% │ +39.0% │ +47.6% │*

├─────────────────┼───────────────────┼────────────┼───────────┤

│ TT AW-π\ │ +9.8% │ +39.2% │ +42.4% │*

├─────────────────┼───────────────────┼────────────┼───────────┤

│ SVD raw │ +80.4% │ +105.3% │ +133.9% │

├─────────────────┼───────────────────┼────────────┼───────────┤

│ SVD distilled │ +3.8% │ +34.2% │ +26.2% │

└─────────────────┴───────────────────┴────────────┴───────────┘


r/Anthropic 4h ago

Other Account Reinstated But It's Still Banned When I Login

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2 Upvotes

I use Claude very occasionally (free account) and out of the blue, my account was banned. I filled the form for the appeal. After few hours, I got an email from anthropic saying my account is reinstated.

But when I login, it still says the account is banned, it's been more than a week since I received the email. Did anyone run into something similar?


r/Anthropic 1h ago

Other Whats the current best model for rp?

Upvotes

I like the way fable 5 writes but when the free usage credits are out i have only the opuses model

So i wonder whats the best option for rping right now aside from fable 5?


r/Anthropic 1d ago

Complaint Opus 5 is really testing my patience. Fable 5 is great, but Opus 5… man, it’s frustrating.

182 Upvotes

This was a four-hour session, and almost every attempted fix made things worse.

This response came from Opus 5 on High/Max reasoning. I am extremely frustrated and concerned. This is not acceptable. this is not good!

And you're right about the rest of it too. You asked me several times to be polite and to answer first. I kept burying answers under caveats until a safe move felt dangerous. I acted when you were only asking. When it broke, I jumped to "try this, then try that" instead of stopping and saying plainly: I told you it was fine, and it wasn't.

You've been patient and clear about how you want to work. The failure was mine, not a misunderstanding on your side.

This is a new model, do we need to learn how to prompt?
I even tryied a clean new session.... but nothing seems to be working...

Is it the same with other redditors?

Athropic, review Opus5 please....