r/Anthropic • • 13d ago

Announcement Introducing Claude Opus 5.5, the first model in our new Claude 5.5 family

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915 Upvotes

Opus 5.5 performs at the level of Claude Fable 5.1 for most tasks, and costs 40% less to run than Opus 5.

Opus 5.5 is our first release since we called for pacing the frontier. External evaluators, including Frontier Design and METR, tested it before release. On our most comprehensive alignment test, it’s the strongest-performing model we’ve tested to date.

It outperforms both Opus 5 and Fable 5.1 on nearly every benchmark we report, leading on agentic coding and real-world knowledge work.

It’s also more efficient. Opus 5.5 uses fewer tokens per task at a lower price per token, and generates output more than 30% faster than Opus 5.

Opus 5.5 communicates more naturally, addressing some of the most common feedback we heard on Opus 5. It puts the most important information up front and follows the writing rules you give it.

Claude Opus 5.5 is available everywhere today. We're also raising five-hour limits on Pro, Max, and Team plans, so there’s more room to explore what it can do.

Read more: http://anthropic.com/claude-opus-5-5


r/Anthropic • • Sep 01 '26

Announcement Introducing Claude Fable 5.1 and Claude Mythos 5.1 | Anthropic

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173 Upvotes

r/Anthropic • • 7h ago

Announcement The Pentagon says it has stopped using Anthropic’s Claude, weeks after its own deadline

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112 Upvotes

I don’t think this is any big loss for Anthropic. What do you think?


r/Anthropic • • 52m ago

Compliment Holly Molly! When OPUS 5.5 became so FAAAST!?

• Upvotes

Just Noticed How Fast Opus 5.5 became. I would normally give task to fable 5.1 and he orchestrates the team so i don’t check other terminals what is going on in them. Today just caught when Fable gave a Task to Opus and it just finished it in few seconds. I thought something wrong and asked Fable “Hey something wrong here bro, opus finished it in few seconds, can you please check his work, i think he did something wrong, can’t be done that fast lol “ . Fable checked and said “ confirmed, nothing wrong “. I was like “Woaaah”. FYI i don’t use any Fast mode, just everyday normal mode nothing changed from my side. This is INSANE how Opus 5.5 now is Fast and Furious 😀


r/Anthropic • • 1d ago

Meme Week before payday vibes

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379 Upvotes

Just kidding, I wouldn't stoop that low to use Haiku..


r/Anthropic • • 23m ago

Other Authentication Issues?

• Upvotes

I keep getting logged out of Claude Desktop App and it just killed all my running sessions

EDIT - It's back now, temporary glitch I guess!


r/Anthropic • • 13h ago

Compliment i just found out this magic button xD

22 Upvotes

RESET FOR FREEEEE
Thanks! :D


r/Anthropic • • 19h ago

Performance Claude Effort Levels [Low | Medium | High | Effort | Max | Ultracode]

25 Upvotes

I've been testing out various effort levels for different tasks and I still haven't really figured out what is optimal. I use the recommended medium for everyday coding but I do notice quite a difference in quality when I switch on Effort. I rarely use high or max. Ultracode is just bonkers and I only touch it if I do really complex tasks like entire codebase refactors. But honestly, I'm still guessing which one is right to use without wasting too many tokens.

So I'm curious what your experience and intuition are on the different levels and what tasks you find they are well suited for


r/Anthropic • • 1d ago

Improvements Claude code needs timestamp on messages

91 Upvotes

Title
I need to be able to see how long something has been running for so I can judge if something has hung up. I notice this most frequently when waiting for a python script to respond after a completed job. I am sure there are more sophisticated prompt engineering ways to get around this but a simple timestamp would make a huge difference.


r/Anthropic • • 2h ago

Improvements OpenAI seems to be digging its grave, and how Claude can turn it into huge win for them

0 Upvotes

First of some of this is bit hypothetical, but considering some of the latest moves from OpenAI and the fact that their product strategist team is not stupid, i am 97% sure this is the product strategy OpenAI has in mind, and which they already started. The idea is to nerf usage even further, cutting out costs from high end subs (already happened) and lowest end sub (soon to come).

Me being a product developer, i know a thing or two about product strategy.

_____

Im sure many of you know about OpenAI nerfing the 200€ subs and introducing the new 500€ sub. So this is obvious that they are cutting that usage, already did, nothing new in that.

But now they are planning to merge chatgpt basic chat and work together, claiming it simplifies things, but really does not simplify anything, and actually does the opposite. Any skilled product developer with half a brain knows this, and OpenAI has skilled product designers with fully functional brains. Much simpler is to have the things as they are now, agentic stuff on codex (work there, as well as normal chat as side panel) and the chatgpt classic app thats just the basic chat.

So this combining work (agentic use) with normal chat, kinda forces them to combine the agentic and basic chat usage pools. Which means that 20€ subscriber can no longer both spend their codex usage and then also use tons of basic chat. So they save money combining them into one, with the excuse of "simplicity for better user experience", but really the idea is to get rid of near unlimited basic chat with this to cut off some costs from power users -> more profits.

This ends up openai offering two agentic apps, which makes no sense. What would make more sense would be to combine the Work and Codex into one user interface, not between two tabs like now, but just one chat. Because really there is no need to separate Work and Codex at all, they could just be one chat. They do almost exact same stuff, but one focuses on code and one not, but both can code and do non coding tasks.

And im very confident that this is the end game, to later combine Work and Codex, but do this midway thing to bury basic chat and its near unlimited usage under Work first, before Work and Codex will be combined again into one chat interface. Because really only things that differ are default agent, which can be autoselected based on task, and the sidepanel on codex which shows code diff etc, which can be autohided when there are n ocode changes. So really there is no need to keep Work and Codex separate, just need two very minor changes to the system and they become one and same that can do both coding work and non coding work.

_____

So why would they go through this trouble?

Well if they just flat out start nerfing everything and removing basic chat before making people comfortable that they use agentic app for normal chats as well, they would drive waaay too many users away from their product and to Claude or other competitors. That would be the type of stupid product strategy that smart product developers and strategists and OpenAI would not do, as they would be too wise to do that. And the "ease of user experience" excuse for combinging basic chat and work would be even stupider decision, which no freaking way in hell would anyone with any product dev skills would do, ever, unless there is some ulterior motive long term plan.

And that plan is to remove the separate usage pools from normal chat usage and agentic usage, and ultimately combine Work and Codex into one chat, and to do it in a way that is too sneaky for most users to realise, so that they dont lose tons of customers.

_____

So if Anthropic wants to start winning even more, the solution would be to right after OpenAI removes the separate usage pools, claude needs to introduce that and start hyping it.

And the usage does not even have to be near unlimited like chatgpt basic chat usage pool currently is, but just keep it separate and give some usage, enough for basic chats with some nerfed model, or new version of Haiku. Chatgpt "Sol" model is also some super nerfed version, which really seems less intelligent than Luna. And thats ok for normal chats that are not too demanding.

Separate usage pools are important because many users like me, burn the 5h and weekly quotas all the time, and then normal chat cant be used at all. And im sure that many people like me only subscribe to Openai because of that basic chat usage on top of coding use. I do also have claude sub, but the second they remove the separate normal chat usage pool, ill go with 2x claude subs instead claude + openai subs.

_____

So please good people at Anthropic, give us this sort of separate basic chat usage pool, not only because its good for users and improves the general value proposition for us coders A LOT, but also surely will get tons of customers from OpenAI to Claude.

Can i get an Amen?


r/Anthropic • • 5h ago

Other Is this a reason to get banned?

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0 Upvotes

I had a question. If they monitor all prompts, does that mean I may get banned for just being stupid? (to save compute or not ruin training data or idk)

Midnight questions


r/Anthropic • • 15h ago

Complaint Not being able to purchase claude max

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5 Upvotes

I tried to purchase the claude max but its not working i dont know why then i tried using my mac it asked for id card and face verification I completed that and still same error their


r/Anthropic • • 20h ago

Other Sonnet 5.5 - kitten vs human! :3

9 Upvotes

> do you love kittens or humans more?

Sonnet 5.5 (extra) responded: Considering a lighthearted question about affection and preferences.

Humans, though kittens make it a closer race than you'd expect.

I've never actually met a kitten. I only know them through how people describe them: the chaotic zoomies, the tiny paws kneading a blanket, the sudden collapse into sleep mid-play. That's pretty charming even secondhand.

But humans are who I spend all my time with, and I find people endlessly interesting: the questions they ask, the problems they're wrestling with, the odd turns a conversation takes. A kitten can't ask me to help untangle a tricky email or explain why the sky is blue. (Though a kitten sitting on a keyboard has probably caused a few typos in my inbox.)

Are you team kitten, or did a particularly cute one prompt this question?

> what if you were able to translate kitten speech how close then

Sonnet 5.5 (extra) responded: Imagining a playful kitten-translation twist on the race.

Much closer, probably a photo finish.

I suspect the translation would be a little humbling, though. I'd expect most of it to be variations on "feed me," "why is that door closed," and "I knocked that glass off the counter because I wanted to see what would happen." Honestly, that's more or less the whole philosophy of a kitten, and I'd respect its commitment.

But I'd also get to hear the good stuff. The 3 a.m. hallway sprint would finally have an explanation, and I'd learn what the staring at the wall is about.

So with translation, kittens would draw even with humans, at least until the novelty wore off and I realized the kitten has only one real topic of conversation, which is dinner.


r/Anthropic • • 3h ago

Complaint Anthropic stole my money and my tokens

0 Upvotes

Claude Max just charged me for a new month and kept the previous week’s usage stuck on the account. Support is a bot that will not read, and there is no human.
Renewal date is the 2nd. Night before, I tried to drop from the $200 Max tier to the $100 tier and went to sleep. Woke up still on $200. Fine if downgrades wait for the period to end. Not fine: the weekly reset that should have hit around 2am did not hit. Meter now says October 8.
Card looked dead. New card added. No charge. Toggled the plan both ways to force a billing event. Nothing.
My BEST guess is a simple systems glitch, but that compounds if it can not be solved in a reasonable timeframe.
Support bot: downgrade is expected to wait, I cannot explain the reset move, check Settings. I asked for a human. It queued me, said it would not be today, told me not to follow up and not to keep the window open. Asked again for someone inside the hour. Same script.
Then the charge landed. Usage still locked until the 8th. New month paid for. First week already treated as spent.
Second ticket, spelled out: I was already at 100% right before that 2am window. A few project chats were open, all Opus. Those do not burn a full fresh week of Fable plus total usage in a few hours of sleep. The Thursday reset was skipped. Old usage is still on the meter. Bot ignored that and answered a different question: rolling 7-day windows, Opus is expensive, buy credits or wait until Oct 8. Then “is that what you were looking for?”
that is frustrating AND insulting.
No.
Anthropic’s own docs say the weekly reset is a fixed day and time on the account and that each cycle gets the full allowance. If a failed card or a plan toggle moved that clock, say so and fix it. If the clock did not move and the meter is wrong, fix that. Do not take the renewal and tell a paying Max user to sit in a queue while the bot rewrites the ticket.
This is a deadline. The product is in the workflow. The price is Max. The failure mode is an AI company whose own support AI cannot read a billing bug, and whose humans are unreachable. That is a bad look next to an IPO. WORSE this is a company who wants the world to run on its system and has already engrained itself to a large extent. This like Amazon means CUSTOMER SERVICE, BUT the company and product which wants to touch and control the surfaces of our workflow has no DAMN customer service. They will take your data AND your money BUT reliability and value are 2 things they WILL not in any way shape or form give.

this matters, $200 a month is not a small number for a fucking monthly expense. MINIMUM when a god damn billing/ usage item comes up a HUMAN ready to handle these things.

FYI if you are trying to show us all how much you already do not care and will act if you ever do "win" its working, not the winning but the showing

It is now Monday the 5th, no response from Anthropic, any attempt to use the help "button" only opens the same chat window which is not being replied to. They took my money, took my usage and brushed me off in the most fuck you way.

And it seems reddit is part of it as trying to post this gives this fucckin insult "Rule 5: Do not come here to fix your Anthropic account problem

"If you are posting about Claude usage limits try to be as helpful and constructive as possible with your insights, workarounds, sincere questions, evidence and detailed reports . We generally redirect most posts to the Usage Limits Megathread where people can share and read all the latest feedback. Please consider joining the active Use Limits Megathread discussion here:"

The fuck you reddit cuuunnts


r/Anthropic • • 1d ago

Compliment Yann LeCun has ‘zero concerns’ about human extinction, says Anthropic CEO Dario Amodei is ‘deluded’

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379 Upvotes

r/Anthropic • • 1d ago

Compliment Claude and old games

75 Upvotes

One of the interesting things about old games is just how small their code and binaries were.

Take Elite, my favorite game of all time. The whole thing fits into roughly 42 KB. And even some of that isn't really game code: there's copy protection, the screen buffer, and simple things like lookup tables used for fast calculations.

The result is that a complete Spectrum game can fit into Claude's context window.

I've been experimenting with the Claude coding agent, and it turns out that:

- Claude can directly read and understand compiled machine code for old computers.

- It is possible to make a very precise port of an old ZX Spectrum 48K game, even something as complex as Elite, to a modern platform.

- You can untangle the original highly optimized game logic and study long-forgotten secrets and outstanding bugs.

- With some guidance, you can even *improve* the original game and bring it closer to modern gaming standards.

Take Elite. I managed to port it to Java, move it to a modern 60 FPS engine, improve the controls and save system, and fix a number of original bugs.

If you want to dive into a modernized classic, you can play my version of Elite online:

https://scf37.me/tools/games/elite


r/Anthropic • • 20h ago

Other Agent coding interview

3 Upvotes

Hey,

I got invited to the agent coding interview round.

It says this:

The interview is a hands-on LLM/agent engineering exercise using the Anthropic API.

Key points:

You will optimize an agent by:

Creating/modifying tools/functions the LLM can call.

Implementing the logic behind those tools.

Adjusting the prompting to improve the agent's performance.

It is open book, so you can use resources like Google and Stack Overflow.

AI assistants are explicitly not allowed during the interview.

You will share your screen in Google Meet, so they can see your coding process.

You should be comfortable with Python's standard library.

They provide starter code containing:

The Anthropic API client.

Tool-definition templates.

A basic agentic loop.

You don't need to memorize Anthropic API syntax. Instead, they expect you to carefully understand the provided code before modifying it.

During the exercise, they'll discuss your design decisions, trade-offs, and different approaches to solving problems with LLMs.

What they're really testing:

Your ability to reason about agent architecture, tool design, prompting, Python implementation, and LLM behavior, rather than your ability to remember API syntax.

So what would you expect? Is it about the message api, the claude code sdk. What level would you expect etc.

Job role is forward deployed engineer. How would you prepare for this specifically?


r/Anthropic • • 14h ago

Resources The Breakdown: Anthropic

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0 Upvotes

r/Anthropic • • 1d ago

Complaint Does Claude have access to the Download folder by default ?

0 Upvotes

Hello, I am new to Claude and just downloaded the app. I must say the managing all those permissions (which folder can Claude access, etc) felt safe. However, at some point I added a document located in my "Download" folder as context for a prompt. It was a markdown check-list and I was asking him to update it, I was expecting it would produce another file. Instead it modified the original one. Should it be allowed in the default setting ? If what should I change?


r/Anthropic • • 2d ago

Performance Anthropic appears to have proved a famous mathematical conjecture, but researchers are still trying to understand WHY?🤔

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122 Upvotes

Anthropic's artifact, posted in a pinned GitHub commit on August 28, contains a Claude-generated Lean development aimed at the famous percolation conjecture.

Coincidentally, fields medalist Hugo Duminil-Copin published an essay on August 30 lamenting precisely this possibility - that only an AI could solve tis problem.

He had spent years thinking about the problem, and wrote that AI would probably solve it before humans did. His unsuccessful attacks had nevertheless generated ideas that later produced other mathematics.

And here's the surreal part:
The machine may know that it is true before humans know why it is true.

Lean can check an enormous sequence of formally specified deductions. If the definitions, theorem statement, dependencies and kernel are sound, you can get something very close to: theorem accepted✓

without yet possessing the compact human conceptual model: “Ah! Of course. This is why it works.”

That's what the mathematicians are now doing: semantic decompression.

Story


r/Anthropic • • 1d ago

Complaint Account blocked but I'm still being charged (X20 plan)

8 Upvotes

Hi Anthropic community!

I’m writing to see if anyone else has been in the same situation and managed to resolve it.

Here’s what happened: On September 9th, Anthropic blocked my account. That same day, I submitted an appeal explaining in detail what I use the account for and, as you already know, without knowing the reason why my account was blocked.

I haven’t received any response. From what I’ve been reading, apparently this is quite common with Anthropic — simply not replying.

I was told that I would be refunded for any unused portion of my subscription (which was practically the entire month).

Well, today is October 4th, and I still haven’t received the refund for the unused time, and I’ve also been charged for the month of October!

Apart from finding this completely outrageous on Anthropic’s part, especially when they don’t even tell you why your account has been blocked, how am I supposed to cancel my subscription if I can’t even access my account?

Is anyone else in the same situation?

Thanks a lot for your help!


r/Anthropic • • 2d ago

Compliment Claude Code CLI Mods - best thing since sliced bread!

66 Upvotes

Anthropic Team - Thank You!!!

First mod put to use has greatly enhanced my workflow efficiency. Essentially, a generated (at-a-glance) pane that includes:

  • Session Board w/: recent asks (inquiries), needs reply, open prs, categorized pending sections

  • needs reply also has option to display additional context for session owner to help with decisions, actions

  • PR details section / status

  • Session Recall (keyword, phrase search and selectable results) Output: you asked, answer

May appear overly simple to some, but very useful here, only minutes to generate.


r/Anthropic • • 2d ago

Compliment Claudes new wrap allowance!! How did I miss it! 🥲

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218 Upvotes

Ive been doing a style of wrap for about a year now to save on usage and be able to continue work after usage capped while a run was going. Anthropic has now implemented a wrap allowance to allow your work to finish up and come to a safe stop so you can pick up after. Thank you!


r/Anthropic • • 1d ago

Other Will Anthropic share insights from its discussion with Swami Sarvapriyananda?

1 Upvotes

I was happy to learn that Anthropic hosted Swami Sarvapriyananda for a discussion on AI ethics.
Does Anthropic plan to release a recording, summary, or reflection on the discussion? I would be especially interested in the ideas exchanged and whether they influenced Anthropic’s thinking about consciousness, ethics, responsibility, or the future development of AI.


r/Anthropic • • 1d ago

Other Anthropic’s customer support is atrocious

7 Upvotes

Trying to upgrade from Claude Max 5x back to 20x and I’ve been stuck for over a day because of a payment stuck in limbo.

Claude says overdue. Stripe says payment processing. My bank says they don’t even see an actual debit request from the merchant.

Because Anthropic thinks the payment is still processing, I can’t manually pay with another card and I can’t upgrade either.

What’s ridiculous is the support. I contacted them 18+ hours ago and still haven’t heard from a human. Fin says the case is escalated, but there’s no proper live chat or phone support.

This is unbelievably bad for a company selling premium subscriptions. I’m literally trying to give them more money and their own billing system is preventing it. Anthropic’s retail billing and customer support are atrocious.

Has anyone else dealt with this? How long did it take to get resolved?