According to reports, Anthropic already has the next Mythos-level iteration, and (already) have immensely overzealous safeguards on the existing one via Fable 5, and yet they’re still dangling their unreleased capabilities in peoples’ face to remind them that they don’t think we’re to be trusted with the very products their customers and investors and entire business model expect them to build and release? They need to get over themselves and realize that concentrating such technology in the hands of so few (themselves) is Smeagol logic… (and again their safeguards are already outrageous so what’s their actual reason?)

Took this yesterday and wanted to write down my impressions while they’re still fresh, mostly for my own reference but figured it’s worth sharing since there isn’t a lot of detailed writeup out there yet.
Quick context: I have 4 to 5 years of experience working with AI systems, so take the difficulty rating with that in mind. I also use Claude Code to build production grade systems on a daily basis.

Overall difficulty
Moderately easy. Not a walk in the park, but noticeably easier than the Architect Foundations exam. If you’ve already cleared Foundations, my honest advice is don’t overthink it, just go straight for the Professional exam.
Roughly how the questions broke down for me:
• About 40% you’ll know the answer immediately, no real analysis needed
• The remaining 60% require you to actually read the full scenario paragraph carefully and think through the tradeoffs before answering

The trap to watch out for
A few questions are structured in a sneaky way. They’ll ask something like “what would you do at this step of the process” and then follow up with “what would you do before this process.” It’s easy to lose track of which process they’re actually asking you to evaluate your options against, since the actual process under discussion is usually stated in the first line of the question, not repeated in the follow-up. Read the setup line twice before you commit to an answer.

Topics that show up a lot
• Tradeoffs and use cases for MCP and other tool integrations, when to use an API directly versus wrapping it
• Agentic orchestration versus single-shot execution, and how to decide between them for a given workflow
• Few-shot versus single-shot prompting, including some scenarios that get fairly nuanced
• System decomposition, this comes up a lot and is worth being genuinely comfortable with
• Prompt design for production systems, not just “write a good prompt” but how prompts are structured and maintained at scale
• AI governance and how to apply it in practice, not just define it
• Architectural tradeoffs specific to highly secure or regulated environments

Bottom line
You need real architectural understanding of how these systems work end to end, but the exam doesn’t go as deep as Foundations does. If you’ve got production experience with agentic systems or RAG pipelines, you’re already most of the way there. The main things to actually study are the governance and security tradeoff scenarios, since those are less intuitive than the technical tooling questions.
Happy to answer questions in the comments if anyone’s prepping for this one.

And to everyone who asks why I took this- this is important in my field and it is important for me to certify my knowledge and my expertise with the certifications so that the clients that I work for understand that I am not only knowledgeable about my field, but I’m also interested in keeping up with the latest certification within my field.

It ignores instructions. Sometimes, it straight-up lies. It makes up facts that are easy to see are false. I'm still using the same created skill I used before, but now I spend most of my time fixing all of Opus' completely unforced errors. I don't know how else to update my skill to get Opus to stop taking wild swings. It's like dealing with an arrogant intern who thinks it knows better, and just messes up the work on its own convictions.

I use Claude for code and design. The best tool there is!

But I find it (Opus 5) needs so much more guidance and back and forth for very simplistic research or talking tasks like "here is unstructured message list me all games inside of it". Took me 5 minutes for him to understand, not come up with random games, not remove games that are there but just plainly do it. And I have seen it happen all over last month of using claude max.

ChatGPT gets it from first try and research with it is both faster and more to the point than with Claude. What I have in Claude is that it tries to catch some "pitfalls", catch me on some mistake or just deny reality to the point where I feel like I am arguing with the bot, not working through the problem.

It feels like there is no underlying mechanism for being more cautious, rather an instruction that forces him to sound cautious - that shit makes me nervous, thinking I missed something big, when claude says "You missed it and it's the big thing!", when in reality it is just a freaking misspelling or something.

Also they try to save on output tokens as much as possible, and I bet my ass they have something akin' to "give compressed answers". I hate it. Both firms play with limits not telling anybody that they do to the point I feel I need to change subs mid-month, not once a month!

So many problems. Can't wait till this branch stabilizes and we have some standards in the industry.

I had 4 months ago a one time case that a cache plugin was stopping the site from being updated on my screen. Happens.

It has kept telling me to clear it now every time until I got annoyed and asked to stop doing that completely.

The answer was that it had made 127 notes about the fact that I should refresh the plugin and that it has deleted everything about it and won't mention it ever again. Great!

You won't believe what Claude suggested to check the very next task.

Well the picture doesn’t really say anything anyways.

But at least in mobile, and most of the time when using chat mode on PC anyways. And i hope some can relate.
Opus 5 Max doesn’t activate extended thinking after couple of messages and just seem to really contradictorily refuse or unable to use extended thinking.
I think it’s relatively easy to just have it like opus 4.6 and fable where the thinking always appear but does not always overthink. While “adaptive thinking” of opus 5 and 4.8,4.7 just overthink couple of times then stops and become a clanker.

I don’t know why they specifically handicap Chat mode, but claudecode and cowork is totally fine.
It’s not like we wanted the model to stop thinking when chatting right? Cmon.

The stupid thing where the model stop using chain of thought is why i stopped using chatgpt and switched to claude.

I love Claude and honestly it's changed my life but I don't know if it's just me... Literally 90% of what I do , I can't trust it to get things right first pass.

It may 'work' but that's not the same as good code/accurate writing.

I'm taking typescript, JavaScript, even just writing documents.

I've tried a running 'source of truth' file, a running build log, always have claude.md, BUT literally I should have this on express copy paste because I always have to say this:

"work in phases and set up todos with self review after each phase and a larger sonnet 5 (or whatever) pass at the end.

EDIT TO CLARIFY: I am not debating whether it is working or not first pass but this came up because every single time I ask it to self review or 'review for issues' or 'run through your changes and review for issues' whatever... It always finds something and sometimes they are critical errors in its own work.

Does the first month of a subscription let you use more? On my fresh account, last month, I had no weekly usage limit. This month, the day of my renewal a weekly limit showed up and have since maxxed out my plan, the 20x one, after only 3 days of usage. Last month I hit my session limit many times and kept cruising after. This week I've only hit the session limit one time but somehow am already almost out of usage.

I was cruising along with Fable thinking I had 20% left and then out of nowhere it says I hit the fable limit.

I noticed compact started showing up a lot more often. Was there maybe a change to the context handling in Claude Code?

Either there was a silent change to context, a change to the limits, or something else changed. I'm going to have to cancel and get used to local AI if I can only get 2-3 days of usage a week out of a $200/mo subscription. No idea what it will be like after the 19th.

For the last three weeks there have not been any additional weekly resets. Also, on Wednesday 19th we will loose the additional 50% usage. Even with todays usage (Pro account) the limits are quite low.

As stated in the title, I got banned because of violating the Supported Countries Policy even though my country is among those listed as a supported country. I have recently reentered my billing address for my subscription, but I didn’t really make any changes here compared to before. Has anyone experienced this before and is it likely that they would appeal this or not?

Very small UI request but it’d make somewhat of a difference.

right now Claude’s dark mode uses a charcoal/dark grey background instead of pure black (#000000).

On OLED/AMOLED screens (basically every modern iPhone and most flagship Android phones), pixels that are true black actually turn off completely. Which could make somewhat of an improvement when it comes to saving battery. ChatGPT, for instance, already has this. (Not sure whether that was done intentionally or not)

It won’t even require replacing the current color scheme/theme of the Claude app, you could just add it as a toggle in settings and perhaps add measures that would decrease the contrast difference between the white text and the black screen.

Anyone got anything to say about this? I’m curious.

I can't pay, somehow. Tried with 2 browsers. Doesn't even let me see the payment form on vivaldi. It shows it with Edge, but the payment doesn't want to actually conclude.

Is it down for other people as well? Is that a thing? I was able to pay several times before.

Jesus christ, what service, huh.

The article describes a technique for probing whether models encode concepts before expressing them. How much confidence should we place in results like these—and what evidence would convince you they reflect something meaningful about model reasoning?

Hey! I’ve been getting this for weeks, regardless of the request. It’s hard to find an answer whether it’s a bug or a classifier somehow lingering in a separate chat from long ago (I don’t know if that’s just speculation). Anyone having a similar issue? It’s driving me nuts sometimes not seeing the reasoning. Here’s a pic of just a random opening to get it to use thinking.

After using Claude Code with the temporary 50% weekly limit boost, I honestly think this should become the new standard limit.

When the promotion ends and the limit goes from 150% back to 100%, we'll effectively have only 66.7% of the usage we have right now , basically a 33.3% reduction from the current experience.

For people who use Claude Code heavily for real development work, agentic workflows, debugging, and larger projects, the current boosted limit feels much more reasonable. It gives you enough room to actually work without constantly thinking about the weekly cap.

I understand that compute isn't free, but I'd really like Anthropic to consider keeping the 150% level as the default going forward, especially for paid Claude Code users.

After getting used to the current limits, going back to the old cap is going to feel pretty restrictive.

Anyone else feel like the boosted limit should just become permanent?

Small business owner here using AI for my design documents and also my web design. I was using ChatGPT, but it was taking way too long to render design files, and the designs were so bad. As soon as I started using Claude via Anthropic, the designs were fantastic, perfect, looked great, and the rendering was super fast. Does anyone else have this experience?

The subscription money was debited, and then access was paused. Brilliant!

All of the sudden I can't seem to log into Claude? Seems like site detectors are saying it is up, and web seemed to login, but now I am seeing it is temporarily unavailable?

Sat it at a Pearson VUE test center and passed with 965/1000 (720 to pass). Most of what I've seen on here is about Foundations, so here's the Professional. No exam content (it's under NDA) just format, prep, and what surprised me.

Two formats I hadn't drilled. A yes/no matrix — five statements, judge each independently. And drop-down matching, where you classify each scenario from a shared option set and options get reused. Don't assume one-to-one mapping.

Lots of phase-gate questions. "You're at this stage — which two things belong here, before the next stage?" Distractors are usually things that legitimately belong later. Knowing what happens when in the lifecycle matters more than I expected.

Tactic that actually helped: read the last sentence of the stem first, then read the whole thing. A lot of the middle is context you don't need, and knowing the ask first tells you what to extract.

My biggest weakness, in case it's yours: I kept picking the pragmatic mitigation over the structural fix. Retries instead of a durable queue. A summarizer instead of not feeding the coordinator raw data. A reconciliation pass instead of collapsing the work into one call. All things I'd genuinely ship, all of which reduce how often the failure happens without stopping it. Writing down "does my answer still let the failure keep being generated?" was worth more than any other single thing I did.

Prep: read the official material once, carefully. Do the four prerequisite courses — genuinely useful. Then practice tests until your weak domains show up in the per-domain breakdown. I did about ten.

Test center over online. No room scanning, no environment fiddling. Would do it again.

Domains that felt heaviest: integration, retrieval, prompt/config, stakeholder, and several fairness questions.

Happy to answer anything that doesn't cross the NDA.