Anthropic Fable 5 The Ultimate AI Model for Builders

0:00Fable 5 just came out and we need to talk about it because this is going to change how people build forever. What we couldn't build before is now possible with Fable 5 and you have just about 12 days to use it under your subscription before you're going to start paying hefty usage fees. I've had to refactor my databases. I've had to go through my apps easy flip in the magic hand to make my apps a hundred times better and in this video, I'm going to be talking about some of the features on what makes it different than Opus 4.8 and other models in the past and why I think that this model is going to go in its own subscription tier of its own. So, every builder needs to understand that the way of building just previously just changed with Fable. I mean, this is the closest

0:45thing to a one shot model that we've ever seen before and yes, it's expensive. We all knew that and this is not just a small model bump at all. Not like Opus 4.7 to 4.8. Not like Sonnet 4. 5 to 4.6. Nothing like that. This is actually a completely different model. You need to check out the benchmarks here. I'll have it linked down below, but it literally blows every other model out of the water. You have a genetic coding on Sweet Bench at 80%. You have a genetic coding at almost 30% compared to Opus 4.8 at 13.4%. I mean, this is crazy. Knowledge work blows it out of the water. We got spatial reasoning, tool use, you got legal work. I mean, this is definitely

1:30one of the greatest we've seen and I'm just blown away. I mean, you got 10 million per input token, which is pretty I mean, it's not terrible and then you have 50 per million output tokens, which is actually less than half the price of Claude Mythos preview. So, very cool. I just think Anthropic, you know, launched a huge model here and I didn't expect it to come out this early. I was thinking more to mid to end of June, but they hit fast. I mean, I was on vacation. I had to run back to make this video and do a lot of testing and just really it is a smooth overall experience. I had been using Opus 48 under the ultra code feature for all of my usage over these last few weeks and I've been loving it, but Fable is on a

2:15whole different level. Real quick, before we keep going, if you're watching this and you want to actually build with some of these tools, not just watch videos about them, then you're going to want to check out our community down below, Shipping School. We have a full Claude Code course, a full Open Claude course, and four live bootcamps every single week where we actually help you get set up from scratch. Like actually set this thing up, not just watch a tutorial and figure it out by yourself. And we also provide one-on-one coaching so you could book a call with me, we could share screens, and I can help you get Claude Code or Open Claude running on your machine. That's it, no fluff. I built this community because watching YouTube's only gets you so far. We launched it just 3 days ago and we have over 55 members. You need people around

3:03you who are actually building, people who hold you accountable, and coaches who can help you when you get stuck. I'll put the link in the description down below. Get in now before the price goes up. You know, nobody should skip this upgrade. If you have a Claude subscription, you need to use it. So, it's basically the same underlying capability tier that was previously locked behind Project Glasswing, known as Mythos Pro preview. They used it for cyber defenders and now it's just available to builders just like us. As Claude Fable 5 shows, basically more of a dumbed-down version. I don't know if Mythos is going to be something that comes out later in the future, but it's safe to use, let's just say. And you know, that matters because the AI race

3:49is moving from chatbots that answer stupid questions into models that actually run full agentic workflows. You know, they'll hold more context, they'll make more room for decisions and tool use and tool calling and you've seen all these things about loops and recursive loops happening. I really do believe we are going to go from us prompting AI to no longer prompting the AI at all and we are seeing that come true with these new loops and these greater more robust models. This model can recover for more mistakes, too. It can actually check its own work. I think that if you're scared of paying for the Fable 5, you can at least use it as a orchestrator agent. Something that checks maybe Opus 4.8's work to make sure that it's on track so you don't push a buggy code to

4:34production. You know, Anthropic says Fable 5 is its most capable and widely released model that it's ever built and it beats every single Anthropic model has ever made, you know, across software engineering, knowledge work, vision, scientific research and longer complex tasks. I mean, you see it here in the benchmark results, absolutely phenomenal. You can see it here in agentic coding that blows everything out of the water. And just to let you know, 70% of the code that lives on the internet is written by AI. So, it's more about the fact that you don't need to really understand how to code anymore and if you're learning how to code, I'm going to say it right here, stop. You need to learn how to prompt or communicate with AI to code effectively.

5:21That's what we need to be learning as builders and engineers is to actually get the most out of AI to write the code for you because it has now has surpassed senior-level engineering. So, that's what we need to be learning. You can see here Fable 5 is the new state-of-the-art model for tasks involving vision. It can extract precise numbers from detailed scientific figures and can perform complex vision-based tasks like rebuilding an app's source code from screenshots alone. Memory and long context. Fable 5 stays focused across millions of tokens in long-running tasks and improves its outputs using its own notes. It's amazing. And when I say

6:06longer tasks, I do not mean write me a to-do list. That's boring. What are we talking about? I'm talking about Anthropic saying Fable 5 and Mythos 5 can work autonomously for longer than any previous Claude models. The docs specifically say Fable 5 supports a 1 million token context window by default, and that is beautiful. And up to 128,000 output tokens per request. That is the part builders really need to care about. Most people still judge models by one prompt. I mean, what are we doing here? Who writes the better email? I mean, come on, who cares? Who makes a cleaner React component? Who answers the riddle? You know, I've seen those tests before.

6:51It's funny and it's cute. Um but that's not where the game is going. The real question is can the model sit inside of a like a repository and read the whole mess of code that you had maybe Sonic 4.5 do couple months ago and can it actually make a plan, change the right files, test the work, and handle the weird failure, and actually not lose the whole point of what it was actually trying to do halfway through cuz we've seen that before with GPT-4. That is what these releases are actually about. It's Anthropic giving one example from Stripe where basically in early testing, reportedly compressed months of engineering into days and handled a codebase wide migration into 50 million line Ruby codebase in one single day. It

7:36basically compared to over 2 months by hand for a team. Now, I want to be careful about this because that is Anthropic reporting an early customer result. That does not mean you throw Fable at your app and magically get a perfect migration, but builders still need to test. You still need GitHub. You still need code review, and you still need a way to prove the actual work. But, the direction's pretty obvious. I mean, the models are getting good that the bottleneck is no longer whether AI can type code. I mean, come on, the bottleneck is whether your workflow can safely absorb that much intelligence. If we go to Artificial Analysis here, you can see here on the intelligence

8:22scale, we'll pull that up here, that it scores and blows everything out of the water at 64.9 intelligence compared to Opus on Max at 61.4 and GPT 5.5 high at 60.2, coming in much stronger and higher than most frontier models. The model overview says Claude Fable 5 it uses the API model ID Claude Fable 5 and uses Claude Mythos 5 as basically just Claude-Mythos 5. I mean, Fable 5 is generally available on the Claude API, and you know, if you're using your favorite IDE like Cursor or Windsurf or VS Code, all you need to do is go into your terminal, type Claude, and then type Claude update. And once it runs the

9:07update, you usually got to close your IDE, restart, and then you will go forward/model, and you should see it inside of your terminal, and you'll want to select Fable just to test it out. My first prompt that I gave it was just basically to review the code base for, like I said, Magic Hand and Easy Flip, and I just said, "Look, you can see if we can make my app 10 to 100 times better." You know, it reviewed security vulnerabilities, ways it can optimize workflows, maybe trim down some dead code, and it caught many things. And I do this with every model release, but this time it was different. It actually thought through it, it fixed it, and it didn't introduce any new bugs because it usually does that every now and then, especially with Opus 4.8. It's like it may fix one thing, but introduce another bug for another. And it just gets really

9:53annoying. Fable 5 has been beautiful so far. We just got back from California for 24 hours ago, and I've been just using it all day nonstop on this laptop, on this PC, on my Open Claw right behind me, and it's been amazing. So, I'm sure I'm going to hit my usage limit soon, but these are the first prompts that I would give it. Maybe you should do something similar. Just have it review your code base and see how different it is versus other models. So, like I said, available in the API, on AWS, Amazon Bedrock, Vertex AI, and Microsoft Foundry, Mythos 5 is actually limited availability through Project Glasswing. So, pause there as it's not available to the general public. That split is important because Fable 5 is the version for us normal builders, and we can actually reach it. Mythos 5 is the same

10:39capability family without the safety classifiers. And Anthropic basically says that it is approved for customers through Project Glasswing. So, if you're building regular apps or internal tools or business automations, content systems, whatever, coding workflows, Fable 5 is the one to be using and to study. Like I said, you just have 12 days before it goes off of your subscription. If you are trying to do like high-end cyber defense through approved channels, Mythos is the gated version. But for this channel, I care about Fable because it is the one that can affect everyday builders right now. The other important detail that most people are missing here is Fable 5 has safety classifiers that can actually route certain requests. If you're struggling to keep up with content, what I'm about to save you about 40 days

11:25[music] worth of work. I built something called Content Machine. It's 10 AI agents that run on the Open claw orchestration and they handle everything. Scripts, thumbnails, [music] X posts, blogs, outreach, clips, newsletters, all of it. So, I went from 1,000 subscribers to 4,000 subscribers on YouTube in 7 days using this exact system. Every single morning I wake [music] up and the content's already done. I spend maybe 15, 20 minutes reviewing and approving them and I move on with my day. It works for any niche, fitness, finance, real estate, marketing, whatever you are building and it is 100% completely customizable to your use case. So, you get the mission control dashboard, all of the cron jobs,

12:11everything I've built over the last 40 days helping me gain more and more people [music] to subscribe and join the community. So, you plug in your own thing and it molds it to you, it learns how you talk and it [music] writes so it doesn't sound like AI slop. $97 one time, it's not a subscription, I'll put the link down below and you'll thank me later. Basically, away from Fable and down to Claude Opus 4H, which is pretty cool. Anthropic says those safeguards trigger on average in less than 5% of sessions and the docs say when Fable refuses, the API can return the stop-reason refusal as a successful HTTP 200 response, which is nice. And that sounds boring, but it is not boring cuz you need to pay attention. Come on, wake up. If you are building products on top

12:57of this model, refusal is not just a safety policy. It is an engineering state that your app needs to handle, it has to handle. Your app can't just assume every response is normal text. It needs to detect when Fable declines, it needs to decide whether to retry, it needs to route to another model, it needs to tell the user what happened without making the product feel broken. Have you ever built an app and you thought it was going well and then you went to push to production and everything's breaking. Well, that's the safeguard here. So, Anthropic says you are not billed for a request refused before any output is generated, and it has fallback support in beta on the Claude API and Claude platform on AWS. So, refused requests can be rerun on

13:44another model, saving you money. That means a model routing is not optional anymore. Like, what are you doing? I don't even know how you're building if you're not using model routing. So, if you're a serious builder, you are not building a single model app, you are building a system. Fable for the hard long horizon work, like I mentioned earlier, having Fable as like the orchestrator, the one that checks the work, checks the codebase before you push to production. And maybe you just use Opus 4.8 for the general building. Opus 4.8 for fallback is amazing. And Sonnet for smaller models like web scraping. I mean, come on, you can even use Haiku for just simple web scraping. Like, what are you doing using Fable 5? I don't even know, who are you? Like, why would you do that? Local models even can come into play, too, for the smaller cron jobs, simple tasks. I mean, come

14:29on, what are you doing? That's the builder move here, right? The June 9th platform release notes also add a few more details. Fable 5 and Mythos Memphis Mythos Mythos 5 use the tokenizer introduced with Opus 4.7. And Anthropic says the same text produces roughly 30% more tokens than models before Opus 4.7. Pretty cool. Like, if you see here, novel hypotheses in molecular biology, Mythos 5 is our first model to consistently produce novel, compelling scientific hypotheses. In blinded head-to-head comparison against Opus class models, our scientists preferred Mythos molecular biology hypothesis 80%

15:14of the time. This is going to change every single industry, not just in building, but in medicine, in finance, in working out, and cooking and everything that's going on, we are about to see a huge change more than before. And you can see here early feedback from the big companies like Cursor and GitHub and said Cloud Fable is the state-of-the-art model on Cursor bench. GitHub says Cloud Fable 5 is a real step forward for the developers on the GitHub that GitHub serves. I mean, amazing feedback. I haven't seen any posts or anywhere, maybe you have, of any negative about anything about Fable 5. And usually we do. Usually these benchmarks are, you know, bench max and not this one. This one actually works and runs and does what it says it does

15:59and I like that. The docs also say Fable 5 and Mythos 5 are priced at $10 per million input token and $50 per million output tokens. It's not cheap, but I mean, if you want top line frontier models, just to let you know, things aren't going to get cheaper. So, start preparing for that. And that's not the point here. It's the question is not can this answer a cheap prompt, but the question is really can this actually finish the work that a smaller model keeps failing at. Time is money. I don't have a lot of time to waste. I'm sure you don't either. You know, if Fable can save like 6 hours in a simple debugging session or finish basically a migration that eats a whole weekend, the output token price is not the thing. I don't care. It doesn't matter. The thing that matters is whether you used it on the

16:45right task. That is how I would think about it, right? Don't run Fable 5 on everything. Do not use it for tiny copy edits. Don't ask it those stupid questions. How many hours are in strawberry? Come on, don't do that. Do not use it for a one sentence reply. Use it for the hard work. Use it for where failure is expensive or your time is money, right? Big repo migrations or deep debugging that you're having problems with. High context planning, same thing and vision tasks where, you know, screenshot actually matters. Research synthesis where you need the model to actually stay focused across basically a ton of material. I mean, this has been an amazing release and I think they hit it out of the park. I know I'm a little late to making the video, but I've been using it for the last 12 to 14 hours and pretty impressed. You know, that's the lane they're in. Anthropic says Fable 5 is

17:32also pretty strong on the vision and including extracting precise numbers from the scientific scientific figures like we talked about. And that's awesome. That's going to be great for building good UI as well because Fable 5 out of the box still sucks at UI, but having it basically dissect, you know, screenshots from reference images, whether you make them in GPT images too, or go to dribbble.com just to get some inspiration. It does a really good job at actually visualizing and creating your brand packaging based on reference photos. That should basically make every builder think about a new workflow when you're building your UI. You know, you can take screenshots of your broken UI or UX and give it to the model and the repo and ask it to find a component and it can do it. And it could patch a bug. And then it could run the app and

18:17compare screenshots again. That is way more interesting than asking it to describe an image. It's basically the same thing with memory, too. Like it says like Fable 5's, well, Anthropic says a Fable 5 stays focused across millions of tokens in long-running tasks and it improves the outputs using its own notes. Like that is kind of crazy. You know, it sounds exactly like the agent world we keep talking about. I mean, the loops and you know, we're kind of going and getting away from prompting these agents and where they're going to prompt themselves and do the work until it's complete. The model is not the product anymore. It hasn't been for months. The memory around it is the model and that's what gives it value. The tools are what gives it value and those matter and the approval flow

19:02matters and the logos matter, the logs matter, the tests matter. The model is the engine, what drives the machine. The agent is the system and it is the car. And if you put a bigger engine into a bad car, you're just going to crash faster. Like come on, have you used local models? I mean, they're terrible. I'm sorry, but I'm sorry, but they're just not good. That is my biggest takeaway from this whole launch of the last 12 to 14 hours and I'm not I'm not saying like benchmarks are false, it's just this model that got released is the closest thing to the benchmarks that we've actually seen to be true. And Fable 5 is not telling builders to stop caring about agent infrastructure or caring about benchmarks. It's actually the opposite. It just makes infrastructure more important. Like if a model can do more work per run, then the

19:50costs of basically bad permissions goes up and the cost of bad test goes up, the cost of stale memory goes up and the cost of vague prompts goes up and the cost of letting it edit without a review loop goes up. So, here's what I would do, like if I was testing Fable for the first time today. You need to pick one task that actually hurts your workflow. One that you just hate. One that just fails all the time. Stop giving it toy prompts. Like pick the migration you've been avoiding. Pick the ugly bug that you just can't solve or whatever outflow that keeps breaking and put it in the place. Send Fable on it. The second thing you need to do is run it against the same task you already ran on Opus 4.1 or Codex or Gemini. I mean, are you using Gemini? What are you doing? Basically, the same prompt, same repo, same everything, no cheating and just see who wins. That's just a fun test you need to be doing all the time every time

20:36a model drops. Third thing is you need to measure the closeout, not the first answer. Did it run the test? Did it explain what changed? Did it find what right files? Did it recover the first approach failed? Did it leave you with a clean diff or a mess? You know, that is how the builders should evaluate these models now, not just vibes and benchmarks, not leader board screenshots, just actual proof in your workflow. Like how's it working for you? Cloud code also shipped with version 2.1.170 with Fable 5 access listed in the change log. You can get it going right now, like I said. So, if you live in cloud code, this is not just an API story. This is actually working on your subscription right now. It is going to show up in the tools that builder already use, but again, do not worship the new model, build the harness, use

21:23Git work trees, use tests, use the second model review, use the logs, and use approvals where money, messages, or production systems are involved. And if you're building for clients, explain the difference between a model and a workflow. Clients don't pay for you to have access to the newest model. They don't care. They just pay because your system gets the work done safely. This is the opportunity and you need to be paying attention. Most people will make content saying, "Fable is insane." I know, but this is actually the best model that is out on the market right now. I'm excited to see what OpenAI does while all the pressure's on them, I will say. And builders don't need to be asking, you know, "Wow, this is insane." Builders should ask, "What work can I now automate that was too complex before, last month, that you could do

22:08now?" There is things that you could do now that was not even close just a week ago. That's the money question. How does your workflow improve? How does How can you make more money? How can you add more money to your bottom line with this new model drop? For people in the community, inside our shipping school community, that is why I keep pushing people towards real workflows instead of just prompt collections. The models keep changing. The winner is the person who knows how to plug the model into a business process and then prove the result over and over again. That's my advice. It's very simple. Just test Fable 5 on a painful job that you have right now. Route cheaper models for everything else in the fallback handling before you ship it to users. And then judge the model by the finished work, not by the screenshot of a benchmark,

22:54even though they're cool. Like we're looking at them, "Wow, that's amazing." But use it in your actual work. What is something that is causing you problems and set Fable 5 on it. That's the new bar. They blew it out of the water and I love it. And if you're not using Fable 5 right now, we're not friends. I'm sorry. We cannot be friends. So, check out the change log down below. I got the links to the source. And if you need to be in a community that's around other builders shipping real code into production, building real apps, I got a link to the community down below. Check it out. We do four live calls a week and we add constant courses in there every single week. We're on a 24-week syllabus plan. We're basically adding things in like AI engineering, installing local models

23:39for, you know, DGX Sparks or M5 MacBooks. Or we also have just Q&A. Come join the party. We'll see you in the next one. Have a blessed day. Bye-bye.