REA use cases you'll love

0:00Everyone's talking about an insane new way to copy software. I played with it, I've used it, I've understood it, but now I want to see some real use cases, which I'm going to show you. These are the best that I found online, and then you tell me whether you think this will actually improve your productivity and your business in legitimate way, or maybe it's just wrong. Presented by Zapier, the AI automation company. But

0:19first, let's understand what it does. This is the best video that I found on that. A new open-source repo that lets your code agent, that might be Claude code, cursor, codex, whatever you use, look inside an app that it has no source code for, figure out how a feature works, show you the evidence, and then build you a version. People are doing this for games, for software. They're cracking desktop applications that have been closed source for the last 20 years. So, it's called REA, which stands for reverse engineer [music] anything. And it's one of the fastest rising repos on GitHub right now. Something like By the way, since this video was shot,

0:53it actually has climbed even more. It is up to over 330,000 stars. I think this is growing faster than than Open Claw, and just about any other fast uh This might be the fastest growing repo on out there. Let's talk about how to set it up, and then I want to really get you into the use cases. Setup is super simple. It's just NPX

1:10REA-agent-setup. It shows you a plan of what it's going to change. It backs up your config, adds the MCP server, and a skill that teaches your agent how to do the investigation. And then it asks before touching anything critical. Super easy. Let's get into QuickTime Clone. Let's look at it for a So, what you're looking at on screen is the before and after of rebuilding something called QuickTime Player. It's been a staple app to help you replay any video, whether it's an MP3, .mov, or what have you. Now, I use this app to rewatch the final version of any YouTube video before it goes live and you see

1:44it. But it has a flaw. And the flaw is, let's say I want to vary the speed at which I'm playing it back. I only have a few options I can pick from: double, faster, fast, normal, or half. Now, obviously, there are other softwares out there that I can use that have this feature. But, let's say I really like the UI and the simplicity and the elegance of this app. And all I want is a carbon copy that has this additional feature. So, Okay, interesting. Fair point. I wouldn't call it a flaw that it doesn't have this speed the way that he wants it, but I understand the real legitimate

2:14use for that. Let's look at the prompt that he used. just have to send a prompt like this, which is install this and help me use it to reverse engineer an app. And then I just simply give it the GitHub link. And even if you're using something like GLM 5.2 in the cloud, it will install it in under a minute. And all you have to do is tell the target. And once I told it my target was QuickTime Player. Since this harness is running on your computer, it has access to all of these applications and can get to work right away. And depending on what model you're

2:39using, within 20 to 30 minutes you'll have the first version ready to go. Shockingly simple. Let's look at the result that he got. And just like any other app, you'll be able to right click, click on open with. I'll click on Tempo here. And 80% of this was in one shot. The only things that I added on after with a couple extra prompts was basically changing the font, the look and feel, and allowing me to export to different formats. And from the get-go I was able to increase the speed to whatever I wanted at a much more granular level, see the audio waves, change the pitch, and do anything

3:10that I could do in QuickTime Player. You know what? This was actually always the dream of open-source software. Somebody gives you software that works one way, but allows you to change it and make it into something else. And now essentially REA has made every software into open-source software. I want to look at just a quick image of how it works, and then we'll get into more use

3:29cases. REA itself isn't a decompiler. It's nothing revolutionary or special. It's basically wrapping the serious tools reverse engineers already use, which is things like Ghidra, which is free and from the NSA, Hopper on the Mac, and IDA Pro, which is the expensive industry standard. So, all of this reverse engineering was possible before with enough time and enough money. The difference now is the friction has been removed. So, these tools are all incredibly powerful and also notoriously hard to learn. What RIIA does is give your agent dozens of plain text intent tools on top of them. Things like open this binary, find the strings, follow the function callers so it can find its

4:09way through and understand the code. Okay, let's go on. One more um This is one where he just legit just copies an app. Let's take a look at what AI For this example, we're going to use TickTick which millions of people use to capture ideas, organize life, and do something creative. It's basically a to-do list and project management app that I believe is the favorite of MKBHD,

4:36Marques Brownlee, the tech reviewer. Okay, so here's the prompt that he used. You can see the prompt here is find TickTick on my Mac. Use RIIA to figure out the whole app, the task list, the calendar, the timeline, how everything fits together. Show me the evidence you find in the app files. Don't change anything in TickTick itself. Then build me my own version called TaskYard with sample tasks to start. And underneath that, I gave the ground rules. Only read TickTick, never change it. Don't copy its icons, make new ones. Write every findings to an evidence file with where it came from and build a real Mac app

5:15that compiles and runs. If you want to run this yourself, just change out TickTick to the app of your choice and then ask Claude to rewrite the prompt so it's not just a task list, a calendar, and everything like that. Okay. Now, here's one where I like this video because Andy's showing that there were problems with it and what he did about them and and there were also surprises, but let's first take a look at what it

5:38made. As you can see, we have TickTick on the left side and we have my task flow here on the right side. It has the task like call the dentist to reschedule right here as well. Pick up dry cleaning and if I click on one of them as done as you can see it goes down to the completed here as well. Pick up a dry cleaning we get a different sound and it

6:03goes directly down to the completed tab. You can also see that we have the list here of business, work, personal, fitness and everything like that. Exact same goes in my app as well and if we keep going further down you can see that we have all the tags, errands, family, finance and everything like that which is just a tagging or a hashtag system that is working really great. Just look at errands on both of them. We can click here, click here and it looks almost identical. Let

6:36Almost identical. Here's the This is the part that I think some of you are going to go into the comments and complain about and I'd like to hear it if you are really upset about this. Check it out. found out something that actually shocked me. So I don't have the paid version of TickTick and it's so if we click on the calendar view on the side here it says you have to upgrade now but on my own app here if I just open the side you can see that I click on the calendar view and I actually have full access to it. So AREA was actually able

7:07to reverse engineer the calendar view as well even without having access to it because it's written in the code. So here you can see that premium only does a sample data and this is actually real data which is just absolutely crazy that it was able to do this without looking at the source code just from the machine

7:26binary. Unreal. Unreal. Okay, but there were mistakes and I think it's important to talk about the negatives. So for example there are some features that aren't included like for example if I click on do laundry right here, we have a really nice way of writing in the right side. Whereas, if I click on do laundry here, we're only able to actually write in one line. If I click enter, it kind of goes back to the beginning here, and I'm not able to create a new line. And so, this is where we would have to prompt it again to do that. Well, the same goes for if we're

8:06on today, for example, the colors aren't completely correct. You can see here the overdue is white. Here, the overdue is actually red. And if You know what? Let me pause and just say, "Look, they're clearly mistakes." I'm surprised that the color, which seems like an easy thing to copy, was not copied over. Meanwhile, the calendar, which is behind the paywall, was copied. So, I don't see any rhyme or reason to why things were copied versus not, but it's impressive how much it got copied. And I'm going to jump to Andy's conclusion. to pretty much reverse the whole app in about an hour, give or take some extra prompts

8:43just to get it to a final state. But, the main thing that I really want you to get out of this is this is almost 80% of the whole app. And the main benefit of, of course, having your own app like this is that you don't have to pay for it. But, the main benefit being that you can build on

9:03top of it. That's the thing that people are when they get into the legitimate zone, they're saying, "Look, I like this feature. I want to integrate it. I like this pre- this premise for an app. I want to add to it." Let's look at another ex- Oh, before we go to another example, I'll just quickly tell you my sponsor is Zapier. Zapier MCP allows you to save tokens by offloading routine tasks to code, so they're more dependable, they cost less, and then the

9:29intelligent tasks can be handled by AI. I use it all the time to save tokens with my Grok Bot, which is my latest obsession. If you use it, there's a link below for you to use and let them know that Andrew sent you. Let's go on. Um This guy just cloned Whisper Flow. Let's

9:44look at that. we're trying to clone here is called Whisper Flow. Now, it's a voice-to-text AI applications and it lives on my desktop app. So, essentially, you can see that this icon right here, if I click on it or if I do a hotkey, it is just going to automatically try to translate, right? Try to translate any He means transcribe. He's saying translate. By the way, Eric does have

10:04really nice visuals, don't you think? speech that I say into proper text. It is also able to translate meeting notes, right? So, those are really helpful. So, what I want to do here is I want to kind of like using that skill and see if we can actually reverse engineer applications on my local machine. Okay, I've been hesitant about showing prompts, but then again, with something like this, you'll see the prompt is so basic. There is nothing to uh to really hide. The what he is doing, what Eric is doing, is actually kind of a smart take on this. Well, let's just

10:33look at it. see I have prepared the prompt. It's called Find Whisper Flow on my entire desktop app, right? Desktop folder. Use read here to basically inspect the app and use the official website as the background. And also explain what you can be improved from the application file. Let me pause on that. This part, I think, was really interesting. What can you improve on the app files? I think made a big difference in his results, and so I want to underline it. Let's

10:57keep going. Right? Things like that. And we just get a small working version here working. So, I'm going to basically open my Claude here and paste the prompts and just send it over and let Claude here to do the rest. Okay. Look at the results. So, now you can see that once we have our application is fully complete. Here, if I were to open the app, here is what it looks like. So, we have the exact clone of Whisper Flow right here in my desktop app. So, you can see that currently we have all the conversation, everything that I said is inside of this. I can also click on note taker

11:27here to see the past notes that I have took, right? So, I can view the entire transcript or resume if I want to. And I can also be able to start to using a shortcut, right? A short key. So, I'm going to type in the short key right here which He says type, but what he means I think is just press the short key that

11:44triggers the dictation. option plus one. So, I want to start a new application. And you can see that we have text here showing, okay? And that of course is what Whisper Flow does. Check out the language though. And I can say different languages like uh "Jintian shi jiu liu." So, you can see that we have English and Chinese here also in the same uh input, right? So, we can do that. We also have the ability here to do that. And also it's really really fast. So, it's not like, you know, it takes a long time here to load. It's transcribed locally on my machine. So, the

12:18Let me emphasize that. That is the difference that this prompt that he had improved. Local dictation I find to be much faster and safer than sending it to the cloud, and that's why he was able to get a faster result than you usually can get from Whisper Flow. conversation or the voice here does not go on the internet, which you can see here, okay? So, as you can see that it's actually able to using reverse engineering tool here to analyze exactly how it works. And you can see that it's able to creating a similar versions of

12:45this using our AI agents. Okay. Again, I'm curious what you think about this. Honestly, because it's not just me farming for comments, though I'd love to get comments. It's because when I I showed this off on Friday's GitHub show, and I said this was the top trending repo of the week, I didn't realize how many people would be upset by that. I think I was very cavalier

13:05about it can copy software, ha ha ha. And then Adam, a developer who was on with me, said, "This seems like a a wrong thing to do. It's like copying the Mona Lisa and selling it, or copying the Mona Lisa and using it." I guess that wasn't his analogy, but anyway, you get it. And a lot of you in the comments came back at me and said, "This is wrong." And so, I want to know if any of this is changing you or firming you. And if it's firming you up, give me give me your opinions. Let's go on to the next

13:29one. You can also run R E A on any feature in your own app to find issues. Okay, so now we're looking at no longer building, but actually finding bugs and problems. And I think this is going to be a use case that everyone is going to say, "Okay, I agree with that." can look fine when you try it once and still break in the rare cases you didn't try. And most of those can't be spotted from the code alone. It's worth catching these bugs early because if a customer finds a bug while using your app, it can cost you that customer. To do that, you

13:59just need to ask Claude to use this tool and you need to give it the link to your site. Then you need to have it check that the feature works exactly the way it's supposed to. If anything doesn't work as expected, you need to ask it to tell you what went wrong in a full report. And we asked it not to change anything or read the code, so it has to work everything out from the site itself. That way, it can uncover deeper issues that it might miss if it only worked from the code. It I don't know of anyone else, by the way, who's talked about this. Um, I do like

14:27AI labs because their their channel does stuff like this. I do wish that it wasn't um a disembodied voice. I'd like to get the sense of the person. It first writes all the test scenarios into a folder and then it calls the MCP to run them one by one. And if you want to watch the browser while it runs the tests, you can ask it not to use headless mode. This tool runs in headless mode by default, which means you can't see the browser, but you can ask the agent to turn it off so you can watch what it's doing. Once all the tests are done, it gives you a full

14:58report of every issue it found. In our case, it reported that the prices shown in our app were different from the prices charged. This one wouldn't have been found by looking at the code alone because the pricing code itself looked fine. It checked our billing page against the pricing rules we wrote down and the promises on our home page. Most accounts were priced correctly, but two accounts saw one price on screen and got charged another with one seeing half the real total and the other seeing zero. It also traced the bug step by step. The price on screen gets worked out inside the browser and the line items,

15:31discount, and tax were all correct. So, it only goes wrong at the very last step where it adds up the total. It found smaller problems on top of that like the server accepting a negative number of seats and selling more seats than the plan allows. What All right. Not bad, okay. Let's go on to

15:47one more. Better than not bad. Here is cloning a video editor and the reason I wanted to show what Mehal was doing here is because when it comes to CapCut, I've actually heard a lot of people have problems with TikTok, the company behind CapCut, and they're saying, "Well, I don't trust it on my computer." If you don't trust it, do you feel comfortable copying it? Or

16:07what Mehal did is not exactly copy it. Well, let's take a look. We will try to reverse engineer CapCut. By the way, I really love showing off videos like this. This one had, I think, 3,000 views and as I watch it, I go, "This really deserves more than 3,000 views." So, I should say links to

16:23everything below. See what it does. So, I have linked the CapCut location to it and I'm going to say "You will copy uh to reverse engineer this." And now we wait and see if it is going to reverse engineer or clone CapCut. So, Claude is asking, "What do you want to understand about CapCut?" And I'm going to write everything about video editing, captions, animations, layouts,

16:49transitions. So, we are going to start short and not include everything in one go. Okay, there's something to be said when it comes to CapCut of starting short and not including everything. It is just packed with so many features that it gets more and more distracting as it gets more and more useful. Correct. Okay, let's see. A full CapCut is millions of lines of code built by a lot of team. Okay, so it's going to take lots of time and music, I think. So, we are going to make it, you know, as small as possible. So, what kind of file we'll use? WebM. And what features? Timeline

17:22player, export. Okay, we're going to choose that. That's obviously required. Then we'll see we can do text animation transition and auto captions as well. Okay. And let's see the results. Okay, now let's get into our browser and open it up. So, this is how it looks. So, Cloud specifically tried to, you know, not make it very similar to

17:44CapCut, but kind of similar, right? Yeah, this is actually to call this similar to CapCut is ridiculous. This is similar to any video editing tool. Um and it doesn't look CapCut-like to me at all. Okay, so here we have the import option. Let's import the same screen recording which I was doing for this video. Okay, so now let's try to split it from where I am talking. Okay, so I'm talking from here. We're going to do CTR to split it. Split option was just like in CapCut. Delete it. Okay. Now let's try to use auto captions. Where is the auto caption button right here? Auto

18:20caption, English, generate. Done. It was pretty fast. Okay, Ria. So, Ria has been set up on my PC. Now we will try to reverse engineer CapCut. And you can see the caption work really well. Okay, I can just drag it just like in CapCut and, you know, place it wherever I want. I'm going to say that even though he calls it basically a CapCut copy, this is really not. It's inspired by maybe CapCut, but maybe every other video

18:52editing platform or software out there. Which actually brings up another another interesting use case. What if you just want to be inspired by software? No issues there. Now you have software that inspired your idea. And once you start cutting back features and making your own decisions, isn't it your own software? And therefore, you You up with a head start because you're building based on how others have done it. I'm wondering what you think about that. In a more dramatic example I would give you there was someone who said, "Look, I don't like the software that comes with my air conditioning unit. I actually want it to be in my Mac menu

19:23bar at the top. I made the version of their software that fits in my menu bar. I don't think there's an issue there, right? Um let's look at one last one. This is a software that many of you used. It's called Loom and the issue with Loom of course is people keep complaining that um that Loom's prices go up. Here is what

19:44Nick did with that. this thing right here which is basically the Loom clone that I made from using this repo, right? Like I had it look at Loom, I had it understand how it can work with like the different bubbles. You can see it does the recording countdown. It might not work because my face cam is recording right right somewhere else. So, I'll play a clip real quick. All right, so I just wanted to test out how this actually works to make sure that this is like a decent software. So, I'm

20:09going to see if I can pause this. And now we can go ahead and keep on rolling. I can move this thing around. I can also make it smaller or larger while I'm recording. That's very nice. And let's go ahead and stop. Let's see what happens. But the thing that's important to realize is that we didn't clone Loom. This is a very different looking app. We didn't clone like all of the exact UI and the design elements. We cloned the functionality. We understood how does the little bubble work? How can you move it around? How can you change

20:34the window that you're recording, right? Like we talked about this sort of stuff and we had it analyze that sort of stuff. Loom obviously records and stores your things in the cloud in Loom's cloud, but this one is just local. So, it's storing these files in my own folder inside of this app called Herk Recorder. I also

20:49Okay. So, there you have it. Super easy. Most of these just taken minutes. All I think under an hour. Very easy to copy their prompts and copy software that you have. What do you think of this? Again, let me know in the comments and if you like this one you should know that this was the number one repo of the week last week and there were nine others that were super impressive that I didn't break down in this level of depth, but I did show you how they work and I think you should go check those out next. I'll

21:14see you in there.