As I hinted in my story about multi-window on the iPhone Duo, I find myself increasingly relying on Apple’s diminutive foldable as a pocket computer for getting work done with an external keyboard. It reminds me of the early days of iPad productivity: there’s something to be said about turning the multitasking limitations of the machine into a way to focus more and be less incentivized to switch between apps. Also, you know me: it’s fun to prove a point and show how you can get work done on an iPhone Duo if you want to.As part of this, we’re dealing with the fact that we’ve received almost 600 submissions from developers about their iPhone Duo apps and app updates. I haven’t seen this kind of influx of new apps since the early days of the iPad (again, another parallel between these devices). John and I are working hard to make sense of all these app pitches, picking the ones that are worth our readers’ attention, time, and money. In the era of software abundance caused by AI, I think it’s more important than ever to test and curate software that wasn’t simply put together with two Claude Code prompts. This is why, rather than assembling an overflowing directory of iPhone Duo apps with no editorial curation, we’re going to write these old-fashioned roundups instead.In the past two weeks since I’ve been testing the iPhone Duo, I’ve been impressed by the variety of productivity apps that have landed on the App Store. Most of these strike a fascinating balance of something in between an iPadOS and iOS experience – which, I guess, is the whole point of this new breed of pocket computer.Below are some of my early favorites, which I’m using every day on my iPhone Duo. Expect more to follow over the next few weeks.T3 CodeT3 Code is my favorite app for working with multiple coding agents in a single interface. I’ve mentioned this on AppStories before, but in case you haven’t listened: we’re working on two apps at MacStories, and both John and I are doing so almost exclusively in T3 Code. There’s so much that Theo and his team have gotten right here: from supporting multiple providers in the same UI and offering the best-performing ADE out there to an orchestration engine that can delegate to subagents and threads, T3 Code works beautifully in combination with Claude Opus 5.5. The app is fast, updated nearly every day, full of power-user details and fun touches, and even comes with its own built-in iOS simulator. It is, quite frankly, incredible that this team is beating OpenAI and Anthropic at their own game when it comes to building a desktop app for the modern era of software development.T3 Code on iPhone Duo.T3 Code’s own split-screen for subagents.T3 Code, however, is also excellent on iPhone and iPad thanks to its (again, best-in-class) support for remote control. And as you can imagine, the app is particularly impressive on the iPhone Duo, which has become my favorite way to manage my agents and threads from anywhere I am. When the Duo is unfolded, T3 Code shows your threads in a left sidebar, where you can long-press one to get access to a variety of actions via a context menu. Your session takes up the majority of the display on the right, with toolbar controls natively relocated to the rightmost edge of the display, per Apple’s new conventions. If a thread has spawned any subagents, you can tap them to view their nested session, which will open inside the app in split-screen on the right. There is a dedicated button to dismiss the software keyboard (more apps should do this!), and the Duo’s semi-unfolded “book” pose is also supported.Clearly, the T3 Code folks have spent a lot of time thinking about Duo interactions and remote control, and it shows. These days, I manage my agents running remotely on my Mac Studio exclusively via T3 Code. If you’re serious about this new kind of workflow and have an iPhone Duo, you can’t go wrong with T3 Code.SillCreated by indie developer Noah Saffer, Sill is a free and open-source Mac remote control utility that lets you stream your Mac’s display to an iPhone or iPad, with a couple of twists: unlike traditional VNC or RDP apps, it establishes a Direct Wireless connection between your Mac and iPhone; and, it lets you either stream the full desktop or specific Mac windows only, which get resized on the fly for whatever display you’re using.For the technically inclined: Sill uses ScreenCaptureKit to capture your Mac’s screen contents, then uses an HEVC encoder to stream video at low latency, and instead of queuing video frames on a slow connection, it dynamically drops frames to ensure you can keep interacting with the Mac. There are lots of clever decisions behind the scenes in this app.Once you’re connected and unfold the Duo’s display, you can see why I decided to highlight Sill in this roundup: it is unlike any other remote desktop utility I’ve tested in recent years, and it is one of the best examples of how to leverage the Duo’s inner display.Sill is, arguably, the most impressive showcase of the iPhone Duo’s inner display so far.At the top of the screen, Sill features a horizontal bar that lets you scroll thumbnails of individual Mac app windows as well as a ‘Desktop’ button that instantly loads your full desktop instead. Pick a specific window thumbnail, however, and only that particular app gets streamed and resized to fit the Duo’s screen. At this point, you can touch the screen (or use Apple Pencil) to click, swipe to scroll, and long-press to invoke macOS’ contextual menus. The transition from full desktop to single app takes a second, and, in my experience with a good Wi-Fi 7 network and my iPhone connected to my wired Mac Studio over Tailscale on the same LAN, I’ve had good results with ‘Pro’ quality in the app (that’s a 40 Mbps stream, with Retina resolution and 120 fps).There is a lot more to uncover here, though. You can long-press window thumbnails to reveal the classic “traffic light” controls, so you can minimize, full-screen, or close a window directly from Sill. There’s a built-in app launcher, which lets you quickly switch to apps open right now as well as launch anything from your Applications folder. You can natively invoke menu bar items, adjust the zoom level of every window with a swipe gesture, and tweak various settings to get the app’s performance just right.Single-window mode.There’s even an app launcher built in.And if that wasn’t enough, Sill comes with one of the wildest and most useful implementations of screen sharing on a small display I’ve ever seen. I mean, just look at the app on the Duo’s outer display yourself:Sill also makes the best use of the small outer display.I never thought I’d find logging into my Mac Studio remotely from the iPhone Duo’s outer display a pleasant affair, but Sill makes it possible. Noah Saffer’s app is an outstanding example of how to combine cutting-edge technology with device-specific optimizations to turn an old concept into something new and better than what we had before. I have no idea how this app is free, but if you like it, please consider making a donation to the developer on GitHub.MarkoI’m always on the lookout for nice ways to quickly preview Markdown files – especially on iOS, where Marked doesn’t exist – and this new utility called Marko is worth a look.The app works with Files’ native document browser, so anything that is accessible from the Files app – whether it’s an iA Writer document or a Markdown file stored in Working Copy – can be previewed from the app. Marko doesn’t have any custom themes for now, but the default appearance is minimal and elegant enough, and it gets the job done.I like the extra options included in the app’s Markdown preview: you can summarize and ask questions about the current document with Apple Intelligence, read a document aloud with iOS’ built-in voices, and – critically for the iPhone Duo – view sections of a document in a left sidebar that opens next to the main Markdown preview.PasteMy favorite clipboard manager for Apple platforms got a lot better on the iPhone Duo not because of new system frameworks that let it run in the background (sadly, that is still not the case), but because of Split View. On the Duo’s inner display, Paste now opens as a good-looking grid of your previously copied items and snippets visualized as rich thumbnails. The app is reminiscent of the iPad version in this mode, but what makes it special on the Duo is that you can tile another app next to it and start dragging and dropping content from Paste into a second app – a first for the iPhone.The iPhone has supported inter-app drag and drop for a while now, but without native split-screen multitasking, you were always forced to keep holding onto a drag item with a finger, navigate back to the Home Screen or use the app switcher, find the target app, and only then drop the item. It worked, but it was awkward.These issues are entirely remedied by Split View, which makes Paste fit into more workflows than ever on an iPhone. For instance, I can now keep Paste – which I also use to store reusable agent prompts – next to T3 Code on my Duo, tap an item to copy it, and instantly paste it in the ADE.Paste continues to be the best-looking and most versatile clipboard manager for Apple devices, and I highly recommend setting it up on the iPhone Duo.CalendariaCreated by indie developer Jorge Cohen, Calendaria is an interesting new take on the classic calendar app category in that it doesn’t aim to replace full-featured calendar clients, but instead focuses on being a good all-year planner that takes advantage of the iPhone Duo’s inner display.You will not find the (many) features of Fantastical, Outlook, or, to an extent, even Apple’s Calendar app here. Instead, think of Calendaria as a companion utility to the calendar app you already use. There are three main views in the app: a year planner that shows you a summary of months and key events for each month in a left sidebar, with a vertical, scrollable stream of months and days on the right; tap an event on the right, and you’re taken to the second view, which is a more detailed monthly planner with a complete list of days on the left, and the currently selected day on the right; tap again, and the view advances horizontally again so you can pick between different events for the selected day and open an inspector panel for the selected event as the rightmost panel in the app. This kind of progressive, horizontal disclosure makes a lot more sense when you see it in action inside the app.Calendaria’s first two pages.Events and event details.In fact, while you can alternate between views from the iPhone Duo’s right toolbar, my favorite way to use Calendaria is to swipe to fluidly move across views. Other touches I appreciate include the ability to write down a list of events in natural language and have on-device Apple Intelligence add them to your calendar, plus an option to “pencil in” events instead of fully adding them to your schedule.I always appreciate it when someone brings new ideas to an established category of apps such as calendar clients; Calendaria is the first one I’ve tested in a while that actually gave me a reason to put it on my Home Screen.document.addEventListener( 'DOMContentLoaded', function () {function processIcons(scope) {scope.querySelectorAll('.media-wrapper').forEach(function (wrapper) {var next = wrapper.nextElementSibling;if (!next || next.tagName !== 'H3') {return;}wrapper.querySelectorAll('img').forEach(function (img) {var caption = img.nextElementSibling;if (caption && caption.matches('p.image-caption')) {caption.parentNode.removeChild(caption);}});wrapper.classList.add('media-wrapper-icon');});}function insertHrBeforeHeadings(scope) {var headings = scope.querySelectorAll('h3');// Start at 1 — the first app needs no separator above it.for (var i = 1; i < headings.length; i++) {var target = headings[i];var prev = target.previousElementSibling;if (prev && prev.matches('.media-wrapper-icon')) {target = prev;}target.parentNode.insertBefore(document.createElement('hr'), target);}}// Output once per [app_radar] post, so mark processed sections for later copies to skipdocument.querySelectorAll('.section-app-debuts:not([data-ms-processed])').forEach(function (section) {section.setAttribute('data-ms-processed', '');processIcons(section);insertHrBeforeHeadings(section);});} );