It only took a 107-page spec to accomplish.

If you've ever hit Ctrl+Shift+Esc to find out what's eating your PC alive, you've used Dave Plummer's work. Now, some three decades after he wrote the original Windows Task Manager at Microsoft, Plummer is back with a new iteration: TMOG. That's short for Task Manager OG — a twist on the tool he built back in 1996 and was released with Windows NT 4.0 that August.

Taking on X last month, he explained how he (sort of) vibe-coded it using Claude Code. Plummer says he fed it a 107-page spec sheet, let the chatbot do its thing and about four hours later, he had a working app that ran on the first try. All while waiting with his son in hospital, who was recovering from surgery.

The TMOG macOS beta was first released on July 31, with Windows and Linux builds following on August 23. The third iteration of the software was released on September 7 alongside the first builds of a paid Pro tier. 

What TMOG does

TMOG packs 12 views into one window, covering a summary dashboard, per-process resource use, startup apps, service, power and frequency, network connections, installed apps, disk space and benchmarks. 

Status meters are animated at 60Hz instead of ticking over once a second as with Windows Task Manager, and efficiency cores get their own colors. There are also retro phosphor themes, available in green, amber and blue. Plummer has promised that the app will "never make up an answer."

Look under the hood and you'll find each platform runs genuine native code with Swift and AppKit on macOS, Direct2D on Windows and Qt 6 on Linux. They all utilize a shared C++ core. There's a self-monitoring option too, which adds TMOG's own process to the readings so you can see what it's using to run.

Plummer's aim with TMOG is to make diagnostics easier. Windows' built-in tool isn't always much use in helping you figure out why your PC has suddenly slowed to a crawl. It's well known that Task Manager lies to you about CPU usage, and background processes like Windows Runtime Broker spike resource use without explanation. TMOG does things differently by showing whole-machine history next to process activity, making it a lot easier to track issues back to the culprit in areas like compute or memory.

Built on a freemium model

The free version of TMOG handles live system and process monitoring on all three platforms. Pro adds Flight Recorder, a record-and-replay mode for scrubbing back through slowdowns as a sort-of postmortem into why they happened. It costs $39.95 and went on sale through Plummer's own Lemon Squeezy store. It can't be sold via the App Store because Apple's sandboxing forbids apps from listing system processes or killing other programs.

Plummer says that the entire project began as an argument over whether anyone could vibe code Microsoft Word. He didn't think so, but figured something smaller might work. Given he's the creator of Task Manager, it's something he knows better than anyone. "You can't just tell Claude, 'Hey, write a task manager!" he wrote on X. "Well, you can, but it'll be hot garbage." 

Instead, he bashed together a 107-page spec sheet, likening it to the work of "some caffeine-addled PM from the 90s," not something you'd really expect from a developer famous for hand-optimizing the original down to roughly 80KB.

Many cross-platform apps deal with supporting three operating systems by wrapping one web app in Electron and calling it a day. Deploying code on every platform is pretty laborious and expensive, and usually takes a team to do. Plummer coded his in under six weeks with two collaborators and Claude Code doing the heavy lifting. You can bash vibe coding all you want, but you can't argue that it isn't changing the economics of a project like this.

For now, it's in beta, and Plummer says early adopters are still uncovering bugs for him to squash. The free version doesn't expire though, and you can download it now for macOS, Windows and Linux without creating an account.