# A writing app for trapping lions > Hitchcock's MacGuffin was a joke about a package on a train. I have been building one, and it is turning into a serious tool for writing fiction. - URL: https://thirdeyefiles.net/a-writing-app-for-trapping-lions - Author: Pablo Núñez - Published: 2026-08-31 - Topics: Speculative, Entanglements --- In a [1939 lecture](https://en.wikipedia.org/wiki/MacGuffin), Alfred Hitchcock explained the origin of the name with a joke. > It might be a Scottish name, taken from a story about two men on a train. One man says, "What's that package up there in the baggage rack?" And the other answers, "Oh, that's a MacGuffin." The first one asks, "What's a MacGuffin?" "Well," the other man says, "it's an apparatus for trapping lions in the Scottish Highlands." The first man says, "But there are no lions in the Scottish Highlands," and the other one answers, "Well then, that's no MacGuffin!" A MacGuffin is a pretext for action, but at its core it is nothing at all. It is the suitcase in *Pulp Fiction* whose contents are never shown; the Ark of the Covenant in *Raiders of the Lost Ark*; the formula in Hitchcock's own *The 39 Steps*, memorised by a music-hall performer so no document exists; the money in *Fargo*, buried in the snow, by a fence, and marked with an ice scraper, that nobody comes back for. The MacGuffin is what everybody chases, and nobody needs to understand, and it exists only to put characters in motion. I've been developing this concept for two weeks: a creative writing methodology that helps narrative writers explore the genuine capabilities of LLMs, using the MacGuffin as the device that sets the process in motion. I call it an app, not in the sense of an application, but as an apparatus. An app is a digital programme packaged to possess value in its own right. One might also regard an app as a kind of artefact, in the way that a watch or a fancy coffee machine can be appreciated as an object in itself. An apparatus, by contrast, is something you switch on, setting off a chain of reactions whose outcome eclipses the apparatus that produced it. A trap is an apparatus. You set it, you walk away, and what you come back to is not the trap. Bluntly, the MacGuffin is a folder system with a folder inside it, also called `macguffin`. You put things inside — texts, images, sounds, whatever you like — then you close it and don't look back. That folder becomes the seed that sets everything else in motion. There is nothing to install; it is a set of instructions in plain files, which, by the way, is the only kind of software I know how to write. In my early iterations, I wanted it to be universal, something that could equally plot a novel or plan your holidays. Flexibility is what these models are for, after all, and it is in the impossible constraints you hand them that they can shine (sometimes). So I tested it: sixteen sessions with thirteen simulated participants, and finally an afternoon with it myself. The simulations improved prompts and caught bugs, but they never questioned the mechanism. Sitting down with it myself, I saw the contradiction: too many questions leave no room for deep thinking or imagining, and without that you can't make anything other than slop. A system designed to help you create has to leave you space to create. That's a lesson learned. >> Playfulness is different from playing seriously. Playing with a machine without giving it well-thought-out, meaningful input will always leave you feeling insecure, as if whatever you made came out at random. So after two full days iterating, I went back to the drawing board and started a new MacGuffin. This one is narrower in ambition, more token-efficient, and more serious: a co-writing partner specialised in fiction that helps you get a treatment for a story and nothing else. It's for writing and for learning to engage with LLMs through workshops: a teaching tool, but also a real writing tool. The specificity is what stops it from being a gimmick. Underneath is an assumption worth saying out loud. Working with a language model properly means upgrading your writer's toolkit. Nobody edits video professionally in MovieMaker; they use DaVinci Resolve or Final Cut. Musicians do not produce records in the editor that comes with SoundCloud; they use a DAW — a digital audio workstation — and they learn it. What those tools buy is closeness to the material: the footage, the sound. The consumer chat window is the MovieMaker of writing, and it keeps you at a distance. For a writer, the material is language. Staying close to it means a command-line interface (or at least a code editor) and Markdown files you own, which lets you version your work, streamline it, collaborate with others, and choose your model (maybe you don't care about that now, but eventually you might). An early version of the MacGuffin App is [public on GitHub](https://github.com/thirdeye-media/macguffin-app). And I mean early in the way the word usually means — nobody but me has properly run this version yet. Nothing is settled, but it is the first time it has felt less like a game I built and more like something I would reach for. It continues the [Trees of Thoughts](/introducing-tot) line of research I have been slowly pulling at. That's the field note for now. I will hopefully be reporting more on this in the coming weeks.