Today, personal computing is organized around apps: large prefabricated units of software developed by professionals for the masses, with few opportunities for customization. How might we organize computers so that people can deeply tailor software to meet their unique needs, or even make their own tools from scratch?

We think that a promising direction is to start with familiar text documents, and allow people to gradually enrich those documents with computation and interaction to the point that they can replace entire applications. We propose a computing model where people can 1) create searches that find structured information inside everyday documents, 2) transform this information using reactive computations, and 3) display the results as annotations in the original document.

In this essay, we present a prototype called Potluck that implements this interaction model in a text notes application. We demonstrate that this simple tool is versatile enough to replicate the functionality of simple apps across many domains: recipes, workouts, household chores, and more. Potluck also provides a smooth slope from a plain text note to an interactive experience, and naturally encourages decomposing monolithic applications into smaller reusable tools.

More broadly, we envision a computing environment based on these ideas, where entire classes of applications can be replaced by a simpler set of building blocks: plain documents, with structure and computation overlayed as needed, and the user in control at every step.