## Hoard things you know how to do Many of my tips for working productively with coding agents are extensions of advice I've found useful in my career without them. Here's a great example of that: **hoard things you know how to do**. ==A big part of the skill in building software is understanding what's possible and what isn't, and having at least a rough idea of how those things can be accomplished.== These questions can be broad or quite obscure. Can a web page run OCR operations in JavaScript alone? Can an iPhone app pair with a Bluetooth device even when the app isn't running? Can we process a 100GB JSON file in Python without loading the entire thing into memory first? ==The more answers to questions like this you have under your belt, the more likely you'll be able to spot opportunities to deploy technology to solve problems in ways other people may not have thought of yet.== Knowing that something is theoretically possible is not the same as having seen it done for yourself. A key asset to develop as a software professional is a deep collection of answers to questions like this, ideally illustrated by running code. I hoard solutions like this in a number of different ways. My [blog](https://simonwillison.net/) and [TIL blog](https://til.simonwillison.net/) are crammed with notes on things I've figured out how to do. I have [over a thousand GitHub repos](https://github.com/simonw) collecting code I've written for different projects, many of them small proof-of-concepts that demonstrate a key idea. More recently I've used LLMs to help expand my collection of code solutions to interesting problems. [tools.simonwillison.net](https://tools.simonwillison.net/) is my largest collection of LLM-assisted tools and prototypes. I use this to collect what I call [HTML tools](https://simonwillison.net/2025/Dec/10/html-tools/) - single HTML pages that embed JavaScript and CSS and solve a specific problem. My [simonw/research](https://github.com/simonw/research) repository has larger, more complex examples where I’ve challenged a coding agent to research a problem and come back with working code and a written report detailing what it found out. ## Recombining things from your hoard Why collect all of this stuff? ==Aside from helping you build and extend your own abilities, the assets you generate along the way become incredibly powerful inputs for your coding agents.== One of my favorite prompting patterns is to ==tell an agent to build something new by combining two or more existing working examples==. > [!quote]- Trimmed > Original article continues at the source URL. The key idea here is that ==coding agents mean we only ever need to figure out a useful trick *once*. If that trick is then documented somewhere with a working code example our agents can consult that example and use it to solve any similar shaped project in the future==.