@mattm

Introducing Dejavu: Recomposition Testing for Jetpack Compose

Mar 9 · 4 min read · Where This Idea Came From At Square, most of the app is built on Workflow. There is an internal testing framework that lets you assert exactly how many render passes are triggered for a given interact

Cook Together, Clean Together, Build Together

Mar 3 · 3 min read · Ask anyone who worked at Block/Square what they loved most and I guarantee you the first thing they'll say is "its the people". Square's mission of economic empowerment and growing by helping others g

Claude Status Lines Are the New Terminal Prompt

Jan 5 · 3 min read · If you've spent time tweaking your shell prompt or configuring Starship, you know the feeling, there's something nice about having the right information visible when you need it. Claude Code supports custom status lines, so I put one together for my ...

Agents Keep Fighting Over My CPU

Dec 18, 2025 · 4 min read · I prefer running two or three AI agents locally rather than offloading to remote agents. The feedback loop is faster, I can see what's happening, use the tools I like, and context switching between tasks is easier when everything is on my machine. My...

A Framework for Engineering Variance with AI Agents

Dec 4, 2025 · 5 min read · The Piston and the Cup Holder In mechanical engineering, "tolerance" is the permissible limit of variation in a physical dimension. It is the acknowledgement that the world isn’t perfect, and designs needs to account for that. A plastic cup holder in...