Developer Builds Custom Background Monitoring Tool for Terminal Coding Agent Pi

A software developer who uses Neovim as their primary editor began experimenting with Pi, an extensible terminal-based coding agent, alongside their usual Claude Code setup. After obtaining an OpenAI subscription, they ran Pi with Codex and began customizing it, starting with a status-line extension that displayed real-time API rate-limit usage. The developer's key breakthrough came while working on CI pipelines, when they needed a way to monitor pull request checks in the background without blocking the main conversation thread. They prompted Pi to build a custom extension called background_monitor, which runs long-lived shell commands asynchronously, captures output, and automatically triggers a follow-up agent turn upon process completion. The experience highlighted that registering a new tool is not enough — precise routing instructions are needed to reliably guide the model toward using it.