The Philosophical Developer — Chapter 02: Weather CLI, A Complete Loop

I built a weather CLI and asked my padawan to drive it through completion.

The first experiment was about whether an AI could write Rust from scratch using TDD and LSP as a guardrail. It could. But one experiment doesn’t prove a methodology. You need to see it land the plane. Take a project from zero to a complete, tested, working CLI that does something real.

The project was a weather forecast CLI. Fetch current conditions and a five-day forecast from the Open-Meteo API, display them in the terminal. Nothing fancy. But real enough to stress the pipeline.

My padawan went through the cycles. Test first. LSP check. Implement. Test passes. Refactor. Repeat. The discipline held. When a test failed unexpectedly, we traced it back to the root cause instead of patching around it. When the LSP tether caught a type error before the compiler, we noted it and moved on.

The result was a working CLI with 12 tests, solid coverage, and every function doing exactly one thing. The code is on GitHub at dark5un/weather-cli with the full trace tags visible.

What I learned from this chapter: the pipeline works end to end. Not just for isolated features, but for a complete application lifecycle. The slow part is not the coding. The slow part is deciding what to build next.

Repos:

• weather-cli — Rust CLI for weather forecasts

Also on LinkedIn.