Text, Structure, Meaning: grep, ast-grep and a Local LLM Classifier

Introduction
Every codebase eventually needs the same change in many places: a library swap, an API that changed shape, a convention the team agreed on last week. You know the usual options. Find and replace sees only text. Doing it by hand works for ten places and falls apart at three hundred. An AI assistant will happily make all three hundred edits, and then someone has to review each one.
In this blog, we will look at three tools that read code at three different levels. grep reads text. ast-grep reads structure, the syntax tree your editor already builds. A small local model, asked through classif, reads meaning. They are separate tools, each takes the part of the job it can see, and the interesting part is where each one stops.

