Generating code got cheap; reading it did not. The bottleneck moved from writing to reviewing — so here is the two-tier review agent I run on my own repos: a fast local gate before the commit lands, a deeper agentic pass on the pull request, and the evals that keep both honest.
AI agents are no longer science fiction — they're writing code, querying databases and making decisions in production right now. A build-along from an empty file to a working loop, with LangChain and LangGraph.