34. Project 3: "Vibe Coder" Assistant for Your Own Repo

The Goal

We are going to build a CLI tool (or VS Code extension) that understands your project. You can ask it:

"Where is the user authentication logic?"

"Refactor the `User` class to add a `phoneNumber` field and update all call sites."

It won't just hallucinate generic code—it will read your actual files and propose a diff.

High-Level Architecture

1. Indexer: A script that walks your directory, respects `.gitignore`, and creates a "map" of your codebase (file paths + summaries).
2. Retriever: When you ask a question, it finds the relevant files using the map.
3. Context Builder: It packages the user query + the file contents into a prompt.
4. Generator: The model generates a response (answer or code patch).

Where to go next

• 34.1 Requirements: what it should and shouldn’t do
• 34.2 Repo indexing strategy
• 34.3 Change proposal workflow (plan → diff → tests)
• 34.4 PR descriptions and code review assistance
• 34.5 Guardrails: refuse risky changes and require approvals