# What Is the .last-branch File? Ralph Branch Tracking Explained

> Discover the .last-branch file and how Ralph branch tracking works. Ralph automatically archives previous work when you switch Git branches for seamless feature development.

- Repository: [Ryan Carson/ralph](https://github.com/snarktank/ralph)
- Tags: internals
- Published: 2026-04-13

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**The `.last-branch` file stores the active Git branch name extracted from your PRD, enabling Ralph to detect when you switch features and automatically archive previous work before starting fresh.**

Ralph is an autonomous AI-agent loop that manages feature development through PRD (product-requirement-document) driven workflows. According to the snarktank/ralph source code, the `.last-branch` file serves as the lightweight state mechanism that tracks which feature branch is currently active, allowing the tool to safely manage multiple features in the same working directory without mixing state.

## How