I Used Ralph to Build a Full Feature – Here's How It Works

Ralph (Wrath Wigum) is a technique for prompting AI agents using a bash loop that iterates over a structured JSON to-do list, letting the agent tackle one task at a time across multiple iterations. The author demonstrates building a prompt history feature in a React Native tattoo app using Claude CLI, a for-loop bash script, and a JSON feature list. The agent commits changes after each task, uses git for version control, and exits early when all tasks are complete. The feature cost roughly $1 in API credits and produced working core functionality, though not exactly as originally specified.