Definition◆Article
Ralph is deliberately a simple, deterministic Bash loop that re-prompts the agent repeatedly, and despite its defects it can replace most outsourced greenfield engineering work while still requiring senior engineers to guide it.
Geoffrey Huntley describes 'Ralph' as a bare-bones Bash loop repeatedly feeding a prompt file to a coding agent, calling it deterministically bad but useful — and insists it still requires senior engineers to guide it, dismissing claims that agents alone can do 100% of the work. ✦ AI generated
Geoffrey Huntley · The Pragmatic Engineer · 2026-07-14 · original ↗
Ralph is a technique. In its purest form, Ralph is a Bash loop: while :; do cat PROMPT.md | claude-code ; done. Ralph can replace the majority of outsourcing at most companies for greenfield projects. It has defects, but these are identifiable and resolvable through various styles of prompts. That's the beauty of Ralph - the technique is deterministically bad in a nondeterministic world.
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- ·Ralph = a bare Bash loop, not a framework
- ·Repeatedly pipes PROMPT.md into a coding agent
- ·Deliberately simple and deterministic by design
- ·Has known defects, but they're identifiable
- ·Defects resolved via different prompt styles
- ·Replaces majority of outsourced greenfield work
- ·Huntley rejects claims agents do 100% of work
- ·Senior engineers still required to guide Ralph
- ·Technique, not autonomous full-stack replacement
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gives example → Loop engineering means designing the system that prompts the agent, instead of being the person who prompts it yourself.Addy Osmani · The Pragmatic Engineergives example → My job is no longer to write prompts for Claude — it's to write loops that prompt Claude and figure out what to do.Boris Cherny · The Pragmatic Engineer