What is an agentic harness

For a while now, posts and articles everywhere have started mentioning ‘coding harness’, ‘agentic harness’ and so on. Also the Pi home page says “There are many agent harnesses but this one is yours”.

If you’re a native speaker, this is probably trivial, but for me it was a word that I had never come across before and I had to research what it meant, especially in the software engineering context (a literal Italian translation didn’t help).

In this context, a harness is the deterministic code that wraps the LLM in a loop with tools. Claude Code, Codex and Pi are all coding harnesses.