Developer releases Halfcycle, a five-layer harness for coding agents

On November 3, 2026 at 13:59, a developer published an article on DEV Community's AI section titled "Building a harness for your coding agent: a five-layer engineering method", introducing Halfcycle. According to the piece, Halfcycle is a module that runs a five-layer build method inside your own Claude Code or OpenAI Codex, invoked through npx halfcycle.

The article's core idea is to split a coding agent into two parts: the model and the harness. The model writes the code, while the harness is everything around it, covering what the agent is told, what it is allowed to touch, what checks its work, what it remembers, and who decides it is finished. The author argues that all of these pieces should be designed on purpose, and calls the practice of deliberately building that second part harness engineering. The piece adds that the term caught on because teams kept noticing the same thing when swapping in a new model.

This is the only available report on the topic, so the story currently rests at the stage of an author presenting the method and calling for harness work to be done intentionally. No other sources have followed up so far, and no independent verification of the claims is available yet.