Harness engineering: the missing layer for reliable coding agents (opens in new tab)

Harness engineering: the missing layer for reliable coding agents OpenAI’s recent discussion of harness engineering is a useful reminder that agentic coding is not just a model problem. Once an agent is allowed to work for hours, call tools, edit files, run tests, and make its own judgments, the quality of the surrounding system matters as much as the quality of the model itself. In that setting, prompts are only the starting point. The real question becomes: what environment do we build so t...