Prompt, Context, Harness, Loop: The Real Agent Engineering Stack
· 9 min read
Last week I asked my coding agent to delete an unused workflow harness, keep the docs honest, and ship a release. It reviewed the change, bumped the version, opened a PR — tripped three CI gates, from four self-inflicted root causes — fixed every one, went green, and shipped. A human signed exactly one thing: the irreversible step.
That small episode is the whole argument of this post. The thing that made the agent trustworthy wasn't a clever prompt. It was the layers around the prompt.
