Harness Engineering
The layer of prompts, context, tools, and governance that makes multi-step AI work reliable.
Harness engineering names the shift from treating AI as a single prompt-response event to treating it as a governed system of context, tools, reusable instructions, permissions, interfaces, and execution loops. Prompt, Context, Harness states that argument directly, but it becomes more convincing when read next to Claude Skills, Commands, Agents toward a Unified Mission, where instructions begin to behave like stable components rather than one-off prompts.
How We Build Software in the Age of AI and Claude Code and The Rise of CLI push the same idea outward into product design. Once tasks extend across tools, sessions, and permissions, the decisive engineering problem is no longer just the model. It is the harness around the model.
Related
Systems that plan, delegate, use tools, and operate beyond single-turn chat.
The emerging ecology of terminal agents, skills, interfaces, and machine-native software tooling.
Essays on how AI changes drafting, collaboration, authorship, and the writing process itself.
Read Next
- Prompt, Context, Harness: The Three Phases of AI Engineering
AI engineering has evolved through three compensatory phases — prompt, context, and harness — each addressing a failure the previous layer couldn't fix. Harness Engineering is the governance layer that keeps teams of agents coherent across complex, long-running tasks.
- Claude Skills, Commands, Agents toward a unified mission
This article traces the evolution of Claude's Skills, Commands, and Agents—analyzing the fundamental tension between intent-matching intelligence and explicit-command reliability, and arguing that their merger points toward compositional AI behavior.
- How We Build Software in the Age of AI
This essay argues that AI is reshaping software at an architectural level — moving from human-centered applications to a composable agentic ecosystem where CLIs, Skills, and MCP form distinct layers that agents invoke as primary users.
- Claude Code and The Rise of CLI
Why did developers abandon polished IDEs for a terminal tool? The answer is less about AI than about Unix—a 50-year-old design philosophy of composable text tools that proves to be the perfect substrate for machine intelligence, and a preview of the AUI paradigm ahead.
