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AI Harness Engineering
The model is only half the system. Learn to design the scaffolding, tools, sandboxes, verification loops, and memory that turn raw LLMs into reliable, production-grade AI agents that actually finish the job.
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For two years, the AI conversation has fixated on models: which one codes cleanest, hallucinates least, or tops the latest benchmark. That debate has produced extraordinary models, but it has obscured a quieter truth: the model is just one input into a running agent. The rest of the system, the harness, matters just as much, and often more.
AI Harness Engineering is the definitive practitioner's guide to designing the scaffolding that turns a raw language model into a reliable, production-grade agent. Written for engineers, technical leads, and architects who already ship with AI tools and want to stop blaming the model for failures they can fix themselves, this book walks the full surface area of a modern agent harness: filesystems and git as durable state, tool design and MCP servers, context engineering and the war on context rot, sandboxes and permissions, the agent loop, planning for long-horizon work, subagent orchestration, verification and evaluation, observability and cost metering, and memory systems that let agents learn from every mistake.
Drawing on architectural patterns from Claude Code, Codex, Cursor, Aider, and the open-source ecosystem, with more than a dozen chapters of runnable code and worked examples, this book teaches the discipline that closes the gap between what today's models can do and what you actually see them doing. The thesis is simple: a decent model with a great harness beats a great model with a bad harness almost every time. Learn to build the scaffolding, and you'll engineer systems where AI agents finish the job, not just start it.
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SouthStone Publications
SouthStone Publications is a publisher dedicated to advancing practical knowledge across web development, IT engineering, programming, artificial intelligence, and cybersecurity. Working closely with a network of subject matter experts and industry practitioners, SouthStone produces books, guides, and training programs designed to translate complex technical concepts into clear, actionable knowledge. Its catalog has supported developers, engineers, analysts, and security professionals around the world in building more resilient, scalable, and well-architected systems.
Proud to be the first publisher in the Cybersecurity category on LeanPub, SouthStone Publications is committed to bridging the gap between deep technical expertise and accessible education, helping practitioners at every stage of their careers stay ahead in a rapidly evolving digital landscape.
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