Are Agent Harnesses the new “secret sauce” for Product Teams?
Square’s Head of Product thinks so. A closer look at AI Agent Harnesses: design patterns and practices worth knowing as a non-engineer.
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When Square’s Head of Product recently announced1 the company’s impressive new agentic features which proactively monitor every user’s store and deliver insights on demand, he said that the AI Agent harness powering the feature was its “secret sauce”:
Actually, managing the context and managing the way that we progressively disclose tools, and some of the other innovation that we have at the harness layer, is I think some of the secret sauce.”
Block’s CEO Jack Dorsey has also echoed this sentiment, saying that his vision is that the harness becomes infrastructure for organizational intelligence rather than just developer tooling.
Agent harnesses are helping some of the world’s leading product teams ship powerful new features and Anthropic and OpenAI have also both announced major updates to their AI Agent SDKs to offer enhanced AI Agent harness capabilities for product teams.
Google Trends data certainly shows a clear signal of an increased interest in the term in 2026, too:
But what exactly is an agent harness and what do non-engineering members of product teams need to know about them?
In this Knowledge Series, we’re going to explore what an AI Agent harness is, together with some of the most common harness architectural patterns to understand how they work. Plus, we’ll take a look at how real world companies like Stripe, Microsoft, Square and others are actually using these harness patterns and AI agents to build innovative new internal and external features and capabilities.
Coming up:
What is an AI Agent harness and why do they matter to product teams?
Examples of emerging Agent Harness patterns and principles worth knowing
Agents and harnesses in practice: 20+ real world examples of patterns and features built with AI agents and harnesses from Stripe, Microsoft, OpenAI, Square and others
What is an Agent Harness and why do they matter to product teams?
An agent harness is the scaffolding or framework that surrounds an AI agent to help it work more effectively on complex tasks.
The raw AI model alone often isn’t enough for complex real-world tasks and so a well-designed harness can dramatically improve what the model can achieve. In practice, a harness can typically handle things like: