Agent = Model + Harness
· One min read
The model does the thinking. The harness makes that thinking useful in the real world.
This visual captures a practical truth:
- Same model, different harness, huge difference.
- Reliable agents are not only about model quality.
- Real outcomes come from the system around the model.
The harness is what turns a model into a dependable agent:
- Instructions and rules that define behavior
- Tools and integrations that let the agent act
- Memory and context assembly that keep work coherent
- Execution loops, verification, and guardrails that improve quality and safety
- Observability so teams can monitor, measure, and improve
In short: better prompts help, but production-grade agent systems need better harnesses.