Harness

Also called: agent harness, AI harness, harnesses, scaffolding, agent scaffold

The software wrapped around an AI model that turns it into a working agent. It supplies the tools, the standing instructions, the permission rules and the handling of the conversation. When two products use the same model but behave very differently, the harness is usually the reason.

For example: Two coding tools run the same model, but one can open your files and run your tests while the other can only chat. The difference is the harness.

Connects to 10

AI agent Concept
Model Concept
Tool use Concept
System prompt Concept
Permission mode Concept
Coding agent Concept
Claude Code Tool
Context window Concept
Model provider request Concept
Autocompact Concept