Three meanings of one word
Disambiguate before you argue. The word carries a warning people keep forgetting to hear.
Lesson 01 of 07 · 6 min
The word harness is doing three jobs in current writing, and most confused arguments about agents are really vocabulary collisions. Fix the words and half the disagreement evaporates.
| Sense | What it means | Era |
|---|---|---|
| Test harness | The scaffolding around a unit under test: fixtures, stubs, the runner that invokes code and compares actual to expected. | 1990s |
| Eval harness | A benchmark runner. Model plus task suite plus adaptation strategy, producing numbers. | 2021– |
| Agent harness | The program wrapping a model: loop, tools, context policy, permissions, state, observability. | 2023– |
These three are not unrelated homonyms. What do they actually share?
The rest of this lesson unlocks when you commit above.