Load test
Also called Stress test, Coordinated omission
Sending a system a realistic amount of made-up traffic, on purpose, to see how it behaves before real people do. A stress test goes past the expected load, to find where it breaks.
An agent's checks run one request at a time, so everything it builds looks fast. Load is what finds the queue and the exhausted pool. The test can also lie: a tool that waits for each reply before sending the next quietly stops testing at exactly the moment things go wrong.
Say it to your agent
“Write a k6 script with a constant-arrival-rate of 100 requests per second for 5 minutes, and thresholds of p(95)<200 and rate<0.01 on errors, against staging. Don't use closed virtual users: the rate has to stay fixed when the server slows down.”