How Do You Measure AI Agent Reliability?

Short summary

AI agents are stochastic, so a single passing eval run tells you almost nothing about reliability. You must run each case many times and report a pass rate distribution, not a binary checkmark. Care about the floor (worst case), not the average, and narrow the distribution through temperature control, output constraints, and guardrails before shipping.

• •Reliability is a distribution, not a checkmark — run cases many times and report pass rates
• •The floor matters more than the average: the 5% failure that issues a refund is what hurts
• •Narrow the distribution with lower temperature, constrained output formats, and guardrails before user-facing release

Generated with AI, which can make mistakes.