Lesson 1700 of 2116
Agentic AI: building an eval harness before scaling the agent
A frozen set of input scenarios with graded outcomes is the only way to know if your agent got better or worse with each change.
Lesson map
What this lesson covers
Learning path
The main moves in order
- 1The premise
- 2agent evals
- 3regression testing
- 4graded scenarios
Concept cluster
Terms to connect while reading
Section 1
The premise
Without an eval harness, every prompt change is a vibe-based decision. With one, you can measure whether a model swap or prompt edit actually improved success rate or just shifted which cases fail.
What AI does well here
- Run against a fixed scenario list when one is provided
- Output structured results that map to scenario IDs
- Be deterministic enough to score with temperature 0
What AI cannot do
- Generate the scenarios that matter to your business
- Decide what 'pass' means for an open-ended task
- Replace human judgment on subjective outputs
Key terms in this lesson
End-of-lesson quiz
Check what stuck
15 questions · Score saves to your progress.
Tutor
Curious about “Agentic AI: building an eval harness before scaling the agent”?
Ask anything about this lesson. I’ll answer using just what you’re reading — short, friendly, grounded.
Progress saved locally in this browser. Sign in to sync across devices.
Related lessons
Keep going
Creators · 11 min
Agent Evaluation Harnesses: Beyond Unit Tests for Multi-Step Behaviors
Agent behaviors emerge from multi-step interactions; unit tests on individual tools miss the failures that matter. Real evaluation requires task-completion harnesses with tracing and human review.
Creators · 48 min
Computer Use API: Letting AI Click Through GUIs
Computer Use lets Claude see your screen and use it — mouse, keyboard, apps. The capability is real, the gotchas are real. A hands-on look at what works in 2026.
Creators · 45 min
Browser Agents: Capabilities and Pitfalls
Browser agents — Operator, Atlas, Browser Use, MultiOn — are the most visible agent category. The capability is genuine, the failure modes are specific. Build with eyes open.