# The 3 Layers of Testing AI Agents

DevFeed: [The 3 Layers of Testing AI Agents](<https://devfeed.tech/articles/the-3-layers-of-testing-ai-agents-26894.md>)

Original publisher: [Read original article](<https://thetshaped.dev/p/the-3-layers-of-testing-ai-agents-unittests-mocking-alerts-judge-evals-production-agentic-systems>)

Author: The T-Shaped Dev

Published: 2026-09-15T20:59:04Z

Content type: tutorial

Language: en

Sources: [The T-Shaped Dev](<https://devfeed.tech/sources/the-t-shaped-dev.md>)

Topics: [Testing](<https://devfeed.tech/topics/testing.md>), [Artificial Intelligence](<https://devfeed.tech/topics/ai.md>)

Tags: [agents](<https://devfeed.tech/tags/agents.md>), [ai](<https://devfeed.tech/tags/ai.md>), [ai-agents](<https://devfeed.tech/tags/ai-agents.md>), [how-to](<https://devfeed.tech/tags/how-to.md>), [testing](<https://devfeed.tech/tags/testing.md>)

## AI overview

The article presents a three-layer approach to testing AI agents: deterministic tests for surrounding code such as tools, schemas, routing, state, and failure policies; judged scenarios for model behavior; and continuous production evaluations.

## Source excerpt

Draw the line between the model and the machine, and 80% of agent testing is testing you already know how to do. (7 min)