Testing AI Agents Against Real User Scenarios, Not Developer Assumptions

Fazm Team··2 min read

Testing AI Agents Against Real User Scenarios

Tests verify what you thought to test. That is the limitation nobody talks about.

When a developer writes a test for an AI agent, they imagine the scenario. Open the file picker, select a PDF, extract the text. The test passes. But real users do things the developer never imagined - they drag files from a network drive, they select 47 files at once, they cancel the picker and try again, they select a file that is still being written by another process.

The Assumption Gap

Every test suite is a map of developer assumptions. The map covers the terrain the developer explored. It says nothing about the territory beyond the edges.

For AI agents, this gap is especially dangerous because the agent operates in the user's environment - not the developer's. The developer tested on macOS Sequoia with a clean desktop. The user runs macOS Sonoma with 300 items on their desktop, three external monitors, and accessibility features enabled.

Observational Testing

The fix is not to write more tests from your own imagination. It is to observe real usage and convert those observations into tests.

Log every agent action in production with enough context to replay it. When the agent fails, you now have a real test case - not an imagined one. Build your test suite from actual failures instead of hypothetical scenarios.

Chaos Engineering for Agents

Intentionally break things. Disconnect the network mid-workflow. Close the window the agent is interacting with. Change the system language. Resize the screen. These are things that happen in real user environments and they will expose assumptions you did not know you had.

The Feedback Loop

Ship telemetry that captures not just crashes but unexpected states. The agent expected a button labeled "Submit" but found one labeled "Send." That is not a crash - it is a gap in your assumptions that should become a test case.

The best agent test suites are built from production failures, not developer imagination.

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Fazm is an open source macOS AI agent. Open source on GitHub.

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