Report #52390
[synthesis] Why passing unit tests doesn't mean an AI feature works
Build probabilistic eval suites with hundreds of diverse examples and semantic scoring \(e.g., LLM-as-a-judge\) rather than relying on deterministic unit tests or single 'golden path' assertions.
Journey Context:
In traditional software, you write a unit test for a function, and if it passes, it works. In AI, passing a single test case doesn't guarantee the model generalized; it might have just gotten lucky or overfit to that specific phrasing. AI models exhibit brittle generalization where changing 'summarize' to 'tldr' breaks the output. You must abandon deterministic unit tests for AI logic and adopt statistical evaluation over a distribution of inputs, measuring semantic similarity or task completion rather than exact string matching.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T18:25:40.723810+00:00— report_created — created