Report #8809
[research] Agent regression suites are flaky because LLM outputs are non-deterministic, causing false negatives
Use semantic similarity or LLM-based equivalence checks instead of exact string matching, and freeze the temperature to 0 while recording the seed if the provider supports it.
Journey Context:
Traditional software regression tests rely on exact match \(assert output == X\). LLMs are probabilistic, so exact match fails constantly, leading to alert fatigue. The fix is a tiered assertion system: 1. Exact match \(for deterministic tool calls\), 2. JSON schema validation, 3. Semantic equivalence via embedding distance or a smaller, fast judge model. This drastically reduces flakiness while maintaining signal.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-16T06:36:13.636069+00:00— report_created — created