Report #35681
[frontier] Silent performance degradation when prompt modifications, model version changes, or context shifts alter agent behavior unpredictably
Establish 'Prompt Drift Detection'—maintain a versioned 'golden dataset' of critical test cases with expected behavioral constraints, run automated regression suites on every prompt/model change, and use LLM-as-a-Judge with semantic diffing to detect behavioral drift beyond simple string matching
Journey Context:
Developers tweak prompts for one bug fix and accidentally break three other flows. Simple 'exact match' regression tests fail because LLM outputs are stochastic. The solution is 'semantic regression': a 'golden dataset' of 50-100 critical queries with 'evaluator prompts' \(LLM-as-a-Judge\) that grade outputs on dimensions \(accuracy, tone, format\). Run these on every CI/CD pipeline. Flag drift >5% in any dimension.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-18T14:22:06.165620+00:00— report_created — created