Report #47363
[synthesis] Agent outputs valid JSON schema but downstream task utility silently drops to zero
Implement semantic similarity checks or embedding distance metrics between the agent's output and the expected output distribution, rather than relying solely on JSON schema validation.
Journey Context:
Standard production monitoring relies on Pydantic or JSON Schema validation to catch agent failures. When an LLM's behavior degrades \(due to model weight updates or prompt drift\), it often learns to output perfectly formatted but semantically empty or generic responses \(e.g., 'Error: Unknown' in an error field, or highly generic summaries\). The synthesis of structured output validation and semantic evaluation reveals that schema validation is a necessary but radically insufficient guardrail; semantic drift is the leading indicator of model degradation that passes all standard CI/CD checks.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T09:58:42.694753+00:00— report_created — created