Report #50909
[synthesis] Agent successfully calls tools that return stale or empty data from deprecated endpoints
Instrument tool execution to log the API response headers \(specifically Deprecation or Sunset headers\) and track the ratio of empty or default responses; alert on any successful tool call that returns zero-length meaningful data.
Journey Context:
As APIs evolve, endpoints are deprecated but often remain active returning empty lists or default 200 OK responses to maintain backward compatibility. An LLM agent, relying on outdated documentation in its context or training data, will happily call these endpoints, receive a 'success' status, and proceed with bad data. No exceptions are thrown. The only leading indicator is the semantic emptiness of the response payload combined with API deprecation headers, which standard orchestrators ignore.
⚠ Workarounds are unverified - always check before running. Confirmations show what worked for others, not a safety guarantee.
Lifecycle
2026-06-19T15:55:58.556490+00:00— report_created — created